// File: @uniswap/v2-core/contracts/interfaces/IUniswapV2Factory.sol

pragma solidity >=0.5.0;

interface IUniswapV2Factory {
    event PairCreated(address indexed token0, address indexed token1, address pair, uint);

    function feeTo() external view returns (address);
    function feeToSetter() external view returns (address);

    function getPair(address tokenA, address tokenB) external view returns (address pair);
    function allPairs(uint) external view returns (address pair);
    function allPairsLength() external view returns (uint);

    function createPair(address tokenA, address tokenB) external returns (address pair);

    function setFeeTo(address) external;
    function setFeeToSetter(address) external;
}

// File: @uniswap/lib/contracts/libraries/TransferHelper.sol

pragma solidity >=0.6.0;

// helper methods for interacting with ERC20 tokens and sending ETH that do not consistently return true/false
library TransferHelper {
    function safeApprove(address token, address to, uint value) internal {
        // bytes4(keccak256(bytes('approve(address,uint256)')));
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0x095ea7b3, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), 'TransferHelper: APPROVE_FAILED');
    }

    function safeTransfer(address token, address to, uint value) internal {
        // bytes4(keccak256(bytes('transfer(address,uint256)')));
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0xa9059cbb, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), 'TransferHelper: TRANSFER_FAILED');
    }

    function safeTransferFrom(address token, address from, address to, uint value) internal {
        // bytes4(keccak256(bytes('transferFrom(address,address,uint256)')));
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0x23b872dd, from, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), 'TransferHelper: TRANSFER_FROM_FAILED');
    }

    function safeTransferETH(address to, uint value) internal {
        (bool success,) = to.call{value:value}(new bytes(0));
        require(success, 'TransferHelper: ETH_TRANSFER_FAILED');
    }
}

// File: @uniswap/v2-core/contracts/interfaces/IUniswapV2Pair.sol

pragma solidity >=0.5.0;

interface IUniswapV2Pair {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external pure returns (string memory);
    function symbol() external pure returns (string memory);
    function decimals() external pure returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);

    function DOMAIN_SEPARATOR() external view returns (bytes32);
    function PERMIT_TYPEHASH() external pure returns (bytes32);
    function nonces(address owner) external view returns (uint);

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;

    event Mint(address indexed sender, uint amount0, uint amount1);
    event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
    event Swap(
        address indexed sender,
        uint amount0In,
        uint amount1In,
        uint amount0Out,
        uint amount1Out,
        address indexed to
    );
    event Sync(uint112 reserve0, uint112 reserve1);

    function MINIMUM_LIQUIDITY() external pure returns (uint);
    function factory() external view returns (address);
    function token0() external view returns (address);
    function token1() external view returns (address);
    function getReserves() external view returns (uint112 reserve0, uint112 reserve1, uint32 blockTimestampLast);
    function price0CumulativeLast() external view returns (uint);
    function price1CumulativeLast() external view returns (uint);
    function kLast() external view returns (uint);

    function mint(address to) external returns (uint liquidity);
    function burn(address to) external returns (uint amount0, uint amount1);
    function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external;
    function skim(address to) external;
    function sync() external;

    function initialize(address, address) external;
}

// File: contracts/libraries/SafeMath.sol

pragma solidity =0.6.6;

// a library for performing overflow-safe math, courtesy of DappHub (https://github.com/dapphub/ds-math)

library SafeMath {
    function add(uint x, uint y) internal pure returns (uint z) {
        require((z = x + y) >= x, 'ds-math-add-overflow');
    }

    function sub(uint x, uint y) internal pure returns (uint z) {
        require((z = x - y) <= x, 'ds-math-sub-underflow');
    }

    function mul(uint x, uint y) internal pure returns (uint z) {
        require(y == 0 || (z = x * y) / y == x, 'ds-math-mul-overflow');
    }
}

// File: contracts/libraries/UniswapV2Library.sol

pragma solidity >=0.5.0;



library UniswapV2Library {
    using SafeMath for uint;

    // returns sorted token addresses, used to handle return values from pairs sorted in this order
    function sortTokens(address tokenA, address tokenB) internal pure returns (address token0, address token1) {
        require(tokenA != tokenB, 'UniswapV2Library: IDENTICAL_ADDRESSES');
        (token0, token1) = tokenA < tokenB ? (tokenA, tokenB) : (tokenB, tokenA);
        require(token0 != address(0), 'UniswapV2Library: ZERO_ADDRESS');
    }

    // calculates the CREATE2 address for a pair without making any external calls
    function pairFor(address factory, address tokenA, address tokenB) internal pure returns (address pair) {
        (address token0, address token1) = sortTokens(tokenA, tokenB);
        pair = address(uint(keccak256(abi.encodePacked(
                hex'ff',
                factory,
                keccak256(abi.encodePacked(token0, token1)),
                hex'96e8ac4277198ff8b6f785478aa9a39f403cb768dd02cbee326c3e7da348845f' // init code hash
            ))));
    }

    // fetches and sorts the reserves for a pair
    function getReserves(address factory, address tokenA, address tokenB) internal view returns (uint reserveA, uint reserveB) {
        (address token0,) = sortTokens(tokenA, tokenB);
        (uint reserve0, uint reserve1,) = IUniswapV2Pair(pairFor(factory, tokenA, tokenB)).getReserves();
        (reserveA, reserveB) = tokenA == token0 ? (reserve0, reserve1) : (reserve1, reserve0);
    }

    // given some amount of an asset and pair reserves, returns an equivalent amount of the other asset
    function quote(uint amountA, uint reserveA, uint reserveB) internal pure returns (uint amountB) {
        require(amountA > 0, 'UniswapV2Library: INSUFFICIENT_AMOUNT');
        require(reserveA > 0 && reserveB > 0, 'UniswapV2Library: INSUFFICIENT_LIQUIDITY');
        amountB = amountA.mul(reserveB) / reserveA;
    }

    // given an input amount of an asset and pair reserves, returns the maximum output amount of the other asset
    function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut) internal pure returns (uint amountOut) {
        require(amountIn > 0, 'UniswapV2Library: INSUFFICIENT_INPUT_AMOUNT');
        require(reserveIn > 0 && reserveOut > 0, 'UniswapV2Library: INSUFFICIENT_LIQUIDITY');
        uint amountInWithFee = amountIn.mul(997);
        uint numerator = amountInWithFee.mul(reserveOut);
        uint denominator = reserveIn.mul(1000).add(amountInWithFee);
        amountOut = numerator / denominator;
    }

    // given an output amount of an asset and pair reserves, returns a required input amount of the other asset
    function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut) internal pure returns (uint amountIn) {
        require(amountOut > 0, 'UniswapV2Library: INSUFFICIENT_OUTPUT_AMOUNT');
        require(reserveIn > 0 && reserveOut > 0, 'UniswapV2Library: INSUFFICIENT_LIQUIDITY');
        uint numerator = reserveIn.mul(amountOut).mul(1000);
        uint denominator = reserveOut.sub(amountOut).mul(997);
        amountIn = (numerator / denominator).add(1);
    }

    // performs chained getAmountOut calculations on any number of pairs
    function getAmountsOut(address factory, uint amountIn, address[] memory path) internal view returns (uint[] memory amounts) {
        require(path.length >= 2, 'UniswapV2Library: INVALID_PATH');
        amounts = new uint[](path.length);
        amounts[0] = amountIn;
        for (uint i; i < path.length - 1; i++) {
            (uint reserveIn, uint reserveOut) = getReserves(factory, path[i], path[i + 1]);
            amounts[i + 1] = getAmountOut(amounts[i], reserveIn, reserveOut);
        }
    }

    // performs chained getAmountIn calculations on any number of pairs
    function getAmountsIn(address factory, uint amountOut, address[] memory path) internal view returns (uint[] memory amounts) {
        require(path.length >= 2, 'UniswapV2Library: INVALID_PATH');
        amounts = new uint[](path.length);
        amounts[amounts.length - 1] = amountOut;
        for (uint i = path.length - 1; i > 0; i--) {
            (uint reserveIn, uint reserveOut) = getReserves(factory, path[i - 1], path[i]);
            amounts[i - 1] = getAmountIn(amounts[i], reserveIn, reserveOut);
        }
    }
}

// File: contracts/interfaces/IUniswapV2Router01.sol

pragma solidity >=0.6.2;

interface IUniswapV2Router01 {
    function factory() external pure returns (address);
    function WETH() external pure returns (address);

    function addLiquidity(
        address tokenA,
        address tokenB,
        uint amountADesired,
        uint amountBDesired,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external returns (uint amountA, uint amountB, uint liquidity);
    function addLiquidityETH(
        address token,
        uint amountTokenDesired,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external payable returns (uint amountToken, uint amountETH, uint liquidity);
    function removeLiquidity(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external returns (uint amountA, uint amountB);
    function removeLiquidityETH(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external returns (uint amountToken, uint amountETH);
    function removeLiquidityWithPermit(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountA, uint amountB);
    function removeLiquidityETHWithPermit(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountToken, uint amountETH);
    function swapExactTokensForTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);
    function swapTokensForExactTokens(
        uint amountOut,
        uint amountInMax,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);
    function swapExactETHForTokens(uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        payable
        returns (uint[] memory amounts);
    function swapTokensForExactETH(uint amountOut, uint amountInMax, address[] calldata path, address to, uint deadline)
        external
        returns (uint[] memory amounts);
    function swapExactTokensForETH(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        returns (uint[] memory amounts);
    function swapETHForExactTokens(uint amountOut, address[] calldata path, address to, uint deadline)
        external
        payable
        returns (uint[] memory amounts);

    function quote(uint amountA, uint reserveA, uint reserveB) external pure returns (uint amountB);
    function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut) external pure returns (uint amountOut);
    function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut) external pure returns (uint amountIn);
    function getAmountsOut(uint amountIn, address[] calldata path) external view returns (uint[] memory amounts);
    function getAmountsIn(uint amountOut, address[] calldata path) external view returns (uint[] memory amounts);
}

// File: contracts/interfaces/IERC20.sol

pragma solidity >=0.5.0;

interface IERC20 {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external view returns (string memory);
    function symbol() external view returns (string memory);
    function decimals() external view returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);
}

// File: contracts/interfaces/IWETH.sol

pragma solidity >=0.5.0;

interface IWETH {
    function deposit() external payable;
    function transfer(address to, uint value) external returns (bool);
    function withdraw(uint) external;
}

// File: contracts/UniswapV2Router01.sol

pragma solidity =0.6.6;







contract UniswapV2Router01 is IUniswapV2Router01 {
    address public immutable override factory;
    address public immutable override WETH;

    modifier ensure(uint deadline) {
        require(deadline >= block.timestamp, 'UniswapV2Router: EXPIRED');
        _;
    }

    constructor(address _factory, address _WETH) public {
        factory = _factory;
        WETH = _WETH;
    }

    receive() external payable {
        assert(msg.sender == WETH); // only accept ETH via fallback from the WETH contract
    }

    // **** ADD LIQUIDITY ****
    function _addLiquidity(
        address tokenA,
        address tokenB,
        uint amountADesired,
        uint amountBDesired,
        uint amountAMin,
        uint amountBMin
    ) private returns (uint amountA, uint amountB) {
        // create the pair if it doesn't exist yet
        if (IUniswapV2Factory(factory).getPair(tokenA, tokenB) == address(0)) {
            IUniswapV2Factory(factory).createPair(tokenA, tokenB);
        }
        (uint reserveA, uint reserveB) = UniswapV2Library.getReserves(factory, tokenA, tokenB);
        if (reserveA == 0 && reserveB == 0) {
            (amountA, amountB) = (amountADesired, amountBDesired);
        } else {
            uint amountBOptimal = UniswapV2Library.quote(amountADesired, reserveA, reserveB);
            if (amountBOptimal <= amountBDesired) {
                require(amountBOptimal >= amountBMin, 'UniswapV2Router: INSUFFICIENT_B_AMOUNT');
                (amountA, amountB) = (amountADesired, amountBOptimal);
            } else {
                uint amountAOptimal = UniswapV2Library.quote(amountBDesired, reserveB, reserveA);
                assert(amountAOptimal <= amountADesired);
                require(amountAOptimal >= amountAMin, 'UniswapV2Router: INSUFFICIENT_A_AMOUNT');
                (amountA, amountB) = (amountAOptimal, amountBDesired);
            }
        }
    }
    function addLiquidity(
        address tokenA,
        address tokenB,
        uint amountADesired,
        uint amountBDesired,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external override ensure(deadline) returns (uint amountA, uint amountB, uint liquidity) {
        (amountA, amountB) = _addLiquidity(tokenA, tokenB, amountADesired, amountBDesired, amountAMin, amountBMin);
        address pair = UniswapV2Library.pairFor(factory, tokenA, tokenB);
        TransferHelper.safeTransferFrom(tokenA, msg.sender, pair, amountA);
        TransferHelper.safeTransferFrom(tokenB, msg.sender, pair, amountB);
        liquidity = IUniswapV2Pair(pair).mint(to);
    }
    function addLiquidityETH(
        address token,
        uint amountTokenDesired,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external override payable ensure(deadline) returns (uint amountToken, uint amountETH, uint liquidity) {
        (amountToken, amountETH) = _addLiquidity(
            token,
            WETH,
            amountTokenDesired,
            msg.value,
            amountTokenMin,
            amountETHMin
        );
        address pair = UniswapV2Library.pairFor(factory, token, WETH);
        TransferHelper.safeTransferFrom(token, msg.sender, pair, amountToken);
        IWETH(WETH).deposit{value: amountETH}();
        assert(IWETH(WETH).transfer(pair, amountETH));
        liquidity = IUniswapV2Pair(pair).mint(to);
        if (msg.value > amountETH) TransferHelper.safeTransferETH(msg.sender, msg.value - amountETH); // refund dust eth, if any
    }

    // **** REMOVE LIQUIDITY ****
    function removeLiquidity(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) public override ensure(deadline) returns (uint amountA, uint amountB) {
        address pair = UniswapV2Library.pairFor(factory, tokenA, tokenB);
        IUniswapV2Pair(pair).transferFrom(msg.sender, pair, liquidity); // send liquidity to pair
        (uint amount0, uint amount1) = IUniswapV2Pair(pair).burn(to);
        (address token0,) = UniswapV2Library.sortTokens(tokenA, tokenB);
        (amountA, amountB) = tokenA == token0 ? (amount0, amount1) : (amount1, amount0);
        require(amountA >= amountAMin, 'UniswapV2Router: INSUFFICIENT_A_AMOUNT');
        require(amountB >= amountBMin, 'UniswapV2Router: INSUFFICIENT_B_AMOUNT');
    }
    function removeLiquidityETH(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) public override ensure(deadline) returns (uint amountToken, uint amountETH) {
        (amountToken, amountETH) = removeLiquidity(
            token,
            WETH,
            liquidity,
            amountTokenMin,
            amountETHMin,
            address(this),
            deadline
        );
        TransferHelper.safeTransfer(token, to, amountToken);
        IWETH(WETH).withdraw(amountETH);
        TransferHelper.safeTransferETH(to, amountETH);
    }
    function removeLiquidityWithPermit(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external override returns (uint amountA, uint amountB) {
        address pair = UniswapV2Library.pairFor(factory, tokenA, tokenB);
        uint value = approveMax ? uint(-1) : liquidity;
        IUniswapV2Pair(pair).permit(msg.sender, address(this), value, deadline, v, r, s);
        (amountA, amountB) = removeLiquidity(tokenA, tokenB, liquidity, amountAMin, amountBMin, to, deadline);
    }
    function removeLiquidityETHWithPermit(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external override returns (uint amountToken, uint amountETH) {
        address pair = UniswapV2Library.pairFor(factory, token, WETH);
        uint value = approveMax ? uint(-1) : liquidity;
        IUniswapV2Pair(pair).permit(msg.sender, address(this), value, deadline, v, r, s);
        (amountToken, amountETH) = removeLiquidityETH(token, liquidity, amountTokenMin, amountETHMin, to, deadline);
    }

    // **** SWAP ****
    // requires the initial amount to have already been sent to the first pair
    function _swap(uint[] memory amounts, address[] memory path, address _to) private {
        for (uint i; i < path.length - 1; i++) {
            (address input, address output) = (path[i], path[i + 1]);
            (address token0,) = UniswapV2Library.sortTokens(input, output);
            uint amountOut = amounts[i + 1];
            (uint amount0Out, uint amount1Out) = input == token0 ? (uint(0), amountOut) : (amountOut, uint(0));
            address to = i < path.length - 2 ? UniswapV2Library.pairFor(factory, output, path[i + 2]) : _to;
            IUniswapV2Pair(UniswapV2Library.pairFor(factory, input, output)).swap(amount0Out, amount1Out, to, new bytes(0));
        }
    }
    function swapExactTokensForTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external override ensure(deadline) returns (uint[] memory amounts) {
        amounts = UniswapV2Library.getAmountsOut(factory, amountIn, path);
        require(amounts[amounts.length - 1] >= amountOutMin, 'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT');
        TransferHelper.safeTransferFrom(path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]);
        _swap(amounts, path, to);
    }
    function swapTokensForExactTokens(
        uint amountOut,
        uint amountInMax,
        address[] calldata path,
        address to,
        uint deadline
    ) external override ensure(deadline) returns (uint[] memory amounts) {
        amounts = UniswapV2Library.getAmountsIn(factory, amountOut, path);
        require(amounts[0] <= amountInMax, 'UniswapV2Router: EXCESSIVE_INPUT_AMOUNT');
        TransferHelper.safeTransferFrom(path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]);
        _swap(amounts, path, to);
    }
    function swapExactETHForTokens(uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        override
        payable
        ensure(deadline)
        returns (uint[] memory amounts)
    {
        require(path[0] == WETH, 'UniswapV2Router: INVALID_PATH');
        amounts = UniswapV2Library.getAmountsOut(factory, msg.value, path);
        require(amounts[amounts.length - 1] >= amountOutMin, 'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT');
        IWETH(WETH).deposit{value: amounts[0]}();
        assert(IWETH(WETH).transfer(UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]));
        _swap(amounts, path, to);
    }
    function swapTokensForExactETH(uint amountOut, uint amountInMax, address[] calldata path, address to, uint deadline)
        external
        override
        ensure(deadline)
        returns (uint[] memory amounts)
    {
        require(path[path.length - 1] == WETH, 'UniswapV2Router: INVALID_PATH');
        amounts = UniswapV2Library.getAmountsIn(factory, amountOut, path);
        require(amounts[0] <= amountInMax, 'UniswapV2Router: EXCESSIVE_INPUT_AMOUNT');
        TransferHelper.safeTransferFrom(path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]);
        _swap(amounts, path, address(this));
        IWETH(WETH).withdraw(amounts[amounts.length - 1]);
        TransferHelper.safeTransferETH(to, amounts[amounts.length - 1]);
    }
    function swapExactTokensForETH(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        override
        ensure(deadline)
        returns (uint[] memory amounts)
    {
        require(path[path.length - 1] == WETH, 'UniswapV2Router: INVALID_PATH');
        amounts = UniswapV2Library.getAmountsOut(factory, amountIn, path);
        require(amounts[amounts.length - 1] >= amountOutMin, 'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT');
        TransferHelper.safeTransferFrom(path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]);
        _swap(amounts, path, address(this));
        IWETH(WETH).withdraw(amounts[amounts.length - 1]);
        TransferHelper.safeTransferETH(to, amounts[amounts.length - 1]);
    }
    function swapETHForExactTokens(uint amountOut, address[] calldata path, address to, uint deadline)
        external
        override
        payable
        ensure(deadline)
        returns (uint[] memory amounts)
    {
        require(path[0] == WETH, 'UniswapV2Router: INVALID_PATH');
        amounts = UniswapV2Library.getAmountsIn(factory, amountOut, path);
        require(amounts[0] <= msg.value, 'UniswapV2Router: EXCESSIVE_INPUT_AMOUNT');
        IWETH(WETH).deposit{value: amounts[0]}();
        assert(IWETH(WETH).transfer(UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]));
        _swap(amounts, path, to);
        if (msg.value > amounts[0]) TransferHelper.safeTransferETH(msg.sender, msg.value - amounts[0]); // refund dust eth, if any
    }

    function quote(uint amountA, uint reserveA, uint reserveB) public pure override returns (uint amountB) {
        return UniswapV2Library.quote(amountA, reserveA, reserveB);
    }

    function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut) public pure override returns (uint amountOut) {
        return UniswapV2Library.getAmountOut(amountIn, reserveIn, reserveOut);
    }

    function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut) public pure override returns (uint amountIn) {
        return UniswapV2Library.getAmountOut(amountOut, reserveIn, reserveOut);
    }

    function getAmountsOut(uint amountIn, address[] memory path) public view override returns (uint[] memory amounts) {
        return UniswapV2Library.getAmountsOut(factory, amountIn, path);
    }

    function getAmountsIn(uint amountOut, address[] memory path) public view override returns (uint[] memory amounts) {
        return UniswapV2Library.getAmountsIn(factory, amountOut, path);
    }
}

// File: contracts/interfaces/IUniswapV2Pair.sol

pragma solidity >=0.5.0;

interface IUniswapV2Pair {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external pure returns (string memory);
    function symbol() external pure returns (string memory);
    function decimals() external pure returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);

    function DOMAIN_SEPARATOR() external view returns (bytes32);
    function PERMIT_TYPEHASH() external pure returns (bytes32);
    function nonces(address owner) external view returns (uint);

