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


// OpenZeppelin Contracts (last updated v4.7.0) (utils/Strings.sol)

pragma solidity ^0.8.0;

/**
 * @dev String operations.
 */
library Strings {
    bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";
    uint8 private constant _ADDRESS_LENGTH = 20;

    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        // Inspired by OraclizeAPI's implementation - MIT licence
        // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol

        if (value == 0) {
            return "0";
        }
        uint256 temp = value;
        uint256 digits;
        while (temp != 0) {
            digits++;
            temp /= 10;
        }
        bytes memory buffer = new bytes(digits);
        while (value != 0) {
            digits -= 1;
            buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
            value /= 10;
        }
        return string(buffer);
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
     */
    function toHexString(uint256 value) internal pure returns (string memory) {
        if (value == 0) {
            return "0x00";
        }
        uint256 temp = value;
        uint256 length = 0;
        while (temp != 0) {
            length++;
            temp >>= 8;
        }
        return toHexString(value, length);
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
     */
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
        bytes memory buffer = new bytes(2 * length + 2);
        buffer[0] = "0";
        buffer[1] = "x";
        for (uint256 i = 2 * length + 1; i > 1; --i) {
            buffer[i] = _HEX_SYMBOLS[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        return string(buffer);
    }

    /**
     * @dev Converts an `address` with fixed length of 20 bytes to its not checksummed ASCII `string` hexadecimal representation.
     */
    function toHexString(address addr) internal pure returns (string memory) {
        return toHexString(uint256(uint160(addr)), _ADDRESS_LENGTH);
    }
}

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


// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

/**
 * @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 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.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

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


// OpenZeppelin Contracts (last updated v4.7.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**
 * @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
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 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");

        (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");

        (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");

        (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");

        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal 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
                /// @solidity memory-safe-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

// File: @openzeppelin/contracts/token/ERC721/IERC721Receiver.sol


// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC721/IERC721Receiver.sol)

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 `IERC721Receiver.onERC721Received.selector`.
     */
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}

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


// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)

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);
}

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


// OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165.sol)

pragma solidity ^0.8.0;


/**
 * @dev Implementation of the {IERC165} interface.
 *
 * Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check
 * for the additional interface id that will be supported. For example:
 *
 * ```solidity
 * function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
 *     return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);
 * }
 * ```
 *
 * Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.
 */
abstract contract ERC165 is IERC165 {
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IERC165).interfaceId;
    }
}

// File: @openzeppelin/contracts/token/ERC721/IERC721.sol


// OpenZeppelin Contracts (last updated v4.7.0) (token/ERC721/IERC721.sol)

pragma solidity ^0.8.0;


/**
 * @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`.
     *
     * 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;

    /**
     * @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 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 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 the account approved for `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function getApproved(uint256 tokenId) external view returns (address operator);

    /**
     * @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);
}

// File: @openzeppelin/contracts/token/ERC721/extensions/IERC721Enumerable.sol


// OpenZeppelin Contracts (last updated v4.5.0) (token/ERC721/extensions/IERC721Enumerable.sol)

pragma solidity ^0.8.0;


/**
 * @title ERC-721 Non-Fungible Token Standard, optional enumeration extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721Enumerable is IERC721 {
    /**
     * @dev Returns the total amount of tokens stored by the contract.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns a token ID owned by `owner` at a given `index` of its token list.
     * Use along with {balanceOf} to enumerate all of ``owner``'s tokens.
     */
    function tokenOfOwnerByIndex(address owner, uint256 index) external view returns (uint256);

    /**
     * @dev Returns a token ID at a given `index` of all the tokens stored by the contract.
     * Use along with {totalSupply} to enumerate all tokens.
     */
    function tokenByIndex(uint256 index) external view returns (uint256);
}

// File: @openzeppelin/contracts/token/ERC721/extensions/IERC721Metadata.sol


// OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/IERC721Metadata.sol)

pragma solidity ^0.8.0;


/**
 * @title ERC-721 Non-Fungible Token Standard, optional metadata extension
 * @dev See https://eips.ethereum.org/EIPS/eip-721
 */
interface IERC721Metadata is IERC721 {
    /**
     * @dev Returns the token collection name.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the token collection symbol.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.
     */
    function tokenURI(uint256 tokenId) external view returns (string memory);
}

// File: @openzeppelin/contracts/token/ERC721/ERC721.sol


// OpenZeppelin Contracts (last updated v4.7.0) (token/ERC721/ERC721.sol)

pragma solidity ^0.8.0;








/**
 * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
 * the Metadata extension, but not including the Enumerable extension, which is available separately as
 * {ERC721Enumerable}.
 */
contract ERC721 is Context, ERC165, IERC721, IERC721Metadata {
    using Address for address;
    using Strings for uint256;

    // Token name
    string private _name;

    // Token symbol
    string private _symbol;

    // Mapping from token ID to owner address
    mapping(uint256 => address) private _owners;

    // Mapping owner address to token count
    mapping(address => uint256) private _balances;

    // Mapping from token ID to approved address
    mapping(uint256 => address) private _tokenApprovals;

    // Mapping from owner to operator approvals
    mapping(address => mapping(address => bool)) private _operatorApprovals;

    /**
     * @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.
     */
    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }

    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {
        return
            interfaceId == type(IERC721).interfaceId ||
            interfaceId == type(IERC721Metadata).interfaceId ||
            super.supportsInterface(interfaceId);
    }

    /**
     * @dev See {IERC721-balanceOf}.
     */
    function balanceOf(address owner) public view virtual override returns (uint256) {
        require(owner != address(0), "ERC721: address zero is not a valid owner");
        return _balances[owner];
    }

    /**
     * @dev See {IERC721-ownerOf}.
     */
    function ownerOf(uint256 tokenId) public view virtual override returns (address) {
        address owner = _owners[tokenId];
        require(owner != address(0), "ERC721: invalid token ID");
        return owner;
    }

    /**
     * @dev See {IERC721Metadata-name}.
     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }

    /**
     * @dev See {IERC721Metadata-symbol}.
     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    /**
     * @dev See {IERC721Metadata-tokenURI}.
     */
    function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
        _requireMinted(tokenId);

        string memory baseURI = _baseURI();
        return bytes(baseURI).length > 0 ? string(abi.encodePacked(baseURI, tokenId.toString())) : "";
    }

    /**
     * @dev Base URI for computing {tokenURI}. If set, the resulting URI for each
     * token will be the concatenation of the `baseURI` and the `tokenId`. Empty
     * by default, can be overridden in child contracts.
     */
    function _baseURI() internal view virtual returns (string memory) {
        return "";
    }

    /**
     * @dev See {IERC721-approve}.
     */
    function approve(address to, uint256 tokenId) public virtual override {
        address owner = ERC721.ownerOf(tokenId);
        require(to != owner, "ERC721: approval to current owner");

        require(
            _msgSender() == owner || isApprovedForAll(owner, _msgSender()),
            "ERC721: approve caller is not token owner nor approved for all"
        );

        _approve(to, tokenId);
    }

    /**
     * @dev See {IERC721-getApproved}.
     */
    function getApproved(uint256 tokenId) public view virtual override returns (address) {
        _requireMinted(tokenId);

        return _tokenApprovals[tokenId];
    }

    /**
     * @dev See {IERC721-setApprovalForAll}.
     */
    function setApprovalForAll(address operator, bool approved) public virtual override {
        _setApprovalForAll(_msgSender(), operator, approved);
    }

    /**
     * @dev See {IERC721-isApprovedForAll}.
     */
    function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) {
        return _operatorApprovals[owner][operator];
    }

    /**
     * @dev See {IERC721-transferFrom}.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public virtual override {
        //solhint-disable-next-line max-line-length
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: caller is not token owner nor approved");

        _transfer(from, to, tokenId);
    }

    /**
     * @dev See {IERC721-safeTransferFrom}.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public virtual override {
        safeTransferFrom(from, to, tokenId, "");
    }

    /**
     * @dev See {IERC721-safeTransferFrom}.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes memory data
    ) public virtual override {
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: caller is not token owner nor approved");
        _safeTransfer(from, to, tokenId, data);
    }

    /**
     * @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.
     *
     * `data` is additional data, it has no specified format and it is sent in call to `to`.
     *
     * This internal function is equivalent to {safeTransferFrom}, and can be used to e.g.
     * implement alternative mechanisms to perform token transfer, such as signature-based.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function _safeTransfer(
        address from,
        address to,
        uint256 tokenId,
        bytes memory data
    ) internal virtual {
        _transfer(from, to, tokenId);
        require(_checkOnERC721Received(from, to, tokenId, data), "ERC721: transfer to non ERC721Receiver implementer");
    }

    /**
     * @dev Returns whether `tokenId` exists.
     *
     * Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.
     *
     * Tokens start existing when they are minted (`_mint`),
     * and stop existing when they are burned (`_burn`).
     */
    function _exists(uint256 tokenId) internal view virtual returns (bool) {
        return _owners[tokenId] != address(0);
    }

    /**
     * @dev Returns whether `spender` is allowed to manage `tokenId`.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function _isApprovedOrOwner(address spender, uint256 tokenId) internal view virtual returns (bool) {
        address owner = ERC721.ownerOf(tokenId);
        return (spender == owner || isApprovedForAll(owner, spender) || getApproved(tokenId) == spender);
    }

    /**
     * @dev Safely mints `tokenId` and transfers it to `to`.
     *
     * Requirements:
     *
     * - `tokenId` must not exist.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function _safeMint(address to, uint256 tokenId) internal virtual {
        _safeMint(to, tokenId, "");
    }

    /**
     * @dev Same as {xref-ERC721-_safeMint-address-uint256-}[`_safeMint`], with an additional `data` parameter which is
     * forwarded in {IERC721Receiver-onERC721Received} to contract recipients.
     */
    function _safeMint(
        address to,
        uint256 tokenId,
        bytes memory data
    ) internal virtual {
        _mint(to, tokenId);
        require(
            _checkOnERC721Received(address(0), to, tokenId, data),
            "ERC721: transfer to non ERC721Receiver implementer"
        );
    }

    /**
     * @dev Mints `tokenId` and transfers it to `to`.
     *
     * WARNING: Usage of this method is discouraged, use {_safeMint} whenever possible
     *
     * Requirements:
     *
     * - `tokenId` must not exist.
     * - `to` cannot be the zero address.
     *
     * Emits a {Transfer} event.
     */
    function _mint(address to, uint256 tokenId) internal virtual {
        require(to != address(0), "ERC721: mint to the zero address");
        require(!_exists(tokenId), "ERC721: token already minted");

        _beforeTokenTransfer(address(0), to, tokenId);

        _balances[to] += 1;
        _owners[tokenId] = to;

        emit Transfer(address(0), to, tokenId);

        _afterTokenTransfer(address(0), to, tokenId);
    }

    /**
     * @dev Destroys `tokenId`.
     * The approval is cleared when the token is burned.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     *
     * Emits a {Transfer} event.
     */
    function _burn(uint256 tokenId) internal virtual {
        address owner = ERC721.ownerOf(tokenId);

        _beforeTokenTransfer(owner, address(0), tokenId);

        // Clear approvals
        _approve(address(0), tokenId);

        _balances[owner] -= 1;
        delete _owners[tokenId];

        emit Transfer(owner, address(0), tokenId);

        _afterTokenTransfer(owner, address(0), tokenId);
    }

    /**
     * @dev Transfers `tokenId` from `from` to `to`.
     *  As opposed to {transferFrom}, this imposes no restrictions on msg.sender.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     *
     * Emits a {Transfer} event.
     */
    function _transfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual {
        require(ERC721.ownerOf(tokenId) == from, "ERC721: transfer from incorrect owner");
        require(to != address(0), "ERC721: transfer to the zero address");

        _beforeTokenTransfer(from, to, tokenId);

        // Clear approvals from the previous owner
        _approve(address(0), tokenId);

        _balances[from] -= 1;
        _balances[to] += 1;
        _owners[tokenId] = to;

        emit Transfer(from, to, tokenId);

        _afterTokenTransfer(from, to, tokenId);
    }

    /**
     * @dev Approve `to` to operate on `tokenId`
     *
     * Emits an {Approval} event.
     */
    function _approve(address to, uint256 tokenId) internal virtual {
        _tokenApprovals[tokenId] = to;
        emit Approval(ERC721.ownerOf(tokenId), to, tokenId);
    }

    /**
     * @dev Approve `operator` to operate on all of `owner` tokens
     *
     * Emits an {ApprovalForAll} event.
     */
    function _setApprovalForAll(
        address owner,
        address operator,
        bool approved
    ) internal virtual {
        require(owner != operator, "ERC721: approve to caller");
        _operatorApprovals[owner][operator] = approved;
        emit ApprovalForAll(owner, operator, approved);
    }

    /**
     * @dev Reverts if the `tokenId` has not been minted yet.
     */
    function _requireMinted(uint256 tokenId) internal view virtual {
        require(_exists(tokenId), "ERC721: invalid token ID");
    }

