//SPDX-License-Identifier: MIT
pragma solidity 0.8.2;
import "@openzeppelin/contracts-0.8/token/ERC721/IERC721Receiver.sol";
import "@openzeppelin/contracts-0.8/token/ERC1155/IERC1155Receiver.sol";
import "./ClaimERC1155ERC721ERC20.sol";
import "../../common/BaseWithStorage/WithAdmin.sol";
/// @title MultiGiveaway contract.
/// @notice This contract manages claims for multiple token types.
contract MultiGiveaway is WithAdmin, ClaimERC1155ERC721ERC20 {
    ///////////////////////////////  Data //////////////////////////////
    bytes4 private constant ERC1155_RECEIVED = 0xf23a6e61;
    bytes4 private constant ERC1155_BATCH_RECEIVED = 0xbc197c81;
    bytes4 internal constant ERC721_RECEIVED = 0x150b7a02;
    bytes4 internal constant ERC721_BATCH_RECEIVED = 0x4b808c46;
    mapping(address => mapping(bytes32 => bool)) public claimed;
    mapping(bytes32 => uint256) internal _expiryTime;
    ///////////////////////////////  Events //////////////////////////////
    event NewGiveaway(bytes32 merkleRoot, uint256 expiryTime);
    ///////////////////////////////  Constructor /////////////////////////
    constructor(address admin) {
        _admin = admin;
    }
    ///////////////////////////////  Functions ///////////////////////////
    /// @notice Function to add a new giveaway.
    /// @param merkleRoot The merkle root hash of the claim data.
    /// @param expiryTime The expiry time for the giveaway.
    function addNewGiveaway(bytes32 merkleRoot, uint256 expiryTime) external onlyAdmin {
        _expiryTime[merkleRoot] = expiryTime;
        emit NewGiveaway(merkleRoot, expiryTime);
    }
    /// @notice Function to check which giveaways have been claimed by a particular user.
    /// @param user The user (intended token destination) address.
    /// @param rootHashes The array of giveaway root hashes to check.
    /// @return claimedGiveaways The array of bools confirming whether or not the giveaways relating to the root hashes provided have been claimed.
    function getClaimedStatus(address user, bytes32[] calldata rootHashes) external view returns (bool[] memory) {
        bool[] memory claimedGiveaways = new bool[](rootHashes.length);
        for (uint256 i = 0; i < rootHashes.length; i++) {
            claimedGiveaways[i] = claimed[user][rootHashes[i]];
        }
        return claimedGiveaways;
    }
    /// @notice Function to permit the claiming of multiple tokens from multiple giveaways to a reserved address.
    /// @param claims The array of claim structs, each containing a destination address, the giveaway items to be claimed and an optional salt param.
    /// @param proofs The proofs submitted for verification.
    function claimMultipleTokensFromMultipleMerkleTree(
        bytes32[] calldata rootHashes,
        Claim[] memory claims,
        bytes32[][] calldata proofs
    ) external {
        require(claims.length == rootHashes.length, "INVALID_INPUT");
        require(claims.length == proofs.length, "INVALID_INPUT");
        for (uint256 i = 0; i < rootHashes.length; i++) {
            claimMultipleTokens(rootHashes[i], claims[i], proofs[i]);
        }
    }
    /// @dev Public function used to perform validity checks and progress to claim multiple token types in one claim.
    /// @param merkleRoot The merkle root hash for the specific set of items being claimed.
    /// @param claim The claim struct containing the destination address, all items to be claimed and optional salt param.
    /// @param proof The proof provided by the user performing the claim function.
    function claimMultipleTokens(
        bytes32 merkleRoot,
        Claim memory claim,
        bytes32[] calldata proof
    ) public {
        uint256 giveawayExpiryTime = _expiryTime[merkleRoot];
        require(claim.to != address(0), "INVALID_TO_ZERO_ADDRESS");
        require(claim.to != address(this), "DESTINATION_MULTIGIVEAWAY_CONTRACT");
        require(giveawayExpiryTime != 0, "GIVEAWAY_DOES_NOT_EXIST");
        require(block.timestamp < giveawayExpiryTime, "CLAIM_PERIOD_IS_OVER");
        require(claimed[claim.to][merkleRoot] == false, "DESTINATION_ALREADY_CLAIMED");
        claimed[claim.to][merkleRoot] = true;
        _claimERC1155ERC721ERC20(merkleRoot, claim, proof);
    }
    function onERC721Received(
        address, /*operator*/
        address, /*from*/
        uint256, /*id*/
        bytes calldata /*data*/
    ) external pure returns (bytes4) {
        return ERC721_RECEIVED;
    }
    function onERC721BatchReceived(
        address, /*operator*/
        address, /*from*/
        uint256[] calldata, /*ids*/
        bytes calldata /*data*/
    ) external pure returns (bytes4) {
        return ERC721_BATCH_RECEIVED;
    }
    function onERC1155Received(
        address, /*operator*/
        address, /*from*/
        uint256, /*id*/
        uint256, /*value*/
        bytes calldata /*data*/
    ) external pure returns (bytes4) {
        return ERC1155_RECEIVED;
    }
    function onERC1155BatchReceived(
        address, /*operator*/
        address, /*from*/
        uint256[] calldata, /*ids*/
        uint256[] calldata, /*values*/
        bytes calldata /*data*/
    ) external pure returns (bytes4) {
        return ERC1155_BATCH_RECEIVED;
    }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
 * @title ERC721 token receiver interface
 * @dev Interface for any contract that wants to support safeTransfers
 * from ERC721 asset contracts.