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;

    event Mint(address indexed sender, uint amount0, uint amount1);
    event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
    event Swap(
        address indexed sender,
        uint amount0In,
        uint amount1In,
        uint amount0Out,
        uint amount1Out,
        address indexed to
    );
    event Sync(uint112 reserve0, uint112 reserve1);

    function MINIMUM_LIQUIDITY() external pure returns (uint);
    function factory() external view returns (address);
    function token0() external view returns (address);
    function token1() external view returns (address);
    function getReserves() external view returns (uint112 reserve0, uint112 reserve1, uint32 blockTimestampLast);
    function price0CumulativeLast() external view returns (uint);
    function price1CumulativeLast() external view returns (uint);
    function kLast() external view returns (uint);

    function mint(address to) external returns (uint liquidity);
    function burn(address to) external returns (uint amount0, uint amount1);
    function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external;
    function skim(address to) external;
    function sync() external;

    function initialize(address, address) external;
}

// File: contracts/interfaces/IUniswapV2ERC20.sol

pragma solidity >=0.5.0;

interface IUniswapV2ERC20 {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external pure returns (string memory);
    function symbol() external pure returns (string memory);
    function decimals() external pure returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);

    function DOMAIN_SEPARATOR() external view returns (bytes32);
    function PERMIT_TYPEHASH() external pure returns (bytes32);
    function nonces(address owner) external view returns (uint);

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;
}

// File: contracts/libraries/SafeMath.sol

pragma solidity =0.5.16;

// a library for performing overflow-safe math, courtesy of DappHub (https://github.com/dapphub/ds-math)

library SafeMath {
    function add(uint x, uint y) internal pure returns (uint z) {
        require((z = x + y) >= x, 'ds-math-add-overflow');
    }

    function sub(uint x, uint y) internal pure returns (uint z) {
        require((z = x - y) <= x, 'ds-math-sub-underflow');
    }

    function mul(uint x, uint y) internal pure returns (uint z) {
        require(y == 0 || (z = x * y) / y == x, 'ds-math-mul-overflow');
    }
}

// File: contracts/UniswapV2ERC20.sol

pragma solidity =0.5.16;



contract UniswapV2ERC20 is IUniswapV2ERC20 {
    using SafeMath for uint;

    string public constant name = 'Uniswap V2';
    string public constant symbol = 'UNI-V2';
    uint8 public constant decimals = 18;
    uint  public totalSupply;
    mapping(address => uint) public balanceOf;
    mapping(address => mapping(address => uint)) public allowance;

    bytes32 public DOMAIN_SEPARATOR;
    // keccak256("Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)");
    bytes32 public constant PERMIT_TYPEHASH = 0x6e71edae12b1b97f4d1f60370fef10105fa2faae0126114a169c64845d6126c9;
    mapping(address => uint) public nonces;

    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    constructor() public {
        uint chainId;
        assembly {
            chainId := chainid
        }
        DOMAIN_SEPARATOR = keccak256(
            abi.encode(
                keccak256('EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)'),
                keccak256(bytes(name)),
                keccak256(bytes('1')),
                chainId,
                address(this)
            )
        );
    }

    function _mint(address to, uint value) internal {
        totalSupply = totalSupply.add(value);
        balanceOf[to] = balanceOf[to].add(value);
        emit Transfer(address(0), to, value);
    }

    function _burn(address from, uint value) internal {
        balanceOf[from] = balanceOf[from].sub(value);
        totalSupply = totalSupply.sub(value);
        emit Transfer(from, address(0), value);
    }

    function _approve(address owner, address spender, uint value) private {
        allowance[owner][spender] = value;
        emit Approval(owner, spender, value);
    }

    function _transfer(address from, address to, uint value) private {
        balanceOf[from] = balanceOf[from].sub(value);
        balanceOf[to] = balanceOf[to].add(value);
        emit Transfer(from, to, value);
    }

    function approve(address spender, uint value) external returns (bool) {
        _approve(msg.sender, spender, value);
        return true;
    }

    function transfer(address to, uint value) external returns (bool) {
        _transfer(msg.sender, to, value);
        return true;
    }

    function transferFrom(address from, address to, uint value) external returns (bool) {
        if (allowance[from][msg.sender] != uint(-1)) {
            allowance[from][msg.sender] = allowance[from][msg.sender].sub(value);
        }
        _transfer(from, to, value);
        return true;
    }

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external {
        require(deadline >= block.timestamp, 'UniswapV2: EXPIRED');
        bytes32 digest = keccak256(
            abi.encodePacked(
                '\x19\x01',
                DOMAIN_SEPARATOR,
                keccak256(abi.encode(PERMIT_TYPEHASH, owner, spender, value, nonces[owner]++, deadline))
            )
        );
        address recoveredAddress = ecrecover(digest, v, r, s);
        require(recoveredAddress != address(0) && recoveredAddress == owner, 'UniswapV2: INVALID_SIGNATURE');
        _approve(owner, spender, value);
    }
}

// File: contracts/libraries/Math.sol

pragma solidity =0.5.16;

// a library for performing various math operations

library Math {
    function min(uint x, uint y) internal pure returns (uint z) {
        z = x < y ? x : y;
    }

    // babylonian method (https://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Babylonian_method)
    function sqrt(uint y) internal pure returns (uint z) {
        if (y > 3) {
            z = y;
            uint x = y / 2 + 1;
            while (x < z) {
                z = x;
                x = (y / x + x) / 2;
            }
        } else if (y != 0) {
            z = 1;
        }
    }
}

// File: contracts/libraries/UQ112x112.sol

pragma solidity =0.5.16;

// a library for handling binary fixed point numbers (https://en.wikipedia.org/wiki/Q_(number_format))

// range: [0, 2**112 - 1]
// resolution: 1 / 2**112

library UQ112x112 {
    uint224 constant Q112 = 2**112;

    // encode a uint112 as a UQ112x112
    function encode(uint112 y) internal pure returns (uint224 z) {
        z = uint224(y) * Q112; // never overflows
    }

    // divide a UQ112x112 by a uint112, returning a UQ112x112
    function uqdiv(uint224 x, uint112 y) internal pure returns (uint224 z) {
        z = x / uint224(y);
    }
}

// File: contracts/interfaces/IERC20.sol

pragma solidity >=0.5.0;

interface IERC20 {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external view returns (string memory);
    function symbol() external view returns (string memory);
    function decimals() external view returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);
}

// File: contracts/interfaces/IUniswapV2Factory.sol

pragma solidity >=0.5.0;

interface IUniswapV2Factory {
    event PairCreated(address indexed token0, address indexed token1, address pair, uint);

    function feeTo() external view returns (address);
    function feeToSetter() external view returns (address);

    function getPair(address tokenA, address tokenB) external view returns (address pair);
    function allPairs(uint) external view returns (address pair);
    function allPairsLength() external view returns (uint);

    function createPair(address tokenA, address tokenB) external returns (address pair);

    function setFeeTo(address) external;
    function setFeeToSetter(address) external;
}

// File: contracts/interfaces/IUniswapV2Callee.sol

pragma solidity >=0.5.0;

interface IUniswapV2Callee {
    function uniswapV2Call(address sender, uint amount0, uint amount1, bytes calldata data) external;
}

// File: contracts/UniswapV2Pair.sol

pragma solidity =0.5.16;








contract UniswapV2Pair is IUniswapV2Pair, UniswapV2ERC20 {
    using SafeMath  for uint;
    using UQ112x112 for uint224;

    uint public constant MINIMUM_LIQUIDITY = 10**3;
    bytes4 private constant SELECTOR = bytes4(keccak256(bytes('transfer(address,uint256)')));

    address public factory;
    address public token0;
    address public token1;

    uint112 private reserve0;           // uses single storage slot, accessible via getReserves
    uint112 private reserve1;           // uses single storage slot, accessible via getReserves
    uint32  private blockTimestampLast; // uses single storage slot, accessible via getReserves

    uint public price0CumulativeLast;
    uint public price1CumulativeLast;
    uint public kLast; // reserve0 * reserve1, as of immediately after the most recent liquidity event

    uint private unlocked = 1;
    modifier lock() {
        require(unlocked == 1, 'UniswapV2: LOCKED');
        unlocked = 0;
        _;
        unlocked = 1;
    }

    function getReserves() public view returns (uint112 _reserve0, uint112 _reserve1, uint32 _blockTimestampLast) {
        _reserve0 = reserve0;
        _reserve1 = reserve1;
        _blockTimestampLast = blockTimestampLast;
    }

    function _safeTransfer(address token, address to, uint value) private {
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(SELECTOR, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), 'UniswapV2: TRANSFER_FAILED');
    }

    event Mint(address indexed sender, uint amount0, uint amount1);
    event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
    event Swap(
        address indexed sender,
        uint amount0In,
        uint amount1In,
        uint amount0Out,
        uint amount1Out,
        address indexed to
    );
    event Sync(uint112 reserve0, uint112 reserve1);

    constructor() public {
        factory = msg.sender;
    }

    // called once by the factory at time of deployment
    function initialize(address _token0, address _token1) external {
        require(msg.sender == factory, 'UniswapV2: FORBIDDEN'); // sufficient check
        token0 = _token0;
        token1 = _token1;
    }

    // update reserves and, on the first call per block, price accumulators
    function _update(uint balance0, uint balance1, uint112 _reserve0, uint112 _reserve1) private {
        require(balance0 <= uint112(-1) && balance1 <= uint112(-1), 'UniswapV2: OVERFLOW');
        uint32 blockTimestamp = uint32(block.timestamp % 2**32);
        uint32 timeElapsed = blockTimestamp - blockTimestampLast; // overflow is desired
        if (timeElapsed > 0 && _reserve0 != 0 && _reserve1 != 0) {
            // * never overflows, and + overflow is desired
            price0CumulativeLast += uint(UQ112x112.encode(_reserve1).uqdiv(_reserve0)) * timeElapsed;
            price1CumulativeLast += uint(UQ112x112.encode(_reserve0).uqdiv(_reserve1)) * timeElapsed;
        }
        reserve0 = uint112(balance0);
        reserve1 = uint112(balance1);
        blockTimestampLast = blockTimestamp;
        emit Sync(reserve0, reserve1);
    }

    // if fee is on, mint liquidity equivalent to 1/6th of the growth in sqrt(k)
    function _mintFee(uint112 _reserve0, uint112 _reserve1) private returns (bool feeOn) {
        address feeTo = IUniswapV2Factory(factory).feeTo();
        feeOn = feeTo != address(0);
        uint _kLast = kLast; // gas savings
        if (feeOn) {
            if (_kLast != 0) {
                uint rootK = Math.sqrt(uint(_reserve0).mul(_reserve1));
                uint rootKLast = Math.sqrt(_kLast);
                if (rootK > rootKLast) {
                    uint numerator = totalSupply.mul(rootK.sub(rootKLast));
                    uint denominator = rootK.mul(5).add(rootKLast);
                    uint liquidity = numerator / denominator;
                    if (liquidity > 0) _mint(feeTo, liquidity);
                }
            }
        } else if (_kLast != 0) {
            kLast = 0;
        }
    }

    // this low-level function should be called from a contract which performs important safety checks
    function mint(address to) external lock returns (uint liquidity) {
        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
        uint balance0 = IERC20(token0).balanceOf(address(this));
        uint balance1 = IERC20(token1).balanceOf(address(this));
        uint amount0 = balance0.sub(_reserve0);
        uint amount1 = balance1.sub(_reserve1);

        bool feeOn = _mintFee(_reserve0, _reserve1);
        uint _totalSupply = totalSupply; // gas savings, must be defined here since totalSupply can update in _mintFee
        if (_totalSupply == 0) {
            liquidity = Math.sqrt(amount0.mul(amount1)).sub(MINIMUM_LIQUIDITY);
           _mint(address(0), MINIMUM_LIQUIDITY); // permanently lock the first MINIMUM_LIQUIDITY tokens
        } else {
            liquidity = Math.min(amount0.mul(_totalSupply) / _reserve0, amount1.mul(_totalSupply) / _reserve1);
        }
        require(liquidity > 0, 'UniswapV2: INSUFFICIENT_LIQUIDITY_MINTED');
        _mint(to, liquidity);

        _update(balance0, balance1, _reserve0, _reserve1);
        if (feeOn) kLast = uint(reserve0).mul(reserve1); // reserve0 and reserve1 are up-to-date
        emit Mint(msg.sender, amount0, amount1);
    }

    // this low-level function should be called from a contract which performs important safety checks
    function burn(address to) external lock returns (uint amount0, uint amount1) {
        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
        address _token0 = token0;                                // gas savings
        address _token1 = token1;                                // gas savings
        uint balance0 = IERC20(_token0).balanceOf(address(this));
        uint balance1 = IERC20(_token1).balanceOf(address(this));
        uint liquidity = balanceOf[address(this)];

        bool feeOn = _mintFee(_reserve0, _reserve1);
        uint _totalSupply = totalSupply; // gas savings, must be defined here since totalSupply can update in _mintFee
        amount0 = liquidity.mul(balance0) / _totalSupply; // using balances ensures pro-rata distribution
        amount1 = liquidity.mul(balance1) / _totalSupply; // using balances ensures pro-rata distribution
        require(amount0 > 0 && amount1 > 0, 'UniswapV2: INSUFFICIENT_LIQUIDITY_BURNED');
        _burn(address(this), liquidity);
        _safeTransfer(_token0, to, amount0);
        _safeTransfer(_token1, to, amount1);
        balance0 = IERC20(_token0).balanceOf(address(this));
        balance1 = IERC20(_token1).balanceOf(address(this));

        _update(balance0, balance1, _reserve0, _reserve1);
        if (feeOn) kLast = uint(reserve0).mul(reserve1); // reserve0 and reserve1 are up-to-date
        emit Burn(msg.sender, amount0, amount1, to);
    }

    // this low-level function should be called from a contract which performs important safety checks
    function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external lock {
        require(amount0Out > 0 || amount1Out > 0, 'UniswapV2: INSUFFICIENT_OUTPUT_AMOUNT');
        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
        require(amount0Out < _reserve0 && amount1Out < _reserve1, 'UniswapV2: INSUFFICIENT_LIQUIDITY');

        uint balance0;
        uint balance1;
        { // scope for _token{0,1}, avoids stack too deep errors
        address _token0 = token0;
        address _token1 = token1;
        require(to != _token0 && to != _token1, 'UniswapV2: INVALID_TO');
        if (amount0Out > 0) _safeTransfer(_token0, to, amount0Out); // optimistically transfer tokens
        if (amount1Out > 0) _safeTransfer(_token1, to, amount1Out); // optimistically transfer tokens
        if (data.length > 0) IUniswapV2Callee(to).uniswapV2Call(msg.sender, amount0Out, amount1Out, data);
        balance0 = IERC20(_token0).balanceOf(address(this));
        balance1 = IERC20(_token1).balanceOf(address(this));
        }
        uint amount0In = balance0 > _reserve0 - amount0Out ? balance0 - (_reserve0 - amount0Out) : 0;
        uint amount1In = balance1 > _reserve1 - amount1Out ? balance1 - (_reserve1 - amount1Out) : 0;
        require(amount0In > 0 || amount1In > 0, 'UniswapV2: INSUFFICIENT_INPUT_AMOUNT');
        { // scope for reserve{0,1}Adjusted, avoids stack too deep errors
        uint balance0Adjusted = balance0.mul(1000).sub(amount0In.mul(3));
        uint balance1Adjusted = balance1.mul(1000).sub(amount1In.mul(3));
        require(balance0Adjusted.mul(balance1Adjusted) >= uint(_reserve0).mul(_reserve1).mul(1000**2), 'UniswapV2: K');
        }

        _update(balance0, balance1, _reserve0, _reserve1);
        emit Swap(msg.sender, amount0In, amount1In, amount0Out, amount1Out, to);
    }

    // force balances to match reserves
    function skim(address to) external lock {
        address _token0 = token0; // gas savings
        address _token1 = token1; // gas savings
        _safeTransfer(_token0, to, IERC20(_token0).balanceOf(address(this)).sub(reserve0));
        _safeTransfer(_token1, to, IERC20(_token1).balanceOf(address(this)).sub(reserve1));
    }

    // force reserves to match balances
    function sync() external lock {
        _update(IERC20(token0).balanceOf(address(this)), IERC20(token1).balanceOf(address(this)), reserve0, reserve1);
    }
}

// BUILT FOR FREE ON https://vittominacori.github.io/erc20-generator

// File: @openzeppelin/contracts/GSN/Context.sol

pragma solidity ^0.6.0;

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
contract Context {
    // Empty internal constructor, to prevent people from mistakenly deploying
    // an instance of this contract, which should be used via inheritance.
    constructor () internal { }

    function _msgSender() internal view virtual returns (address payable) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol

pragma solidity ^0.6.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

// File: @openzeppelin/contracts/math/SafeMath.sol

pragma solidity ^0.6.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, "SafeMath: modulo by zero");
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

// File: @openzeppelin/contracts/utils/Address.sol

pragma solidity ^0.6.2;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
        // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
        // for accounts without code, i.e. `keccak256('')`
        bytes32 codehash;
        bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        // solhint-disable-next-line no-inline-assembly
        assembly { codehash := extcodehash(account) }
        return (codehash != accountHash && codehash != 0x0);
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (bool success, ) = recipient.call{ value: amount }("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }
}

// File: @openzeppelin/contracts/token/ERC20/ERC20.sol

pragma solidity ^0.6.0;





/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20MinterPauser}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * We have followed general OpenZeppelin guidelines: functions revert instead
 * of returning `false` on failure. This behavior is nonetheless conventional
 * and does not conflict with the expectations of ERC20 applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20 is Context, IERC20 {
    using SafeMath for uint256;
    using Address for address;

    mapping (address => uint256) private _balances;

    mapping (address => mapping (address => uint256)) private _allowances;

    uint256 private _totalSupply;

    string private _name;
    string private _symbol;
    uint8 private _decimals;

    /**
     * @dev Sets the values for {name} and {symbol}, initializes {decimals} with
     * a default value of 18.
     *
     * To select a different value for {decimals}, use {_setupDecimals}.
     *
     * All three of these values are immutable: they can only be set once during
     * construction.
     */
    constructor (string memory name, string memory symbol) public {
        _name = name;
        _symbol = symbol;
        _decimals = 18;
    }

    /**
     * @dev Returns the name of the token.
     */
    function name() public view returns (string memory) {
        return _name;
    }

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view returns (string memory) {
        return _symbol;
    }

    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5,05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei. This is the value {ERC20} uses, unless {_setupDecimals} is
     * called.
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view returns (uint8) {
        return _decimals;
    }

    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public view override returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view override returns (uint256) {
        return _balances[account];
    }

    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `recipient` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }

    /**
     * @dev See {IERC20-allowance}.
     */
    function allowance(address owner, address spender) public view virtual override returns (uint256) {
        return _allowances[owner][spender];
    }

    /**
     * @dev See {IERC20-approve}.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount) public virtual override returns (bool) {
        _approve(_msgSender(), spender, amount);
        return true;
    }

    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC20};
     *
     * Requirements:
     * - `sender` and `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     * - the caller must have allowance for ``sender``'s tokens of at least
     * `amount`.
     */
    function transferFrom(address sender, address recipient, uint256 amount) public virtual override returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
        return true;
    }

    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
        return true;
    }

    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero"));
        return true;
    }

    /**
     * @dev Moves tokens `amount` from `sender` to `recipient`.
     *
     * This is internal function is equivalent to {transfer}, and can be used to
     * e.g. implement automatic token fees, slashing mechanisms, etc.
     *
     * Emits a {Transfer} event.
     *
     * Requirements:
     *
     * - `sender` cannot be the zero address.
     * - `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     */
    function _transfer(address sender, address recipient, uint256 amount) internal virtual {
        require(sender != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0), "ERC20: transfer to the zero address");

        _beforeTokenTransfer(sender, recipient, amount);

        _balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
        _balances[recipient] = _balances[recipient].add(amount);
        emit Transfer(sender, recipient, amount);
    }

    /** @dev Creates `amount` tokens and assigns them to `account`, increasing
     * the total supply.
     *
     * Emits a {Transfer} event with `from` set to the zero address.
     *
     * Requirements
     *
     * - `to` cannot be the zero address.
     */
    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");

        _beforeTokenTransfer(address(0), account, amount);

        _totalSupply = _totalSupply.add(amount);
        _balances[account] = _balances[account].add(amount);
        emit Transfer(address(0), account, amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`, reducing the
     * total supply.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * Requirements
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     */
    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");

        _beforeTokenTransfer(account, address(0), amount);

        _balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance");
        _totalSupply = _totalSupply.sub(amount);
        emit Transfer(account, address(0), amount);
    }

    /**
     * @dev Sets `amount` as the allowance of `spender` over the `owner`s tokens.
     *
     * This is internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     */
    function _approve(address owner, address spender, uint256 amount) internal virtual {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    /**
     * @dev Sets {decimals} to a value other than the default one of 18.
     *
     * WARNING: This function should only be called from the constructor. Most
     * applications that interact with token contracts will not expect
     * {decimals} to ever change, and may work incorrectly if it does.
     */
    function _setupDecimals(uint8 decimals_) internal {
        _decimals = decimals_;
    }