    /**
     * @dev Internal function to invoke {IERC721Receiver-onERC721Received} 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 ID
     * @param to target address that will receive the tokens
     * @param tokenId uint256 ID of the token to be transferred
     * @param data bytes optional data to send along with the call
     * @return bool whether the call correctly returned the expected magic value
     */
    function _checkOnERC721Received(
        address from,
        address to,
        uint256 tokenId,
        bytes memory data
    ) private returns (bool) {
        if (to.isContract()) {
            try IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, data) returns (bytes4 retval) {
                return retval == IERC721Receiver.onERC721Received.selector;
            } catch (bytes memory reason) {
                if (reason.length == 0) {
                    revert("ERC721: transfer to non ERC721Receiver implementer");
                } else {
                    /// @solidity memory-safe-assembly
                    assembly {
                        revert(add(32, reason), mload(reason))
                    }
                }
            }
        } else {
            return true;
        }
    }

    /**
     * @dev Hook that is called before any token transfer. This includes minting
     * and burning.
     *
     * Calling conditions:
     *
     * - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be
     * transferred to `to`.
     * - When `from` is zero, `tokenId` will be minted for `to`.
     * - When `to` is zero, ``from``'s `tokenId` 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 tokenId
    ) internal virtual {}

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

// File: @openzeppelin/contracts/token/ERC721/extensions/ERC721Enumerable.sol


// OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/ERC721Enumerable.sol)

pragma solidity ^0.8.0;



/**
 * @dev This implements an optional extension of {ERC721} defined in the EIP that adds
 * enumerability of all the token ids in the contract as well as all token ids owned by each
 * account.
 */
abstract contract ERC721Enumerable is ERC721, IERC721Enumerable {
    // Mapping from owner to list of owned token IDs
    mapping(address => mapping(uint256 => uint256)) private _ownedTokens;

    // Mapping from token ID to index of the owner tokens list
    mapping(uint256 => uint256) private _ownedTokensIndex;

    // Array with all token ids, used for enumeration
    uint256[] private _allTokens;

    // Mapping from token id to position in the allTokens array
    mapping(uint256 => uint256) private _allTokensIndex;

    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override(IERC165, ERC721) returns (bool) {
        return interfaceId == type(IERC721Enumerable).interfaceId || super.supportsInterface(interfaceId);
    }

    /**
     * @dev See {IERC721Enumerable-tokenOfOwnerByIndex}.
     */
    function tokenOfOwnerByIndex(address owner, uint256 index) public view virtual override returns (uint256) {
        require(index < ERC721.balanceOf(owner), "ERC721Enumerable: owner index out of bounds");
        return _ownedTokens[owner][index];
    }

    /**
     * @dev See {IERC721Enumerable-totalSupply}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        return _allTokens.length;
    }

    /**
     * @dev See {IERC721Enumerable-tokenByIndex}.
     */
    function tokenByIndex(uint256 index) public view virtual override returns (uint256) {
        require(index < ERC721Enumerable.totalSupply(), "ERC721Enumerable: global index out of bounds");
        return _allTokens[index];
    }

    /**
     * @dev Hook that is called before any token transfer. This includes minting
     * and burning.
     *
     * Calling conditions:
     *
     * - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be
     * transferred to `to`.
     * - When `from` is zero, `tokenId` will be minted for `to`.
     * - When `to` is zero, ``from``'s `tokenId` will be burned.
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual override {
        super._beforeTokenTransfer(from, to, tokenId);

        if (from == address(0)) {
            _addTokenToAllTokensEnumeration(tokenId);
        } else if (from != to) {
            _removeTokenFromOwnerEnumeration(from, tokenId);
        }
        if (to == address(0)) {
            _removeTokenFromAllTokensEnumeration(tokenId);
        } else if (to != from) {
            _addTokenToOwnerEnumeration(to, tokenId);
        }
    }

    /**
     * @dev Private function to add a token to this extension's ownership-tracking data structures.
     * @param to address representing the new owner of the given token ID
     * @param tokenId uint256 ID of the token to be added to the tokens list of the given address
     */
    function _addTokenToOwnerEnumeration(address to, uint256 tokenId) private {
        uint256 length = ERC721.balanceOf(to);
        _ownedTokens[to][length] = tokenId;
        _ownedTokensIndex[tokenId] = length;
    }

    /**
     * @dev Private function to add a token to this extension's token tracking data structures.
     * @param tokenId uint256 ID of the token to be added to the tokens list
     */
    function _addTokenToAllTokensEnumeration(uint256 tokenId) private {
        _allTokensIndex[tokenId] = _allTokens.length;
        _allTokens.push(tokenId);
    }

    /**
     * @dev Private function to remove a token from this extension's ownership-tracking data structures. Note that
     * while the token is not assigned a new owner, the `_ownedTokensIndex` mapping is _not_ updated: this allows for
     * gas optimizations e.g. when performing a transfer operation (avoiding double writes).
     * This has O(1) time complexity, but alters the order of the _ownedTokens array.
     * @param from address representing the previous owner of the given token ID
     * @param tokenId uint256 ID of the token to be removed from the tokens list of the given address
     */
    function _removeTokenFromOwnerEnumeration(address from, uint256 tokenId) private {
        // To prevent a gap in from's tokens array, we store the last token in the index of the token to delete, and
        // then delete the last slot (swap and pop).

        uint256 lastTokenIndex = ERC721.balanceOf(from) - 1;
        uint256 tokenIndex = _ownedTokensIndex[tokenId];

        // When the token to delete is the last token, the swap operation is unnecessary
        if (tokenIndex != lastTokenIndex) {
            uint256 lastTokenId = _ownedTokens[from][lastTokenIndex];

            _ownedTokens[from][tokenIndex] = lastTokenId; // Move the last token to the slot of the to-delete token
            _ownedTokensIndex[lastTokenId] = tokenIndex; // Update the moved token's index
        }

        // This also deletes the contents at the last position of the array
        delete _ownedTokensIndex[tokenId];
        delete _ownedTokens[from][lastTokenIndex];
    }

    /**
     * @dev Private function to remove a token from this extension's token tracking data structures.
     * This has O(1) time complexity, but alters the order of the _allTokens array.
     * @param tokenId uint256 ID of the token to be removed from the tokens list
     */
    function _removeTokenFromAllTokensEnumeration(uint256 tokenId) private {
        // To prevent a gap in the tokens array, we store the last token in the index of the token to delete, and
        // then delete the last slot (swap and pop).

        uint256 lastTokenIndex = _allTokens.length - 1;
        uint256 tokenIndex = _allTokensIndex[tokenId];

        // When the token to delete is the last token, the swap operation is unnecessary. However, since this occurs so
        // rarely (when the last minted token is burnt) that we still do the swap here to avoid the gas cost of adding
        // an 'if' statement (like in _removeTokenFromOwnerEnumeration)
        uint256 lastTokenId = _allTokens[lastTokenIndex];

        _allTokens[tokenIndex] = lastTokenId; // Move the last token to the slot of the to-delete token
        _allTokensIndex[lastTokenId] = tokenIndex; // Update the moved token's index

        // This also deletes the contents at the last position of the array
        delete _allTokensIndex[tokenId];
        _allTokens.pop();
    }
}

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


// OpenZeppelin Contracts (last updated v4.6.0) (utils/math/SafeMath.sol)

pragma solidity ^0.8.0;

// CAUTION
// This version of SafeMath should only be used with Solidity 0.8 or later,
// because it relies on the compiler's built in overflow checks.

/**
 * @dev Wrappers over Solidity's arithmetic operations.
 *
 * NOTE: `SafeMath` is generally not needed starting with Solidity 0.8, since the compiler
 * now has built in overflow checking.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            uint256 c = a + b;
            if (c < a) return (false, 0);
            return (true, c);
        }
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b > a) return (false, 0);
            return (true, a - b);
        }
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            // 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 (true, 0);
            uint256 c = a * b;
            if (c / a != b) return (false, 0);
            return (true, c);
        }
    }

    /**
     * @dev Returns the division of two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a / b);
        }
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a % b);
        }
    }

    /**
     * @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) {
        return a + b;
    }

    /**
     * @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 a - b;
    }

    /**
     * @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) {
        return a * b;
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator.
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return a / b;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting 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 a % b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {trySub}.
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b <= a, errorMessage);
            return a - b;
        }
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting 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) {
        unchecked {
            require(b > 0, errorMessage);
            return a / b;
        }
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting with custom message when dividing by zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryMod}.
     *
     * 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) {
        unchecked {
            require(b > 0, errorMessage);
            return a % b;
        }
    }
}

// File: @openzeppelin/contracts/utils/math/SafeCast.sol


// OpenZeppelin Contracts (last updated v4.7.0) (utils/math/SafeCast.sol)

pragma solidity ^0.8.0;

/**
 * @dev Wrappers over Solidity's uintXX/intXX casting operators with added overflow
 * checks.
 *
 * Downcasting from uint256/int256 in Solidity does not revert on overflow. This can
 * easily result in undesired exploitation or bugs, since developers usually
 * assume that overflows raise errors. `SafeCast` restores this intuition by
 * reverting the transaction when such 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.
 *
 * Can be combined with {SafeMath} and {SignedSafeMath} to extend it to smaller types, by performing
 * all math on `uint256` and `int256` and then downcasting.
 */
library SafeCast {
    /**
     * @dev Returns the downcasted uint248 from uint256, reverting on
     * overflow (when the input is greater than largest uint248).
     *
     * Counterpart to Solidity's `uint248` operator.
     *
     * Requirements:
     *
     * - input must fit into 248 bits
     *
     * _Available since v4.7._
     */
    function toUint248(uint256 value) internal pure returns (uint248) {
        require(value <= type(uint248).max, "SafeCast: value doesn't fit in 248 bits");
        return uint248(value);
    }

    /**
     * @dev Returns the downcasted uint240 from uint256, reverting on
     * overflow (when the input is greater than largest uint240).
     *
     * Counterpart to Solidity's `uint240` operator.
     *
     * Requirements:
     *
     * - input must fit into 240 bits
     *
     * _Available since v4.7._
     */
    function toUint240(uint256 value) internal pure returns (uint240) {
        require(value <= type(uint240).max, "SafeCast: value doesn't fit in 240 bits");
        return uint240(value);
    }

    /**
     * @dev Returns the downcasted uint232 from uint256, reverting on
     * overflow (when the input is greater than largest uint232).
     *
     * Counterpart to Solidity's `uint232` operator.
     *
     * Requirements:
     *
     * - input must fit into 232 bits
     *
     * _Available since v4.7._
     */
    function toUint232(uint256 value) internal pure returns (uint232) {
        require(value <= type(uint232).max, "SafeCast: value doesn't fit in 232 bits");
        return uint232(value);
    }

    /**
     * @dev Returns the downcasted uint224 from uint256, reverting on
     * overflow (when the input is greater than largest uint224).
     *
     * Counterpart to Solidity's `uint224` operator.
     *
     * Requirements:
     *
     * - input must fit into 224 bits
     *
     * _Available since v4.2._
     */
    function toUint224(uint256 value) internal pure returns (uint224) {
        require(value <= type(uint224).max, "SafeCast: value doesn't fit in 224 bits");
        return uint224(value);
    }

    /**
     * @dev Returns the downcasted uint216 from uint256, reverting on
     * overflow (when the input is greater than largest uint216).
     *
     * Counterpart to Solidity's `uint216` operator.
     *
     * Requirements:
     *
     * - input must fit into 216 bits
     *
     * _Available since v4.7._
     */
    function toUint216(uint256 value) internal pure returns (uint216) {
        require(value <= type(uint216).max, "SafeCast: value doesn't fit in 216 bits");
        return uint216(value);
    }

    /**
     * @dev Returns the downcasted uint208 from uint256, reverting on
     * overflow (when the input is greater than largest uint208).
     *
     * Counterpart to Solidity's `uint208` operator.
     *
     * Requirements:
     *
     * - input must fit into 208 bits
     *
     * _Available since v4.7._
     */
    function toUint208(uint256 value) internal pure returns (uint208) {
        require(value <= type(uint208).max, "SafeCast: value doesn't fit in 208 bits");
        return uint208(value);
    }

    /**
     * @dev Returns the downcasted uint200 from uint256, reverting on
     * overflow (when the input is greater than largest uint200).
     *
     * Counterpart to Solidity's `uint200` operator.
     *
     * Requirements:
     *
     * - input must fit into 200 bits
     *
     * _Available since v4.7._
     */
    function toUint200(uint256 value) internal pure returns (uint200) {
        require(value <= type(uint200).max, "SafeCast: value doesn't fit in 200 bits");
        return uint200(value);
    }

    /**
     * @dev Returns the downcasted uint192 from uint256, reverting on
     * overflow (when the input is greater than largest uint192).
     *
     * Counterpart to Solidity's `uint192` operator.
     *
     * Requirements:
     *
     * - input must fit into 192 bits
     *
     * _Available since v4.7._
     */
    function toUint192(uint256 value) internal pure returns (uint192) {
        require(value <= type(uint192).max, "SafeCast: value doesn't fit in 192 bits");
        return uint192(value);
    }

    /**
     * @dev Returns the downcasted uint184 from uint256, reverting on
     * overflow (when the input is greater than largest uint184).
     *
     * Counterpart to Solidity's `uint184` operator.
     *
     * Requirements:
     *
     * - input must fit into 184 bits
     *
     * _Available since v4.7._
     */
    function toUint184(uint256 value) internal pure returns (uint184) {
        require(value <= type(uint184).max, "SafeCast: value doesn't fit in 184 bits");
        return uint184(value);
    }