 */
interface IERC721Receiver {
    /**
     * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
     * by `operator` from `from`, this function is called.
     *
     * It must return its Solidity selector to confirm the token transfer.
     * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
     *
     * The selector can be obtained in Solidity with `IERC721.onERC721Received.selector`.
     */
    function onERC721Received(address operator, address from, uint256 tokenId, bytes calldata data) external returns (bytes4);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "../../utils/introspection/IERC165.sol";
/**
 * _Available since v3.1._
 */
interface IERC1155Receiver is IERC165 {
    /**
        @dev Handles the receipt of a single ERC1155 token type. This function is
        called at the end of a `safeTransferFrom` after the balance has been updated.
        To accept the transfer, this must return
        `bytes4(keccak256("onERC1155Received(address,address,uint256,uint256,bytes)"))`
        (i.e. 0xf23a6e61, or its own function selector).
        @param operator The address which initiated the transfer (i.e. msg.sender)
        @param from The address which previously owned the token
        @param id The ID of the token being transferred
        @param value The amount of tokens being transferred
        @param data Additional data with no specified format
        @return `bytes4(keccak256("onERC1155Received(address,address,uint256,uint256,bytes)"))` if transfer is allowed
    */
    function onERC1155Received(
        address operator,
        address from,
        uint256 id,
        uint256 value,
        bytes calldata data
    )
        external
        returns(bytes4);
    /**
        @dev Handles the receipt of a multiple ERC1155 token types. This function
        is called at the end of a `safeBatchTransferFrom` after the balances have
        been updated. To accept the transfer(s), this must return
        `bytes4(keccak256("onERC1155BatchReceived(address,address,uint256[],uint256[],bytes)"))`
        (i.e. 0xbc197c81, or its own function selector).
        @param operator The address which initiated the batch transfer (i.e. msg.sender)
        @param from The address which previously owned the token
        @param ids An array containing ids of each token being transferred (order and length must match values array)
        @param values An array containing amounts of each token being transferred (order and length must match ids array)
        @param data Additional data with no specified format
        @return `bytes4(keccak256("onERC1155BatchReceived(address,address,uint256[],uint256[],bytes)"))` if transfer is allowed
    */
    function onERC1155BatchReceived(
        address operator,
        address from,
        uint256[] calldata ids,
        uint256[] calldata values,
        bytes calldata data
    )
        external
        returns(bytes4);
}
//SPDX-License-Identifier: MIT
pragma solidity 0.8.2;
import "@openzeppelin/contracts-0.8/token/ERC1155/IERC1155.sol";
import "@openzeppelin/contracts-0.8/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts-0.8/token/ERC20/utils/SafeERC20.sol";
import "../../common/interfaces/IERC721Extended.sol";
import "../../common/Libraries/Verify.sol";
contract ClaimERC1155ERC721ERC20 {
    ///////////////////////////////  Libs //////////////////////////////
    using SafeERC20 for IERC20;
    ///////////////////////////////  Data //////////////////////////////
    struct Claim {
        address to;
        ERC1155Claim[] erc1155;
        ERC721Claim[] erc721;
        ERC20Claim erc20;
        bytes32 salt;
    }
    struct ERC1155Claim {
        uint256[] ids;
        uint256[] values;
        address contractAddress;
    }
    struct ERC721Claim {
        uint256[] ids;
        address contractAddress;
    }
    struct ERC20Claim {
        uint256[] amounts;
        address[] contractAddresses;
    }
    ///////////////////////////////  Events //////////////////////////////
    /// @dev Emits when a successful claim occurs.
    /// @param to The destination address for the claimed ERC1155, ERC721 and ERC20 tokens.
    /// @param erc1155 The array of ERC1155Claim structs containing the ids, values and ERC1155 contract address.
    /// @param erc721 The array of ERC721Claim structs containing the ids and ERC721 contract address.
    /// @param erc20 The ERC20Claim struct containing the amounts and ERC20 contract addresses.
    event ClaimedMultipleTokens(address to, ERC1155Claim[] erc1155, ERC721Claim[] erc721, ERC20Claim erc20);
    ///////////////////////////////  Functions ///////////////////////////
    /// @dev Internal function used to claim multiple token types in one claim.
    /// @param merkleRoot The merkle root hash for the specific set of items being claimed.
    /// @param claim The claim struct containing the destination address, all items to be claimed and optional salt param.
    /// @param proof The proof provided by the user performing the claim function.
    function _claimERC1155ERC721ERC20(
        bytes32 merkleRoot,
        Claim memory claim,
        bytes32[] calldata proof
    ) internal {
        _checkValidity(merkleRoot, claim, proof);
        for (uint256 i = 0; i < claim.erc1155.length; i++) {
            require(claim.erc1155[i].ids.length == claim.erc1155[i].values.length, "INVALID_INPUT");
            _transferERC1155(claim.to, claim.erc1155[i].ids, claim.erc1155[i].values, claim.erc1155[i].contractAddress);
        }
        for (uint256 i = 0; i < claim.erc721.length; i++) {
            _transferERC721(claim.to, claim.erc721[i].ids, claim.erc721[i].contractAddress);
        }
        if (claim.erc20.amounts.length != 0) {
            require(claim.erc20.amounts.length == claim.erc20.contractAddresses.length, "INVALID_INPUT");
            _transferERC20(claim.to, claim.erc20.amounts, claim.erc20.contractAddresses);
        }
        emit ClaimedMultipleTokens(claim.to, claim.erc1155, claim.erc721, claim.erc20);
    }
    /// @dev Private function used to check the validity of a specific claim.