    /**
     * @dev Hook that is called before any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * will be to transferred to `to`.
     * - when `from` is zero, `amount` tokens will be minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual { }
}

// File: @openzeppelin/contracts/token/ERC20/ERC20Capped.sol

pragma solidity ^0.6.0;


/**
 * @dev Extension of {ERC20} that adds a cap to the supply of tokens.
 */
abstract contract ERC20Capped is ERC20 {
    uint256 private _cap;

    /**
     * @dev Sets the value of the `cap`. This value is immutable, it can only be
     * set once during construction.
     */
    constructor (uint256 cap) public {
        require(cap > 0, "ERC20Capped: cap is 0");
        _cap = cap;
    }

    /**
     * @dev Returns the cap on the token's total supply.
     */
    function cap() public view returns (uint256) {
        return _cap;
    }

    /**
     * @dev See {ERC20-_beforeTokenTransfer}.
     *
     * Requirements:
     *
     * - minted tokens must not cause the total supply to go over the cap.
     */
    function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual override {
        super._beforeTokenTransfer(from, to, amount);

        if (from == address(0)) { // When minting tokens
            require(totalSupply().add(amount) <= _cap, "ERC20Capped: cap exceeded");
        }
    }
}

// File: @openzeppelin/contracts/token/ERC20/ERC20Burnable.sol

pragma solidity ^0.6.0;



/**
 * @dev Extension of {ERC20} that allows token holders to destroy both their own
 * tokens and those that they have an allowance for, in a way that can be
 * recognized off-chain (via event analysis).
 */
abstract contract ERC20Burnable is Context, ERC20 {
    /**
     * @dev Destroys `amount` tokens from the caller.
     *
     * See {ERC20-_burn}.
     */
    function burn(uint256 amount) public virtual {
        _burn(_msgSender(), amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`, deducting from the caller's
     * allowance.
     *
     * See {ERC20-_burn} and {ERC20-allowance}.
     *
     * Requirements:
     *
     * - the caller must have allowance for ``accounts``'s tokens of at least
     * `amount`.
     */
    function burnFrom(address account, uint256 amount) public virtual {
        uint256 decreasedAllowance = allowance(account, _msgSender()).sub(amount, "ERC20: burn amount exceeds allowance");

        _approve(account, _msgSender(), decreasedAllowance);
        _burn(account, amount);
    }
}

// File: @openzeppelin/contracts/introspection/IERC165.sol

pragma solidity ^0.6.0;

/**
 * @dev Interface of the ERC165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[EIP].
 *
 * Implementers can declare support of contract interfaces, which can then be
 * queried by others ({ERC165Checker}).
 *
 * For an implementation, see {ERC165}.
 */
interface IERC165 {
    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}

// File: erc-payable-token/contracts/token/ERC1363/IERC1363.sol

pragma solidity ^0.6.0;



/**
 * @title IERC1363 Interface
 * @author Vittorio Minacori (https://github.com/vittominacori)
 * @dev Interface for a Payable Token contract as defined in
 *  https://github.com/ethereum/EIPs/blob/master/EIPS/eip-1363.md
 */
interface IERC1363 is IERC20, IERC165 {
    /*
     * Note: the ERC-165 identifier for this interface is 0x4bbee2df.
     * 0x4bbee2df ===
     *   bytes4(keccak256('transferAndCall(address,uint256)')) ^
     *   bytes4(keccak256('transferAndCall(address,uint256,bytes)')) ^
     *   bytes4(keccak256('transferFromAndCall(address,address,uint256)')) ^
     *   bytes4(keccak256('transferFromAndCall(address,address,uint256,bytes)'))
     */

    /*
     * Note: the ERC-165 identifier for this interface is 0xfb9ec8ce.
     * 0xfb9ec8ce ===
     *   bytes4(keccak256('approveAndCall(address,uint256)')) ^
     *   bytes4(keccak256('approveAndCall(address,uint256,bytes)'))
     */

    /**
     * @notice Transfer tokens from `msg.sender` to another address and then call `onTransferReceived` on receiver
     * @param to address The address which you want to transfer to
     * @param value uint256 The amount of tokens to be transferred
     * @return true unless throwing
     */
    function transferAndCall(address to, uint256 value) external returns (bool);

    /**
     * @notice Transfer tokens from `msg.sender` to another address and then call `onTransferReceived` on receiver
     * @param to address The address which you want to transfer to
     * @param value uint256 The amount of tokens to be transferred
     * @param data bytes Additional data with no specified format, sent in call to `to`
     * @return true unless throwing
     */
    function transferAndCall(address to, uint256 value, bytes calldata data) external returns (bool);

    /**
     * @notice Transfer tokens from one address to another and then call `onTransferReceived` on receiver
     * @param from address The address which you want to send tokens from
     * @param to address The address which you want to transfer to
     * @param value uint256 The amount of tokens to be transferred
     * @return true unless throwing
     */
    function transferFromAndCall(address from, address to, uint256 value) external returns (bool);

    /**
     * @notice Transfer tokens from one address to another and then call `onTransferReceived` on receiver
     * @param from address The address which you want to send tokens from
     * @param to address The address which you want to transfer to
     * @param value uint256 The amount of tokens to be transferred
     * @param data bytes Additional data with no specified format, sent in call to `to`
     * @return true unless throwing
     */
    function transferFromAndCall(address from, address to, uint256 value, bytes calldata data) external returns (bool);

    /**
     * @notice Approve the passed address to spend the specified amount of tokens on behalf of msg.sender
     * and then call `onApprovalReceived` on spender.
     * Beware that changing an allowance with this method brings the risk that someone may use both the old
     * and the new allowance by unfortunate transaction ordering. One possible solution to mitigate this
     * race condition is to first reduce the spender's allowance to 0 and set the desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     * @param spender address The address which will spend the funds
     * @param value uint256 The amount of tokens to be spent
     */
    function approveAndCall(address spender, uint256 value) external returns (bool);

    /**
     * @notice Approve the passed address to spend the specified amount of tokens on behalf of msg.sender
     * and then call `onApprovalReceived` on spender.
     * Beware that changing an allowance with this method brings the risk that someone may use both the old
     * and the new allowance by unfortunate transaction ordering. One possible solution to mitigate this
     * race condition is to first reduce the spender's allowance to 0 and set the desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     * @param spender address The address which will spend the funds
     * @param value uint256 The amount of tokens to be spent
     * @param data bytes Additional data with no specified format, sent in call to `spender`
     */
    function approveAndCall(address spender, uint256 value, bytes calldata data) external returns (bool);
}

// File: erc-payable-token/contracts/token/ERC1363/IERC1363Receiver.sol

pragma solidity ^0.6.0;

/**
 * @title IERC1363Receiver Interface
 * @author Vittorio Minacori (https://github.com/vittominacori)
 * @dev Interface for any contract that wants to support transferAndCall or transferFromAndCall
 *  from ERC1363 token contracts as defined in
 *  https://github.com/ethereum/EIPs/blob/master/EIPS/eip-1363.md
 */
interface IERC1363Receiver {
    /*
     * Note: the ERC-165 identifier for this interface is 0x88a7ca5c.
     * 0x88a7ca5c === bytes4(keccak256("onTransferReceived(address,address,uint256,bytes)"))
     */

    /**
     * @notice Handle the receipt of ERC1363 tokens
     * @dev Any ERC1363 smart contract calls this function on the recipient
     * after a `transfer` or a `transferFrom`. This function MAY throw to revert and reject the
     * transfer. Return of other than the magic value MUST result in the
     * transaction being reverted.
     * Note: the token contract address is always the message sender.
     * @param operator address The address which called `transferAndCall` or `transferFromAndCall` function
     * @param from address The address which are token transferred from
     * @param value uint256 The amount of tokens transferred
     * @param data bytes Additional data with no specified format
     * @return `bytes4(keccak256("onTransferReceived(address,address,uint256,bytes)"))`
     *  unless throwing
     */
    function onTransferReceived(address operator, address from, uint256 value, bytes calldata data) external returns (bytes4); // solhint-disable-line  max-line-length
}

// File: erc-payable-token/contracts/token/ERC1363/IERC1363Spender.sol

pragma solidity ^0.6.0;

/**
 * @title IERC1363Spender Interface
 * @author Vittorio Minacori (https://github.com/vittominacori)
 * @dev Interface for any contract that wants to support approveAndCall
 *  from ERC1363 token contracts as defined in
 *  https://github.com/ethereum/EIPs/blob/master/EIPS/eip-1363.md
 */
interface IERC1363Spender {
    /*
     * Note: the ERC-165 identifier for this interface is 0x7b04a2d0.
     * 0x7b04a2d0 === bytes4(keccak256("onApprovalReceived(address,uint256,bytes)"))
     */

    /**
     * @notice Handle the approval of ERC1363 tokens
     * @dev Any ERC1363 smart contract calls this function on the recipient
     * after an `approve`. This function MAY throw to revert and reject the
     * approval. Return of other than the magic value MUST result in the
     * transaction being reverted.
     * Note: the token contract address is always the message sender.
     * @param owner address The address which called `approveAndCall` function
     * @param value uint256 The amount of tokens to be spent
     * @param data bytes Additional data with no specified format
     * @return `bytes4(keccak256("onApprovalReceived(address,uint256,bytes)"))`
     *  unless throwing
     */
    function onApprovalReceived(address owner, uint256 value, bytes calldata data) external returns (bytes4);
}

// File: @openzeppelin/contracts/introspection/ERC165Checker.sol

pragma solidity ^0.6.2;

/**
 * @dev Library used to query support of an interface declared via {IERC165}.
 *
 * Note that these functions return the actual result of the query: they do not
 * `revert` if an interface is not supported. It is up to the caller to decide
 * what to do in these cases.
 */
library ERC165Checker {
    // As per the EIP-165 spec, no interface should ever match 0xffffffff
    bytes4 private constant _INTERFACE_ID_INVALID = 0xffffffff;

    /*
     * bytes4(keccak256('supportsInterface(bytes4)')) == 0x01ffc9a7
     */
    bytes4 private constant _INTERFACE_ID_ERC165 = 0x01ffc9a7;

    /**
     * @dev Returns true if `account` supports the {IERC165} interface,
     */
    function supportsERC165(address account) internal view returns (bool) {
        // Any contract that implements ERC165 must explicitly indicate support of
        // InterfaceId_ERC165 and explicitly indicate non-support of InterfaceId_Invalid
        return _supportsERC165Interface(account, _INTERFACE_ID_ERC165) &&
            !_supportsERC165Interface(account, _INTERFACE_ID_INVALID);
    }

    /**
     * @dev Returns true if `account` supports the interface defined by
     * `interfaceId`. Support for {IERC165} itself is queried automatically.
     *
     * See {IERC165-supportsInterface}.
     */
    function supportsInterface(address account, bytes4 interfaceId) internal view returns (bool) {
        // query support of both ERC165 as per the spec and support of _interfaceId
        return supportsERC165(account) &&
            _supportsERC165Interface(account, interfaceId);
    }

    /**
     * @dev Returns true if `account` supports all the interfaces defined in
     * `interfaceIds`. Support for {IERC165} itself is queried automatically.
     *
     * Batch-querying can lead to gas savings by skipping repeated checks for
     * {IERC165} support.
     *
     * See {IERC165-supportsInterface}.
     */
    function supportsAllInterfaces(address account, bytes4[] memory interfaceIds) internal view returns (bool) {
        // query support of ERC165 itself
        if (!supportsERC165(account)) {
            return false;
        }

        // query support of each interface in _interfaceIds
        for (uint256 i = 0; i < interfaceIds.length; i++) {
            if (!_supportsERC165Interface(account, interfaceIds[i])) {
                return false;
            }
        }

        // all interfaces supported
        return true;
    }

    /**
     * @notice Query if a contract implements an interface, does not check ERC165 support
     * @param account The address of the contract to query for support of an interface
     * @param interfaceId The interface identifier, as specified in ERC-165
     * @return true if the contract at account indicates support of the interface with
     * identifier interfaceId, false otherwise
     * @dev Assumes that account contains a contract that supports ERC165, otherwise
     * the behavior of this method is undefined. This precondition can be checked
     * with {supportsERC165}.
     * Interface identification is specified in ERC-165.
     */
    function _supportsERC165Interface(address account, bytes4 interfaceId) private view returns (bool) {
        // success determines whether the staticcall succeeded and result determines
        // whether the contract at account indicates support of _interfaceId
        (bool success, bool result) = _callERC165SupportsInterface(account, interfaceId);

        return (success && result);
    }

    /**
     * @notice Calls the function with selector 0x01ffc9a7 (ERC165) and suppresses throw
     * @param account The address of the contract to query for support of an interface
     * @param interfaceId The interface identifier, as specified in ERC-165
     * @return success true if the STATICCALL succeeded, false otherwise
     * @return result true if the STATICCALL succeeded and the contract at account
     * indicates support of the interface with identifier interfaceId, false otherwise
     */
    function _callERC165SupportsInterface(address account, bytes4 interfaceId)
        private
        view
        returns (bool, bool)
    {
        bytes memory encodedParams = abi.encodeWithSelector(_INTERFACE_ID_ERC165, interfaceId);
        (bool success, bytes memory result) = account.staticcall{ gas: 30000 }(encodedParams);
        if (result.length < 32) return (false, false);
        return (success, abi.decode(result, (bool)));
    }
}

// File: @openzeppelin/contracts/introspection/ERC165.sol

pragma solidity ^0.6.0;


/**
 * @dev Implementation of the {IERC165} interface.
 *
 * Contracts may inherit from this and call {_registerInterface} to declare
 * their support of an interface.
 */
contract ERC165 is IERC165 {
    /*
     * bytes4(keccak256('supportsInterface(bytes4)')) == 0x01ffc9a7
     */
    bytes4 private constant _INTERFACE_ID_ERC165 = 0x01ffc9a7;

    /**
     * @dev Mapping of interface ids to whether or not it's supported.
     */
    mapping(bytes4 => bool) private _supportedInterfaces;

    constructor () internal {
        // Derived contracts need only register support for their own interfaces,
        // we register support for ERC165 itself here
        _registerInterface(_INTERFACE_ID_ERC165);
    }

    /**
     * @dev See {IERC165-supportsInterface}.
     *
     * Time complexity O(1), guaranteed to always use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) public view override returns (bool) {
        return _supportedInterfaces[interfaceId];
    }

    /**
     * @dev Registers the contract as an implementer of the interface defined by
     * `interfaceId`. Support of the actual ERC165 interface is automatic and
     * registering its interface id is not required.
     *
     * See {IERC165-supportsInterface}.
     *
     * Requirements:
     *
     * - `interfaceId` cannot be the ERC165 invalid interface (`0xffffffff`).
     */
    function _registerInterface(bytes4 interfaceId) internal virtual {
        require(interfaceId != 0xffffffff, "ERC165: invalid interface id");
        _supportedInterfaces[interfaceId] = true;
    }
}

// File: erc-payable-token/contracts/token/ERC1363/ERC1363.sol

pragma solidity ^0.6.0;








/**
 * @title ERC1363
 * @author Vittorio Minacori (https://github.com/vittominacori)
 * @dev Implementation of an ERC1363 interface
 */
contract ERC1363 is ERC20, IERC1363, ERC165 {
    using Address for address;

    /*
     * Note: the ERC-165 identifier for this interface is 0x4bbee2df.
     * 0x4bbee2df ===
     *   bytes4(keccak256('transferAndCall(address,uint256)')) ^
     *   bytes4(keccak256('transferAndCall(address,uint256,bytes)')) ^
     *   bytes4(keccak256('transferFromAndCall(address,address,uint256)')) ^
     *   bytes4(keccak256('transferFromAndCall(address,address,uint256,bytes)'))
     */
    bytes4 internal constant _INTERFACE_ID_ERC1363_TRANSFER = 0x4bbee2df;

    /*
     * Note: the ERC-165 identifier for this interface is 0xfb9ec8ce.
     * 0xfb9ec8ce ===
     *   bytes4(keccak256('approveAndCall(address,uint256)')) ^
     *   bytes4(keccak256('approveAndCall(address,uint256,bytes)'))
     */
    bytes4 internal constant _INTERFACE_ID_ERC1363_APPROVE = 0xfb9ec8ce;

    // Equals to `bytes4(keccak256("onTransferReceived(address,address,uint256,bytes)"))`
    // which can be also obtained as `IERC1363Receiver(0).onTransferReceived.selector`
    bytes4 private constant _ERC1363_RECEIVED = 0x88a7ca5c;

    // Equals to `bytes4(keccak256("onApprovalReceived(address,uint256,bytes)"))`
    // which can be also obtained as `IERC1363Spender(0).onApprovalReceived.selector`
    bytes4 private constant _ERC1363_APPROVED = 0x7b04a2d0;

    /**
     * @param name Name of the token
     * @param symbol A symbol to be used as ticker
     */
    constructor (
        string memory name,
        string memory symbol
    ) public payable ERC20(name, symbol) {
        // register the supported interfaces to conform to ERC1363 via ERC165
        _registerInterface(_INTERFACE_ID_ERC1363_TRANSFER);
        _registerInterface(_INTERFACE_ID_ERC1363_APPROVE);
    }

    /**
     * @dev Transfer tokens to a specified address and then execute a callback on recipient.
     * @param to The address to transfer to.
     * @param value The amount to be transferred.
     * @return A boolean that indicates if the operation was successful.
     */
    function transferAndCall(address to, uint256 value) public override returns (bool) {
        return transferAndCall(to, value, "");
    }

    /**
     * @dev Transfer tokens to a specified address and then execute a callback on recipient.
     * @param to The address to transfer to
     * @param value The amount to be transferred
     * @param data Additional data with no specified format
     * @return A boolean that indicates if the operation was successful.
     */
    function transferAndCall(address to, uint256 value, bytes memory data) public override returns (bool) {
        transfer(to, value);
        require(_checkAndCallTransfer(_msgSender(), to, value, data), "ERC1363: _checkAndCallTransfer reverts");
        return true;
    }

    /**
     * @dev Transfer tokens from one address to another and then execute a callback on recipient.
     * @param from The address which you want to send tokens from
     * @param to The address which you want to transfer to
     * @param value The amount of tokens to be transferred
     * @return A boolean that indicates if the operation was successful.
     */
    function transferFromAndCall(address from, address to, uint256 value) public override returns (bool) {
        return transferFromAndCall(from, to, value, "");
    }

    /**
     * @dev Transfer tokens from one address to another and then execute a callback on recipient.
     * @param from The address which you want to send tokens from
     * @param to The address which you want to transfer to
     * @param value The amount of tokens to be transferred
     * @param data Additional data with no specified format
     * @return A boolean that indicates if the operation was successful.
     */
    function transferFromAndCall(address from, address to, uint256 value, bytes memory data) public override returns (bool) {
        transferFrom(from, to, value);
        require(_checkAndCallTransfer(from, to, value, data), "ERC1363: _checkAndCallTransfer reverts");
        return true;
    }

    /**
     * @dev Approve spender to transfer tokens and then execute a callback on recipient.
     * @param spender The address allowed to transfer to
     * @param value The amount allowed to be transferred
     * @return A boolean that indicates if the operation was successful.
     */
    function approveAndCall(address spender, uint256 value) public override returns (bool) {
        return approveAndCall(spender, value, "");
    }

    /**
     * @dev Approve spender to transfer tokens and then execute a callback on recipient.
     * @param spender The address allowed to transfer to.
     * @param value The amount allowed to be transferred.
     * @param data Additional data with no specified format.
     * @return A boolean that indicates if the operation was successful.
     */
    function approveAndCall(address spender, uint256 value, bytes memory data) public override returns (bool) {
        approve(spender, value);
        require(_checkAndCallApprove(spender, value, data), "ERC1363: _checkAndCallApprove reverts");
        return true;
    }

    /**
     * @dev Internal function to invoke `onTransferReceived` on a target address
     *  The call is not executed if the target address is not a contract
     * @param from address Representing the previous owner of the given token value
     * @param to address Target address that will receive the tokens
     * @param value uint256 The amount mount of tokens to be transferred
     * @param data bytes Optional data to send along with the call
     * @return whether the call correctly returned the expected magic value
     */
    function _checkAndCallTransfer(address from, address to, uint256 value, bytes memory data) internal returns (bool) {
        if (!to.isContract()) {
            return false;
        }
        bytes4 retval = IERC1363Receiver(to).onTransferReceived(
            _msgSender(), from, value, data
        );
        return (retval == _ERC1363_RECEIVED);
    }

    /**
     * @dev Internal function to invoke `onApprovalReceived` on a target address
     *  The call is not executed if the target address is not a contract
     * @param spender address The address which will spend the funds
     * @param value uint256 The amount of tokens to be spent
     * @param data bytes Optional data to send along with the call
     * @return whether the call correctly returned the expected magic value
     */
    function _checkAndCallApprove(address spender, uint256 value, bytes memory data) internal returns (bool) {
        if (!spender.isContract()) {
            return false;
        }
        bytes4 retval = IERC1363Spender(spender).onApprovalReceived(
            _msgSender(), value, data
        );
        return (retval == _ERC1363_APPROVED);
    }
}

// File: @openzeppelin/contracts/access/Ownable.sol

pragma solidity ^0.6.0;