    /**
     * @dev Returns the downcasted uint176 from uint256, reverting on
     * overflow (when the input is greater than largest uint176).
     *
     * Counterpart to Solidity's `uint176` operator.
     *
     * Requirements:
     *
     * - input must fit into 176 bits
     *
     * _Available since v4.7._
     */
    function toUint176(uint256 value) internal pure returns (uint176) {
        require(value <= type(uint176).max, "SafeCast: value doesn't fit in 176 bits");
        return uint176(value);
    }

    /**
     * @dev Returns the downcasted uint168 from uint256, reverting on
     * overflow (when the input is greater than largest uint168).
     *
     * Counterpart to Solidity's `uint168` operator.
     *
     * Requirements:
     *
     * - input must fit into 168 bits
     *
     * _Available since v4.7._
     */
    function toUint168(uint256 value) internal pure returns (uint168) {
        require(value <= type(uint168).max, "SafeCast: value doesn't fit in 168 bits");
        return uint168(value);
    }

    /**
     * @dev Returns the downcasted uint160 from uint256, reverting on
     * overflow (when the input is greater than largest uint160).
     *
     * Counterpart to Solidity's `uint160` operator.
     *
     * Requirements:
     *
     * - input must fit into 160 bits
     *
     * _Available since v4.7._
     */
    function toUint160(uint256 value) internal pure returns (uint160) {
        require(value <= type(uint160).max, "SafeCast: value doesn't fit in 160 bits");
        return uint160(value);
    }

    /**
     * @dev Returns the downcasted uint152 from uint256, reverting on
     * overflow (when the input is greater than largest uint152).
     *
     * Counterpart to Solidity's `uint152` operator.
     *
     * Requirements:
     *
     * - input must fit into 152 bits
     *
     * _Available since v4.7._
     */
    function toUint152(uint256 value) internal pure returns (uint152) {
        require(value <= type(uint152).max, "SafeCast: value doesn't fit in 152 bits");
        return uint152(value);
    }

    /**
     * @dev Returns the downcasted uint144 from uint256, reverting on
     * overflow (when the input is greater than largest uint144).
     *
     * Counterpart to Solidity's `uint144` operator.
     *
     * Requirements:
     *
     * - input must fit into 144 bits
     *
     * _Available since v4.7._
     */
    function toUint144(uint256 value) internal pure returns (uint144) {
        require(value <= type(uint144).max, "SafeCast: value doesn't fit in 144 bits");
        return uint144(value);
    }

    /**
     * @dev Returns the downcasted uint136 from uint256, reverting on
     * overflow (when the input is greater than largest uint136).
     *
     * Counterpart to Solidity's `uint136` operator.
     *
     * Requirements:
     *
     * - input must fit into 136 bits
     *
     * _Available since v4.7._
     */
    function toUint136(uint256 value) internal pure returns (uint136) {
        require(value <= type(uint136).max, "SafeCast: value doesn't fit in 136 bits");
        return uint136(value);
    }

    /**
     * @dev Returns the downcasted uint128 from uint256, reverting on
     * overflow (when the input is greater than largest uint128).
     *
     * Counterpart to Solidity's `uint128` operator.
     *
     * Requirements:
     *
     * - input must fit into 128 bits
     *
     * _Available since v2.5._
     */
    function toUint128(uint256 value) internal pure returns (uint128) {
        require(value <= type(uint128).max, "SafeCast: value doesn't fit in 128 bits");
        return uint128(value);
    }

    /**
     * @dev Returns the downcasted uint120 from uint256, reverting on
     * overflow (when the input is greater than largest uint120).
     *
     * Counterpart to Solidity's `uint120` operator.
     *
     * Requirements:
     *
     * - input must fit into 120 bits
     *
     * _Available since v4.7._
     */
    function toUint120(uint256 value) internal pure returns (uint120) {
        require(value <= type(uint120).max, "SafeCast: value doesn't fit in 120 bits");
        return uint120(value);
    }

    /**
     * @dev Returns the downcasted uint112 from uint256, reverting on
     * overflow (when the input is greater than largest uint112).
     *
     * Counterpart to Solidity's `uint112` operator.
     *
     * Requirements:
     *
     * - input must fit into 112 bits
     *
     * _Available since v4.7._
     */
    function toUint112(uint256 value) internal pure returns (uint112) {
        require(value <= type(uint112).max, "SafeCast: value doesn't fit in 112 bits");
        return uint112(value);
    }

    /**
     * @dev Returns the downcasted uint104 from uint256, reverting on
     * overflow (when the input is greater than largest uint104).
     *
     * Counterpart to Solidity's `uint104` operator.
     *
     * Requirements:
     *
     * - input must fit into 104 bits
     *
     * _Available since v4.7._
     */
    function toUint104(uint256 value) internal pure returns (uint104) {
        require(value <= type(uint104).max, "SafeCast: value doesn't fit in 104 bits");
        return uint104(value);
    }

    /**
     * @dev Returns the downcasted uint96 from uint256, reverting on
     * overflow (when the input is greater than largest uint96).
     *
     * Counterpart to Solidity's `uint96` operator.
     *
     * Requirements:
     *
     * - input must fit into 96 bits
     *
     * _Available since v4.2._
     */
    function toUint96(uint256 value) internal pure returns (uint96) {
        require(value <= type(uint96).max, "SafeCast: value doesn't fit in 96 bits");
        return uint96(value);
    }

    /**
     * @dev Returns the downcasted uint88 from uint256, reverting on
     * overflow (when the input is greater than largest uint88).
     *
     * Counterpart to Solidity's `uint88` operator.
     *
     * Requirements:
     *
     * - input must fit into 88 bits
     *
     * _Available since v4.7._
     */
    function toUint88(uint256 value) internal pure returns (uint88) {
        require(value <= type(uint88).max, "SafeCast: value doesn't fit in 88 bits");
        return uint88(value);
    }

    /**
     * @dev Returns the downcasted uint80 from uint256, reverting on
     * overflow (when the input is greater than largest uint80).
     *
     * Counterpart to Solidity's `uint80` operator.
     *
     * Requirements:
     *
     * - input must fit into 80 bits
     *
     * _Available since v4.7._
     */
    function toUint80(uint256 value) internal pure returns (uint80) {
        require(value <= type(uint80).max, "SafeCast: value doesn't fit in 80 bits");
        return uint80(value);
    }

    /**
     * @dev Returns the downcasted uint72 from uint256, reverting on
     * overflow (when the input is greater than largest uint72).
     *
     * Counterpart to Solidity's `uint72` operator.
     *
     * Requirements:
     *
     * - input must fit into 72 bits
     *
     * _Available since v4.7._
     */
    function toUint72(uint256 value) internal pure returns (uint72) {
        require(value <= type(uint72).max, "SafeCast: value doesn't fit in 72 bits");
        return uint72(value);
    }

    /**
     * @dev Returns the downcasted uint64 from uint256, reverting on
     * overflow (when the input is greater than largest uint64).
     *
     * Counterpart to Solidity's `uint64` operator.
     *
     * Requirements:
     *
     * - input must fit into 64 bits
     *
     * _Available since v2.5._
     */
    function toUint64(uint256 value) internal pure returns (uint64) {
        require(value <= type(uint64).max, "SafeCast: value doesn't fit in 64 bits");
        return uint64(value);
    }

    /**
     * @dev Returns the downcasted uint56 from uint256, reverting on
     * overflow (when the input is greater than largest uint56).
     *
     * Counterpart to Solidity's `uint56` operator.
     *
     * Requirements:
     *
     * - input must fit into 56 bits
     *
     * _Available since v4.7._
     */
    function toUint56(uint256 value) internal pure returns (uint56) {
        require(value <= type(uint56).max, "SafeCast: value doesn't fit in 56 bits");
        return uint56(value);
    }

    /**
     * @dev Returns the downcasted uint48 from uint256, reverting on
     * overflow (when the input is greater than largest uint48).
     *
     * Counterpart to Solidity's `uint48` operator.
     *
     * Requirements:
     *
     * - input must fit into 48 bits
     *
     * _Available since v4.7._
     */
    function toUint48(uint256 value) internal pure returns (uint48) {
        require(value <= type(uint48).max, "SafeCast: value doesn't fit in 48 bits");
        return uint48(value);
    }

    /**
     * @dev Returns the downcasted uint40 from uint256, reverting on
     * overflow (when the input is greater than largest uint40).
     *
     * Counterpart to Solidity's `uint40` operator.
     *
     * Requirements:
     *
     * - input must fit into 40 bits
     *
     * _Available since v4.7._
     */
    function toUint40(uint256 value) internal pure returns (uint40) {
        require(value <= type(uint40).max, "SafeCast: value doesn't fit in 40 bits");
        return uint40(value);
    }

    /**
     * @dev Returns the downcasted uint32 from uint256, reverting on
     * overflow (when the input is greater than largest uint32).
     *
     * Counterpart to Solidity's `uint32` operator.
     *
     * Requirements:
     *
     * - input must fit into 32 bits
     *
     * _Available since v2.5._
     */
    function toUint32(uint256 value) internal pure returns (uint32) {
        require(value <= type(uint32).max, "SafeCast: value doesn't fit in 32 bits");
        return uint32(value);
    }

    /**
     * @dev Returns the downcasted uint24 from uint256, reverting on
     * overflow (when the input is greater than largest uint24).
     *
     * Counterpart to Solidity's `uint24` operator.
     *
     * Requirements:
     *
     * - input must fit into 24 bits
     *
     * _Available since v4.7._
     */
    function toUint24(uint256 value) internal pure returns (uint24) {
        require(value <= type(uint24).max, "SafeCast: value doesn't fit in 24 bits");
        return uint24(value);
    }

    /**
     * @dev Returns the downcasted uint16 from uint256, reverting on
     * overflow (when the input is greater than largest uint16).
     *
     * Counterpart to Solidity's `uint16` operator.
     *
     * Requirements:
     *
     * - input must fit into 16 bits
     *
     * _Available since v2.5._
     */
    function toUint16(uint256 value) internal pure returns (uint16) {
        require(value <= type(uint16).max, "SafeCast: value doesn't fit in 16 bits");
        return uint16(value);
    }

    /**
     * @dev Returns the downcasted uint8 from uint256, reverting on
     * overflow (when the input is greater than largest uint8).
     *
     * Counterpart to Solidity's `uint8` operator.
     *
     * Requirements:
     *
     * - input must fit into 8 bits
     *
     * _Available since v2.5._
     */
    function toUint8(uint256 value) internal pure returns (uint8) {
        require(value <= type(uint8).max, "SafeCast: value doesn't fit in 8 bits");
        return uint8(value);
    }

    /**
     * @dev Converts a signed int256 into an unsigned uint256.
     *
     * Requirements:
     *
     * - input must be greater than or equal to 0.
     *
     * _Available since v3.0._
     */
    function toUint256(int256 value) internal pure returns (uint256) {
        require(value >= 0, "SafeCast: value must be positive");
        return uint256(value);
    }

    /**
     * @dev Returns the downcasted int248 from int256, reverting on
     * overflow (when the input is less than smallest int248 or
     * greater than largest int248).
     *
     * Counterpart to Solidity's `int248` operator.
     *
     * Requirements:
     *
     * - input must fit into 248 bits
     *
     * _Available since v4.7._
     */
    function toInt248(int256 value) internal pure returns (int248) {
        require(value >= type(int248).min && value <= type(int248).max, "SafeCast: value doesn't fit in 248 bits");
        return int248(value);
    }

    /**
     * @dev Returns the downcasted int240 from int256, reverting on
     * overflow (when the input is less than smallest int240 or
     * greater than largest int240).
     *
     * Counterpart to Solidity's `int240` operator.
     *
     * Requirements:
     *
     * - input must fit into 240 bits
     *
     * _Available since v4.7._
     */
    function toInt240(int256 value) internal pure returns (int240) {
        require(value >= type(int240).min && value <= type(int240).max, "SafeCast: value doesn't fit in 240 bits");
        return int240(value);
    }

    /**
     * @dev Returns the downcasted int232 from int256, reverting on
     * overflow (when the input is less than smallest int232 or
     * greater than largest int232).
     *
     * Counterpart to Solidity's `int232` operator.
     *
     * Requirements:
     *
     * - input must fit into 232 bits
     *
     * _Available since v4.7._
     */
    function toInt232(int256 value) internal pure returns (int232) {
        require(value >= type(int232).min && value <= type(int232).max, "SafeCast: value doesn't fit in 232 bits");
        return int232(value);
    }

    /**
     * @dev Returns the downcasted int224 from int256, reverting on
     * overflow (when the input is less than smallest int224 or
     * greater than largest int224).
     *
     * Counterpart to Solidity's `int224` operator.
     *
     * Requirements:
     *
     * - input must fit into 224 bits
     *
     * _Available since v4.7._
     */
    function toInt224(int256 value) internal pure returns (int224) {
        require(value >= type(int224).min && value <= type(int224).max, "SafeCast: value doesn't fit in 224 bits");
        return int224(value);
    }