    /// @param merkleRoot The merkle root hash for the specific set of items being claimed.
    /// @param claim The claim struct containing the destination address, all items to be claimed and optional salt param.
    /// @param proof The proof provided by the user performing the claim function.
    function _checkValidity(
        bytes32 merkleRoot,
        Claim memory claim,
        bytes32[] memory proof
    ) private pure {
        bytes32 leaf = _generateClaimHash(claim);
        require(Verify.doesComputedHashMatchMerkleRootHash(merkleRoot, proof, leaf), "INVALID_CLAIM");
    }
    /// @dev Private function used to generate a hash from an encoded claim.
    /// @param claim The claim struct.
    function _generateClaimHash(Claim memory claim) private pure returns (bytes32) {
        return keccak256(abi.encode(claim));
    }
    /// @dev Private function used to transfer the ERC1155 tokens specified in a specific claim.
    /// @param to The destination address for the claimed tokens.
    /// @param ids The array of ERC1155 ids.
    /// @param values The amount of ERC1155 tokens of each id to be transferred.
    /// @param contractAddress The ERC1155 token contract address.
    function _transferERC1155(
        address to,
        uint256[] memory ids,
        uint256[] memory values,
        address contractAddress
    ) private {
        require(contractAddress != address(0), "INVALID_CONTRACT_ZERO_ADDRESS");
        IERC1155(contractAddress).safeBatchTransferFrom(address(this), to, ids, values, "");
    }
    /// @dev Private function used to transfer the ERC721tokens specified in a specific claim.
    /// @param to The destination address for the claimed tokens.
    /// @param ids The array of ERC721 ids.
    /// @param contractAddress The ERC721 token contract address.
    function _transferERC721(
        address to,
        uint256[] memory ids,
        address contractAddress
    ) private {
        require(contractAddress != address(0), "INVALID_CONTRACT_ZERO_ADDRESS");
        IERC721Extended(contractAddress).safeBatchTransferFrom(address(this), to, ids, "");
    }
    /// @dev Private function used to transfer the ERC20 tokens specified in a specific claim.
    /// @param to The destination address for the claimed tokens.
    /// @param amounts The array of amounts of ERC20 tokens to be transferred.
    /// @param contractAddresses The array of ERC20 token contract addresses.
    function _transferERC20(
        address to,
        uint256[] memory amounts,
        address[] memory contractAddresses
    ) private {
        for (uint256 i = 0; i < amounts.length; i++) {
            address erc20ContractAddress = contractAddresses[i];
            uint256 erc20Amount = amounts[i];
            require(erc20ContractAddress != address(0), "INVALID_CONTRACT_ZERO_ADDRESS");
            IERC20(erc20ContractAddress).safeTransferFrom(address(this), to, erc20Amount);
        }
    }
}
//SPDX-License-Identifier: MIT
// solhint-disable-next-line compiler-version
pragma solidity 0.8.2;
contract WithAdmin {
    address internal _admin;
    /// @dev Emits when the contract administrator is changed.
    /// @param oldAdmin The address of the previous administrator.
    /// @param newAdmin The address of the new administrator.
    event AdminChanged(address oldAdmin, address newAdmin);
    modifier onlyAdmin() {
        require(msg.sender == _admin, "ADMIN_ONLY");
        _;
    }
    /// @dev Get the current administrator of this contract.
    /// @return The current administrator of this contract.
    function getAdmin() external view returns (address) {
        return _admin;
    }
    /// @dev Change the administrator to be `newAdmin`.
    /// @param newAdmin The address of the new administrator.
    function changeAdmin(address newAdmin) external {
        require(msg.sender == _admin, "ADMIN_ACCESS_DENIED");
        emit AdminChanged(_admin, newAdmin);
        _admin = newAdmin;
    }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
 * @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);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "../../utils/introspection/IERC165.sol";
/**
 * @dev Required interface of an ERC1155 compliant contract, as defined in the
 * https://eips.ethereum.org/EIPS/eip-1155[EIP].
 *
 * _Available since v3.1._
 */
interface IERC1155 is IERC165 {
    /**
     * @dev Emitted when `value` tokens of token type `id` are transferred from `from` to `to` by `operator`.
     */
    event TransferSingle(address indexed operator, address indexed from, address indexed to, uint256 id, uint256 value);
    /**
     * @dev Equivalent to multiple {TransferSingle} events, where `operator`, `from` and `to` are the same for all
     * transfers.
     */
    event TransferBatch(address indexed operator, address indexed from, address indexed to, uint256[] ids, uint256[] values);
    /**
     * @dev Emitted when `account` grants or revokes permission to `operator` to transfer their tokens, according to
     * `approved`.
     */
    event ApprovalForAll(address indexed account, address indexed operator, bool approved);
    /**
     * @dev Emitted when the URI for token type `id` changes to `value`, if it is a non-programmatic URI.
     *
     * If an {URI} event was emitted for `id`, the standard
     * https://eips.ethereum.org/EIPS/eip-1155#metadata-extensions[guarantees] that `value` will equal the value
     * returned by {IERC1155MetadataURI-uri}.
     */
    event URI(string value, uint256 indexed id);
    /**
     * @dev Returns the amount of tokens of token type `id` owned by `account`.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     */
    function balanceOf(address account, uint256 id) external view returns (uint256);
    /**
     * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {balanceOf}.
     *
     * Requirements:
     *
     * - `accounts` and `ids` must have the same length.