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor () internal {
        address msgSender = _msgSender();
        _owner = msgSender;
        emit OwnershipTransferred(address(0), msgSender);
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(_owner == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

// File: eth-token-recover/contracts/TokenRecover.sol

pragma solidity ^0.6.0;



/**
 * @title TokenRecover
 * @author Vittorio Minacori (https://github.com/vittominacori)
 * @dev Allow to recover any ERC20 sent into the contract for error
 */
contract TokenRecover is Ownable {

    /**
     * @dev Remember that only owner can call so be careful when use on contracts generated from other contracts.
     * @param tokenAddress The token contract address
     * @param tokenAmount Number of tokens to be sent
     */
    function recoverERC20(address tokenAddress, uint256 tokenAmount) public onlyOwner {
        IERC20(tokenAddress).transfer(owner(), tokenAmount);
    }
}

// File: @openzeppelin/contracts/utils/EnumerableSet.sol

pragma solidity ^0.6.0;

/**
 * @dev Library for managing
 * https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive
 * types.
 *
 * Sets have the following properties:
 *
 * - Elements are added, removed, and checked for existence in constant time
 * (O(1)).
 * - Elements are enumerated in O(n). No guarantees are made on the ordering.
 *
 * ```
 * contract Example {
 *     // Add the library methods
 *     using EnumerableSet for EnumerableSet.AddressSet;
 *
 *     // Declare a set state variable
 *     EnumerableSet.AddressSet private mySet;
 * }
 * ```
 *
 * As of v3.0.0, only sets of type `address` (`AddressSet`) and `uint256`
 * (`UintSet`) are supported.
 */
library EnumerableSet {
    // To implement this library for multiple types with as little code
    // repetition as possible, we write it in terms of a generic Set type with
    // bytes32 values.
    // The Set implementation uses private functions, and user-facing
    // implementations (such as AddressSet) are just wrappers around the
    // underlying Set.
    // This means that we can only create new EnumerableSets for types that fit
    // in bytes32.

    struct Set {
        // Storage of set values
        bytes32[] _values;

        // Position of the value in the `values` array, plus 1 because index 0
        // means a value is not in the set.
        mapping (bytes32 => uint256) _indexes;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function _add(Set storage set, bytes32 value) private returns (bool) {
        if (!_contains(set, value)) {
            set._values.push(value);
            // The value is stored at length-1, but we add 1 to all indexes
            // and use 0 as a sentinel value
            set._indexes[value] = set._values.length;
            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function _remove(Set storage set, bytes32 value) private returns (bool) {
        // We read and store the value's index to prevent multiple reads from the same storage slot
        uint256 valueIndex = set._indexes[value];

        if (valueIndex != 0) { // Equivalent to contains(set, value)
            // To delete an element from the _values array in O(1), we swap the element to delete with the last one in
            // the array, and then remove the last element (sometimes called as 'swap and pop').
            // This modifies the order of the array, as noted in {at}.

            uint256 toDeleteIndex = valueIndex - 1;
            uint256 lastIndex = set._values.length - 1;

            // When the value to delete is the last one, the swap operation is unnecessary. However, since this occurs
            // so rarely, we still do the swap anyway to avoid the gas cost of adding an 'if' statement.

            bytes32 lastvalue = set._values[lastIndex];

            // Move the last value to the index where the value to delete is
            set._values[toDeleteIndex] = lastvalue;
            // Update the index for the moved value
            set._indexes[lastvalue] = toDeleteIndex + 1; // All indexes are 1-based

            // Delete the slot where the moved value was stored
            set._values.pop();

            // Delete the index for the deleted slot
            delete set._indexes[value];

            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function _contains(Set storage set, bytes32 value) private view returns (bool) {
        return set._indexes[value] != 0;
    }

    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function _length(Set storage set) private view returns (uint256) {
        return set._values.length;
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function _at(Set storage set, uint256 index) private view returns (bytes32) {
        require(set._values.length > index, "EnumerableSet: index out of bounds");
        return set._values[index];
    }

    // AddressSet

    struct AddressSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(AddressSet storage set, address value) internal returns (bool) {
        return _add(set._inner, bytes32(uint256(value)));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(AddressSet storage set, address value) internal returns (bool) {
        return _remove(set._inner, bytes32(uint256(value)));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(AddressSet storage set, address value) internal view returns (bool) {
        return _contains(set._inner, bytes32(uint256(value)));
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(AddressSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function at(AddressSet storage set, uint256 index) internal view returns (address) {
        return address(uint256(_at(set._inner, index)));
    }


    // UintSet

    struct UintSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(UintSet storage set, uint256 value) internal returns (bool) {
        return _add(set._inner, bytes32(value));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(UintSet storage set, uint256 value) internal returns (bool) {
        return _remove(set._inner, bytes32(value));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(UintSet storage set, uint256 value) internal view returns (bool) {
        return _contains(set._inner, bytes32(value));
    }

    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function length(UintSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function at(UintSet storage set, uint256 index) internal view returns (uint256) {
        return uint256(_at(set._inner, index));
    }
}

// File: @openzeppelin/contracts/access/AccessControl.sol

pragma solidity ^0.6.0;




/**
 * @dev Contract module that allows children to implement role-based access
 * control mechanisms.
 *
 * Roles are referred to by their `bytes32` identifier. These should be exposed
 * in the external API and be unique. The best way to achieve this is by
 * using `public constant` hash digests:
 *
 * ```
 * bytes32 public constant MY_ROLE = keccak256("MY_ROLE");
 * ```
 *
 * Roles can be used to represent a set of permissions. To restrict access to a
 * function call, use {hasRole}:
 *
 * ```
 * function foo() public {
 *     require(hasRole(MY_ROLE, _msgSender()));
 *     ...
 * }
 * ```
 *
 * Roles can be granted and revoked dynamically via the {grantRole} and
 * {revokeRole} functions. Each role has an associated admin role, and only
 * accounts that have a role's admin role can call {grantRole} and {revokeRole}.
 *
 * By default, the admin role for all roles is `DEFAULT_ADMIN_ROLE`, which means
 * that only accounts with this role will be able to grant or revoke other
 * roles. More complex role relationships can be created by using
 * {_setRoleAdmin}.
 */
abstract contract AccessControl is Context {
    using EnumerableSet for EnumerableSet.AddressSet;
    using Address for address;

    struct RoleData {
        EnumerableSet.AddressSet members;
        bytes32 adminRole;
    }

    mapping (bytes32 => RoleData) private _roles;

    bytes32 public constant DEFAULT_ADMIN_ROLE = 0x00;

    /**
     * @dev Emitted when `account` is granted `role`.
     *
     * `sender` is the account that originated the contract call, an admin role
     * bearer except when using {_setupRole}.
     */
    event RoleGranted(bytes32 indexed role, address indexed account, address indexed sender);

    /**
     * @dev Emitted when `account` is revoked `role`.
     *
     * `sender` is the account that originated the contract call:
     *   - if using `revokeRole`, it is the admin role bearer
     *   - if using `renounceRole`, it is the role bearer (i.e. `account`)
     */
    event RoleRevoked(bytes32 indexed role, address indexed account, address indexed sender);

    /**
     * @dev Returns `true` if `account` has been granted `role`.
     */
    function hasRole(bytes32 role, address account) public view returns (bool) {
        return _roles[role].members.contains(account);
    }

    /**
     * @dev Returns the number of accounts that have `role`. Can be used
     * together with {getRoleMember} to enumerate all bearers of a role.
     */
    function getRoleMemberCount(bytes32 role) public view returns (uint256) {
        return _roles[role].members.length();
    }

    /**
     * @dev Returns one of the accounts that have `role`. `index` must be a
     * value between 0 and {getRoleMemberCount}, non-inclusive.
     *
     * Role bearers are not sorted in any particular way, and their ordering may
     * change at any point.
     *
     * WARNING: When using {getRoleMember} and {getRoleMemberCount}, make sure
     * you perform all queries on the same block. See the following
     * https://forum.openzeppelin.com/t/iterating-over-elements-on-enumerableset-in-openzeppelin-contracts/2296[forum post]
     * for more information.
     */
    function getRoleMember(bytes32 role, uint256 index) public view returns (address) {
        return _roles[role].members.at(index);
    }

    /**
     * @dev Returns the admin role that controls `role`. See {grantRole} and
     * {revokeRole}.
     *
     * To change a role's admin, use {_setRoleAdmin}.
     */
    function getRoleAdmin(bytes32 role) public view returns (bytes32) {
        return _roles[role].adminRole;
    }

    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function grantRole(bytes32 role, address account) public virtual {
        require(hasRole(_roles[role].adminRole, _msgSender()), "AccessControl: sender must be an admin to grant");

        _grantRole(role, account);
    }

    /**
     * @dev Revokes `role` from `account`.
     *
     * If `account` had been granted `role`, emits a {RoleRevoked} event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function revokeRole(bytes32 role, address account) public virtual {
        require(hasRole(_roles[role].adminRole, _msgSender()), "AccessControl: sender must be an admin to revoke");

        _revokeRole(role, account);
    }

    /**
     * @dev Revokes `role` from the calling account.
     *
     * Roles are often managed via {grantRole} and {revokeRole}: this function's
     * purpose is to provide a mechanism for accounts to lose their privileges
     * if they are compromised (such as when a trusted device is misplaced).
     *
     * If the calling account had been granted `role`, emits a {RoleRevoked}
     * event.
     *
     * Requirements:
     *
     * - the caller must be `account`.
     */
    function renounceRole(bytes32 role, address account) public virtual {
        require(account == _msgSender(), "AccessControl: can only renounce roles for self");

        _revokeRole(role, account);
    }

    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event. Note that unlike {grantRole}, this function doesn't perform any
     * checks on the calling account.
     *
     * [WARNING]
     * ====
     * This function should only be called from the constructor when setting
     * up the initial roles for the system.
     *
     * Using this function in any other way is effectively circumventing the admin
     * system imposed by {AccessControl}.
     * ====
     */
    function _setupRole(bytes32 role, address account) internal virtual {
        _grantRole(role, account);
    }

    /**
     * @dev Sets `adminRole` as ``role``'s admin role.
     */
    function _setRoleAdmin(bytes32 role, bytes32 adminRole) internal virtual {
        _roles[role].adminRole = adminRole;
    }

    function _grantRole(bytes32 role, address account) private {
        if (_roles[role].members.add(account)) {
            emit RoleGranted(role, account, _msgSender());
        }
    }

    function _revokeRole(bytes32 role, address account) private {
        if (_roles[role].members.remove(account)) {
            emit RoleRevoked(role, account, _msgSender());
        }
    }
}

// File: contracts/access/Roles.sol

pragma solidity ^0.6.0;


contract Roles is AccessControl {

    bytes32 public constant MINTER_ROLE = keccak256("MINTER");
    bytes32 public constant OPERATOR_ROLE = keccak256("OPERATOR");

    constructor () public {
        _setupRole(DEFAULT_ADMIN_ROLE, _msgSender());
        _setupRole(MINTER_ROLE, _msgSender());
        _setupRole(OPERATOR_ROLE, _msgSender());
    }

    modifier onlyMinter() {
        require(hasRole(MINTER_ROLE, _msgSender()), "Roles: caller does not have the MINTER role");
        _;
    }

    modifier onlyOperator() {
        require(hasRole(OPERATOR_ROLE, _msgSender()), "Roles: caller does not have the OPERATOR role");
        _;
    }
}

// File: contracts/BaseToken.sol

pragma solidity ^0.6.0;






/**
 * @title BaseToken
 * @author Vittorio Minacori (https://github.com/vittominacori)
 * @dev Implementation of the BaseToken
 */
contract BaseToken is ERC20Capped, ERC20Burnable, ERC1363, Roles, TokenRecover {

    // indicates if minting is finished
    bool private _mintingFinished = false;

    // indicates if transfer is enabled
    bool private _transferEnabled = false;

    string public constant BUILT_ON = "https://vittominacori.github.io/erc20-generator";

    /**
     * @dev Emitted during finish minting
     */
    event MintFinished();

    /**
     * @dev Emitted during transfer enabling
     */
    event TransferEnabled();

    /**
     * @dev Tokens can be minted only before minting finished.
     */
    modifier canMint() {
        require(!_mintingFinished, "BaseToken: minting is finished");
        _;
    }

    /**
     * @dev Tokens can be moved only after if transfer enabled or if you are an approved operator.
     */
    modifier canTransfer(address from) {
        require(
            _transferEnabled || hasRole(OPERATOR_ROLE, from),
            "BaseToken: transfer is not enabled or from does not have the OPERATOR role"
        );
        _;
    }

    /**
     * @param name Name of the token
     * @param symbol A symbol to be used as ticker
     * @param decimals Number of decimals. All the operations are done using the smallest and indivisible token unit
     * @param cap Maximum number of tokens mintable
     * @param initialSupply Initial token supply
     * @param transferEnabled If transfer is enabled on token creation
     * @param mintingFinished If minting is finished after token creation
     */
    constructor(
        string memory name,
        string memory symbol,
        uint8 decimals,
        uint256 cap,
        uint256 initialSupply,
        bool transferEnabled,
        bool mintingFinished
    )
        public
        ERC20Capped(cap)
        ERC1363(name, symbol)
    {
        require(
            mintingFinished == false || cap == initialSupply,
            "BaseToken: if finish minting, cap must be equal to initialSupply"
        );

        _setupDecimals(decimals);

        if (initialSupply > 0) {
            _mint(owner(), initialSupply);
        }

        if (mintingFinished) {
            finishMinting();
        }

        if (transferEnabled) {
            enableTransfer();
        }
    }

    /**
     * @return if minting is finished or not.
     */
    function mintingFinished() public view returns (bool) {
        return _mintingFinished;
    }

    /**
     * @return if transfer is enabled or not.
     */
    function transferEnabled() public view returns (bool) {
        return _transferEnabled;
    }

    /**
     * @dev Function to mint tokens.
     * @param to The address that will receive the minted tokens
     * @param value The amount of tokens to mint
     */
    function mint(address to, uint256 value) public canMint onlyMinter {
        _mint(to, value);
    }

    /**
     * @dev Transfer tokens to a specified address.
     * @param to The address to transfer to
     * @param value The amount to be transferred
     * @return A boolean that indicates if the operation was successful.
     */
    function transfer(address to, uint256 value) public virtual override(ERC20) canTransfer(_msgSender()) returns (bool) {
        return super.transfer(to, value);
    }

    /**
     * @dev Transfer tokens from one address to another.
     * @param from The address which you want to send tokens from
     * @param to The address which you want to transfer to
     * @param value the amount of tokens to be transferred
     * @return A boolean that indicates if the operation was successful.
     */
    function transferFrom(address from, address to, uint256 value) public virtual override(ERC20) canTransfer(from) returns (bool) {
        return super.transferFrom(from, to, value);
    }

    /**
     * @dev Function to stop minting new tokens.
     */
    function finishMinting() public canMint onlyOwner {
        _mintingFinished = true;

        emit MintFinished();
    }

    /**
     * @dev Function to enable transfers.
     */
    function enableTransfer() public onlyOwner {
        _transferEnabled = true;

        emit TransferEnabled();
    }

    /**
     * @dev See {ERC20-_beforeTokenTransfer}.
     */
    function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual override(ERC20, ERC20Capped) {
        super._beforeTokenTransfer(from, to, amount);
    }
}

pragma solidity 0.5.13;

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
contract Context {
    // Empty internal constructor, to prevent people from mistakenly deploying
    // an instance of this contract, which should be used via inheritance.
    constructor () internal { }
    // solhint-disable-previous-line no-empty-blocks

    function _msgSender() internal view returns (address payable) {
        return msg.sender;
    }

    function _msgData() internal view returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

/**
 * @dev Interface of the ERC20 standard as defined in the EIP. Does not include
 * the optional functions; to access them see {ERC20Detailed}.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     *
     * _Available since v2.4.0._
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     *
     * _Available since v2.4.0._
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, "SafeMath: modulo by zero");
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     *
     * _Available since v2.4.0._
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20Mintable}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * We have followed general OpenZeppelin guidelines: functions revert instead
 * of returning `false` on failure. This behavior is nonetheless conventional
 * and does not conflict with the expectations of ERC20 applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20 is Context, IERC20 {
    using SafeMath for uint256;

    mapping (address => uint256) private _balances;

    mapping (address => mapping (address => uint256)) private _allowances;

    uint256 private _totalSupply;

    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public view returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view returns (uint256) {
        return _balances[account];
    }

    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `recipient` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address recipient, uint256 amount) public returns (bool) {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }

    /**
     * @dev See {IERC20-allowance}.
     */
    function allowance(address owner, address spender) public view returns (uint256) {
        return _allowances[owner][spender];
    }

    /**
     * @dev See {IERC20-approve}.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount) public returns (bool) {
        _approve(_msgSender(), spender, amount);
        return true;
    }

    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC20};
     *
     * Requirements:
     * - `sender` and `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     * - the caller must have allowance for `sender`'s tokens of at least
     * `amount`.
     */
    function transferFrom(address sender, address recipient, uint256 amount) public returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
        return true;
    }

    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
        return true;
    }

    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero"));
        return true;
    }

    /**
     * @dev Moves tokens `amount` from `sender` to `recipient`.
     *
     * This is internal function is equivalent to {transfer}, and can be used to
     * e.g. implement automatic token fees, slashing mechanisms, etc.
     *
     * Emits a {Transfer} event.
     *
     * Requirements:
     *
     * - `sender` cannot be the zero address.
     * - `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     */
    function _transfer(address sender, address recipient, uint256 amount) internal {
        require(sender != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0), "ERC20: transfer to the zero address");

        _balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
        _balances[recipient] = _balances[recipient].add(amount);
        emit Transfer(sender, recipient, amount);
    }

    /** @dev Creates `amount` tokens and assigns them to `account`, increasing
     * the total supply.
     *
     * Emits a {Transfer} event with `from` set to the zero address.
     *
     * Requirements
     *
     * - `to` cannot be the zero address.
     */
    function _mint(address account, uint256 amount) internal {
        require(account != address(0), "ERC20: mint to the zero address");

        _totalSupply = _totalSupply.add(amount);
        _balances[account] = _balances[account].add(amount);
        emit Transfer(address(0), account, amount);
    }

     /**
     * @dev Destroys `amount` tokens from `account`, reducing the
     * total supply.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * Requirements
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     */
    function _burn(address account, uint256 amount) internal {
        require(account != address(0), "ERC20: burn from the zero address");

        _balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance");
        _totalSupply = _totalSupply.sub(amount);
        emit Transfer(account, address(0), amount);
    }

    /**
     * @dev Sets `amount` as the allowance of `spender` over the `owner`s tokens.
     *
     * This is internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     */
    function _approve(address owner, address spender, uint256 amount) internal {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`.`amount` is then deducted
     * from the caller's allowance.
     *
     * See {_burn} and {_approve}.
     */
    function _burnFrom(address account, uint256 amount) internal {
        _burn(account, amount);
        _approve(account, _msgSender(), _allowances[account][_msgSender()].sub(amount, "ERC20: burn amount exceeds allowance"));
    }
}

contract GlobalsAndUtility is ERC20 {
    /*  XfLobbyEnter      (auto-generated event)

        uint40            timestamp       -->  data0 [ 39:  0]
        address  indexed  memberAddr
        uint256  indexed  entryId
        uint96            rawAmount       -->  data0 [135: 40]
        address  indexed  referrerAddr
    */
    event XfLobbyEnter(
        uint256 data0,
        address indexed memberAddr,
        uint256 indexed entryId,
        address indexed referrerAddr
    );

    /*  XfLobbyExit       (auto-generated event)

        uint40            timestamp       -->  data0 [ 39:  0]
        address  indexed  memberAddr
        uint256  indexed  entryId
        uint72            xfAmount        -->  data0 [111: 40]
        address  indexed  referrerAddr
    */
    event XfLobbyExit(
        uint256 data0,
        address indexed memberAddr,
        uint256 indexed entryId,
        address indexed referrerAddr
    );

    /*  DailyDataUpdate   (auto-generated event)

        uint40            timestamp       -->  data0 [ 39:  0]
        uint16            beginDay        -->  data0 [ 55: 40]
        uint16            endDay          -->  data0 [ 71: 56]
        bool              isAutoUpdate    -->  data0 [ 79: 72]
        address  indexed  updaterAddr
    */
    event DailyDataUpdate(
        uint256 data0,
        address indexed updaterAddr
    );

    /*  Claim             (auto-generated event)

        uint40            timestamp       -->  data0 [ 39:  0]
        bytes20  indexed  btcAddr
        uint56            rawSatoshis     -->  data0 [ 95: 40]
        uint56            adjSatoshis     -->  data0 [151: 96]
        address  indexed  claimToAddr
        uint8             claimFlags      -->  data0 [159:152]
        uint72            claimedHearts   -->  data0 [231:160]
        address  indexed  referrerAddr
        address           senderAddr      -->  data1 [159:  0]
    */
    event Claim(
        uint256 data0,
        uint256 data1,
        bytes20 indexed btcAddr,
        address indexed claimToAddr,
        address indexed referrerAddr
    );