    /**
     * @dev Returns the downcasted int216 from int256, reverting on
     * overflow (when the input is less than smallest int216 or
     * greater than largest int216).
     *
     * Counterpart to Solidity's `int216` operator.
     *
     * Requirements:
     *
     * - input must fit into 216 bits
     *
     * _Available since v4.7._
     */
    function toInt216(int256 value) internal pure returns (int216) {
        require(value >= type(int216).min && value <= type(int216).max, "SafeCast: value doesn't fit in 216 bits");
        return int216(value);
    }

    /**
     * @dev Returns the downcasted int208 from int256, reverting on
     * overflow (when the input is less than smallest int208 or
     * greater than largest int208).
     *
     * Counterpart to Solidity's `int208` operator.
     *
     * Requirements:
     *
     * - input must fit into 208 bits
     *
     * _Available since v4.7._
     */
    function toInt208(int256 value) internal pure returns (int208) {
        require(value >= type(int208).min && value <= type(int208).max, "SafeCast: value doesn't fit in 208 bits");
        return int208(value);
    }

    /**
     * @dev Returns the downcasted int200 from int256, reverting on
     * overflow (when the input is less than smallest int200 or
     * greater than largest int200).
     *
     * Counterpart to Solidity's `int200` operator.
     *
     * Requirements:
     *
     * - input must fit into 200 bits
     *
     * _Available since v4.7._
     */
    function toInt200(int256 value) internal pure returns (int200) {
        require(value >= type(int200).min && value <= type(int200).max, "SafeCast: value doesn't fit in 200 bits");
        return int200(value);
    }

    /**
     * @dev Returns the downcasted int192 from int256, reverting on
     * overflow (when the input is less than smallest int192 or
     * greater than largest int192).
     *
     * Counterpart to Solidity's `int192` operator.
     *
     * Requirements:
     *
     * - input must fit into 192 bits
     *
     * _Available since v4.7._
     */
    function toInt192(int256 value) internal pure returns (int192) {
        require(value >= type(int192).min && value <= type(int192).max, "SafeCast: value doesn't fit in 192 bits");
        return int192(value);
    }

    /**
     * @dev Returns the downcasted int184 from int256, reverting on
     * overflow (when the input is less than smallest int184 or
     * greater than largest int184).
     *
     * Counterpart to Solidity's `int184` operator.
     *
     * Requirements:
     *
     * - input must fit into 184 bits
     *
     * _Available since v4.7._
     */
    function toInt184(int256 value) internal pure returns (int184) {
        require(value >= type(int184).min && value <= type(int184).max, "SafeCast: value doesn't fit in 184 bits");
        return int184(value);
    }

    /**
     * @dev Returns the downcasted int176 from int256, reverting on
     * overflow (when the input is less than smallest int176 or
     * greater than largest int176).
     *
     * Counterpart to Solidity's `int176` operator.
     *
     * Requirements:
     *
     * - input must fit into 176 bits
     *
     * _Available since v4.7._
     */
    function toInt176(int256 value) internal pure returns (int176) {
        require(value >= type(int176).min && value <= type(int176).max, "SafeCast: value doesn't fit in 176 bits");
        return int176(value);
    }

    /**
     * @dev Returns the downcasted int168 from int256, reverting on
     * overflow (when the input is less than smallest int168 or
     * greater than largest int168).
     *
     * Counterpart to Solidity's `int168` operator.
     *
     * Requirements:
     *
     * - input must fit into 168 bits
     *
     * _Available since v4.7._
     */
    function toInt168(int256 value) internal pure returns (int168) {
        require(value >= type(int168).min && value <= type(int168).max, "SafeCast: value doesn't fit in 168 bits");
        return int168(value);
    }

    /**
     * @dev Returns the downcasted int160 from int256, reverting on
     * overflow (when the input is less than smallest int160 or
     * greater than largest int160).
     *
     * Counterpart to Solidity's `int160` operator.
     *
     * Requirements:
     *
     * - input must fit into 160 bits
     *
     * _Available since v4.7._
     */
    function toInt160(int256 value) internal pure returns (int160) {
        require(value >= type(int160).min && value <= type(int160).max, "SafeCast: value doesn't fit in 160 bits");
        return int160(value);
    }

    /**
     * @dev Returns the downcasted int152 from int256, reverting on
     * overflow (when the input is less than smallest int152 or
     * greater than largest int152).
     *
     * Counterpart to Solidity's `int152` operator.
     *
     * Requirements:
     *
     * - input must fit into 152 bits
     *
     * _Available since v4.7._
     */
    function toInt152(int256 value) internal pure returns (int152) {
        require(value >= type(int152).min && value <= type(int152).max, "SafeCast: value doesn't fit in 152 bits");
        return int152(value);
    }

    /**
     * @dev Returns the downcasted int144 from int256, reverting on
     * overflow (when the input is less than smallest int144 or
     * greater than largest int144).
     *
     * Counterpart to Solidity's `int144` operator.
     *
     * Requirements:
     *
     * - input must fit into 144 bits
     *
     * _Available since v4.7._
     */
    function toInt144(int256 value) internal pure returns (int144) {
        require(value >= type(int144).min && value <= type(int144).max, "SafeCast: value doesn't fit in 144 bits");
        return int144(value);
    }

    /**
     * @dev Returns the downcasted int136 from int256, reverting on
     * overflow (when the input is less than smallest int136 or
     * greater than largest int136).
     *
     * Counterpart to Solidity's `int136` operator.
     *
     * Requirements:
     *
     * - input must fit into 136 bits
     *
     * _Available since v4.7._
     */
    function toInt136(int256 value) internal pure returns (int136) {
        require(value >= type(int136).min && value <= type(int136).max, "SafeCast: value doesn't fit in 136 bits");
        return int136(value);
    }

    /**
     * @dev Returns the downcasted int128 from int256, reverting on
     * overflow (when the input is less than smallest int128 or
     * greater than largest int128).
     *
     * Counterpart to Solidity's `int128` operator.
     *
     * Requirements:
     *
     * - input must fit into 128 bits
     *
     * _Available since v3.1._
     */
    function toInt128(int256 value) internal pure returns (int128) {
        require(value >= type(int128).min && value <= type(int128).max, "SafeCast: value doesn't fit in 128 bits");
        return int128(value);
    }

    /**
     * @dev Returns the downcasted int120 from int256, reverting on
     * overflow (when the input is less than smallest int120 or
     * greater than largest int120).
     *
     * Counterpart to Solidity's `int120` operator.
     *
     * Requirements:
     *
     * - input must fit into 120 bits
     *
     * _Available since v4.7._
     */
    function toInt120(int256 value) internal pure returns (int120) {
        require(value >= type(int120).min && value <= type(int120).max, "SafeCast: value doesn't fit in 120 bits");
        return int120(value);
    }

    /**
     * @dev Returns the downcasted int112 from int256, reverting on
     * overflow (when the input is less than smallest int112 or
     * greater than largest int112).
     *
     * Counterpart to Solidity's `int112` operator.
     *
     * Requirements:
     *
     * - input must fit into 112 bits
     *
     * _Available since v4.7._
     */
    function toInt112(int256 value) internal pure returns (int112) {
        require(value >= type(int112).min && value <= type(int112).max, "SafeCast: value doesn't fit in 112 bits");
        return int112(value);
    }

    /**
     * @dev Returns the downcasted int104 from int256, reverting on
     * overflow (when the input is less than smallest int104 or
     * greater than largest int104).
     *
     * Counterpart to Solidity's `int104` operator.
     *
     * Requirements:
     *
     * - input must fit into 104 bits
     *
     * _Available since v4.7._
     */
    function toInt104(int256 value) internal pure returns (int104) {
        require(value >= type(int104).min && value <= type(int104).max, "SafeCast: value doesn't fit in 104 bits");
        return int104(value);
    }

    /**
     * @dev Returns the downcasted int96 from int256, reverting on
     * overflow (when the input is less than smallest int96 or
     * greater than largest int96).
     *
     * Counterpart to Solidity's `int96` operator.
     *
     * Requirements:
     *
     * - input must fit into 96 bits
     *
     * _Available since v4.7._
     */
    function toInt96(int256 value) internal pure returns (int96) {
        require(value >= type(int96).min && value <= type(int96).max, "SafeCast: value doesn't fit in 96 bits");
        return int96(value);
    }

    /**
     * @dev Returns the downcasted int88 from int256, reverting on
     * overflow (when the input is less than smallest int88 or
     * greater than largest int88).
     *
     * Counterpart to Solidity's `int88` operator.
     *
     * Requirements:
     *
     * - input must fit into 88 bits
     *
     * _Available since v4.7._
     */
    function toInt88(int256 value) internal pure returns (int88) {
        require(value >= type(int88).min && value <= type(int88).max, "SafeCast: value doesn't fit in 88 bits");
        return int88(value);
    }

    /**
     * @dev Returns the downcasted int80 from int256, reverting on
     * overflow (when the input is less than smallest int80 or
     * greater than largest int80).
     *
     * Counterpart to Solidity's `int80` operator.
     *
     * Requirements:
     *
     * - input must fit into 80 bits
     *
     * _Available since v4.7._
     */
    function toInt80(int256 value) internal pure returns (int80) {
        require(value >= type(int80).min && value <= type(int80).max, "SafeCast: value doesn't fit in 80 bits");
        return int80(value);
    }

    /**
     * @dev Returns the downcasted int72 from int256, reverting on
     * overflow (when the input is less than smallest int72 or
     * greater than largest int72).
     *
     * Counterpart to Solidity's `int72` operator.
     *
     * Requirements:
     *
     * - input must fit into 72 bits
     *
     * _Available since v4.7._
     */
    function toInt72(int256 value) internal pure returns (int72) {
        require(value >= type(int72).min && value <= type(int72).max, "SafeCast: value doesn't fit in 72 bits");
        return int72(value);
    }

    /**
     * @dev Returns the downcasted int64 from int256, reverting on
     * overflow (when the input is less than smallest int64 or
     * greater than largest int64).
     *
     * Counterpart to Solidity's `int64` operator.
     *
     * Requirements:
     *
     * - input must fit into 64 bits
     *
     * _Available since v3.1._
     */
    function toInt64(int256 value) internal pure returns (int64) {
        require(value >= type(int64).min && value <= type(int64).max, "SafeCast: value doesn't fit in 64 bits");
        return int64(value);
    }

    /**
     * @dev Returns the downcasted int56 from int256, reverting on
     * overflow (when the input is less than smallest int56 or
     * greater than largest int56).
     *
     * Counterpart to Solidity's `int56` operator.
     *
     * Requirements:
     *
     * - input must fit into 56 bits
     *
     * _Available since v4.7._
     */
    function toInt56(int256 value) internal pure returns (int56) {
        require(value >= type(int56).min && value <= type(int56).max, "SafeCast: value doesn't fit in 56 bits");
        return int56(value);
    }

    /**
     * @dev Returns the downcasted int48 from int256, reverting on
     * overflow (when the input is less than smallest int48 or
     * greater than largest int48).
     *
     * Counterpart to Solidity's `int48` operator.
     *
     * Requirements:
     *
     * - input must fit into 48 bits
     *
     * _Available since v4.7._
     */
    function toInt48(int256 value) internal pure returns (int48) {
        require(value >= type(int48).min && value <= type(int48).max, "SafeCast: value doesn't fit in 48 bits");
        return int48(value);
    }

    /**
     * @dev Returns the downcasted int40 from int256, reverting on
     * overflow (when the input is less than smallest int40 or
     * greater than largest int40).
     *
     * Counterpart to Solidity's `int40` operator.
     *
     * Requirements:
     *
     * - input must fit into 40 bits
     *
     * _Available since v4.7._
     */
    function toInt40(int256 value) internal pure returns (int40) {
        require(value >= type(int40).min && value <= type(int40).max, "SafeCast: value doesn't fit in 40 bits");
        return int40(value);
    }

    /**
     * @dev Returns the downcasted int32 from int256, reverting on
     * overflow (when the input is less than smallest int32 or
     * greater than largest int32).
     *
     * Counterpart to Solidity's `int32` operator.
     *
     * Requirements:
     *
     * - input must fit into 32 bits
     *
     * _Available since v3.1._
     */
    function toInt32(int256 value) internal pure returns (int32) {
        require(value >= type(int32).min && value <= type(int32).max, "SafeCast: value doesn't fit in 32 bits");
        return int32(value);
    }

    /**
     * @dev Returns the downcasted int24 from int256, reverting on
     * overflow (when the input is less than smallest int24 or
     * greater than largest int24).
     *
     * Counterpart to Solidity's `int24` operator.
     *
     * Requirements:
     *
     * - input must fit into 24 bits
     *
     * _Available since v4.7._
     */
    function toInt24(int256 value) internal pure returns (int24) {
        require(value >= type(int24).min && value <= type(int24).max, "SafeCast: value doesn't fit in 24 bits");
        return int24(value);
    }

    /**
     * @dev Returns the downcasted int16 from int256, reverting on
     * overflow (when the input is less than smallest int16 or
     * greater than largest int16).
     *
     * Counterpart to Solidity's `int16` operator.
     *
     * Requirements:
     *
     * - input must fit into 16 bits
     *
     * _Available since v3.1._
     */
    function toInt16(int256 value) internal pure returns (int16) {
        require(value >= type(int16).min && value <= type(int16).max, "SafeCast: value doesn't fit in 16 bits");
        return int16(value);
    }