     */
    function balanceOfBatch(address[] calldata accounts, uint256[] calldata ids) external view returns (uint256[] memory);
    /**
     * @dev Grants or revokes permission to `operator` to transfer the caller's tokens, according to `approved`,
     *
     * Emits an {ApprovalForAll} event.
     *
     * Requirements:
     *
     * - `operator` cannot be the caller.
     */
    function setApprovalForAll(address operator, bool approved) external;
    /**
     * @dev Returns true if `operator` is approved to transfer ``account``'s tokens.
     *
     * See {setApprovalForAll}.
     */
    function isApprovedForAll(address account, address operator) external view returns (bool);
    /**
     * @dev Transfers `amount` tokens of token type `id` from `from` to `to`.
     *
     * Emits a {TransferSingle} event.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - If the caller is not `from`, it must be have been approved to spend ``from``'s tokens via {setApprovalForAll}.
     * - `from` must have a balance of tokens of type `id` of at least `amount`.
     * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155Received} and return the
     * acceptance magic value.
     */
    function safeTransferFrom(address from, address to, uint256 id, uint256 amount, bytes calldata data) external;
    /**
     * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {safeTransferFrom}.
     *
     * Emits a {TransferBatch} event.
     *
     * Requirements:
     *
     * - `ids` and `amounts` must have the same length.
     * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155BatchReceived} and return the
     * acceptance magic value.
     */
    function safeBatchTransferFrom(address from, address to, uint256[] calldata ids, uint256[] calldata amounts, bytes calldata data) external;
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
 * @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);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "../IERC20.sol";
import "../../../utils/Address.sol";
/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using Address for address;
    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }
    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }
    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(IERC20 token, address spender, uint256 value) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        // solhint-disable-next-line max-line-length
        require((value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }
    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender) + value;
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }
    function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        unchecked {
            uint256 oldAllowance = token.allowance(address(this), spender);
            require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
            uint256 newAllowance = oldAllowance - value;
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
        }
    }
    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.
        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        if (returndata.length > 0) { // Return data is optional
            // solhint-disable-next-line max-line-length
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}
//SPDX-License-Identifier: MIT
pragma solidity 0.8.2;
import "@openzeppelin/contracts-0.8/token/ERC721/IERC721.sol";
interface IERC721Extended is IERC721 {
    function approveFor(
        address sender,
        address operator,
        uint256 id
    ) external;
    function batchTransferFrom(
        address from,
        address to,
        uint256[] calldata ids,
        bytes calldata data
    ) external;
    function safeBatchTransferFrom(
        address from,
        address to,
        uint256[] calldata ids,
        bytes calldata data
    ) external;
    function setApprovalForAllFor(
        address sender,
        address operator,
        bool approved
    ) external;
    function burn(uint256 id) external;
    function burnFrom(address from, uint256 id) external;
}
//SPDX-License-Identifier: MIT
pragma solidity 0.8.2;
/**
 * @title Verify
 * @dev Merkle root comparison function.
 */
library Verify {
    /// @dev Check if the computedHash == comparisonHash.
    /// @param comparisonHash The merkle root hash passed to the function.
    /// @param proof The proof provided by the user.
    /// @param leaf The generated hash.
    /// @return Whether the computedHash == comparisonHash.
    function doesComputedHashMatchMerkleRootHash(
        bytes32 comparisonHash,
        bytes32[] memory proof,
        bytes32 leaf
    ) internal pure returns (bool) {
        bytes32 computedHash = leaf;
        for (uint256 i = 0; i < proof.length; i++) {
            bytes32 proofElement = proof[i];
            if (computedHash < proofElement) {
                computedHash = keccak256(abi.encodePacked(computedHash, proofElement));
            } else {
                computedHash = keccak256(abi.encodePacked(proofElement, computedHash));
            }
        }
        return computedHash == comparisonHash;
    }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
 * @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) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.
        uint256 size;
        // solhint-disable-next-line no-inline-assembly
        assembly { size := extcodesize(account) }
        return size > 0;
    }
    /**
     * @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");
    }
    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain`call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
      return functionCall(target, data, "Address: low-level call failed");
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }
    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");
        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.call{ value: value }(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");
        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.staticcall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");
        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }
    function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly
                // solhint-disable-next-line no-inline-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "../../utils/introspection/IERC165.sol";
/**
 * @dev Required interface of an ERC721 compliant contract.
 */
interface IERC721 is IERC165 {
    /**
     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
     */
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);
    /**
     * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
     */
    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);
    /**
     * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
     */
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);
    /**
     * @dev Returns the number of tokens in ``owner``'s account.
     */
    function balanceOf(address owner) external view returns (uint256 balance);
    /**
     * @dev Returns the owner of the `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function ownerOf(uint256 tokenId) external view returns (address owner);
    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
     * are aware of the ERC721 protocol to prevent tokens from being forever locked.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(address from, address to, uint256 tokenId) external;
    /**
     * @dev Transfers `tokenId` token from `from` to `to`.
     *
     * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address from, address to, uint256 tokenId) external;
    /**
     * @dev Gives permission to `to` to transfer `tokenId` token to another account.
     * The approval is cleared when the token is transferred.
     *
     * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
     *
     * Requirements:
     *
     * - The caller must own the token or be an approved operator.
     * - `tokenId` must exist.
     *
     * Emits an {Approval} event.
     */
    function approve(address to, uint256 tokenId) external;
    /**
     * @dev Returns the account approved for `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function getApproved(uint256 tokenId) external view returns (address operator);
    /**
     * @dev Approve or remove `operator` as an operator for the caller.
     * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
     *
     * Requirements:
     *
     * - The `operator` cannot be the caller.
     *
     * Emits an {ApprovalForAll} event.
     */
    function setApprovalForAll(address operator, bool _approved) external;
    /**
     * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
     *
     * See {setApprovalForAll}
     */
    function isApprovedForAll(address owner, address operator) external view returns (bool);
    /**
      * @dev Safely transfers `tokenId` token from `from` to `to`.
      *
      * Requirements:
      *
      * - `from` cannot be the zero address.
      * - `to` cannot be the zero address.
      * - `tokenId` token must exist and be owned by `from`.
      * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
      * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
      *
      * Emits a {Transfer} event.
      */
    function safeTransferFrom(address from, address to, uint256 tokenId, bytes calldata data) external;
}

pragma solidity ^0.5.2;
contract Admin {
    address internal _admin;
    event AdminChanged(address oldAdmin, address newAdmin);
    /// @notice gives the current administrator of this contract.
    /// @return the current administrator of this contract.
    function getAdmin() external view returns (address) {
        return _admin;
    }
    /// @notice change the administrator to be `newAdmin`.
    /// @param newAdmin address of the new administrator.
    function changeAdmin(address newAdmin) external {
        require(msg.sender == _admin, "only admin can change admin");
        emit AdminChanged(_admin, newAdmin);
        _admin = newAdmin;
    }
}
pragma solidity ^0.5.2;
import "./Admin.sol";
contract SuperOperators is Admin {
    mapping(address => bool) internal _superOperators;
    event SuperOperator(address superOperator, bool enabled);
    /// @notice Enable or disable the ability of `superOperator` to transfer tokens of all (superOperator rights).
    /// @param superOperator address that will be given/removed superOperator right.
    /// @param enabled set whether the superOperator is enabled or disabled.
    function setSuperOperator(address superOperator, bool enabled) external {
        require(
            msg.sender == _admin,
            "only admin is allowed to add super operators"
        );
        _superOperators[superOperator] = enabled;
        emit SuperOperator(superOperator, enabled);
    }
    /// @notice check whether address `who` is given superOperator rights.
    /// @param who The address to query.
    /// @return whether the address has superOperator rights.
    function isSuperOperator(address who) public view returns (bool) {
        return _superOperators[who];
    }
}
pragma solidity ^0.5.2;
/* interface */
contract ERC20Events {
    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(
        address indexed owner,
        address indexed spender,
        uint256 value
    );
}
pragma solidity ^0.5.2;
library BytesUtil {
    function memcpy(uint256 dest, uint256 src, uint256 len) internal pure {
        // Copy word-length chunks while possible
        for (; len >= 32; len -= 32) {
            assembly {
                mstore(dest, mload(src))
            }
            dest += 32;
            src += 32;
        }
        // Copy remaining bytes
        uint256 mask = 256**(32 - len) - 1;
        assembly {
            let srcpart := and(mload(src), not(mask))
            let destpart := and(mload(dest), mask)
            mstore(dest, or(destpart, srcpart))
        }
    }
    function pointerToBytes(uint256 src, uint256 len)
        internal
        pure
        returns (bytes memory)
    {
        bytes memory ret = new bytes(len);
        uint256 retptr;
        assembly {
            retptr := add(ret, 32)
        }
        memcpy(retptr, src, len);
        return ret;
    }
    function addressToBytes(address a) internal pure returns (bytes memory b) {
        assembly {
            let m := mload(0x40)
            mstore(
                add(m, 20),
                xor(0x140000000000000000000000000000000000000000, a)
            )
            mstore(0x40, add(m, 52))
            b := m
        }
    }
    function uint256ToBytes(uint256 a) internal pure returns (bytes memory b) {
        assembly {
            let m := mload(0x40)
            mstore(add(m, 32), a)
            mstore(0x40, add(m, 64))
            b := m
        }
    }
    function doFirstParamEqualsAddress(bytes memory data, address _address)
        internal
        pure
        returns (bool)
    {
        if (data.length < (36 + 32)) {
            return false;
        }
        uint256 value;
        assembly {
            value := mload(add(data, 36))
        }
        return value == uint256(_address);
    }
    function doParamEqualsUInt256(bytes memory data, uint256 i, uint256 value)
        internal
        pure
        returns (bool)
    {
        if (data.length < (36 + (i + 1) * 32)) {
            return false;
        }
        uint256 offset = 36 + i * 32;
        uint256 valuePresent;
        assembly {
            valuePresent := mload(add(data, offset))
        }
        return valuePresent == value;
    }
    function overrideFirst32BytesWithAddress(
        bytes memory data,
        address _address
    ) internal pure returns (bytes memory) {
        uint256 dest;
        assembly {
            dest := add(data, 48)
        } // 48 = 32 (offset) + 4 (func sig) + 12 (address is only 20 bytes)
        bytes memory addressBytes = addressToBytes(_address);
        uint256 src;
        assembly {
            src := add(addressBytes, 32)