    /*  ClaimAssist       (auto-generated event)

        uint40            timestamp       -->  data0 [ 39:  0]
        bytes20           btcAddr         -->  data0 [199: 40]
        uint56            rawSatoshis     -->  data0 [255:200]
        uint56            adjSatoshis     -->  data1 [ 55:  0]
        address           claimToAddr     -->  data1 [215: 56]
        uint8             claimFlags      -->  data1 [223:216]
        uint72            claimedHearts   -->  data2 [ 71:  0]
        address           referrerAddr    -->  data2 [231: 72]
        address  indexed  senderAddr
    */
    event ClaimAssist(
        uint256 data0,
        uint256 data1,
        uint256 data2,
        address indexed senderAddr
    );

    /*  StakeStart        (auto-generated event)

        uint40            timestamp       -->  data0 [ 39:  0]
        address  indexed  stakerAddr
        uint40   indexed  stakeId
        uint72            stakedHearts    -->  data0 [111: 40]
        uint72            stakeShares     -->  data0 [183:112]
        uint16            stakedDays      -->  data0 [199:184]
        bool              isAutoStake     -->  data0 [207:200]
    */
    event StakeStart(
        uint256 data0,
        address indexed stakerAddr,
        uint40 indexed stakeId
    );

    /*  StakeGoodAccounting(auto-generated event)

        uint40            timestamp       -->  data0 [ 39:  0]
        address  indexed  stakerAddr
        uint40   indexed  stakeId
        uint72            stakedHearts    -->  data0 [111: 40]
        uint72            stakeShares     -->  data0 [183:112]
        uint72            payout          -->  data0 [255:184]
        uint72            penalty         -->  data1 [ 71:  0]
        address  indexed  senderAddr
    */
    event StakeGoodAccounting(
        uint256 data0,
        uint256 data1,
        address indexed stakerAddr,
        uint40 indexed stakeId,
        address indexed senderAddr
    );

    /*  StakeEnd          (auto-generated event)

        uint40            timestamp       -->  data0 [ 39:  0]
        address  indexed  stakerAddr
        uint40   indexed  stakeId
        uint72            stakedHearts    -->  data0 [111: 40]
        uint72            stakeShares     -->  data0 [183:112]
        uint72            payout          -->  data0 [255:184]
        uint72            penalty         -->  data1 [ 71:  0]
        uint16            servedDays      -->  data1 [ 87: 72]
        bool              prevUnlocked    -->  data1 [ 95: 88]
    */
    event StakeEnd(
        uint256 data0,
        uint256 data1,
        address indexed stakerAddr,
        uint40 indexed stakeId
    );

    /*  ShareRateChange   (auto-generated event)

        uint40            timestamp       -->  data0 [ 39:  0]
        uint40            shareRate       -->  data0 [ 79: 40]
        uint40   indexed  stakeId
    */
    event ShareRateChange(
        uint256 data0,
        uint40 indexed stakeId
    );

    /* Origin address */
    address internal constant ORIGIN_ADDR = 0x9A6a414D6F3497c05E3b1De90520765fA1E07c03;

    /* Flush address */
    address payable internal constant FLUSH_ADDR = 0xDEC9f2793e3c17cd26eeFb21C4762fA5128E0399;

    /* ERC20 constants */
    string public constant name = "HEX";
    string public constant symbol = "HEX";
    uint8 public constant decimals = 8;

    /* Hearts per Satoshi = 10,000 * 1e8 / 1e8 = 1e4 */
    uint256 private constant HEARTS_PER_HEX = 10 ** uint256(decimals); // 1e8
    uint256 private constant HEX_PER_BTC = 1e4;
    uint256 private constant SATOSHIS_PER_BTC = 1e8;
    uint256 internal constant HEARTS_PER_SATOSHI = HEARTS_PER_HEX / SATOSHIS_PER_BTC * HEX_PER_BTC;

    /* Time of contract launch (2019-12-03T00:00:00Z) */
    uint256 internal constant LAUNCH_TIME = 1575331200;

    /* Size of a Hearts or Shares uint */
    uint256 internal constant HEART_UINT_SIZE = 72;

    /* Size of a transform lobby entry index uint */
    uint256 internal constant XF_LOBBY_ENTRY_INDEX_SIZE = 40;
    uint256 internal constant XF_LOBBY_ENTRY_INDEX_MASK = (1 << XF_LOBBY_ENTRY_INDEX_SIZE) - 1;

    /* Seed for WAAS Lobby */
    uint256 internal constant WAAS_LOBBY_SEED_HEX = 1e9;
    uint256 internal constant WAAS_LOBBY_SEED_HEARTS = WAAS_LOBBY_SEED_HEX * HEARTS_PER_HEX;

    /* Start of claim phase */
    uint256 internal constant PRE_CLAIM_DAYS = 1;
    uint256 internal constant CLAIM_PHASE_START_DAY = PRE_CLAIM_DAYS;

    /* Length of claim phase */
    uint256 private constant CLAIM_PHASE_WEEKS = 50;
    uint256 internal constant CLAIM_PHASE_DAYS = CLAIM_PHASE_WEEKS * 7;

    /* End of claim phase */
    uint256 internal constant CLAIM_PHASE_END_DAY = CLAIM_PHASE_START_DAY + CLAIM_PHASE_DAYS;

    /* Number of words to hold 1 bit for each transform lobby day */
    uint256 internal constant XF_LOBBY_DAY_WORDS = (CLAIM_PHASE_END_DAY + 255) >> 8;

    /* BigPayDay */
    uint256 internal constant BIG_PAY_DAY = CLAIM_PHASE_END_DAY + 1;

    /* Root hash of the UTXO Merkle tree */
    bytes32 internal constant MERKLE_TREE_ROOT = 0x4e831acb4223b66de3b3d2e54a2edeefb0de3d7916e2886a4b134d9764d41bec;

    /* Size of a Satoshi claim uint in a Merkle leaf */
    uint256 internal constant MERKLE_LEAF_SATOSHI_SIZE = 45;

    /* Zero-fill between BTC address and Satoshis in a Merkle leaf */
    uint256 internal constant MERKLE_LEAF_FILL_SIZE = 256 - 160 - MERKLE_LEAF_SATOSHI_SIZE;
    uint256 internal constant MERKLE_LEAF_FILL_BASE = (1 << MERKLE_LEAF_FILL_SIZE) - 1;
    uint256 internal constant MERKLE_LEAF_FILL_MASK = MERKLE_LEAF_FILL_BASE << MERKLE_LEAF_SATOSHI_SIZE;

    /* Size of a Satoshi total uint */
    uint256 internal constant SATOSHI_UINT_SIZE = 51;
    uint256 internal constant SATOSHI_UINT_MASK = (1 << SATOSHI_UINT_SIZE) - 1;

    /* Total Satoshis from all BTC addresses in UTXO snapshot */
    uint256 internal constant FULL_SATOSHIS_TOTAL = 1807766732160668;

    /* Total Satoshis from supported BTC addresses in UTXO snapshot after applying Silly Whale */
    uint256 internal constant CLAIMABLE_SATOSHIS_TOTAL = 910087996911001;

    /* Number of claimable BTC addresses in UTXO snapshot */
    uint256 internal constant CLAIMABLE_BTC_ADDR_COUNT = 27997742;

    /* Largest BTC address Satoshis balance in UTXO snapshot (sanity check) */
    uint256 internal constant MAX_BTC_ADDR_BALANCE_SATOSHIS = 25550214098481;

    /* Percentage of total claimed Hearts that will be auto-staked from a claim */
    uint256 internal constant AUTO_STAKE_CLAIM_PERCENT = 90;

    /* Stake timing parameters */
    uint256 internal constant MIN_STAKE_DAYS = 1;
    uint256 internal constant MIN_AUTO_STAKE_DAYS = 350;

    uint256 internal constant MAX_STAKE_DAYS = 5555; // Approx 15 years

    uint256 internal constant EARLY_PENALTY_MIN_DAYS = 90;

    uint256 private constant LATE_PENALTY_GRACE_WEEKS = 2;
    uint256 internal constant LATE_PENALTY_GRACE_DAYS = LATE_PENALTY_GRACE_WEEKS * 7;

    uint256 private constant LATE_PENALTY_SCALE_WEEKS = 100;
    uint256 internal constant LATE_PENALTY_SCALE_DAYS = LATE_PENALTY_SCALE_WEEKS * 7;

    /* Stake shares Longer Pays Better bonus constants used by _stakeStartBonusHearts() */
    uint256 private constant LPB_BONUS_PERCENT = 20;
    uint256 private constant LPB_BONUS_MAX_PERCENT = 200;
    uint256 internal constant LPB = 364 * 100 / LPB_BONUS_PERCENT;
    uint256 internal constant LPB_MAX_DAYS = LPB * LPB_BONUS_MAX_PERCENT / 100;

    /* Stake shares Bigger Pays Better bonus constants used by _stakeStartBonusHearts() */
    uint256 private constant BPB_BONUS_PERCENT = 10;
    uint256 private constant BPB_MAX_HEX = 150 * 1e6;
    uint256 internal constant BPB_MAX_HEARTS = BPB_MAX_HEX * HEARTS_PER_HEX;
    uint256 internal constant BPB = BPB_MAX_HEARTS * 100 / BPB_BONUS_PERCENT;

    /* Share rate is scaled to increase precision */
    uint256 internal constant SHARE_RATE_SCALE = 1e5;

    /* Share rate max (after scaling) */
    uint256 internal constant SHARE_RATE_UINT_SIZE = 40;
    uint256 internal constant SHARE_RATE_MAX = (1 << SHARE_RATE_UINT_SIZE) - 1;

    /* Constants for preparing the claim message text */
    uint8 internal constant ETH_ADDRESS_BYTE_LEN = 20;
    uint8 internal constant ETH_ADDRESS_HEX_LEN = ETH_ADDRESS_BYTE_LEN * 2;

    uint8 internal constant CLAIM_PARAM_HASH_BYTE_LEN = 12;
    uint8 internal constant CLAIM_PARAM_HASH_HEX_LEN = CLAIM_PARAM_HASH_BYTE_LEN * 2;

    uint8 internal constant BITCOIN_SIG_PREFIX_LEN = 24;
    bytes24 internal constant BITCOIN_SIG_PREFIX_STR = "Bitcoin Signed Message:\n";

    bytes internal constant STD_CLAIM_PREFIX_STR = "Claim_HEX_to_0x";
    bytes internal constant OLD_CLAIM_PREFIX_STR = "Claim_BitcoinHEX_to_0x";

    bytes16 internal constant HEX_DIGITS = "0123456789abcdef";

    /* Claim flags passed to btcAddressClaim()  */
    uint8 internal constant CLAIM_FLAG_MSG_PREFIX_OLD = 1 << 0;
    uint8 internal constant CLAIM_FLAG_BTC_ADDR_COMPRESSED = 1 << 1;
    uint8 internal constant CLAIM_FLAG_BTC_ADDR_P2WPKH_IN_P2SH = 1 << 2;
    uint8 internal constant CLAIM_FLAG_BTC_ADDR_BECH32 = 1 << 3;
    uint8 internal constant CLAIM_FLAG_ETH_ADDR_LOWERCASE = 1 << 4;

    /* Globals expanded for memory (except _latestStakeId) and compact for storage */
    struct GlobalsCache {
        // 1
        uint256 _lockedHeartsTotal;
        uint256 _nextStakeSharesTotal;
        uint256 _shareRate;
        uint256 _stakePenaltyTotal;
        // 2
        uint256 _dailyDataCount;
        uint256 _stakeSharesTotal;
        uint40 _latestStakeId;
        uint256 _unclaimedSatoshisTotal;
        uint256 _claimedSatoshisTotal;
        uint256 _claimedBtcAddrCount;
        //
        uint256 _currentDay;
    }

    struct GlobalsStore {
        // 1
        uint72 lockedHeartsTotal;
        uint72 nextStakeSharesTotal;
        uint40 shareRate;
        uint72 stakePenaltyTotal;
        // 2
        uint16 dailyDataCount;
        uint72 stakeSharesTotal;
        uint40 latestStakeId;
        uint128 claimStats;
    }

    GlobalsStore public globals;

    /* Claimed BTC addresses */
    mapping(bytes20 => bool) public btcAddressClaims;

    /* Daily data */
    struct DailyDataStore {
        uint72 dayPayoutTotal;
        uint72 dayStakeSharesTotal;
        uint56 dayUnclaimedSatoshisTotal;
    }

    mapping(uint256 => DailyDataStore) public dailyData;

    /* Stake expanded for memory (except _stakeId) and compact for storage */
    struct StakeCache {
        uint40 _stakeId;
        uint256 _stakedHearts;
        uint256 _stakeShares;
        uint256 _lockedDay;
        uint256 _stakedDays;
        uint256 _unlockedDay;
        bool _isAutoStake;
    }

    struct StakeStore {
        uint40 stakeId;
        uint72 stakedHearts;
        uint72 stakeShares;
        uint16 lockedDay;
        uint16 stakedDays;
        uint16 unlockedDay;
        bool isAutoStake;
    }

    mapping(address => StakeStore[]) public stakeLists;

    /* Temporary state for calculating daily rounds */
    struct DailyRoundState {
        uint256 _allocSupplyCached;
        uint256 _mintOriginBatch;
        uint256 _payoutTotal;
    }

    struct XfLobbyEntryStore {
        uint96 rawAmount;
        address referrerAddr;
    }

    struct XfLobbyQueueStore {
        uint40 headIndex;
        uint40 tailIndex;
        mapping(uint256 => XfLobbyEntryStore) entries;
    }

    mapping(uint256 => uint256) public xfLobby;
    mapping(uint256 => mapping(address => XfLobbyQueueStore)) public xfLobbyMembers;

    /**
     * @dev PUBLIC FACING: Optionally update daily data for a smaller
     * range to reduce gas cost for a subsequent operation
     * @param beforeDay Only update days before this day number (optional; 0 for current day)
     */
    function dailyDataUpdate(uint256 beforeDay)
        external
    {
        GlobalsCache memory g;
        GlobalsCache memory gSnapshot;
        _globalsLoad(g, gSnapshot);

        /* Skip pre-claim period */
        require(g._currentDay > CLAIM_PHASE_START_DAY, "HEX: Too early");

        if (beforeDay != 0) {
            require(beforeDay <= g._currentDay, "HEX: beforeDay cannot be in the future");

            _dailyDataUpdate(g, beforeDay, false);
        } else {
            /* Default to updating before current day */
            _dailyDataUpdate(g, g._currentDay, false);
        }

        _globalsSync(g, gSnapshot);
    }

    /**
     * @dev PUBLIC FACING: External helper to return multiple values of daily data with
     * a single call. Ugly implementation due to limitations of the standard ABI encoder.
     * @param beginDay First day of data range
     * @param endDay Last day (non-inclusive) of data range
     * @return Fixed array of packed values
     */
    function dailyDataRange(uint256 beginDay, uint256 endDay)
        external
        view
        returns (uint256[] memory list)
    {
        require(beginDay < endDay && endDay <= globals.dailyDataCount, "HEX: range invalid");

        list = new uint256[](endDay - beginDay);

        uint256 src = beginDay;
        uint256 dst = 0;
        uint256 v;
        do {
            v = uint256(dailyData[src].dayUnclaimedSatoshisTotal) << (HEART_UINT_SIZE * 2);
            v |= uint256(dailyData[src].dayStakeSharesTotal) << HEART_UINT_SIZE;
            v |= uint256(dailyData[src].dayPayoutTotal);

            list[dst++] = v;
        } while (++src < endDay);

        return list;
    }

    /**
     * @dev PUBLIC FACING: External helper to return most global info with a single call.
     * Ugly implementation due to limitations of the standard ABI encoder.
     * @return Fixed array of values
     */
    function globalInfo()
        external
        view
        returns (uint256[13] memory)
    {
        uint256 _claimedBtcAddrCount;
        uint256 _claimedSatoshisTotal;
        uint256 _unclaimedSatoshisTotal;

        (_claimedBtcAddrCount, _claimedSatoshisTotal, _unclaimedSatoshisTotal) = _claimStatsDecode(
            globals.claimStats
        );

        return [
            // 1
            globals.lockedHeartsTotal,
            globals.nextStakeSharesTotal,
            globals.shareRate,
            globals.stakePenaltyTotal,
            // 2
            globals.dailyDataCount,
            globals.stakeSharesTotal,
            globals.latestStakeId,
            _unclaimedSatoshisTotal,
            _claimedSatoshisTotal,
            _claimedBtcAddrCount,
            //
            block.timestamp,
            totalSupply(),
            xfLobby[_currentDay()]
        ];
    }

    /**
     * @dev PUBLIC FACING: ERC20 totalSupply() is the circulating supply and does not include any
     * staked Hearts. allocatedSupply() includes both.
     * @return Allocated Supply in Hearts
     */
    function allocatedSupply()
        external
        view
        returns (uint256)
    {
        return totalSupply() + globals.lockedHeartsTotal;
    }

    /**
     * @dev PUBLIC FACING: External helper for the current day number since launch time
     * @return Current day number (zero-based)
     */
    function currentDay()
        external
        view
        returns (uint256)
    {
        return _currentDay();
    }

    function _currentDay()
        internal
        view
        returns (uint256)
    {
        return (block.timestamp - LAUNCH_TIME) / 1 days;
    }

    function _dailyDataUpdateAuto(GlobalsCache memory g)
        internal
    {
        _dailyDataUpdate(g, g._currentDay, true);
    }

    function _globalsLoad(GlobalsCache memory g, GlobalsCache memory gSnapshot)
        internal
        view
    {
        // 1
        g._lockedHeartsTotal = globals.lockedHeartsTotal;
        g._nextStakeSharesTotal = globals.nextStakeSharesTotal;
        g._shareRate = globals.shareRate;
        g._stakePenaltyTotal = globals.stakePenaltyTotal;
        // 2
        g._dailyDataCount = globals.dailyDataCount;
        g._stakeSharesTotal = globals.stakeSharesTotal;
        g._latestStakeId = globals.latestStakeId;
        (g._claimedBtcAddrCount, g._claimedSatoshisTotal, g._unclaimedSatoshisTotal) = _claimStatsDecode(
            globals.claimStats
        );
        //
        g._currentDay = _currentDay();

        _globalsCacheSnapshot(g, gSnapshot);
    }

    function _globalsCacheSnapshot(GlobalsCache memory g, GlobalsCache memory gSnapshot)
        internal
        pure
    {
        // 1
        gSnapshot._lockedHeartsTotal = g._lockedHeartsTotal;
        gSnapshot._nextStakeSharesTotal = g._nextStakeSharesTotal;
        gSnapshot._shareRate = g._shareRate;
        gSnapshot._stakePenaltyTotal = g._stakePenaltyTotal;
        // 2
        gSnapshot._dailyDataCount = g._dailyDataCount;
        gSnapshot._stakeSharesTotal = g._stakeSharesTotal;
        gSnapshot._latestStakeId = g._latestStakeId;
        gSnapshot._unclaimedSatoshisTotal = g._unclaimedSatoshisTotal;
        gSnapshot._claimedSatoshisTotal = g._claimedSatoshisTotal;
        gSnapshot._claimedBtcAddrCount = g._claimedBtcAddrCount;
    }

    function _globalsSync(GlobalsCache memory g, GlobalsCache memory gSnapshot)
        internal
    {
        if (g._lockedHeartsTotal != gSnapshot._lockedHeartsTotal
            || g._nextStakeSharesTotal != gSnapshot._nextStakeSharesTotal
            || g._shareRate != gSnapshot._shareRate
            || g._stakePenaltyTotal != gSnapshot._stakePenaltyTotal) {
            // 1
            globals.lockedHeartsTotal = uint72(g._lockedHeartsTotal);
            globals.nextStakeSharesTotal = uint72(g._nextStakeSharesTotal);
            globals.shareRate = uint40(g._shareRate);
            globals.stakePenaltyTotal = uint72(g._stakePenaltyTotal);
        }
        if (g._dailyDataCount != gSnapshot._dailyDataCount
            || g._stakeSharesTotal != gSnapshot._stakeSharesTotal
            || g._latestStakeId != gSnapshot._latestStakeId
            || g._unclaimedSatoshisTotal != gSnapshot._unclaimedSatoshisTotal
            || g._claimedSatoshisTotal != gSnapshot._claimedSatoshisTotal
            || g._claimedBtcAddrCount != gSnapshot._claimedBtcAddrCount) {
            // 2
            globals.dailyDataCount = uint16(g._dailyDataCount);
            globals.stakeSharesTotal = uint72(g._stakeSharesTotal);
            globals.latestStakeId = g._latestStakeId;
            globals.claimStats = _claimStatsEncode(
                g._claimedBtcAddrCount,
                g._claimedSatoshisTotal,
                g._unclaimedSatoshisTotal
            );
        }
    }

    function _stakeLoad(StakeStore storage stRef, uint40 stakeIdParam, StakeCache memory st)
        internal
        view
    {
        /* Ensure caller's stakeIndex is still current */
        require(stakeIdParam == stRef.stakeId, "HEX: stakeIdParam not in stake");

        st._stakeId = stRef.stakeId;
        st._stakedHearts = stRef.stakedHearts;
        st._stakeShares = stRef.stakeShares;
        st._lockedDay = stRef.lockedDay;
        st._stakedDays = stRef.stakedDays;
        st._unlockedDay = stRef.unlockedDay;
        st._isAutoStake = stRef.isAutoStake;
    }

    function _stakeUpdate(StakeStore storage stRef, StakeCache memory st)
        internal
    {
        stRef.stakeId = st._stakeId;
        stRef.stakedHearts = uint72(st._stakedHearts);
        stRef.stakeShares = uint72(st._stakeShares);
        stRef.lockedDay = uint16(st._lockedDay);
        stRef.stakedDays = uint16(st._stakedDays);
        stRef.unlockedDay = uint16(st._unlockedDay);
        stRef.isAutoStake = st._isAutoStake;
    }

    function _stakeAdd(
        StakeStore[] storage stakeListRef,
        uint40 newStakeId,
        uint256 newStakedHearts,
        uint256 newStakeShares,
        uint256 newLockedDay,
        uint256 newStakedDays,
        bool newAutoStake
    )
        internal
    {
        stakeListRef.push(
            StakeStore(
                newStakeId,
                uint72(newStakedHearts),
                uint72(newStakeShares),
                uint16(newLockedDay),
                uint16(newStakedDays),
                uint16(0), // unlockedDay
                newAutoStake
            )
        );
    }