    /**
     * @dev Returns the downcasted int8 from int256, reverting on
     * overflow (when the input is less than smallest int8 or
     * greater than largest int8).
     *
     * Counterpart to Solidity's `int8` operator.
     *
     * Requirements:
     *
     * - input must fit into 8 bits
     *
     * _Available since v3.1._
     */
    function toInt8(int256 value) internal pure returns (int8) {
        require(value >= type(int8).min && value <= type(int8).max, "SafeCast: value doesn't fit in 8 bits");
        return int8(value);
    }

    /**
     * @dev Converts an unsigned uint256 into a signed int256.
     *
     * Requirements:
     *
     * - input must be less than or equal to maxInt256.
     *
     * _Available since v3.0._
     */
    function toInt256(uint256 value) internal pure returns (int256) {
        // Note: Unsafe cast below is okay because `type(int256).max` is guaranteed to be positive
        require(value <= uint256(type(int256).max), "SafeCast: value doesn't fit in an int256");
        return int256(value);
    }
}

// File: @chainlink/contracts/src/v0.8/interfaces/AggregatorInterface.sol


pragma solidity ^0.8.0;

interface AggregatorInterface {
  function latestAnswer() external view returns (int256);

  function latestTimestamp() external view returns (uint256);

  function latestRound() external view returns (uint256);

  function getAnswer(uint256 roundId) external view returns (int256);

  function getTimestamp(uint256 roundId) external view returns (uint256);

  event AnswerUpdated(int256 indexed current, uint256 indexed roundId, uint256 updatedAt);

  event NewRound(uint256 indexed roundId, address indexed startedBy, uint256 startedAt);
}

// File: Ethereum.sol










pragma solidity >=0.5.0;

interface ILayerZeroUserApplicationConfig {
    // @notice set the configuration of the LayerZero messaging library of the specified version
    // @param _version - messaging library version
    // @param _chainId - the chainId for the pending config change
    // @param _configType - type of configuration. every messaging library has its own convention.
    // @param _config - configuration in the bytes. can encode arbitrary content.
    function setConfig(uint16 _version, uint16 _chainId, uint _configType, bytes calldata _config) external;

    // @notice set the send() LayerZero messaging library version to _version
    // @param _version - new messaging library version
    function setSendVersion(uint16 _version) external;

    // @notice set the lzReceive() LayerZero messaging library version to _version
    // @param _version - new messaging library version
    function setReceiveVersion(uint16 _version) external;

    // @notice Only when the UA needs to resume the message flow in blocking mode and clear the stored payload
    // @param _srcChainId - the chainId of the source chain
    // @param _srcAddress - the contract address of the source contract at the source chain
    function forceResumeReceive(uint16 _srcChainId, bytes calldata _srcAddress) external;
}

// File: contracts/interfaces/ILayerZeroEndpoint.sol



pragma solidity >=0.5.0;


interface ILayerZeroEndpoint is ILayerZeroUserApplicationConfig {
    // @notice send a LayerZero message to the specified address at a LayerZero endpoint.
    // @param _dstChainId - the destination chain identifier
    // @param _destination - the address on destination chain (in bytes). address length/format may vary by chains
    // @param _payload - a custom bytes payload to send to the destination contract
    // @param _refundAddress - if the source transaction is cheaper than the amount of value passed, refund the additional amount to this address
    // @param _zroPaymentAddress - the address of the ZRO token holder who would pay for the transaction
    // @param _adapterParams - parameters for custom functionality. e.g. receive airdropped native gas from the relayer on destination
    function send(uint16 _dstChainId, bytes calldata _destination, bytes calldata _payload, address payable _refundAddress, address _zroPaymentAddress, bytes calldata _adapterParams) external payable;

    // @notice used by the messaging library to publish verified payload
    // @param _srcChainId - the source chain identifier
    // @param _srcAddress - the source contract (as bytes) at the source chain
    // @param _dstAddress - the address on destination chain
    // @param _nonce - the unbound message ordering nonce
    // @param _gasLimit - the gas limit for external contract execution
    // @param _payload - verified payload to send to the destination contract
    function receivePayload(uint16 _srcChainId, bytes calldata _srcAddress, address _dstAddress, uint64 _nonce, uint _gasLimit, bytes calldata _payload) external;

    // @notice get the inboundNonce of a receiver from a source chain which could be EVM or non-EVM chain
    // @param _srcChainId - the source chain identifier
    // @param _srcAddress - the source chain contract address
    function getInboundNonce(uint16 _srcChainId, bytes calldata _srcAddress) external view returns (uint64);

    // @notice get the outboundNonce from this source chain which, consequently, is always an EVM
    // @param _srcAddress - the source chain contract address
    function getOutboundNonce(uint16 _dstChainId, address _srcAddress) external view returns (uint64);

    // @notice gets a quote in source native gas, for the amount that send() requires to pay for message delivery
    // @param _dstChainId - the destination chain identifier
    // @param _userApplication - the user app address on this EVM chain
    // @param _payload - the custom message to send over LayerZero
    // @param _payInZRO - if false, user app pays the protocol fee in native token
    // @param _adapterParam - parameters for the adapter service, e.g. send some dust native token to dstChain
    function estimateFees(uint16 _dstChainId, address _userApplication, bytes calldata _payload, bool _payInZRO, bytes calldata _adapterParam) external view returns (uint nativeFee, uint zroFee);

    // @notice get this Endpoint's immutable source identifier
    function getChainId() external view returns (uint16);

    // @notice the interface to retry failed message on this Endpoint destination
    // @param _srcChainId - the source chain identifier
    // @param _srcAddress - the source chain contract address
    // @param _payload - the payload to be retried
    function retryPayload(uint16 _srcChainId, bytes calldata _srcAddress, bytes calldata _payload) external;

    // @notice query if any STORED payload (message blocking) at the endpoint.
    // @param _srcChainId - the source chain identifier
    // @param _srcAddress - the source chain contract address
    function hasStoredPayload(uint16 _srcChainId, bytes calldata _srcAddress) external view returns (bool);

    // @notice query if the _libraryAddress is valid for sending msgs.
    // @param _userApplication - the user app address on this EVM chain
    function getSendLibraryAddress(address _userApplication) external view returns (address);

    // @notice query if the _libraryAddress is valid for receiving msgs.
    // @param _userApplication - the user app address on this EVM chain
    function getReceiveLibraryAddress(address _userApplication) external view returns (address);

    // @notice query if the non-reentrancy guard for send() is on
    // @return true if the guard is on. false otherwise
    function isSendingPayload() external view returns (bool);

    // @notice query if the non-reentrancy guard for receive() is on
    // @return true if the guard is on. false otherwise
    function isReceivingPayload() external view returns (bool);

    // @notice get the configuration of the LayerZero messaging library of the specified version
    // @param _version - messaging library version
    // @param _chainId - the chainId for the pending config change
    // @param _userApplication - the contract address of the user application
    // @param _configType - type of configuration. every messaging library has its own convention.
    function getConfig(uint16 _version, uint16 _chainId, address _userApplication, uint _configType) external view returns (bytes memory);

    // @notice get the send() LayerZero messaging library version
    // @param _userApplication - the contract address of the user application
    function getSendVersion(address _userApplication) external view returns (uint16);

    // @notice get the lzReceive() LayerZero messaging library version
    // @param _userApplication - the contract address of the user application
    function getReceiveVersion(address _userApplication) external view returns (uint16);
}

// File: contracts/interfaces/ILayerZeroReceiver.sol



pragma solidity >=0.5.0;

interface ILayerZeroReceiver {
    // @notice LayerZero endpoint will invoke this function to deliver the message on the destination
    // @param _srcChainId - the source endpoint identifier
    // @param _srcAddress - the source sending contract address from the source chain
    // @param _nonce - the ordered message nonce
    // @param _payload - the signed payload is the UA bytes has encoded to be sent
    function lzReceive(uint16 _srcChainId, bytes calldata _srcAddress, uint64 _nonce, bytes calldata _payload) external;
}

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


// OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)

pragma solidity ^0.8.0;


/**
 * @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.
 */
abstract 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() {
        _transferOwnership(_msgSender());
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual 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 {
        _transferOwnership(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");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

// File: contracts/NonblockingReceiver.sol


pragma solidity ^0.8.6;
abstract contract NonblockingReceiver is Ownable, ILayerZeroReceiver {

    ILayerZeroEndpoint internal endpoint;

    struct FailedMessages {
        uint payloadLength;
        bytes32 payloadHash;
    }

    mapping(uint16 => mapping(bytes => mapping(uint => FailedMessages))) public failedMessages;
    mapping(uint16 => bytes) public trustedRemoteLookup;

    event MessageFailed(uint16 _srcChainId, bytes _srcAddress, uint64 _nonce, bytes _payload);

    function lzReceive(uint16 _srcChainId, bytes memory _srcAddress, uint64 _nonce, bytes memory _payload) external override {
        require(msg.sender == address(endpoint)); // boilerplate! lzReceive must be called by the endpoint for security
        require(_srcAddress.length == trustedRemoteLookup[_srcChainId].length && keccak256(_srcAddress) == keccak256(trustedRemoteLookup[_srcChainId]), 
            "NonblockingReceiver: invalid source sending contract");

        // try-catch all errors/exceptions
        // having failed messages does not block messages passing
        try this.onLzReceive(_srcChainId, _srcAddress, _nonce, _payload) {
            // do nothing
        } catch {
            // error / exception
            failedMessages[_srcChainId][_srcAddress][_nonce] = FailedMessages(_payload.length, keccak256(_payload));
            emit MessageFailed(_srcChainId, _srcAddress, _nonce, _payload);
        }
    }

    function onLzReceive(uint16 _srcChainId, bytes memory _srcAddress, uint64 _nonce, bytes memory _payload) public {
        // only internal transaction
        require(msg.sender == address(this), "NonblockingReceiver: caller must be Bridge.");

        // handle incoming message
        _LzReceive( _srcChainId, _srcAddress, _nonce, _payload);
    }

    // abstract function
    function _LzReceive(uint16 _srcChainId, bytes memory _srcAddress, uint64 _nonce, bytes memory _payload) virtual internal;

    function _lzSend(uint16 _dstChainId, bytes memory _payload, address payable _refundAddress, address _zroPaymentAddress, bytes memory _txParam) internal {
        endpoint.send{value: msg.value}(_dstChainId, trustedRemoteLookup[_dstChainId], _payload, _refundAddress, _zroPaymentAddress, _txParam);
    }

    function retryMessage(uint16 _srcChainId, bytes memory _srcAddress, uint64 _nonce, bytes calldata _payload) external payable {
        // assert there is message to retry
        FailedMessages storage failedMsg = failedMessages[_srcChainId][_srcAddress][_nonce];
        require(failedMsg.payloadHash != bytes32(0), "NonblockingReceiver: no stored message");
        require(_payload.length == failedMsg.payloadLength && keccak256(_payload) == failedMsg.payloadHash, "LayerZero: invalid payload");
        // clear the stored message
        failedMsg.payloadLength = 0;
        failedMsg.payloadHash = bytes32(0);
        // execute the message. revert if it fails again
        this.onLzReceive(_srcChainId, _srcAddress, _nonce, _payload);
    }

    function setTrustedRemote(uint16 _chainId, bytes calldata _trustedRemote) external onlyOwner {
        trustedRemoteLookup[_chainId] = _trustedRemote;
    }
}

// File: contracts/GhostlyGhosts.sol



pragma solidity ^0.8.7;


/*
 *      _      ______     _____                        _           
 *     | |    |___  /    |  __ \                      (_)          
 *     | |       / /     | |  | | ___  _ __ ___   __ _ _ _ __  ___ 
 *     | |      / /      | |  | |/ _ \| '_ ` _ \ / _` | | '_ \/ __|
 *     | |____ / /__     | |__| | (_) | | | | | | (_| | | | | \__ \
 *     |______/_____|    |_____/ \___/|_| |_| |_|\__,_|_|_| |_|___/
 *                                                                 
 *                                                                 
 */

contract lzCore is Ownable, ERC721Enumerable, NonblockingReceiver {
    using SafeCast for int256;
    using SafeMath for uint256;

    AggregatorInterface internal ethUSDAPI;