        }
        memcpy(dest, src, 20);
        return data;
    }
    function overrideFirstTwo32BytesWithAddressAndInt(
        bytes memory data,
        address _address,
        uint256 _value
    ) internal pure returns (bytes memory) {
        uint256 dest;
        uint256 src;
        assembly {
            dest := add(data, 48)
        } // 48 = 32 (offset) + 4 (func sig) + 12 (address is only 20 bytes)
        bytes memory bbytes = addressToBytes(_address);
        assembly {
            src := add(bbytes, 32)
        }
        memcpy(dest, src, 20);
        assembly {
            dest := add(data, 68)
        } // 48 = 32 (offset) + 4 (func sig) + 32 (next slot)
        bbytes = uint256ToBytes(_value);
        assembly {
            src := add(bbytes, 32)
        }
        memcpy(dest, src, 32);
        return data;
    }
}
pragma solidity 0.5.9;
import "./Sand/erc20/ERC20ExecuteExtension.sol";
import "./Sand/erc20/ERC20BaseToken.sol";
import "./Sand/erc20/ERC20BasicApproveExtension.sol";
contract Sand is ERC20ExecuteExtension, ERC20BasicApproveExtension, ERC20BaseToken {
    constructor(address sandAdmin, address executionAdmin, address beneficiary) public {
        _admin = sandAdmin;
        _executionAdmin = executionAdmin;
        _mint(beneficiary, 3000000000000000000000000000);
    }
    /// @notice A descriptive name for the tokens
    /// @return name of the tokens
    function name() public view returns (string memory) {
        return "SAND";
    }
    /// @notice An abbreviated name for the tokens
    /// @return symbol of the tokens
    function symbol() public view returns (string memory) {
        return "SAND";
    }
}
pragma solidity 0.5.9;
import "../../../contracts_common/src/Interfaces/ERC20Events.sol";
import "../../../contracts_common/src/BaseWithStorage/SuperOperators.sol";
contract ERC20BaseToken is SuperOperators, ERC20Events {
    uint256 internal _totalSupply;
    mapping(address => uint256) internal _balances;
    mapping(address => mapping(address => uint256)) internal _allowances;
    /// @notice Gets the total number of tokens in existence.
    /// @return the total number of tokens in existence.
    function totalSupply() public view returns (uint256) {
        return _totalSupply;
    }
    /// @notice Gets the balance of `owner`.
    /// @param owner The address to query the balance of.
    /// @return The amount owned by `owner`.
    function balanceOf(address owner) public view returns (uint256) {
        return _balances[owner];
    }
    /// @notice gets allowance of `spender` for `owner`'s tokens.
    /// @param owner address whose token is allowed.
    /// @param spender address allowed to transfer.
    /// @return the amount of token `spender` is allowed to transfer on behalf of `owner`.
    function allowance(address owner, address spender)
        public
        view
        returns (uint256 remaining)
    {
        return _allowances[owner][spender];
    }
    /// @notice returns the number of decimals for that token.
    /// @return the number of decimals.
    function decimals() public view returns (uint8) {
        return uint8(18);
    }
    /// @notice Transfer `amount` tokens to `to`.
    /// @param to the recipient address of the tokens transfered.
    /// @param amount the number of tokens transfered.
    /// @return true if success.
    function transfer(address to, uint256 amount)
        public
        returns (bool success)
    {
        _transfer(msg.sender, to, amount);
        return true;
    }
    /// @notice Transfer `amount` tokens from `from` to `to`.
    /// @param from whose token it is transferring from.
    /// @param to the recipient address of the tokens transfered.
    /// @param amount the number of tokens transfered.
    /// @return true if success.
    function transferFrom(address from, address to, uint256 amount)
        public
        returns (bool success)
    {
        if (msg.sender != from && !_superOperators[msg.sender]) {
            uint256 currentAllowance = _allowances[from][msg.sender];
            if (currentAllowance != (2**256) - 1) {
                // save gas when allowance is maximal by not reducing it (see https://github.com/ethereum/EIPs/issues/717)
                require(currentAllowance >= amount, "Not enough funds allowed");
                _allowances[from][msg.sender] = currentAllowance - amount;
            }
        }
        _transfer(from, to, amount);
        return true;
    }
    /// @notice burn `amount` tokens.
    /// @param amount the number of tokens to burn.
    /// @return true if success.
    function burn(uint256 amount) external returns (bool) {
        _burn(msg.sender, amount);
        return true;
    }
    /// @notice burn `amount` tokens from `owner`.
    /// @param owner address whose token is to burn.
    /// @param amount the number of token to burn.
    /// @return true if success.
    function burnFor(address owner, uint256 amount) external returns (bool) {
        _burn(owner, amount);
        return true;
    }
    /// @notice approve `spender` to transfer `amount` tokens.
    /// @param spender address to be given rights to transfer.
    /// @param amount the number of tokens allowed.
    /// @return true if success.
    function approve(address spender, uint256 amount)
        public
        returns (bool success)
    {
        _approveFor(msg.sender, spender, amount);
        return true;
    }
    /// @notice approve `spender` to transfer `amount` tokens from `owner`.
    /// @param owner address whose token is allowed.
    /// @param spender  address to be given rights to transfer.
    /// @param amount the number of tokens allowed.