    /**
     * @dev Efficiently delete from an unordered array by moving the last element
     * to the "hole" and reducing the array length. Can change the order of the list
     * and invalidate previously held indexes.
     * @notice stakeListRef length and stakeIndex are already ensured valid in stakeEnd()
     * @param stakeListRef Reference to stakeLists[stakerAddr] array in storage
     * @param stakeIndex Index of the element to delete
     */
    function _stakeRemove(StakeStore[] storage stakeListRef, uint256 stakeIndex)
        internal
    {
        uint256 lastIndex = stakeListRef.length - 1;

        /* Skip the copy if element to be removed is already the last element */
        if (stakeIndex != lastIndex) {
            /* Copy last element to the requested element's "hole" */
            stakeListRef[stakeIndex] = stakeListRef[lastIndex];
        }

        /*
            Reduce the array length now that the array is contiguous.
            Surprisingly, 'pop()' uses less gas than 'stakeListRef.length = lastIndex'
        */
        stakeListRef.pop();
    }

    function _claimStatsEncode(
        uint256 _claimedBtcAddrCount,
        uint256 _claimedSatoshisTotal,
        uint256 _unclaimedSatoshisTotal
    )
        internal
        pure
        returns (uint128)
    {
        uint256 v = _claimedBtcAddrCount << (SATOSHI_UINT_SIZE * 2);
        v |= _claimedSatoshisTotal << SATOSHI_UINT_SIZE;
        v |= _unclaimedSatoshisTotal;

        return uint128(v);
    }

    function _claimStatsDecode(uint128 v)
        internal
        pure
        returns (uint256 _claimedBtcAddrCount, uint256 _claimedSatoshisTotal, uint256 _unclaimedSatoshisTotal)
    {
        _claimedBtcAddrCount = v >> (SATOSHI_UINT_SIZE * 2);
        _claimedSatoshisTotal = (v >> SATOSHI_UINT_SIZE) & SATOSHI_UINT_MASK;
        _unclaimedSatoshisTotal = v & SATOSHI_UINT_MASK;

        return (_claimedBtcAddrCount, _claimedSatoshisTotal, _unclaimedSatoshisTotal);
    }

    /**
     * @dev Estimate the stake payout for an incomplete day
     * @param g Cache of stored globals
     * @param stakeSharesParam Param from stake to calculate bonuses for
     * @param day Day to calculate bonuses for
     * @return Payout in Hearts
     */
    function _estimatePayoutRewardsDay(GlobalsCache memory g, uint256 stakeSharesParam, uint256 day)
        internal
        view
        returns (uint256 payout)
    {
        /* Prevent updating state for this estimation */
        GlobalsCache memory gTmp;
        _globalsCacheSnapshot(g, gTmp);

        DailyRoundState memory rs;
        rs._allocSupplyCached = totalSupply() + g._lockedHeartsTotal;

        _dailyRoundCalc(gTmp, rs, day);

        /* Stake is no longer locked so it must be added to total as if it were */
        gTmp._stakeSharesTotal += stakeSharesParam;

        payout = rs._payoutTotal * stakeSharesParam / gTmp._stakeSharesTotal;

        if (day == BIG_PAY_DAY) {
            uint256 bigPaySlice = gTmp._unclaimedSatoshisTotal * HEARTS_PER_SATOSHI * stakeSharesParam
                / gTmp._stakeSharesTotal;
            payout += bigPaySlice + _calcAdoptionBonus(gTmp, bigPaySlice);
        }

        return payout;
    }

    function _calcAdoptionBonus(GlobalsCache memory g, uint256 payout)
        internal
        pure
        returns (uint256)
    {
        /*
            VIRAL REWARDS: Add adoption percentage bonus to payout

            viral = payout * (claimedBtcAddrCount / CLAIMABLE_BTC_ADDR_COUNT)
        */
        uint256 viral = payout * g._claimedBtcAddrCount / CLAIMABLE_BTC_ADDR_COUNT;

        /*
            CRIT MASS REWARDS: Add adoption percentage bonus to payout

            crit  = payout * (claimedSatoshisTotal / CLAIMABLE_SATOSHIS_TOTAL)
        */
        uint256 crit = payout * g._claimedSatoshisTotal / CLAIMABLE_SATOSHIS_TOTAL;

        return viral + crit;
    }

    function _dailyRoundCalc(GlobalsCache memory g, DailyRoundState memory rs, uint256 day)
        private
        pure
    {
        /*
            Calculate payout round

            Inflation of 3.69% inflation per 364 days             (approx 1 year)
            dailyInterestRate   = exp(log(1 + 3.69%)  / 364) - 1
                                = exp(log(1 + 0.0369) / 364) - 1
                                = exp(log(1.0369) / 364) - 1
                                = 0.000099553011616349            (approx)

            payout  = allocSupply * dailyInterestRate
                    = allocSupply / (1 / dailyInterestRate)
                    = allocSupply / (1 / 0.000099553011616349)
                    = allocSupply / 10044.899534066692            (approx)
                    = allocSupply * 10000 / 100448995             (* 10000/10000 for int precision)
        */
        rs._payoutTotal = rs._allocSupplyCached * 10000 / 100448995;

        if (day < CLAIM_PHASE_END_DAY) {
            uint256 bigPaySlice = g._unclaimedSatoshisTotal * HEARTS_PER_SATOSHI / CLAIM_PHASE_DAYS;

            uint256 originBonus = bigPaySlice + _calcAdoptionBonus(g, rs._payoutTotal + bigPaySlice);
            rs._mintOriginBatch += originBonus;
            rs._allocSupplyCached += originBonus;

            rs._payoutTotal += _calcAdoptionBonus(g, rs._payoutTotal);
        }

        if (g._stakePenaltyTotal != 0) {
            rs._payoutTotal += g._stakePenaltyTotal;
            g._stakePenaltyTotal = 0;
        }
    }

    function _dailyRoundCalcAndStore(GlobalsCache memory g, DailyRoundState memory rs, uint256 day)
        private
    {
        _dailyRoundCalc(g, rs, day);

        dailyData[day].dayPayoutTotal = uint72(rs._payoutTotal);
        dailyData[day].dayStakeSharesTotal = uint72(g._stakeSharesTotal);
        dailyData[day].dayUnclaimedSatoshisTotal = uint56(g._unclaimedSatoshisTotal);
    }

    function _dailyDataUpdate(GlobalsCache memory g, uint256 beforeDay, bool isAutoUpdate)
        private
    {
        if (g._dailyDataCount >= beforeDay) {
            /* Already up-to-date */
            return;
        }

        DailyRoundState memory rs;
        rs._allocSupplyCached = totalSupply() + g._lockedHeartsTotal;

        uint256 day = g._dailyDataCount;

        _dailyRoundCalcAndStore(g, rs, day);

        /* Stakes started during this day are added to the total the next day */
        if (g._nextStakeSharesTotal != 0) {
            g._stakeSharesTotal += g._nextStakeSharesTotal;
            g._nextStakeSharesTotal = 0;
        }

        while (++day < beforeDay) {
            _dailyRoundCalcAndStore(g, rs, day);
        }

        _emitDailyDataUpdate(g._dailyDataCount, day, isAutoUpdate);
        g._dailyDataCount = day;

        if (rs._mintOriginBatch != 0) {
            _mint(ORIGIN_ADDR, rs._mintOriginBatch);
        }
    }

    function _emitDailyDataUpdate(uint256 beginDay, uint256 endDay, bool isAutoUpdate)
        private
    {
        emit DailyDataUpdate( // (auto-generated event)
            uint256(uint40(block.timestamp))
                | (uint256(uint16(beginDay)) << 40)
                | (uint256(uint16(endDay)) << 56)
                | (isAutoUpdate ? (1 << 72) : 0),
            msg.sender
        );
    }
}

contract StakeableToken is GlobalsAndUtility {
    /**
     * @dev PUBLIC FACING: Open a stake.
     * @param newStakedHearts Number of Hearts to stake
     * @param newStakedDays Number of days to stake
     */
    function stakeStart(uint256 newStakedHearts, uint256 newStakedDays)
        external
    {
        GlobalsCache memory g;
        GlobalsCache memory gSnapshot;
        _globalsLoad(g, gSnapshot);

        /* Enforce the minimum stake time */
        require(newStakedDays >= MIN_STAKE_DAYS, "HEX: newStakedDays lower than minimum");

        /* Check if log data needs to be updated */
        _dailyDataUpdateAuto(g);

        _stakeStart(g, newStakedHearts, newStakedDays, false);

        /* Remove staked Hearts from balance of staker */
        _burn(msg.sender, newStakedHearts);

        _globalsSync(g, gSnapshot);
    }

    /**
     * @dev PUBLIC FACING: Unlocks a completed stake, distributing the proceeds of any penalty
     * immediately. The staker must still call stakeEnd() to retrieve their stake return (if any).
     * @param stakerAddr Address of staker
     * @param stakeIndex Index of stake within stake list
     * @param stakeIdParam The stake's id
     */
    function stakeGoodAccounting(address stakerAddr, uint256 stakeIndex, uint40 stakeIdParam)
        external
    {
        GlobalsCache memory g;
        GlobalsCache memory gSnapshot;
        _globalsLoad(g, gSnapshot);

        /* require() is more informative than the default assert() */
        require(stakeLists[stakerAddr].length != 0, "HEX: Empty stake list");
        require(stakeIndex < stakeLists[stakerAddr].length, "HEX: stakeIndex invalid");

        StakeStore storage stRef = stakeLists[stakerAddr][stakeIndex];

        /* Get stake copy */
        StakeCache memory st;
        _stakeLoad(stRef, stakeIdParam, st);

        /* Stake must have served full term */
        require(g._currentDay >= st._lockedDay + st._stakedDays, "HEX: Stake not fully served");

        /* Stake must still be locked */
        require(st._unlockedDay == 0, "HEX: Stake already unlocked");

        /* Check if log data needs to be updated */
        _dailyDataUpdateAuto(g);

        /* Unlock the completed stake */
        _stakeUnlock(g, st);

        /* stakeReturn value is unused here */
        (, uint256 payout, uint256 penalty, uint256 cappedPenalty) = _stakePerformance(
            g,
            st,
            st._stakedDays
        );

        _emitStakeGoodAccounting(
            stakerAddr,
            stakeIdParam,
            st._stakedHearts,
            st._stakeShares,
            payout,
            penalty
        );

        if (cappedPenalty != 0) {
            _splitPenaltyProceeds(g, cappedPenalty);
        }

        /* st._unlockedDay has changed */
        _stakeUpdate(stRef, st);

        _globalsSync(g, gSnapshot);
    }

    /**
     * @dev PUBLIC FACING: Closes a stake. The order of the stake list can change so
     * a stake id is used to reject stale indexes.
     * @param stakeIndex Index of stake within stake list
     * @param stakeIdParam The stake's id
     */
    function stakeEnd(uint256 stakeIndex, uint40 stakeIdParam)
        external
    {
        GlobalsCache memory g;
        GlobalsCache memory gSnapshot;
        _globalsLoad(g, gSnapshot);

        StakeStore[] storage stakeListRef = stakeLists[msg.sender];

        /* require() is more informative than the default assert() */
        require(stakeListRef.length != 0, "HEX: Empty stake list");
        require(stakeIndex < stakeListRef.length, "HEX: stakeIndex invalid");

        /* Get stake copy */
        StakeCache memory st;
        _stakeLoad(stakeListRef[stakeIndex], stakeIdParam, st);

        /* Check if log data needs to be updated */
        _dailyDataUpdateAuto(g);

        uint256 servedDays = 0;

        bool prevUnlocked = (st._unlockedDay != 0);
        uint256 stakeReturn;
        uint256 payout = 0;
        uint256 penalty = 0;
        uint256 cappedPenalty = 0;

        if (g._currentDay >= st._lockedDay) {
            if (prevUnlocked) {
                /* Previously unlocked in stakeGoodAccounting(), so must have served full term */
                servedDays = st._stakedDays;
            } else {
                _stakeUnlock(g, st);

                servedDays = g._currentDay - st._lockedDay;
                if (servedDays > st._stakedDays) {
                    servedDays = st._stakedDays;
                } else {
                    /* Deny early-unstake before an auto-stake minimum has been served */
                    if (servedDays < MIN_AUTO_STAKE_DAYS) {
                        require(!st._isAutoStake, "HEX: Auto-stake still locked");
                    }
                }
            }

            (stakeReturn, payout, penalty, cappedPenalty) = _stakePerformance(g, st, servedDays);
        } else {
            /* Deny early-unstake before an auto-stake minimum has been served */
            require(!st._isAutoStake, "HEX: Auto-stake still locked");

            /* Stake hasn't been added to the total yet, so no penalties or rewards apply */
            g._nextStakeSharesTotal -= st._stakeShares;

            stakeReturn = st._stakedHearts;
        }

        _emitStakeEnd(
            stakeIdParam,
            st._stakedHearts,
            st._stakeShares,
            payout,
            penalty,
            servedDays,
            prevUnlocked
        );

        if (cappedPenalty != 0 && !prevUnlocked) {
            /* Split penalty proceeds only if not previously unlocked by stakeGoodAccounting() */
            _splitPenaltyProceeds(g, cappedPenalty);
        }

        /* Pay the stake return, if any, to the staker */
        if (stakeReturn != 0) {
            _mint(msg.sender, stakeReturn);

            /* Update the share rate if necessary */
            _shareRateUpdate(g, st, stakeReturn);
        }
        g._lockedHeartsTotal -= st._stakedHearts;

        _stakeRemove(stakeListRef, stakeIndex);

        _globalsSync(g, gSnapshot);
    }

    /**
     * @dev PUBLIC FACING: Return the current stake count for a staker address
     * @param stakerAddr Address of staker
     */
    function stakeCount(address stakerAddr)
        external
        view
        returns (uint256)
    {
        return stakeLists[stakerAddr].length;
    }

    /**
     * @dev Open a stake.
     * @param g Cache of stored globals
     * @param newStakedHearts Number of Hearts to stake
     * @param newStakedDays Number of days to stake
     * @param newAutoStake Stake is automatic directly from a new claim
     */
    function _stakeStart(
        GlobalsCache memory g,
        uint256 newStakedHearts,
        uint256 newStakedDays,
        bool newAutoStake
    )
        internal
    {
        /* Enforce the maximum stake time */
        require(newStakedDays <= MAX_STAKE_DAYS, "HEX: newStakedDays higher than maximum");

        uint256 bonusHearts = _stakeStartBonusHearts(newStakedHearts, newStakedDays);
        uint256 newStakeShares = (newStakedHearts + bonusHearts) * SHARE_RATE_SCALE / g._shareRate;

        /* Ensure newStakedHearts is enough for at least one stake share */
        require(newStakeShares != 0, "HEX: newStakedHearts must be at least minimum shareRate");

        /*
            The stakeStart timestamp will always be part-way through the current
            day, so it needs to be rounded-up to the next day to ensure all
            stakes align with the same fixed calendar days. The current day is
            already rounded-down, so rounded-up is current day + 1.
        */
        uint256 newLockedDay = g._currentDay < CLAIM_PHASE_START_DAY
            ? CLAIM_PHASE_START_DAY + 1
            : g._currentDay + 1;

        /* Create Stake */
        uint40 newStakeId = ++g._latestStakeId;
        _stakeAdd(
            stakeLists[msg.sender],
            newStakeId,
            newStakedHearts,
            newStakeShares,
            newLockedDay,
            newStakedDays,
            newAutoStake
        );

        _emitStakeStart(newStakeId, newStakedHearts, newStakeShares, newStakedDays, newAutoStake);

        /* Stake is added to total in the next round, not the current round */
        g._nextStakeSharesTotal += newStakeShares;

        /* Track total staked Hearts for inflation calculations */
        g._lockedHeartsTotal += newStakedHearts;
    }

    /**
     * @dev Calculates total stake payout including rewards for a multi-day range
     * @param g Cache of stored globals
     * @param stakeSharesParam Param from stake to calculate bonuses for
     * @param beginDay First day to calculate bonuses for
     * @param endDay Last day (non-inclusive) of range to calculate bonuses for
     * @return Payout in Hearts
     */
    function _calcPayoutRewards(
        GlobalsCache memory g,
        uint256 stakeSharesParam,
        uint256 beginDay,
        uint256 endDay
    )
        private
        view
        returns (uint256 payout)
    {
        for (uint256 day = beginDay; day < endDay; day++) {
            payout += dailyData[day].dayPayoutTotal * stakeSharesParam
                / dailyData[day].dayStakeSharesTotal;
        }

        /* Less expensive to re-read storage than to have the condition inside the loop */
        if (beginDay <= BIG_PAY_DAY && endDay > BIG_PAY_DAY) {
            uint256 bigPaySlice = g._unclaimedSatoshisTotal * HEARTS_PER_SATOSHI * stakeSharesParam
                / dailyData[BIG_PAY_DAY].dayStakeSharesTotal;

            payout += bigPaySlice + _calcAdoptionBonus(g, bigPaySlice);
        }
        return payout;
    }

    /**
     * @dev Calculate bonus Hearts for a new stake, if any
     * @param newStakedHearts Number of Hearts to stake
     * @param newStakedDays Number of days to stake
     */
    function _stakeStartBonusHearts(uint256 newStakedHearts, uint256 newStakedDays)
        private
        pure
        returns (uint256 bonusHearts)
    {
        /*
            LONGER PAYS BETTER:

            If longer than 1 day stake is committed to, each extra day
            gives bonus shares of approximately 0.0548%, which is approximately 20%
            extra per year of increased stake length committed to, but capped to a
            maximum of 200% extra.

            extraDays       =  stakedDays - 1

            longerBonus%    = (extraDays / 364) * 20%
                            = (extraDays / 364) / 5
                            =  extraDays / 1820
                            =  extraDays / LPB

            extraDays       =  longerBonus% * 1820
            extraDaysMax    =  longerBonusMax% * 1820
                            =  200% * 1820
                            =  3640
                            =  LPB_MAX_DAYS

            BIGGER PAYS BETTER:

            Bonus percentage scaled 0% to 10% for the first 150M HEX of stake.

            biggerBonus%    = (cappedHearts /  BPB_MAX_HEARTS) * 10%
                            = (cappedHearts /  BPB_MAX_HEARTS) / 10
                            =  cappedHearts / (BPB_MAX_HEARTS * 10)
                            =  cappedHearts /  BPB

            COMBINED:

            combinedBonus%  =            longerBonus%  +  biggerBonus%

                                      cappedExtraDays     cappedHearts
                            =         ---------------  +  ------------
                                            LPB               BPB

                                cappedExtraDays * BPB     cappedHearts * LPB
                            =   ---------------------  +  ------------------
                                      LPB * BPB               LPB * BPB

                                cappedExtraDays * BPB  +  cappedHearts * LPB
                            =   --------------------------------------------
                                                  LPB  *  BPB

            bonusHearts     = hearts * combinedBonus%
                            = hearts * (cappedExtraDays * BPB  +  cappedHearts * LPB) / (LPB * BPB)
        */
        uint256 cappedExtraDays = 0;

        /* Must be more than 1 day for Longer-Pays-Better */
        if (newStakedDays > 1) {
            cappedExtraDays = newStakedDays <= LPB_MAX_DAYS ? newStakedDays - 1 : LPB_MAX_DAYS;
        }

        uint256 cappedStakedHearts = newStakedHearts <= BPB_MAX_HEARTS
            ? newStakedHearts
            : BPB_MAX_HEARTS;

        bonusHearts = cappedExtraDays * BPB + cappedStakedHearts * LPB;
        bonusHearts = newStakedHearts * bonusHearts / (LPB * BPB);

        return bonusHearts;
    }

    function _stakeUnlock(GlobalsCache memory g, StakeCache memory st)
        private
        pure
    {
        g._stakeSharesTotal -= st._stakeShares;
        st._unlockedDay = g._currentDay;
    }

    function _stakePerformance(GlobalsCache memory g, StakeCache memory st, uint256 servedDays)
        private
        view
        returns (uint256 stakeReturn, uint256 payout, uint256 penalty, uint256 cappedPenalty)
    {
        if (servedDays < st._stakedDays) {
            (payout, penalty) = _calcPayoutAndEarlyPenalty(
                g,
                st._lockedDay,
                st._stakedDays,
                servedDays,
                st._stakeShares
            );
            stakeReturn = st._stakedHearts + payout;
        } else {
            // servedDays must == stakedDays here
            payout = _calcPayoutRewards(
                g,
                st._stakeShares,
                st._lockedDay,
                st._lockedDay + servedDays
            );
            stakeReturn = st._stakedHearts + payout;

            penalty = _calcLatePenalty(st._lockedDay, st._stakedDays, st._unlockedDay, stakeReturn);
        }
        if (penalty != 0) {
            if (penalty > stakeReturn) {
                /* Cannot have a negative stake return */
                cappedPenalty = stakeReturn;
                stakeReturn = 0;
            } else {
                /* Remove penalty from the stake return */
                cappedPenalty = penalty;
                stakeReturn -= cappedPenalty;
            }
        }
        return (stakeReturn, payout, penalty, cappedPenalty);
    }

    function _calcPayoutAndEarlyPenalty(
        GlobalsCache memory g,
        uint256 lockedDayParam,
        uint256 stakedDaysParam,
        uint256 servedDays,
        uint256 stakeSharesParam
    )
        private
        view
        returns (uint256 payout, uint256 penalty)
    {
        uint256 servedEndDay = lockedDayParam + servedDays;