    /*
        Ethereum ,
        Binance Chain ,
        Avalanche ,        
        Arbitrum ,
        Optimism ,        
        Fantom ,
        Polygon ,
        Harmony ,
     */
    string public chainName = "Ethereum";
    bool public paused = true;
    string public baseURI;
    int256 private fiveLetter= 5000000000000000000 * 10 **18;
    int256 private fourLetter= 30000000000000000000 * 10 **18;
    int256 private threeLetter= 100000000000000000000 * 10 **18;
    uint256 private tolerance = 98;
    uint gasForDestinationLzReceive = 350000;
    uint256 count = 0;
    struct domainLogs{
        uint256 time;
        uint256 nftID;
    }
    mapping(string => domainLogs) public domainsData;

    struct domainInfos{
        string name;
    }
    mapping(uint256 => domainInfos) public domainInfo;
    constructor(string memory baseURI_, address _layerZeroEndpoint) ERC721("Layer Zero Name Service", "LZNM") { 
        endpoint = ILayerZeroEndpoint(_layerZeroEndpoint);
        baseURI = baseURI_;
        ethUSDAPI = AggregatorInterface(0x5f4eC3Df9cbd43714FE2740f5E3616155c5b8419);
    }
    receive() external payable {
        /* 
            thanks <3
        */
    }
    function ethUSD() public view returns (int256) {
        return ethUSDAPI.latestAnswer()*10**10;
    }
    function burnExpiredDomain(string memory domainName) public onlyOwner{
        require(domainsData[domainName].time < block.timestamp, "Domain is not expired. Error #66");
        if(_exists(domainsData[domainName].nftID)){
            _burn(domainsData[domainName].nftID);
        }        
        delete domainInfo[domainsData[domainName].nftID].name;
        domainsData[domainName].time = 0;
        domainsData[domainName].nftID = 0;
    }
    function otherChainRenew(string memory domainName , uint256 newTime) public onlyOwner{
        domainsData[domainName].time = newTime;
    }
    function register(string memory domainName , uint256 year) public payable{
        require(!paused , "Register now not avaliable. Try again later. Error #1");
        require(year >= 1 , "Invalid year value. Error #30");
        require(bytes(domainName).length >= 3, "Name is too short. Names must be at least 3 characters long. Error #2");
        require(checkDomainAvaliable(domainName) == true , "Domain unavaliable (Has been registered). Error #41");
        uint256 price = domainPrice(domainName) * year;
        require(msg.value >= (price / 100) * tolerance , "Check register price. Error #3");

        domainsData[domainName].time = block.timestamp + year * 31557600;
        domainsData[domainName].nftID = count + 1;

        //set domain names
        domainInfo[count + 1].name = domainName;
        _safeMint(msg.sender, count + 1);
        count += 1;

    }
    function renew(string memory domainName , uint256 year) public payable{
        require(bytes(domainName).length >= 3, "Name is too short. Names must be at least 3 characters long. Error #45");
        require(msg.sender == ownerOf(domainsData[domainName].nftID) , "Access denied. Error #35");
        uint256 price = domainPrice(domainName) * year;
        require(msg.value >= (price / 100) * tolerance , "Check register price. Error #32");
        domainsData[domainName].time += year * 31557600;

    }    
    function domainPrice(string memory domainName) public view returns(uint256){
        uint256 lenCount = bytes(domainName).length;
        if (lenCount <= 3){
            return (threeLetter / ethUSD()).toUint256();
        }
        else if(lenCount == 4){
            return (fourLetter / ethUSD()).toUint256();
        }
        else if(lenCount >= 5){
            return (fiveLetter / ethUSD()).toUint256();
        }
    }
    function checkDomainAvaliable(string memory domainName) public view returns(bool){
        if( domainsData[domainName].time == 0 ){
            return true;
        }
        else{
            return false;
        }
    }
    function estimateFeesView(uint16 _chainId, uint tokenId) public view returns (uint) {
        bytes memory payload = abi.encode(msg.sender , tokenId , domainsData[domainInfo[tokenId].name].time , domainInfo[tokenId].name);

        uint16 version = 1;
        bytes memory adapterParams = abi.encodePacked(version, gasForDestinationLzReceive);

        (uint messageFee, ) = endpoint.estimateFees(_chainId, address(this), payload, false, adapterParams);
        return messageFee;
    }
    function traverseChains(uint16 _chainId, uint tokenId) public payable {
        require(msg.sender == ownerOf(tokenId), "You must own the token to traverse");
        require(trustedRemoteLookup[_chainId].length > 0, "This chain is currently unavailable for travel");

        bytes memory payload = abi.encode(msg.sender , tokenId ,  domainsData[domainInfo[tokenId].name].time , domainInfo[tokenId].name);

        uint16 version = 1;
        bytes memory adapterParams = abi.encodePacked(version, gasForDestinationLzReceive);

        (uint messageFee, ) = endpoint.estimateFees(_chainId, address(this), payload, false, adapterParams);
        
        require(msg.value >= messageFee, "LZ: msg.value not enough to cover messageFee. Send gas for message fees");

        endpoint.send{value: msg.value}(
            _chainId,                           
            trustedRemoteLookup[_chainId],      
            payload,                           
            payable(msg.sender),               
            address(0x0),                       
            adapterParams                      
        );
        _burn(tokenId);
    }
    function _LzReceive(uint16 _srcChainId, bytes memory _srcAddress, uint64 _nonce, bytes memory _payload) override internal {
        // decode
        (address toAddr, uint tokenId, uint256 time, string memory domainName) = abi.decode(_payload, (address, uint, uint256, string));
        domainsData[domainName].time = time;
        domainsData[domainName].nftID = tokenId;
        domainInfo[tokenId].name = domainName;
        _safeMint(toAddr, tokenId);

    }  
    function changePaused() external onlyOwner{
        if (paused == true) {
            paused = false;
        }
        else{
            paused = true;
        }
    }
    function changePrice(int256 a , int256 b , int256 c) public onlyOwner{
        if (a != 0){
            threeLetter = a;
        }
        if ( b != 0){
            fourLetter = b;
        }
        if (c != 0){
            fiveLetter = c;
        }
    }
    function setBaseURI(string memory URI) external onlyOwner {
        baseURI = URI;
    }

    function withdraw() public payable onlyOwner {
        (bool sent, ) = payable(owner()).call{value: address(this).balance}("");
        require(sent);
    }

    function setGasForDestinationLzReceive(uint newVal) external onlyOwner {
        gasForDestinationLzReceive = newVal;
    }

    function changeTolerance(uint256 newTolerance) public onlyOwner{
        tolerance = newTolerance;
    }

    function getCount() public view returns(uint256){
        return count;
    }

    function _baseURI() override internal view returns (string memory) {
        return baseURI;
    }
    
    function walletOfOwner(address _owner) public view returns(uint256[] memory) {
        uint256 ownerTokenCount = balanceOf(_owner);
        uint256[] memory tokenIds = new uint256[](ownerTokenCount);
        for (uint256 i; i < ownerTokenCount; i++) {
            tokenIds [i]
            = tokenOfOwnerByIndex(_owner, i);
        }
        return tokenIds;
    }
}

pragma solidity 0.6.6;


/**
 * @title The Owned contract
 * @notice A contract with helpers for basic contract ownership.
 */
contract Owned {

  address payable public owner;
  address private pendingOwner;

  event OwnershipTransferRequested(
    address indexed from,
    address indexed to
  );
  event OwnershipTransferred(
    address indexed from,
    address indexed to
  );

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

  /**
   * @dev Allows an owner to begin transferring ownership to a new address,
   * pending.
   */
  function transferOwnership(address _to)
    external
    onlyOwner()
  {
    pendingOwner = _to;

    emit OwnershipTransferRequested(owner, _to);
  }

  /**
   * @dev Allows an ownership transfer to be completed by the recipient.
   */
  function acceptOwnership()
    external
  {
    require(msg.sender == pendingOwner, "Must be proposed owner");

    address oldOwner = owner;
    owner = msg.sender;
    pendingOwner = address(0);

    emit OwnershipTransferred(oldOwner, msg.sender);
  }

  /**
   * @dev Reverts if called by anyone other than the contract owner.
   */
  modifier onlyOwner() {
    require(msg.sender == owner, "Only callable by owner");
    _;
  }

}

interface AggregatorInterface {
  function latestAnswer() external view returns (int256);
  function latestTimestamp() external view returns (uint256);
  function latestRound() external view returns (uint256);
  function getAnswer(uint256 roundId) external view returns (int256);
  function getTimestamp(uint256 roundId) external view returns (uint256);

  event AnswerUpdated(int256 indexed current, uint256 indexed roundId, uint256 updatedAt);
  event NewRound(uint256 indexed roundId, address indexed startedBy, uint256 startedAt);
}

interface AggregatorV3Interface {

  function decimals() external view returns (uint8);
  function description() external view returns (string memory);
  function version() external view returns (uint256);

  // getRoundData and latestRoundData should both raise "No data present"
  // if they do not have data to report, instead of returning unset values
  // which could be misinterpreted as actual reported values.
  function getRoundData(uint80 _roundId)
    external
    view
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    );
  function latestRoundData()
    external
    view
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    );

}

interface AggregatorV2V3Interface is AggregatorInterface, AggregatorV3Interface
{
}

/**
 * @title A trusted proxy for updating where current answers are read from
 * @notice This contract provides a consistent address for the
 * CurrentAnwerInterface but delegates where it reads from to the owner, who is
 * trusted to update it.
 */
contract AggregatorProxy is AggregatorV2V3Interface, Owned {

  struct Phase {
    uint16 id;
    AggregatorV2V3Interface aggregator;
  }
  Phase private currentPhase;
  AggregatorV2V3Interface public proposedAggregator;
  mapping(uint16 => AggregatorV2V3Interface) public phaseAggregators;

  uint256 constant private PHASE_OFFSET = 64;
  uint256 constant private PHASE_SIZE = 16;
  uint256 constant private MAX_ID = 2**(PHASE_OFFSET+PHASE_SIZE) - 1;

  constructor(address _aggregator) public Owned() {
    setAggregator(_aggregator);
  }

  /**
   * @notice Reads the current answer from aggregator delegated to.
   *
   * @dev #[deprecated] Use latestRoundData instead. This does not error if no
   * answer has been reached, it will simply return 0. Either wait to point to
   * an already answered Aggregator or use the recommended latestRoundData
   * instead which includes better verification information.
   */
  function latestAnswer()
    public
    view
    virtual
    override
    returns (int256 answer)
  {
    return currentPhase.aggregator.latestAnswer();
  }

  /**
   * @notice Reads the last updated height from aggregator delegated to.
   *
   * @dev #[deprecated] Use latestRoundData instead. This does not error if no
   * answer has been reached, it will simply return 0. Either wait to point to
   * an already answered Aggregator or use the recommended latestRoundData
   * instead which includes better verification information.
   */
  function latestTimestamp()
    public
    view
    virtual
    override
    returns (uint256 updatedAt)
  {
    return currentPhase.aggregator.latestTimestamp();
  }

  /**
   * @notice get past rounds answers
   * @param _roundId the answer number to retrieve the answer for
   *
   * @dev #[deprecated] Use getRoundData instead. This does not error if no
   * answer has been reached, it will simply return 0. Either wait to point to
   * an already answered Aggregator or use the recommended getRoundData
   * instead which includes better verification information.
   */
  function getAnswer(uint256 _roundId)
    public
    view
    virtual
    override
    returns (int256 answer)
  {
    if (_roundId > MAX_ID) return 0;

    (uint16 phaseId, uint64 aggregatorRoundId) = parseIds(_roundId);
    AggregatorV2V3Interface aggregator = phaseAggregators[phaseId];
    if (address(aggregator) == address(0)) return 0;

    return aggregator.getAnswer(aggregatorRoundId);
  }

  /**
   * @notice get block timestamp when an answer was last updated
   * @param _roundId the answer number to retrieve the updated timestamp for
   *
   * @dev #[deprecated] Use getRoundData instead. This does not error if no
   * answer has been reached, it will simply return 0. Either wait to point to
   * an already answered Aggregator or use the recommended getRoundData
   * instead which includes better verification information.
   */
  function getTimestamp(uint256 _roundId)
    public
    view
    virtual
    override
    returns (uint256 updatedAt)
  {
    if (_roundId > MAX_ID) return 0;

    (uint16 phaseId, uint64 aggregatorRoundId) = parseIds(_roundId);
    AggregatorV2V3Interface aggregator = phaseAggregators[phaseId];
    if (address(aggregator) == address(0)) return 0;

    return aggregator.getTimestamp(aggregatorRoundId);
  }

  /**
   * @notice get the latest completed round where the answer was updated. This
   * ID includes the proxy's phase, to make sure round IDs increase even when
   * switching to a newly deployed aggregator.
   *
   * @dev #[deprecated] Use latestRoundData instead. This does not error if no
   * answer has been reached, it will simply return 0. Either wait to point to
   * an already answered Aggregator or use the recommended latestRoundData
   * instead which includes better verification information.
   */
  function latestRound()
    public
    view
    virtual
    override
    returns (uint256 roundId)
  {
    Phase memory phase = currentPhase; // cache storage reads
    return addPhase(phase.id, uint64(phase.aggregator.latestRound()));
  }

  /**
   * @notice get data about a round. Consumers are encouraged to check
   * that they're receiving fresh data by inspecting the updatedAt and
   * answeredInRound return values.
   * Note that different underlying implementations of AggregatorV3Interface
   * have slightly different semantics for some of the return values. Consumers
   * should determine what implementations they expect to receive
   * data from and validate that they can properly handle return data from all
   * of them.
   * @param _roundId the requested round ID as presented through the proxy, this
   * is made up of the aggregator's round ID with the phase ID encoded in the
   * two highest order bytes
   * @return roundId is the round ID from the aggregator for which the data was
   * retrieved combined with an phase to ensure that round IDs get larger as
   * time moves forward.
   * @return answer is the answer for the given round
   * @return startedAt is the timestamp when the round was started.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @return updatedAt is the timestamp when the round last was updated (i.e.
   * answer was last computed)
   * @return answeredInRound is the round ID of the round in which the answer
   * was computed.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @dev Note that answer and updatedAt may change between queries.
   */
  function getRoundData(uint80 _roundId)
    public
    view
    virtual
    override
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    (uint16 phaseId, uint64 aggregatorRoundId) = parseIds(_roundId);