    /// @return true if success.
    function approveFor(address owner, address spender, uint256 amount)
        public
        returns (bool success)
    {
        require(
            msg.sender == owner || _superOperators[msg.sender],
            "msg.sender != owner && !superOperator"
        );
        _approveFor(owner, spender, amount);
        return true;
    }
    function addAllowanceIfNeeded(address owner, address spender, uint256 amountNeeded)
        public
        returns (bool success)
    {
        require(
            msg.sender == owner || _superOperators[msg.sender],
            "msg.sender != owner && !superOperator"
        );
        _addAllowanceIfNeeded(owner, spender, amountNeeded);
        return true;
    }
    function _addAllowanceIfNeeded(address owner, address spender, uint256 amountNeeded)
        internal
    {
        if(amountNeeded > 0 && !isSuperOperator(spender)) {
            uint256 currentAllowance = _allowances[owner][spender];
            if(currentAllowance < amountNeeded) {
                _approveFor(owner, spender, amountNeeded);
            }
        }
    }
    function _approveFor(address owner, address spender, uint256 amount)
        internal
    {
        require(
            owner != address(0) && spender != address(0),
            "Cannot approve with 0x0"
        );
        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }
    function _transfer(address from, address to, uint256 amount) internal {
        require(to != address(0), "Cannot send to 0x0");
        uint256 currentBalance = _balances[from];
        require(currentBalance >= amount, "not enough fund");
        _balances[from] = currentBalance - amount;
        _balances[to] += amount;
        emit Transfer(from, to, amount);
    }
    function _mint(address to, uint256 amount) internal {
        require(to != address(0), "Cannot mint to 0x0");
        require(amount > 0, "cannot mint 0 tokens");
        uint256 currentTotalSupply = _totalSupply;
        uint256 newTotalSupply = currentTotalSupply + amount;
        require(newTotalSupply > currentTotalSupply, "overflow");
        _totalSupply = newTotalSupply;
        _balances[to] += amount;
        emit Transfer(address(0), to, amount);
    }
    function _burn(address from, uint256 amount) internal {
        require(amount > 0, "cannot burn 0 tokens");
        if (msg.sender != from && !_superOperators[msg.sender]) {
            uint256 currentAllowance = _allowances[from][msg.sender];
            require(
                currentAllowance >= amount,
                "Not enough funds allowed"
            );
            if (currentAllowance != (2**256) - 1) {
                // save gas when allowance is maximal by not reducing it (see https://github.com/ethereum/EIPs/issues/717)
                _allowances[from][msg.sender] = currentAllowance - amount;
            }
        }
        uint256 currentBalance = _balances[from];
        require(currentBalance >= amount, "Not enough funds");
        _balances[from] = currentBalance - amount;
        _totalSupply -= amount;
        emit Transfer(from, address(0), amount);
    }
}
pragma solidity 0.5.9;
import "../../../contracts_common/src/Libraries/BytesUtil.sol";
contract ERC20BasicApproveExtension {
    /// @notice approve `target` to spend `amount` and call it with data.
    /// @param target address to be given rights to transfer and destination of the call.
    /// @param amount the number of tokens allowed.
    /// @param data bytes for the call.
    /// @return data of the call.
    function approveAndCall(
        address target,
        uint256 amount,
        bytes calldata data
    ) external payable returns (bytes memory) {
        require(
            BytesUtil.doFirstParamEqualsAddress(data, msg.sender),
            "first param != sender"
        );
        _approveFor(msg.sender, target, amount);
        // solium-disable-next-line security/no-call-value
        (bool success, bytes memory returnData) = target.call.value(msg.value)(data);
        require(success, string(returnData));
        return returnData;
    }
    /// @notice temporarly approve `target` to spend `amount` and call it with data. Previous approvals remains unchanged.
    /// @param target destination of the call, allowed to spend the amount specified
    /// @param amount the number of tokens allowed to spend.
    /// @param data bytes for the call.
    /// @return data of the call.
    function paidCall(
        address target,
        uint256 amount,
        bytes calldata data
    ) external payable returns (bytes memory) {
        require(
            BytesUtil.doFirstParamEqualsAddress(data, msg.sender),
            "first param != sender"
        );
        if (amount > 0) {
            _addAllowanceIfNeeded(msg.sender, target, amount);
        }
        // solium-disable-next-line security/no-call-value
        (bool success, bytes memory returnData) = target.call.value(msg.value)(data);
        require(success, string(returnData));
        return returnData;
    }
    function _approveFor(address owner, address target, uint256 amount) internal;
    function _addAllowanceIfNeeded(address owner, address spender, uint256 amountNeeded) internal;
}
pragma solidity 0.5.9;
contract ERC20ExecuteExtension {
    /// @dev _executionAdmin != _admin so that this super power can be disabled independently
    address internal _executionAdmin;
    event ExecutionAdminAdminChanged(address oldAdmin, address newAdmin);
    /// @notice give the address responsible for adding execution rights.
    /// @return address of the execution administrator.
    function getExecutionAdmin() external view returns (address) {
        return _executionAdmin;
    }
    /// @notice change the execution adminstrator to be `newAdmin`.
    /// @param newAdmin address of the new administrator.
    function changeExecutionAdmin(address newAdmin) external {
        require(msg.sender == _executionAdmin, "only executionAdmin can change executionAdmin");
        emit ExecutionAdminAdminChanged(_executionAdmin, newAdmin);
        _executionAdmin = newAdmin;
    }
    mapping(address => bool) internal _executionOperators;
    event ExecutionOperator(address executionOperator, bool enabled);
    /// @notice set `executionOperator` as executionOperator: `enabled`.
    /// @param executionOperator address that will be given/removed executionOperator right.
    /// @param enabled set whether the executionOperator is enabled or disabled.
    function setExecutionOperator(address executionOperator, bool enabled) external {
        require(
            msg.sender == _executionAdmin,
            "only execution admin is allowed to add execution operators"
        );
        _executionOperators[executionOperator] = enabled;
        emit ExecutionOperator(executionOperator, enabled);
    }
    /// @notice check whether address `who` is given executionOperator rights.
    /// @param who The address to query.