        /* 50% of stakedDays (rounded up) with a minimum applied */
        uint256 penaltyDays = (stakedDaysParam + 1) / 2;
        if (penaltyDays < EARLY_PENALTY_MIN_DAYS) {
            penaltyDays = EARLY_PENALTY_MIN_DAYS;
        }

        if (servedDays == 0) {
            /* Fill penalty days with the estimated average payout */
            uint256 expected = _estimatePayoutRewardsDay(g, stakeSharesParam, lockedDayParam);
            penalty = expected * penaltyDays;
            return (payout, penalty); // Actual payout was 0
        }

        if (penaltyDays < servedDays) {
            /*
                Simplified explanation of intervals where end-day is non-inclusive:

                penalty:    [lockedDay  ...  penaltyEndDay)
                delta:                      [penaltyEndDay  ...  servedEndDay)
                payout:     [lockedDay  .......................  servedEndDay)
            */
            uint256 penaltyEndDay = lockedDayParam + penaltyDays;
            penalty = _calcPayoutRewards(g, stakeSharesParam, lockedDayParam, penaltyEndDay);

            uint256 delta = _calcPayoutRewards(g, stakeSharesParam, penaltyEndDay, servedEndDay);
            payout = penalty + delta;
            return (payout, penalty);
        }

        /* penaltyDays >= servedDays  */
        payout = _calcPayoutRewards(g, stakeSharesParam, lockedDayParam, servedEndDay);

        if (penaltyDays == servedDays) {
            penalty = payout;
        } else {
            /*
                (penaltyDays > servedDays) means not enough days served, so fill the
                penalty days with the average payout from only the days that were served.
            */
            penalty = payout * penaltyDays / servedDays;
        }
        return (payout, penalty);
    }

    function _calcLatePenalty(
        uint256 lockedDayParam,
        uint256 stakedDaysParam,
        uint256 unlockedDayParam,
        uint256 rawStakeReturn
    )
        private
        pure
        returns (uint256)
    {
        /* Allow grace time before penalties accrue */
        uint256 maxUnlockedDay = lockedDayParam + stakedDaysParam + LATE_PENALTY_GRACE_DAYS;
        if (unlockedDayParam <= maxUnlockedDay) {
            return 0;
        }

        /* Calculate penalty as a percentage of stake return based on time */
        return rawStakeReturn * (unlockedDayParam - maxUnlockedDay) / LATE_PENALTY_SCALE_DAYS;
    }

    function _splitPenaltyProceeds(GlobalsCache memory g, uint256 penalty)
        private
    {
        /* Split a penalty 50:50 between Origin and stakePenaltyTotal */
        uint256 splitPenalty = penalty / 2;

        if (splitPenalty != 0) {
            _mint(ORIGIN_ADDR, splitPenalty);
        }

        /* Use the other half of the penalty to account for an odd-numbered penalty */
        splitPenalty = penalty - splitPenalty;
        g._stakePenaltyTotal += splitPenalty;
    }

    function _shareRateUpdate(GlobalsCache memory g, StakeCache memory st, uint256 stakeReturn)
        private
    {
        if (stakeReturn > st._stakedHearts) {
            /*
                Calculate the new shareRate that would yield the same number of shares if
                the user re-staked this stakeReturn, factoring in any bonuses they would
                receive in stakeStart().
            */
            uint256 bonusHearts = _stakeStartBonusHearts(stakeReturn, st._stakedDays);
            uint256 newShareRate = (stakeReturn + bonusHearts) * SHARE_RATE_SCALE / st._stakeShares;

            if (newShareRate > SHARE_RATE_MAX) {
                /*
                    Realistically this can't happen, but there are contrived theoretical
                    scenarios that can lead to extreme values of newShareRate, so it is
                    capped to prevent them anyway.
                */
                newShareRate = SHARE_RATE_MAX;
            }

            if (newShareRate > g._shareRate) {
                g._shareRate = newShareRate;

                _emitShareRateChange(newShareRate, st._stakeId);
            }
        }
    }

    function _emitStakeStart(
        uint40 stakeId,
        uint256 stakedHearts,
        uint256 stakeShares,
        uint256 stakedDays,
        bool isAutoStake
    )
        private
    {
        emit StakeStart( // (auto-generated event)
            uint256(uint40(block.timestamp))
                | (uint256(uint72(stakedHearts)) << 40)
                | (uint256(uint72(stakeShares)) << 112)
                | (uint256(uint16(stakedDays)) << 184)
                | (isAutoStake ? (1 << 200) : 0),
            msg.sender,
            stakeId
        );
    }

    function _emitStakeGoodAccounting(
        address stakerAddr,
        uint40 stakeId,
        uint256 stakedHearts,
        uint256 stakeShares,
        uint256 payout,
        uint256 penalty
    )
        private
    {
        emit StakeGoodAccounting( // (auto-generated event)
            uint256(uint40(block.timestamp))
                | (uint256(uint72(stakedHearts)) << 40)
                | (uint256(uint72(stakeShares)) << 112)
                | (uint256(uint72(payout)) << 184),
            uint256(uint72(penalty)),
            stakerAddr,
            stakeId,
            msg.sender
        );
    }

    function _emitStakeEnd(
        uint40 stakeId,
        uint256 stakedHearts,
        uint256 stakeShares,
        uint256 payout,
        uint256 penalty,
        uint256 servedDays,
        bool prevUnlocked
    )
        private
    {
        emit StakeEnd( // (auto-generated event)
            uint256(uint40(block.timestamp))
                | (uint256(uint72(stakedHearts)) << 40)
                | (uint256(uint72(stakeShares)) << 112)
                | (uint256(uint72(payout)) << 184),
            uint256(uint72(penalty))
                | (uint256(uint16(servedDays)) << 72)
                | (prevUnlocked ? (1 << 88) : 0),
            msg.sender,
            stakeId
        );
    }

    function _emitShareRateChange(uint256 shareRate, uint40 stakeId)
        private
    {
        emit ShareRateChange( // (auto-generated event)
            uint256(uint40(block.timestamp))
                | (uint256(uint40(shareRate)) << 40),
            stakeId
        );
    }
}

/**
 * @dev These functions deal with verification of Merkle trees (hash trees),
 */
library MerkleProof {
    /**
     * @dev Returns true if a `leaf` can be proved to be a part of a Merkle tree
     * defined by `root`. For this, a `proof` must be provided, containing
     * sibling hashes on the branch from the leaf to the root of the tree. Each
     * pair of leaves and each pair of pre-images are assumed to be sorted.
     */
    function verify(bytes32[] memory proof, bytes32 root, bytes32 leaf) internal pure returns (bool) {
        bytes32 computedHash = leaf;

        for (uint256 i = 0; i < proof.length; i++) {
            bytes32 proofElement = proof[i];

            if (computedHash < proofElement) {
                // Hash(current computed hash + current element of the proof)
                computedHash = keccak256(abi.encodePacked(computedHash, proofElement));
            } else {
                // Hash(current element of the proof + current computed hash)
                computedHash = keccak256(abi.encodePacked(proofElement, computedHash));
            }
        }

        // Check if the computed hash (root) is equal to the provided root
        return computedHash == root;
    }
}

contract UTXOClaimValidation is StakeableToken {
    /**
     * @dev PUBLIC FACING: Verify a BTC address and balance are unclaimed and part of the Merkle tree
     * @param btcAddr Bitcoin address (binary; no base58-check encoding)
     * @param rawSatoshis Raw BTC address balance in Satoshis
     * @param proof Merkle tree proof
     * @return True if can be claimed
     */
    function btcAddressIsClaimable(bytes20 btcAddr, uint256 rawSatoshis, bytes32[] calldata proof)
        external
        view
        returns (bool)
    {
        uint256 day = _currentDay();

        require(day >= CLAIM_PHASE_START_DAY, "HEX: Claim phase has not yet started");
        require(day < CLAIM_PHASE_END_DAY, "HEX: Claim phase has ended");

        /* Don't need to check Merkle proof if UTXO BTC address has already been claimed    */
        if (btcAddressClaims[btcAddr]) {
            return false;
        }

        /* Verify the Merkle tree proof */
        return _btcAddressIsValid(btcAddr, rawSatoshis, proof);
    }

    /**
     * @dev PUBLIC FACING: Verify a BTC address and balance are part of the Merkle tree
     * @param btcAddr Bitcoin address (binary; no base58-check encoding)
     * @param rawSatoshis Raw BTC address balance in Satoshis
     * @param proof Merkle tree proof
     * @return True if valid
     */
    function btcAddressIsValid(bytes20 btcAddr, uint256 rawSatoshis, bytes32[] calldata proof)
        external
        pure
        returns (bool)
    {
        return _btcAddressIsValid(btcAddr, rawSatoshis, proof);
    }

    /**
     * @dev PUBLIC FACING: Verify a Merkle proof using the UTXO Merkle tree
     * @param merkleLeaf Leaf asserted to be present in the Merkle tree
     * @param proof Generated Merkle tree proof
     * @return True if valid
     */
    function merkleProofIsValid(bytes32 merkleLeaf, bytes32[] calldata proof)
        external
        pure
        returns (bool)
    {
        return _merkleProofIsValid(merkleLeaf, proof);
    }

    /**
     * @dev PUBLIC FACING: Verify that a Bitcoin signature matches the claim message containing
     * the Ethereum address and claim param hash
     * @param claimToAddr Eth address within the signed claim message
     * @param claimParamHash Param hash within the signed claim message
     * @param pubKeyX First  half of uncompressed ECDSA public key
     * @param pubKeyY Second half of uncompressed ECDSA public key
     * @param claimFlags Claim flags specifying address and message formats
     * @param v v parameter of ECDSA signature
     * @param r r parameter of ECDSA signature
     * @param s s parameter of ECDSA signature
     * @return True if matching
     */
    function claimMessageMatchesSignature(
        address claimToAddr,
        bytes32 claimParamHash,
        bytes32 pubKeyX,
        bytes32 pubKeyY,
        uint8 claimFlags,
        uint8 v,
        bytes32 r,
        bytes32 s
    )
        public
        pure
        returns (bool)
    {
        require(v >= 27 && v <= 30, "HEX: v invalid");

        /*
            ecrecover() returns an Eth address rather than a public key, so
            we must do the same to compare.
        */
        address pubKeyEthAddr = pubKeyToEthAddress(pubKeyX, pubKeyY);

        /* Create and hash the claim message text */
        bytes32 messageHash = _hash256(
            _claimMessageCreate(claimToAddr, claimParamHash, claimFlags)
        );

        /* Verify the public key */
        return ecrecover(messageHash, v, r, s) == pubKeyEthAddr;
    }

    /**
     * @dev PUBLIC FACING: Derive an Ethereum address from an ECDSA public key
     * @param pubKeyX First  half of uncompressed ECDSA public key
     * @param pubKeyY Second half of uncompressed ECDSA public key
     * @return Derived Eth address
     */
    function pubKeyToEthAddress(bytes32 pubKeyX, bytes32 pubKeyY)
        public
        pure
        returns (address)
    {
        return address(uint160(uint256(keccak256(abi.encodePacked(pubKeyX, pubKeyY)))));
    }

    /**
     * @dev PUBLIC FACING: Derive a Bitcoin address from an ECDSA public key
     * @param pubKeyX First  half of uncompressed ECDSA public key
     * @param pubKeyY Second half of uncompressed ECDSA public key
     * @param claimFlags Claim flags specifying address and message formats
     * @return Derived Bitcoin address (binary; no base58-check encoding)
     */
    function pubKeyToBtcAddress(bytes32 pubKeyX, bytes32 pubKeyY, uint8 claimFlags)
        public
        pure
        returns (bytes20)
    {
        /*
            Helpful references:
             - https://en.bitcoin.it/wiki/Technical_background_of_version_1_Bitcoin_addresses
             - https://github.com/cryptocoinjs/ecurve/blob/master/lib/point.js
        */
        uint8 startingByte;
        bytes memory pubKey;
        bool compressed = (claimFlags & CLAIM_FLAG_BTC_ADDR_COMPRESSED) != 0;
        bool nested = (claimFlags & CLAIM_FLAG_BTC_ADDR_P2WPKH_IN_P2SH) != 0;
        bool bech32 = (claimFlags & CLAIM_FLAG_BTC_ADDR_BECH32) != 0;

        if (compressed) {
            /* Compressed public key format */
            require(!(nested && bech32), "HEX: claimFlags invalid");

            startingByte = (pubKeyY[31] & 0x01) == 0 ? 0x02 : 0x03;
            pubKey = abi.encodePacked(startingByte, pubKeyX);
        } else {
            /* Uncompressed public key format */
            require(!nested && !bech32, "HEX: claimFlags invalid");

            startingByte = 0x04;
            pubKey = abi.encodePacked(startingByte, pubKeyX, pubKeyY);
        }

        bytes20 pubKeyHash = _hash160(pubKey);
        if (nested) {
            return _hash160(abi.encodePacked(hex"0014", pubKeyHash));
        }
        return pubKeyHash;
    }

    /**
     * @dev Verify a BTC address and balance are part of the Merkle tree
     * @param btcAddr Bitcoin address (binary; no base58-check encoding)
     * @param rawSatoshis Raw BTC address balance in Satoshis
     * @param proof Merkle tree proof
     * @return True if valid
     */
    function _btcAddressIsValid(bytes20 btcAddr, uint256 rawSatoshis, bytes32[] memory proof)
        internal
        pure
        returns (bool)
    {
        /*
            Ensure the proof does not attempt to treat a Merkle leaf as if it were an
            internal Merkle tree node. A leaf will always have the zero-fill. An
            internal node will never have the zero-fill, as guaranteed by HEX's Merkle
            tree construction.

            The first element, proof[0], will always be a leaf because it is the pair
            of the leaf being validated. The rest of the elements, proof[1..length-1],
            must be internal nodes.

            The number of leaves (CLAIMABLE_BTC_ADDR_COUNT) is even, as guaranteed by
            HEX's Merkle tree construction, which eliminates the only edge-case where
            this validation would not apply.
        */
        require((uint256(proof[0]) & MERKLE_LEAF_FILL_MASK) == 0, "HEX: proof invalid");
        for (uint256 i = 1; i < proof.length; i++) {
            require((uint256(proof[i]) & MERKLE_LEAF_FILL_MASK) != 0, "HEX: proof invalid");
        }

        /*
            Calculate the 32 byte Merkle leaf associated with this BTC address and balance
                160 bits: BTC address
                 52 bits: Zero-fill
                 45 bits: Satoshis (limited by MAX_BTC_ADDR_BALANCE_SATOSHIS)
        */
        bytes32 merkleLeaf = bytes32(btcAddr) | bytes32(rawSatoshis);

        /* Verify the Merkle tree proof */
        return _merkleProofIsValid(merkleLeaf, proof);
    }

    /**
     * @dev Verify a Merkle proof using the UTXO Merkle tree
     * @param merkleLeaf Leaf asserted to be present in the Merkle tree
     * @param proof Generated Merkle tree proof
     * @return True if valid
     */
    function _merkleProofIsValid(bytes32 merkleLeaf, bytes32[] memory proof)
        private
        pure
        returns (bool)
    {
        return MerkleProof.verify(proof, MERKLE_TREE_ROOT, merkleLeaf);
    }

    function _claimMessageCreate(address claimToAddr, bytes32 claimParamHash, uint8 claimFlags)
        private
        pure
        returns (bytes memory)
    {
        bytes memory prefixStr = (claimFlags & CLAIM_FLAG_MSG_PREFIX_OLD) != 0
            ? OLD_CLAIM_PREFIX_STR
            : STD_CLAIM_PREFIX_STR;

        bool includeAddrChecksum = (claimFlags & CLAIM_FLAG_ETH_ADDR_LOWERCASE) == 0;

        bytes memory addrStr = _addressStringCreate(claimToAddr, includeAddrChecksum);

        if (claimParamHash == 0) {
            return abi.encodePacked(
                BITCOIN_SIG_PREFIX_LEN,
                BITCOIN_SIG_PREFIX_STR,
                uint8(prefixStr.length) + ETH_ADDRESS_HEX_LEN,
                prefixStr,
                addrStr
            );
        }

        bytes memory claimParamHashStr = new bytes(CLAIM_PARAM_HASH_HEX_LEN);

        _hexStringFromData(claimParamHashStr, claimParamHash, CLAIM_PARAM_HASH_BYTE_LEN);

        return abi.encodePacked(
            BITCOIN_SIG_PREFIX_LEN,
            BITCOIN_SIG_PREFIX_STR,
            uint8(prefixStr.length) + ETH_ADDRESS_HEX_LEN + 1 + CLAIM_PARAM_HASH_HEX_LEN,
            prefixStr,
            addrStr,
            "_",
            claimParamHashStr
        );
    }

    function _addressStringCreate(address addr, bool includeAddrChecksum)
        private
        pure
        returns (bytes memory addrStr)
    {
        addrStr = new bytes(ETH_ADDRESS_HEX_LEN);
        _hexStringFromData(addrStr, bytes32(bytes20(addr)), ETH_ADDRESS_BYTE_LEN);

        if (includeAddrChecksum) {
            bytes32 addrStrHash = keccak256(addrStr);

            uint256 offset = 0;

            for (uint256 i = 0; i < ETH_ADDRESS_BYTE_LEN; i++) {
                uint8 b = uint8(addrStrHash[i]);

                _addressStringChecksumChar(addrStr, offset++, b >> 4);
                _addressStringChecksumChar(addrStr, offset++, b & 0x0f);
            }
        }

        return addrStr;
    }

    function _addressStringChecksumChar(bytes memory addrStr, uint256 offset, uint8 hashNybble)
        private
        pure
    {
        bytes1 ch = addrStr[offset];

        if (ch >= "a" && hashNybble >= 8) {
            addrStr[offset] = ch ^ 0x20;
        }
    }

    function _hexStringFromData(bytes memory hexStr, bytes32 data, uint256 dataLen)
        private
        pure
    {
        uint256 offset = 0;

        for (uint256 i = 0; i < dataLen; i++) {
            uint8 b = uint8(data[i]);

            hexStr[offset++] = HEX_DIGITS[b >> 4];
            hexStr[offset++] = HEX_DIGITS[b & 0x0f];
        }
    }

    /**
     * @dev sha256(sha256(data))
     * @param data Data to be hashed
     * @return 32-byte hash
     */
    function _hash256(bytes memory data)
        private
        pure
        returns (bytes32)
    {
        return sha256(abi.encodePacked(sha256(data)));
    }

    /**
     * @dev ripemd160(sha256(data))
     * @param data Data to be hashed
     * @return 20-byte hash
     */
    function _hash160(bytes memory data)
        private
        pure
        returns (bytes20)
    {
        return ripemd160(abi.encodePacked(sha256(data)));
    }
}

contract UTXORedeemableToken is UTXOClaimValidation {
    /**
     * @dev PUBLIC FACING: Claim a BTC address and its Satoshi balance in Hearts
     * crediting the appropriate amount to a specified Eth address. Bitcoin ECDSA
     * signature must be from that BTC address and must match the claim message
     * for the Eth address.
     * @param rawSatoshis Raw BTC address balance in Satoshis
     * @param proof Merkle tree proof
     * @param claimToAddr Destination Eth address to credit Hearts to
     * @param pubKeyX First  half of uncompressed ECDSA public key for the BTC address
     * @param pubKeyY Second half of uncompressed ECDSA public key for the BTC address
     * @param claimFlags Claim flags specifying address and message formats
     * @param v v parameter of ECDSA signature
     * @param r r parameter of ECDSA signature
     * @param s s parameter of ECDSA signature
     * @param autoStakeDays Number of days to auto-stake, subject to minimum auto-stake days
     * @param referrerAddr Eth address of referring user (optional; 0x0 for no referrer)
     * @return Total number of Hearts credited, if successful
     */
    function btcAddressClaim(
        uint256 rawSatoshis,
        bytes32[] calldata proof,
        address claimToAddr,
        bytes32 pubKeyX,
        bytes32 pubKeyY,
        uint8 claimFlags,
        uint8 v,
        bytes32 r,
        bytes32 s,
        uint256 autoStakeDays,
        address referrerAddr
    )
        external
        returns (uint256)
    {
        /* Sanity check */
        require(rawSatoshis <= MAX_BTC_ADDR_BALANCE_SATOSHIS, "HEX: CHK: rawSatoshis");