    (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 ansIn
    ) = phaseAggregators[phaseId].getRoundData(aggregatorRoundId);

    return addPhaseIds(roundId, answer, startedAt, updatedAt, ansIn, phaseId);
  }

  /**
   * @notice get data about the latest round. Consumers are encouraged to check
   * that they're receiving fresh data by inspecting the updatedAt and
   * answeredInRound return values.
   * Note that different underlying implementations of AggregatorV3Interface
   * have slightly different semantics for some of the return values. Consumers
   * should determine what implementations they expect to receive
   * data from and validate that they can properly handle return data from all
   * of them.
   * @return roundId is the round ID from the aggregator for which the data was
   * retrieved combined with an phase to ensure that round IDs get larger as
   * time moves forward.
   * @return answer is the answer for the given round
   * @return startedAt is the timestamp when the round was started.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @return updatedAt is the timestamp when the round last was updated (i.e.
   * answer was last computed)
   * @return answeredInRound is the round ID of the round in which the answer
   * was computed.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @dev Note that answer and updatedAt may change between queries.
   */
  function latestRoundData()
    public
    view
    virtual
    override
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    Phase memory current = currentPhase; // cache storage reads

    (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 ansIn
    ) = current.aggregator.latestRoundData();

    return addPhaseIds(roundId, answer, startedAt, updatedAt, ansIn, current.id);
  }

  /**
   * @notice Used if an aggregator contract has been proposed.
   * @param _roundId the round ID to retrieve the round data for
   * @return roundId is the round ID for which data was retrieved
   * @return answer is the answer for the given round
   * @return startedAt is the timestamp when the round was started.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @return updatedAt is the timestamp when the round last was updated (i.e.
   * answer was last computed)
   * @return answeredInRound is the round ID of the round in which the answer
   * was computed.
  */
  function proposedGetRoundData(uint80 _roundId)
    public
    view
    virtual
    hasProposal()
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    return proposedAggregator.getRoundData(_roundId);
  }

  /**
   * @notice Used if an aggregator contract has been proposed.
   * @return roundId is the round ID for which data was retrieved
   * @return answer is the answer for the given round
   * @return startedAt is the timestamp when the round was started.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @return updatedAt is the timestamp when the round last was updated (i.e.
   * answer was last computed)
   * @return answeredInRound is the round ID of the round in which the answer
   * was computed.
  */
  function proposedLatestRoundData()
    public
    view
    virtual
    hasProposal()
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    return proposedAggregator.latestRoundData();
  }

  /**
   * @notice returns the current phase's aggregator address.
   */
  function aggregator()
    external
    view
    returns (address)
  {
    return address(currentPhase.aggregator);
  }

  /**
   * @notice returns the current phase's ID.
   */
  function phaseId()
    external
    view
    returns (uint16)
  {
    return currentPhase.id;
  }

  /**
   * @notice represents the number of decimals the aggregator responses represent.
   */
  function decimals()
    external
    view
    override
    returns (uint8)
  {
    return currentPhase.aggregator.decimals();
  }

  /**
   * @notice the version number representing the type of aggregator the proxy
   * points to.
   */
  function version()
    external
    view
    override
    returns (uint256)
  {
    return currentPhase.aggregator.version();
  }

  /**
   * @notice returns the description of the aggregator the proxy points to.
   */
  function description()
    external
    view
    override
    returns (string memory)
  {
    return currentPhase.aggregator.description();
  }

  /**
   * @notice Allows the owner to propose a new address for the aggregator
   * @param _aggregator The new address for the aggregator contract
   */
  function proposeAggregator(address _aggregator)
    external
    onlyOwner()
  {
    proposedAggregator = AggregatorV2V3Interface(_aggregator);
  }

  /**
   * @notice Allows the owner to confirm and change the address
   * to the proposed aggregator
   * @dev Reverts if the given address doesn't match what was previously
   * proposed
   * @param _aggregator The new address for the aggregator contract
   */
  function confirmAggregator(address _aggregator)
    external
    onlyOwner()
  {
    require(_aggregator == address(proposedAggregator), "Invalid proposed aggregator");
    delete proposedAggregator;
    setAggregator(_aggregator);
  }


  /*
   * Internal
   */

  function setAggregator(address _aggregator)
    internal
  {
    uint16 id = currentPhase.id + 1;
    currentPhase = Phase(id, AggregatorV2V3Interface(_aggregator));
    phaseAggregators[id] = AggregatorV2V3Interface(_aggregator);
  }

  function addPhase(
    uint16 _phase,
    uint64 _originalId
  )
    internal
    view
    returns (uint80)
  {
    return uint80(uint256(_phase) << PHASE_OFFSET | _originalId);
  }

  function parseIds(
    uint256 _roundId
  )
    internal
    view
    returns (uint16, uint64)
  {
    uint16 phaseId = uint16(_roundId >> PHASE_OFFSET);
    uint64 aggregatorRoundId = uint64(_roundId);

    return (phaseId, aggregatorRoundId);
  }

  function addPhaseIds(
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound,
      uint16 phaseId
  )
    internal
    view
    returns (uint80, int256, uint256, uint256, uint80)
  {
    return (
      addPhase(phaseId, uint64(roundId)),
      answer,
      startedAt,
      updatedAt,
      addPhase(phaseId, uint64(answeredInRound))
    );
  }

  /*
   * Modifiers
   */

  modifier hasProposal() {
    require(address(proposedAggregator) != address(0), "No proposed aggregator present");
    _;
  }

}

interface AccessControllerInterface {
  function hasAccess(address user, bytes calldata data) external view returns (bool);
}

/**
 * @title External Access Controlled Aggregator Proxy
 * @notice A trusted proxy for updating where current answers are read from
 * @notice This contract provides a consistent address for the
 * Aggregator and AggregatorV3Interface but delegates where it reads from to the owner, who is
 * trusted to update it.
 * @notice Only access enabled addresses are allowed to access getters for
 * aggregated answers and round information.
 */
contract EACAggregatorProxy is AggregatorProxy {

  AccessControllerInterface public accessController;

  constructor(
    address _aggregator,
    address _accessController
  )
    public
    AggregatorProxy(_aggregator)
  {
    setController(_accessController);
  }

  /**
   * @notice Allows the owner to update the accessController contract address.
   * @param _accessController The new address for the accessController contract
   */
  function setController(address _accessController)
    public
    onlyOwner()
  {
    accessController = AccessControllerInterface(_accessController);
  }

  /**
   * @notice Reads the current answer from aggregator delegated to.
   * @dev overridden function to add the checkAccess() modifier
   *
   * @dev #[deprecated] Use latestRoundData instead. This does not error if no
   * answer has been reached, it will simply return 0. Either wait to point to
   * an already answered Aggregator or use the recommended latestRoundData
   * instead which includes better verification information.
   */
  function latestAnswer()
    public
    view
    override
    checkAccess()
    returns (int256)
  {
    return super.latestAnswer();
  }

  /**
   * @notice get the latest completed round where the answer was updated. This
   * ID includes the proxy's phase, to make sure round IDs increase even when
   * switching to a newly deployed aggregator.
   *
   * @dev #[deprecated] Use latestRoundData instead. This does not error if no
   * answer has been reached, it will simply return 0. Either wait to point to
   * an already answered Aggregator or use the recommended latestRoundData
   * instead which includes better verification information.
   */
  function latestTimestamp()
    public
    view
    override
    checkAccess()
    returns (uint256)
  {
    return super.latestTimestamp();
  }

  /**
   * @notice get past rounds answers
   * @param _roundId the answer number to retrieve the answer for
   * @dev overridden function to add the checkAccess() modifier
   *
   * @dev #[deprecated] Use getRoundData instead. This does not error if no
   * answer has been reached, it will simply return 0. Either wait to point to
   * an already answered Aggregator or use the recommended getRoundData
   * instead which includes better verification information.
   */
  function getAnswer(uint256 _roundId)
    public
    view
    override
    checkAccess()
    returns (int256)
  {
    return super.getAnswer(_roundId);
  }

  /**
   * @notice get block timestamp when an answer was last updated
   * @param _roundId the answer number to retrieve the updated timestamp for
   * @dev overridden function to add the checkAccess() modifier
   *
   * @dev #[deprecated] Use getRoundData instead. This does not error if no
   * answer has been reached, it will simply return 0. Either wait to point to
   * an already answered Aggregator or use the recommended getRoundData
   * instead which includes better verification information.
   */
  function getTimestamp(uint256 _roundId)
    public
    view
    override
    checkAccess()
    returns (uint256)
  {
    return super.getTimestamp(_roundId);
  }

  /**
   * @notice get the latest completed round where the answer was updated
   * @dev overridden function to add the checkAccess() modifier
   *
   * @dev #[deprecated] Use latestRoundData instead. This does not error if no
   * answer has been reached, it will simply return 0. Either wait to point to
   * an already answered Aggregator or use the recommended latestRoundData
   * instead which includes better verification information.
   */
  function latestRound()
    public
    view
    override
    checkAccess()
    returns (uint256)
  {
    return super.latestRound();
  }

  /**
   * @notice get data about a round. Consumers are encouraged to check
   * that they're receiving fresh data by inspecting the updatedAt and
   * answeredInRound return values.
   * Note that different underlying implementations of AggregatorV3Interface
   * have slightly different semantics for some of the return values. Consumers
   * should determine what implementations they expect to receive
   * data from and validate that they can properly handle return data from all
   * of them.
   * @param _roundId the round ID to retrieve the round data for
   * @return roundId is the round ID from the aggregator for which the data was
   * retrieved combined with a phase to ensure that round IDs get larger as
   * time moves forward.
   * @return answer is the answer for the given round
   * @return startedAt is the timestamp when the round was started.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @return updatedAt is the timestamp when the round last was updated (i.e.
   * answer was last computed)
   * @return answeredInRound is the round ID of the round in which the answer
   * was computed.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @dev Note that answer and updatedAt may change between queries.
   */
  function getRoundData(uint80 _roundId)
    public
    view
    checkAccess()
    override
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    return super.getRoundData(_roundId);
  }

  /**
   * @notice get data about the latest round. Consumers are encouraged to check
   * that they're receiving fresh data by inspecting the updatedAt and
   * answeredInRound return values.
   * Note that different underlying implementations of AggregatorV3Interface
   * have slightly different semantics for some of the return values. Consumers
   * should determine what implementations they expect to receive
   * data from and validate that they can properly handle return data from all
   * of them.
   * @return roundId is the round ID from the aggregator for which the data was
   * retrieved combined with a phase to ensure that round IDs get larger as
   * time moves forward.
   * @return answer is the answer for the given round
   * @return startedAt is the timestamp when the round was started.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @return updatedAt is the timestamp when the round last was updated (i.e.
   * answer was last computed)
   * @return answeredInRound is the round ID of the round in which the answer
   * was computed.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @dev Note that answer and updatedAt may change between queries.
   */
  function latestRoundData()
    public
    view
    checkAccess()
    override
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    return super.latestRoundData();
  }

  /**
   * @notice Used if an aggregator contract has been proposed.
   * @param _roundId the round ID to retrieve the round data for
   * @return roundId is the round ID for which data was retrieved
   * @return answer is the answer for the given round
   * @return startedAt is the timestamp when the round was started.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @return updatedAt is the timestamp when the round last was updated (i.e.
   * answer was last computed)
   * @return answeredInRound is the round ID of the round in which the answer
   * was computed.
  */
  function proposedGetRoundData(uint80 _roundId)
    public
    view
    checkAccess()
    hasProposal()
    override
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    return super.proposedGetRoundData(_roundId);
  }

  /**
   * @notice Used if an aggregator contract has been proposed.
   * @return roundId is the round ID for which data was retrieved
   * @return answer is the answer for the given round
   * @return startedAt is the timestamp when the round was started.
   * (Only some AggregatorV3Interface implementations return meaningful values)
   * @return updatedAt is the timestamp when the round last was updated (i.e.
   * answer was last computed)
   * @return answeredInRound is the round ID of the round in which the answer
   * was computed.
  */
  function proposedLatestRoundData()
    public
    view
    checkAccess()
    hasProposal()
    override
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    return super.proposedLatestRoundData();
  }