    /// @return whether the address has executionOperator rights.
    function isExecutionOperator(address who) public view returns (bool) {
        return _executionOperators[who];
    }
    /// @notice execute on behalf of the contract.
    /// @param to destination address fo the call.
    /// @param gasLimit exact amount of gas to be passed to the call.
    /// @param data the bytes sent to the destination address.
    /// @return success whether the execution was successful.
    /// @return returnData data resulting from the execution.
    function executeWithSpecificGas(address to, uint256 gasLimit, bytes calldata data) external returns (bool success, bytes memory returnData) {
        require(_executionOperators[msg.sender], "only execution operators allowed to execute on SAND behalf");
        (success, returnData) = to.call.gas(gasLimit)(data);
        assert(gasleft() > gasLimit / 63); // not enough gas provided, assert to throw all gas // TODO use EIP-1930
    }
    /// @notice approve a specific amount of token for `from` and execute on behalf of the contract.
    /// @param from address of which token will be transfered.
    /// @param to destination address fo the call.
    /// @param amount number of tokens allowed that can be transfer by the code at `to`.
    /// @param gasLimit exact amount of gas to be passed to the call.
    /// @param data the bytes sent to the destination address.
    /// @return success whether the execution was successful.
    /// @return returnData data resulting from the execution.
    function approveAndExecuteWithSpecificGas(
        address from,
        address to,
        uint256 amount,
        uint256 gasLimit,
        bytes calldata data
    ) external returns (bool success, bytes memory returnData) {
        require(_executionOperators[msg.sender], "only execution operators allowed to execute on SAND behalf");
        return _approveAndExecuteWithSpecificGas(from, to, amount, gasLimit, data);
    }
    /// @dev the reason for this function is that charging for gas here is more gas-efficient than doing it in the caller.
    /// @notice approve a specific amount of token for `from` and execute on behalf of the contract. Plus charge the gas required to perform it.
    /// @param from address of which token will be transfered.
    /// @param to destination address fo the call.
    /// @param amount number of tokens allowed that can be transfer by the code at `to`.
    /// @param gasLimit exact amount of gas to be passed to the call.
    /// @param tokenGasPrice price in token for the gas to be charged.
    /// @param baseGasCharge amount of gas charged on top of the gas used for the call.
    /// @param tokenReceiver recipient address of the token charged for the gas used.
    /// @param data the bytes sent to the destination address.
    /// @return success whether the execution was successful.
    /// @return returnData data resulting from the execution.
    function approveAndExecuteWithSpecificGasAndChargeForIt(
        address from,
        address to,
        uint256 amount,
        uint256 gasLimit,
        uint256 tokenGasPrice,
        uint256 baseGasCharge,
        address tokenReceiver,
        bytes calldata data
    ) external returns (bool success, bytes memory returnData) {
        uint256 initialGas = gasleft();
        require(_executionOperators[msg.sender], "only execution operators allowed to execute on SAND behalf");
        (success, returnData) = _approveAndExecuteWithSpecificGas(from, to, amount, gasLimit, data);
        if (tokenGasPrice > 0) {
            _charge(from, gasLimit, tokenGasPrice, initialGas, baseGasCharge, tokenReceiver);
        }
    }
    /// @notice transfer 1amount1 token from `from` to `to` and charge the gas required to perform that transfer.
    /// @param from address of which token will be transfered.
    /// @param to destination address fo the call.
    /// @param amount number of tokens allowed that can be transfer by the code at `to`.
    /// @param gasLimit exact amount of gas to be passed to the call.
    /// @param tokenGasPrice price in token for the gas to be charged.
    /// @param baseGasCharge amount of gas charged on top of the gas used for the call.
    /// @param tokenReceiver recipient address of the token charged for the gas used.
    /// @return whether the transfer was successful.
    function transferAndChargeForGas(
        address from,
        address to,
        uint256 amount,
        uint256 gasLimit,
        uint256 tokenGasPrice,
        uint256 baseGasCharge,
        address tokenReceiver
    ) external returns (bool) {
        uint256 initialGas = gasleft();
        require(_executionOperators[msg.sender], "only execution operators allowed to perfrom transfer and charge");
        _transfer(from, to, amount);
        if (tokenGasPrice > 0) {
            _charge(from, gasLimit, tokenGasPrice, initialGas, baseGasCharge, tokenReceiver);
        }
        return true;
    }
    function _charge(
        address from,
        uint256 gasLimit,
        uint256 tokenGasPrice,
        uint256 initialGas,
        uint256 baseGasCharge,
        address tokenReceiver
    ) internal {
        uint256 gasCharge = initialGas - gasleft();
        if(gasCharge > gasLimit) {
            gasCharge = gasLimit;
        }
        gasCharge += baseGasCharge;
        uint256 tokensToCharge = gasCharge * tokenGasPrice;
        require(tokensToCharge / gasCharge == tokenGasPrice, "overflow");
        _transfer(from, tokenReceiver, tokensToCharge);
    }
    function _approveAndExecuteWithSpecificGas(
        address from,
        address to,
        uint256 amount,
        uint256 gasLimit,
        bytes memory data
    ) internal returns (bool success, bytes memory returnData) {
        if (amount > 0) {
            _addAllowanceIfNeeded(from, to, amount);
        }
        (success, returnData) = to.call.gas(gasLimit)(data);
        assert(gasleft() > gasLimit / 63); // not enough gas provided, assert to throw all gas // TODO use EIP-1930
    }
    function _transfer(address from, address to, uint256 amount) internal;
    function _addAllowanceIfNeeded(address owner, address spender, uint256 amountNeeded) internal;
}