        /* Enforce the minimum stake time for the auto-stake from this claim */
        require(autoStakeDays >= MIN_AUTO_STAKE_DAYS, "HEX: autoStakeDays lower than minimum");

        /* Ensure signature matches the claim message containing the Eth address and claimParamHash */
        {
            bytes32 claimParamHash = 0;

            if (claimToAddr != msg.sender) {
                /* Claimer did not send this, so claim params must be signed */
                claimParamHash = keccak256(
                    abi.encodePacked(MERKLE_TREE_ROOT, autoStakeDays, referrerAddr)
                );
            }

            require(
                claimMessageMatchesSignature(
                    claimToAddr,
                    claimParamHash,
                    pubKeyX,
                    pubKeyY,
                    claimFlags,
                    v,
                    r,
                    s
                ),
                "HEX: Signature mismatch"
            );
        }

        /* Derive BTC address from public key */
        bytes20 btcAddr = pubKeyToBtcAddress(pubKeyX, pubKeyY, claimFlags);

        /* Ensure BTC address has not yet been claimed */
        require(!btcAddressClaims[btcAddr], "HEX: BTC address balance already claimed");

        /* Ensure BTC address is part of the Merkle tree */
        require(
            _btcAddressIsValid(btcAddr, rawSatoshis, proof),
            "HEX: BTC address or balance unknown"
        );

        /* Mark BTC address as claimed */
        btcAddressClaims[btcAddr] = true;

        return _satoshisClaimSync(
            rawSatoshis,
            claimToAddr,
            btcAddr,
            claimFlags,
            autoStakeDays,
            referrerAddr
        );
    }

    function _satoshisClaimSync(
        uint256 rawSatoshis,
        address claimToAddr,
        bytes20 btcAddr,
        uint8 claimFlags,
        uint256 autoStakeDays,
        address referrerAddr
    )
        private
        returns (uint256 totalClaimedHearts)
    {
        GlobalsCache memory g;
        GlobalsCache memory gSnapshot;
        _globalsLoad(g, gSnapshot);

        totalClaimedHearts = _satoshisClaim(
            g,
            rawSatoshis,
            claimToAddr,
            btcAddr,
            claimFlags,
            autoStakeDays,
            referrerAddr
        );

        _globalsSync(g, gSnapshot);

        return totalClaimedHearts;
    }

    /**
     * @dev Credit an Eth address with the Hearts value of a raw Satoshis balance
     * @param g Cache of stored globals
     * @param rawSatoshis Raw BTC address balance in Satoshis
     * @param claimToAddr Destination Eth address for the claimed Hearts to be sent
     * @param btcAddr Bitcoin address (binary; no base58-check encoding)
     * @param autoStakeDays Number of days to auto-stake, subject to minimum auto-stake days
     * @param referrerAddr Eth address of referring user (optional; 0x0 for no referrer)
     * @return Total number of Hearts credited, if successful
     */
    function _satoshisClaim(
        GlobalsCache memory g,
        uint256 rawSatoshis,
        address claimToAddr,
        bytes20 btcAddr,
        uint8 claimFlags,
        uint256 autoStakeDays,
        address referrerAddr
    )
        private
        returns (uint256 totalClaimedHearts)
    {
        /* Allowed only during the claim phase */
        require(g._currentDay >= CLAIM_PHASE_START_DAY, "HEX: Claim phase has not yet started");
        require(g._currentDay < CLAIM_PHASE_END_DAY, "HEX: Claim phase has ended");

        /* Check if log data needs to be updated */
        _dailyDataUpdateAuto(g);

        /* Sanity check */
        require(
            g._claimedBtcAddrCount < CLAIMABLE_BTC_ADDR_COUNT,
            "HEX: CHK: _claimedBtcAddrCount"
        );

        (uint256 adjSatoshis, uint256 claimedHearts, uint256 claimBonusHearts) = _calcClaimValues(
            g,
            rawSatoshis
        );

        /* Increment claim count to track viral rewards */
        g._claimedBtcAddrCount++;

        totalClaimedHearts = _remitBonuses(
            claimToAddr,
            btcAddr,
            claimFlags,
            rawSatoshis,
            adjSatoshis,
            claimedHearts,
            claimBonusHearts,
            referrerAddr
        );

        /* Auto-stake a percentage of the successful claim */
        uint256 autoStakeHearts = totalClaimedHearts * AUTO_STAKE_CLAIM_PERCENT / 100;
        _stakeStart(g, autoStakeHearts, autoStakeDays, true);

        /* Mint remaining claimed Hearts to claim address */
        _mint(claimToAddr, totalClaimedHearts - autoStakeHearts);

        return totalClaimedHearts;
    }

    function _remitBonuses(
        address claimToAddr,
        bytes20 btcAddr,
        uint8 claimFlags,
        uint256 rawSatoshis,
        uint256 adjSatoshis,
        uint256 claimedHearts,
        uint256 claimBonusHearts,
        address referrerAddr
    )
        private
        returns (uint256 totalClaimedHearts)
    {
        totalClaimedHearts = claimedHearts + claimBonusHearts;

        uint256 originBonusHearts = claimBonusHearts;

        if (referrerAddr == address(0)) {
            /* No referrer */
            _emitClaim(
                claimToAddr,
                btcAddr,
                claimFlags,
                rawSatoshis,
                adjSatoshis,
                totalClaimedHearts,
                referrerAddr
            );
        } else {
            /* Referral bonus of 10% of total claimed Hearts to claimer */
            uint256 referralBonusHearts = totalClaimedHearts / 10;

            totalClaimedHearts += referralBonusHearts;

            /* Then a cumulative referrer bonus of 20% to referrer */
            uint256 referrerBonusHearts = totalClaimedHearts / 5;

            originBonusHearts += referralBonusHearts + referrerBonusHearts;

            if (referrerAddr == claimToAddr) {
                /* Self-referred */
                totalClaimedHearts += referrerBonusHearts;
                _emitClaim(
                    claimToAddr,
                    btcAddr,
                    claimFlags,
                    rawSatoshis,
                    adjSatoshis,
                    totalClaimedHearts,
                    referrerAddr
                );
            } else {
                /* Referred by different address */
                _emitClaim(
                    claimToAddr,
                    btcAddr,
                    claimFlags,
                    rawSatoshis,
                    adjSatoshis,
                    totalClaimedHearts,
                    referrerAddr
                );
                _mint(referrerAddr, referrerBonusHearts);
            }
        }

        _mint(ORIGIN_ADDR, originBonusHearts);

        return totalClaimedHearts;
    }

    function _emitClaim(
        address claimToAddr,
        bytes20 btcAddr,
        uint8 claimFlags,
        uint256 rawSatoshis,
        uint256 adjSatoshis,
        uint256 claimedHearts,
        address referrerAddr
    )
        private
    {
        emit Claim( // (auto-generated event)
            uint256(uint40(block.timestamp))
                | (uint256(uint56(rawSatoshis)) << 40)
                | (uint256(uint56(adjSatoshis)) << 96)
                | (uint256(claimFlags) << 152)
                | (uint256(uint72(claimedHearts)) << 160),
            uint256(uint160(msg.sender)),
            btcAddr,
            claimToAddr,
            referrerAddr
        );

        if (claimToAddr == msg.sender) {
            return;
        }

        emit ClaimAssist( // (auto-generated event)
            uint256(uint40(block.timestamp))
                | (uint256(uint160(btcAddr)) << 40)
                | (uint256(uint56(rawSatoshis)) << 200),
            uint256(uint56(adjSatoshis))
                | (uint256(uint160(claimToAddr)) << 56)
                | (uint256(claimFlags) << 216),
            uint256(uint72(claimedHearts))
                | (uint256(uint160(referrerAddr)) << 72),
            msg.sender
        );
    }

    function _calcClaimValues(GlobalsCache memory g, uint256 rawSatoshis)
        private
        pure
        returns (uint256 adjSatoshis, uint256 claimedHearts, uint256 claimBonusHearts)
    {
        /* Apply Silly Whale reduction */
        adjSatoshis = _adjustSillyWhale(rawSatoshis);
        require(
            g._claimedSatoshisTotal + adjSatoshis <= CLAIMABLE_SATOSHIS_TOTAL,
            "HEX: CHK: _claimedSatoshisTotal"
        );
        g._claimedSatoshisTotal += adjSatoshis;

        uint256 daysRemaining = CLAIM_PHASE_END_DAY - g._currentDay;

        /* Apply late-claim reduction */
        adjSatoshis = _adjustLateClaim(adjSatoshis, daysRemaining);
        g._unclaimedSatoshisTotal -= adjSatoshis;

        /* Convert to Hearts and calculate speed bonus */
        claimedHearts = adjSatoshis * HEARTS_PER_SATOSHI;
        claimBonusHearts = _calcSpeedBonus(claimedHearts, daysRemaining);

        return (adjSatoshis, claimedHearts, claimBonusHearts);
    }

    /**
     * @dev Apply Silly Whale adjustment
     * @param rawSatoshis Raw BTC address balance in Satoshis
     * @return Adjusted BTC address balance in Satoshis
     */
    function _adjustSillyWhale(uint256 rawSatoshis)
        private
        pure
        returns (uint256)
    {
        if (rawSatoshis < 1000e8) {
            /* For < 1,000 BTC: no penalty */
            return rawSatoshis;
        }
        if (rawSatoshis >= 10000e8) {
            /* For >= 10,000 BTC: penalty is 75%, leaving 25% */
            return rawSatoshis / 4;
        }
        /*
            For 1,000 <= BTC < 10,000: penalty scales linearly from 50% to 75%

            penaltyPercent  = (btc - 1000) / (10000 - 1000) * (75 - 50) + 50
                            = (btc - 1000) / 9000 * 25 + 50
                            = (btc - 1000) / 360 + 50

            appliedPercent  = 100 - penaltyPercent
                            = 100 - ((btc - 1000) / 360 + 50)
                            = 100 - (btc - 1000) / 360 - 50
                            = 50 - (btc - 1000) / 360
                            = (18000 - (btc - 1000)) / 360
                            = (18000 - btc + 1000) / 360
                            = (19000 - btc) / 360

            adjustedBtc     = btc * appliedPercent / 100
                            = btc * ((19000 - btc) / 360) / 100
                            = btc * (19000 - btc) / 36000

            adjustedSat     = 1e8 * adjustedBtc
                            = 1e8 * (btc * (19000 - btc) / 36000)
                            = 1e8 * ((sat / 1e8) * (19000 - (sat / 1e8)) / 36000)
                            = 1e8 * (sat / 1e8) * (19000 - (sat / 1e8)) / 36000
                            = (sat / 1e8) * 1e8 * (19000 - (sat / 1e8)) / 36000
                            = (sat / 1e8) * (19000e8 - sat) / 36000
                            = sat * (19000e8 - sat) / 36000e8
        */
        return rawSatoshis * (19000e8 - rawSatoshis) / 36000e8;
    }

    /**
     * @dev Apply late-claim adjustment to scale claim to zero by end of claim phase
     * @param adjSatoshis Adjusted BTC address balance in Satoshis (after Silly Whale)
     * @param daysRemaining Number of reward days remaining in claim phase
     * @return Adjusted BTC address balance in Satoshis (after Silly Whale and Late-Claim)
     */
    function _adjustLateClaim(uint256 adjSatoshis, uint256 daysRemaining)
        private
        pure
        returns (uint256)
    {
        /*
            Only valid from CLAIM_PHASE_DAYS to 1, and only used during that time.

            adjustedSat = sat * (daysRemaining / CLAIM_PHASE_DAYS) * 100%
                        = sat *  daysRemaining / CLAIM_PHASE_DAYS
        */
        return adjSatoshis * daysRemaining / CLAIM_PHASE_DAYS;
    }

    /**
     * @dev Calculates speed bonus for claiming earlier in the claim phase
     * @param claimedHearts Hearts claimed from adjusted BTC address balance Satoshis
     * @param daysRemaining Number of claim days remaining in claim phase
     * @return Speed bonus in Hearts
     */
    function _calcSpeedBonus(uint256 claimedHearts, uint256 daysRemaining)
        private
        pure
        returns (uint256)
    {
        /*
            Only valid from CLAIM_PHASE_DAYS to 1, and only used during that time.
            Speed bonus is 20% ... 0% inclusive.

            bonusHearts = claimedHearts  * ((daysRemaining - 1)  /  (CLAIM_PHASE_DAYS - 1)) * 20%
                        = claimedHearts  * ((daysRemaining - 1)  /  (CLAIM_PHASE_DAYS - 1)) * 20/100
                        = claimedHearts  * ((daysRemaining - 1)  /  (CLAIM_PHASE_DAYS - 1)) / 5
                        = claimedHearts  *  (daysRemaining - 1)  / ((CLAIM_PHASE_DAYS - 1)  * 5)
        */
        return claimedHearts * (daysRemaining - 1) / ((CLAIM_PHASE_DAYS - 1) * 5);
    }
}

contract TransformableToken is UTXORedeemableToken {
    /**
     * @dev PUBLIC FACING: Enter the tranform lobby for the current round
     * @param referrerAddr Eth address of referring user (optional; 0x0 for no referrer)
     */
    function xfLobbyEnter(address referrerAddr)
        external
        payable
    {
        uint256 enterDay = _currentDay();
        require(enterDay < CLAIM_PHASE_END_DAY, "HEX: Lobbies have ended");

        uint256 rawAmount = msg.value;
        require(rawAmount != 0, "HEX: Amount required");

        XfLobbyQueueStore storage qRef = xfLobbyMembers[enterDay][msg.sender];

        uint256 entryIndex = qRef.tailIndex++;

        qRef.entries[entryIndex] = XfLobbyEntryStore(uint96(rawAmount), referrerAddr);

        xfLobby[enterDay] += rawAmount;

        _emitXfLobbyEnter(enterDay, entryIndex, rawAmount, referrerAddr);
    }

    /**
     * @dev PUBLIC FACING: Leave the transform lobby after the round is complete
     * @param enterDay Day number when the member entered
     * @param count Number of queued-enters to exit (optional; 0 for all)
     */
    function xfLobbyExit(uint256 enterDay, uint256 count)
        external
    {
        require(enterDay < _currentDay(), "HEX: Round is not complete");

        XfLobbyQueueStore storage qRef = xfLobbyMembers[enterDay][msg.sender];

        uint256 headIndex = qRef.headIndex;
        uint256 endIndex;

        if (count != 0) {
            require(count <= qRef.tailIndex - headIndex, "HEX: count invalid");
            endIndex = headIndex + count;
        } else {
            endIndex = qRef.tailIndex;
            require(headIndex < endIndex, "HEX: count invalid");
        }

        uint256 waasLobby = _waasLobby(enterDay);
        uint256 _xfLobby = xfLobby[enterDay];
        uint256 totalXfAmount = 0;
        uint256 originBonusHearts = 0;

        do {
            uint256 rawAmount = qRef.entries[headIndex].rawAmount;
            address referrerAddr = qRef.entries[headIndex].referrerAddr;

            delete qRef.entries[headIndex];

            uint256 xfAmount = waasLobby * rawAmount / _xfLobby;

            if (referrerAddr == address(0)) {
                /* No referrer */
                _emitXfLobbyExit(enterDay, headIndex, xfAmount, referrerAddr);
            } else {
                /* Referral bonus of 10% of xfAmount to member */
                uint256 referralBonusHearts = xfAmount / 10;

                xfAmount += referralBonusHearts;

                /* Then a cumulative referrer bonus of 20% to referrer */
                uint256 referrerBonusHearts = xfAmount / 5;

                if (referrerAddr == msg.sender) {
                    /* Self-referred */
                    xfAmount += referrerBonusHearts;
                    _emitXfLobbyExit(enterDay, headIndex, xfAmount, referrerAddr);
                } else {
                    /* Referred by different address */
                    _emitXfLobbyExit(enterDay, headIndex, xfAmount, referrerAddr);
                    _mint(referrerAddr, referrerBonusHearts);
                }
                originBonusHearts += referralBonusHearts + referrerBonusHearts;
            }

            totalXfAmount += xfAmount;
        } while (++headIndex < endIndex);

        qRef.headIndex = uint40(headIndex);

        if (originBonusHearts != 0) {
            _mint(ORIGIN_ADDR, originBonusHearts);
        }
        if (totalXfAmount != 0) {
            _mint(msg.sender, totalXfAmount);
        }
    }

    /**
     * @dev PUBLIC FACING: Release any value that has been sent to the contract
     */
    function xfLobbyFlush()
        external
    {
        require(address(this).balance != 0, "HEX: No value");

        FLUSH_ADDR.transfer(address(this).balance);
    }

    /**
     * @dev PUBLIC FACING: External helper to return multiple values of xfLobby[] with
     * a single call
     * @param beginDay First day of data range
     * @param endDay Last day (non-inclusive) of data range
     * @return Fixed array of values
     */
    function xfLobbyRange(uint256 beginDay, uint256 endDay)
        external
        view
        returns (uint256[] memory list)
    {
        require(
            beginDay < endDay && endDay <= CLAIM_PHASE_END_DAY && endDay <= _currentDay(),
            "HEX: invalid range"
        );

        list = new uint256[](endDay - beginDay);

        uint256 src = beginDay;
        uint256 dst = 0;
        do {
            list[dst++] = uint256(xfLobby[src++]);
        } while (src < endDay);

        return list;
    }

    /**
     * @dev PUBLIC FACING: Return a current lobby member queue entry.
     * Only needed due to limitations of the standard ABI encoder.
     * @param memberAddr Eth address of the lobby member
     * @param entryId 49 bit compound value. Top 9 bits: enterDay, Bottom 40 bits: entryIndex
     * @return 1: Raw amount that was entered with; 2: Referring Eth addr (optional; 0x0 for no referrer)
     */
    function xfLobbyEntry(address memberAddr, uint256 entryId)
        external
        view
        returns (uint256 rawAmount, address referrerAddr)
    {
        uint256 enterDay = entryId >> XF_LOBBY_ENTRY_INDEX_SIZE;
        uint256 entryIndex = entryId & XF_LOBBY_ENTRY_INDEX_MASK;

        XfLobbyEntryStore storage entry = xfLobbyMembers[enterDay][memberAddr].entries[entryIndex];

        require(entry.rawAmount != 0, "HEX: Param invalid");

        return (entry.rawAmount, entry.referrerAddr);
    }

    /**
     * @dev PUBLIC FACING: Return the lobby days that a user is in with a single call
     * @param memberAddr Eth address of the user
     * @return Bit vector of lobby day numbers
     */
    function xfLobbyPendingDays(address memberAddr)
        external
        view
        returns (uint256[XF_LOBBY_DAY_WORDS] memory words)
    {
        uint256 day = _currentDay() + 1;

        if (day > CLAIM_PHASE_END_DAY) {
            day = CLAIM_PHASE_END_DAY;
        }

        while (day-- != 0) {
            if (xfLobbyMembers[day][memberAddr].tailIndex > xfLobbyMembers[day][memberAddr].headIndex) {
                words[day >> 8] |= 1 << (day & 255);
            }
        }

        return words;
    }

    function _waasLobby(uint256 enterDay)
        private
        returns (uint256 waasLobby)
    {
        if (enterDay >= CLAIM_PHASE_START_DAY) {
            GlobalsCache memory g;
            GlobalsCache memory gSnapshot;
            _globalsLoad(g, gSnapshot);

            _dailyDataUpdateAuto(g);

            uint256 unclaimed = dailyData[enterDay].dayUnclaimedSatoshisTotal;
            waasLobby = unclaimed * HEARTS_PER_SATOSHI / CLAIM_PHASE_DAYS;

            _globalsSync(g, gSnapshot);
        } else {
            waasLobby = WAAS_LOBBY_SEED_HEARTS;
        }
        return waasLobby;
    }

    function _emitXfLobbyEnter(
        uint256 enterDay,
        uint256 entryIndex,
        uint256 rawAmount,
        address referrerAddr
    )
        private
    {
        emit XfLobbyEnter( // (auto-generated event)
            uint256(uint40(block.timestamp))
                | (uint256(uint96(rawAmount)) << 40),
            msg.sender,
            (enterDay << XF_LOBBY_ENTRY_INDEX_SIZE) | entryIndex,
            referrerAddr
        );
    }

    function _emitXfLobbyExit(
        uint256 enterDay,
        uint256 entryIndex,
        uint256 xfAmount,
        address referrerAddr
    )
        private
    {
        emit XfLobbyExit( // (auto-generated event)
            uint256(uint40(block.timestamp))
                | (uint256(uint72(xfAmount)) << 40),
            msg.sender,
            (enterDay << XF_LOBBY_ENTRY_INDEX_SIZE) | entryIndex,
            referrerAddr
        );
    }
}

contract HEX is TransformableToken {
    constructor()
        public
    {
        /* Initialize global shareRate to 1 */
        globals.shareRate = uint40(1 * SHARE_RATE_SCALE);

        /* Initialize dailyDataCount to skip pre-claim period */
        globals.dailyDataCount = uint16(PRE_CLAIM_DAYS);

        /* Add all Satoshis from UTXO snapshot to contract */
        globals.claimStats = _claimStatsEncode(
            0, // _claimedBtcAddrCount
            0, // _claimedSatoshisTotal
            FULL_SATOSHIS_TOTAL // _unclaimedSatoshisTotal
        );
    }

    function() external payable {}
}