  /**
   * @dev reverts if the caller does not have access by the accessController
   * contract or is the contract itself.
   */
  modifier checkAccess() {
    AccessControllerInterface ac = accessController;
    require(address(ac) == address(0) || ac.hasAccess(msg.sender, msg.data), "No access");
    _;
  }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.7.1;
import "./OffchainAggregator.sol";
import "./SimpleReadAccessController.sol";
/**
 * @notice Wrapper of OffchainAggregator which checks read access on Aggregator-interface methods
 */
contract AccessControlledOffchainAggregator is OffchainAggregator, SimpleReadAccessController {
  constructor(
    uint32 _maximumGasPrice,
    uint32 _reasonableGasPrice,
    uint32 _microLinkPerEth,
    uint32 _linkGweiPerObservation,
    uint32 _linkGweiPerTransmission,
    address _link,
    int192 _minAnswer,
    int192 _maxAnswer,
    AccessControllerInterface _billingAccessController,
    AccessControllerInterface _requesterAccessController,
    uint8 _decimals,
    string memory description
  )
    OffchainAggregator(
      _maximumGasPrice,
      _reasonableGasPrice,
      _microLinkPerEth,
      _linkGweiPerObservation,
      _linkGweiPerTransmission,
      _link,
      _minAnswer,
      _maxAnswer,
      _billingAccessController,
      _requesterAccessController,
      _decimals,
      description
    ) {
    }
  /*
   * Versioning
   */
  function typeAndVersion()
    external
    override
    pure
    virtual
    returns (string memory)
  {
    return "AccessControlledOffchainAggregator 2.0.0";
  }
  /*
   * v2 Aggregator interface
   */
  /// @inheritdoc OffchainAggregator
  function latestAnswer()
    public
    override
    view
    checkAccess()
    returns (int256)
  {
    return super.latestAnswer();
  }
  /// @inheritdoc OffchainAggregator
  function latestTimestamp()
    public
    override
    view
    checkAccess()
    returns (uint256)
  {
    return super.latestTimestamp();
  }
  /// @inheritdoc OffchainAggregator
  function latestRound()
    public
    override
    view
    checkAccess()
    returns (uint256)
  {
    return super.latestRound();
  }
  /// @inheritdoc OffchainAggregator
  function getAnswer(uint256 _roundId)
    public
    override
    view
    checkAccess()
    returns (int256)
  {
    return super.getAnswer(_roundId);
  }
  /// @inheritdoc OffchainAggregator
  function getTimestamp(uint256 _roundId)
    public
    override
    view
    checkAccess()
    returns (uint256)
  {
    return super.getTimestamp(_roundId);
  }
  /*
   * v3 Aggregator interface
   */
  /// @inheritdoc OffchainAggregator
  function description()
    public
    override
    view
    checkAccess()
    returns (string memory)
  {
    return super.description();
  }
  /// @inheritdoc OffchainAggregator
  function getRoundData(uint80 _roundId)
    public
    override
    view
    checkAccess()
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    return super.getRoundData(_roundId);
  }
  /// @inheritdoc OffchainAggregator
  function latestRoundData()
    public
    override
    view
    checkAccess()
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    return super.latestRoundData();
  }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
import "./AccessControllerInterface.sol";
import "./AggregatorV2V3Interface.sol";
import "./AggregatorValidatorInterface.sol";
import "./LinkTokenInterface.sol";
import "./Owned.sol";
import "./OffchainAggregatorBilling.sol";
import "./TypeAndVersionInterface.sol";
/**
  * @notice Onchain verification of reports from the offchain reporting protocol
  * @dev For details on its operation, see the offchain reporting protocol design
  * @dev doc, which refers to this contract as simply the "contract".
*/
contract OffchainAggregator is Owned, OffchainAggregatorBilling, AggregatorV2V3Interface, TypeAndVersionInterface {
  uint256 constant private maxUint32 = (1 << 32) - 1;
  // Storing these fields used on the hot path in a HotVars variable reduces the
  // retrieval of all of them to a single SLOAD. If any further fields are
  // added, make sure that storage of the struct still takes at most 32 bytes.
  struct HotVars {
    // Provides 128 bits of security against 2nd pre-image attacks, but only
    // 64 bits against collisions. This is acceptable, since a malicious owner has
    // easier way of messing up the protocol than to find hash collisions.
    bytes16 latestConfigDigest;
    uint40 latestEpochAndRound; // 32 most sig bits for epoch, 8 least sig bits for round
    // Current bound assumed on number of faulty/dishonest oracles participating
    // in the protocol, this value is referred to as f in the design
    uint8 threshold;
    // Chainlink Aggregators expose a roundId to consumers. The offchain reporting
    // protocol does not use this id anywhere. We increment it whenever a new
    // transmission is made to provide callers with contiguous ids for successive
    // reports.
    uint32 latestAggregatorRoundId;
  }
  HotVars internal s_hotVars;
  // Transmission records the median answer from the transmit transaction at
  // time timestamp
  struct Transmission {
    int192 answer; // 192 bits ought to be enough for anyone
    uint64 timestamp;
  }
  mapping(uint32 /* aggregator round ID */ => Transmission) internal s_transmissions;
  // incremented each time a new config is posted. This count is incorporated
  // into the config digest, to prevent replay attacks.
  uint32 internal s_configCount;
  uint32 internal s_latestConfigBlockNumber; // makes it easier for offchain systems
                                             // to extract config from logs.
  // Lowest answer the system is allowed to report in response to transmissions
  int192 immutable public minAnswer;
  // Highest answer the system is allowed to report in response to transmissions
  int192 immutable public maxAnswer;
  /*
   * @param _maximumGasPrice highest gas price for which transmitter will be compensated
   * @param _reasonableGasPrice transmitter will receive reward for gas prices under this value
   * @param _microLinkPerEth reimbursement per ETH of gas cost, in 1e-6LINK units
   * @param _linkGweiPerObservation reward to oracle for contributing an observation to a successfully transmitted report, in 1e-9LINK units
   * @param _linkGweiPerTransmission reward to transmitter of a successful report, in 1e-9LINK units
   * @param _link address of the LINK contract
   * @param _minAnswer lowest answer the median of a report is allowed to be
   * @param _maxAnswer highest answer the median of a report is allowed to be
   * @param _billingAccessController access controller for billing admin functions
   * @param _requesterAccessController access controller for requesting new rounds
   * @param _decimals answers are stored in fixed-point format, with this many digits of precision
   * @param _description short human-readable description of observable this contract's answers pertain to
   */
  constructor(
    uint32 _maximumGasPrice,
    uint32 _reasonableGasPrice,
    uint32 _microLinkPerEth,
    uint32 _linkGweiPerObservation,
    uint32 _linkGweiPerTransmission,
    address _link,
    int192 _minAnswer,
    int192 _maxAnswer,
    AccessControllerInterface _billingAccessController,
    AccessControllerInterface _requesterAccessController,
    uint8 _decimals,
    string memory _description
  )
    OffchainAggregatorBilling(_maximumGasPrice, _reasonableGasPrice, _microLinkPerEth,
      _linkGweiPerObservation, _linkGweiPerTransmission, _link,
      _billingAccessController
    )
  {
    decimals = _decimals;
    s_description = _description;
    setRequesterAccessController(_requesterAccessController);
    setValidatorConfig(AggregatorValidatorInterface(0x0), 0);
    minAnswer = _minAnswer;
    maxAnswer = _maxAnswer;
  }
  /*
   * Versioning
   */
  function typeAndVersion()
    external
    override
    pure
    virtual
    returns (string memory)
  {
    return "OffchainAggregator 2.0.0";
  }
  /*
   * Config logic
   */
  /**
   * @notice triggers a new run of the offchain reporting protocol
   * @param previousConfigBlockNumber block in which the previous config was set, to simplify historic analysis
   * @param configCount ordinal number of this config setting among all config settings over the life of this contract
   * @param signers ith element is address ith oracle uses to sign a report
   * @param transmitters ith element is address ith oracle uses to transmit a report via the transmit method
   * @param threshold maximum number of faulty/dishonest oracles the protocol can tolerate while still working correctly
   * @param encodedConfigVersion version of the serialization format used for "encoded" parameter
   * @param encoded serialized data used by oracles to configure their offchain operation
   */
  event ConfigSet(
    uint32 previousConfigBlockNumber,
    uint64 configCount,
    address[] signers,
    address[] transmitters,
    uint8 threshold,
    uint64 encodedConfigVersion,
    bytes encoded
  );
  // Reverts transaction if config args are invalid
  modifier checkConfigValid (
    uint256 _numSigners, uint256 _numTransmitters, uint256 _threshold
  ) {
    require(_numSigners <= maxNumOracles, "too many signers");
    require(_threshold > 0, "threshold must be positive");
    require(
      _numSigners == _numTransmitters,
      "oracle addresses out of registration"
    );
    require(_numSigners > 3*_threshold, "faulty-oracle threshold too high");
    _;
  }
  /**
   * @notice sets offchain reporting protocol configuration incl. participating oracles
   * @param _signers addresses with which oracles sign the reports
   * @param _transmitters addresses oracles use to transmit the reports
   * @param _threshold number of faulty oracles the system can tolerate
   * @param _encodedConfigVersion version number for offchainEncoding schema
   * @param _encoded encoded off-chain oracle configuration
   */
  function setConfig(
    address[] calldata _signers,
    address[] calldata _transmitters,
    uint8 _threshold,
    uint64 _encodedConfigVersion,
    bytes calldata _encoded
  )
    external
    checkConfigValid(_signers.length, _transmitters.length, _threshold)
    onlyOwner()
  {
    while (s_signers.length != 0) { // remove any old signer/transmitter addresses
      uint lastIdx = s_signers.length - 1;
      address signer = s_signers[lastIdx];
      address transmitter = s_transmitters[lastIdx];
      payOracle(transmitter);
      delete s_oracles[signer];
      delete s_oracles[transmitter];
      s_signers.pop();
      s_transmitters.pop();
    }
    for (uint i = 0; i < _signers.length; i++) { // add new signer/transmitter addresses
      require(
        s_oracles[_signers[i]].role == Role.Unset,
        "repeated signer address"
      );
      s_oracles[_signers[i]] = Oracle(uint8(i), Role.Signer);
      require(s_payees[_transmitters[i]] != address(0), "payee must be set");
      require(
        s_oracles[_transmitters[i]].role == Role.Unset,
        "repeated transmitter address"
      );
      s_oracles[_transmitters[i]] = Oracle(uint8(i), Role.Transmitter);
      s_signers.push(_signers[i]);
      s_transmitters.push(_transmitters[i]);
    }
    s_hotVars.threshold = _threshold;
    uint32 previousConfigBlockNumber = s_latestConfigBlockNumber;
    s_latestConfigBlockNumber = uint32(block.number);
    s_configCount += 1;
    uint64 configCount = s_configCount;
    {
      s_hotVars.latestConfigDigest = configDigestFromConfigData(
        address(this),
        configCount,
        _signers,
        _transmitters,
        _threshold,
        _encodedConfigVersion,
        _encoded
      );
      s_hotVars.latestEpochAndRound = 0;
    }
    emit ConfigSet(
      previousConfigBlockNumber,
      configCount,
      _signers,
      _transmitters,
      _threshold,
      _encodedConfigVersion,
      _encoded
    );
  }
  function configDigestFromConfigData(
    address _contractAddress,
    uint64 _configCount,
    address[] calldata _signers,
    address[] calldata _transmitters,
    uint8 _threshold,
    uint64 _encodedConfigVersion,
    bytes calldata _encodedConfig
  ) internal pure returns (bytes16) {
    return bytes16(keccak256(abi.encode(_contractAddress, _configCount,
      _signers, _transmitters, _threshold, _encodedConfigVersion, _encodedConfig
    )));
  }
  /**
   * @notice information about current offchain reporting protocol configuration
   * @return configCount ordinal number of current config, out of all configs applied to this contract so far
   * @return blockNumber block at which this config was set
   * @return configDigest domain-separation tag for current config (see configDigestFromConfigData)
   */
  function latestConfigDetails()
    external
    view
    returns (
      uint32 configCount,
      uint32 blockNumber,
      bytes16 configDigest
    )
  {
    return (s_configCount, s_latestConfigBlockNumber, s_hotVars.latestConfigDigest);
  }
  /**
   * @return list of addresses permitted to transmit reports to this contract
   * @dev The list will match the order used to specify the transmitter during setConfig
   */
  function transmitters()
    external
    view
    returns(address[] memory)
  {
      return s_transmitters;
  }
  /*
   * On-chain validation logc
   */
  // Configuration for validator
  struct ValidatorConfig {
    AggregatorValidatorInterface validator;
    uint32 gasLimit;
  }
  ValidatorConfig private s_validatorConfig;
  /**
   * @notice indicates that the validator configuration has been set
   * @param previousValidator previous validator contract
   * @param previousGasLimit previous gas limit for validate calls
   * @param currentValidator current validator contract
   * @param currentGasLimit current gas limit for validate calls
   */
  event ValidatorConfigSet(
    AggregatorValidatorInterface indexed previousValidator,
    uint32 previousGasLimit,
    AggregatorValidatorInterface indexed currentValidator,
    uint32 currentGasLimit
  );
  /**
   * @notice validator configuration
   * @return validator validator contract
   * @return gasLimit gas limit for validate calls
   */
  function validatorConfig()
    external
    view
    returns (AggregatorValidatorInterface validator, uint32 gasLimit)
  {
    ValidatorConfig memory vc = s_validatorConfig;
    return (vc.validator, vc.gasLimit);
  }
  /**
   * @notice sets validator configuration
   * @dev set _newValidator to 0x0 to disable validate calls
   * @param _newValidator address of the new validator contract
   * @param _newGasLimit new gas limit for validate calls
   */
  function setValidatorConfig(AggregatorValidatorInterface _newValidator, uint32 _newGasLimit)
    public
    onlyOwner()
  {
    ValidatorConfig memory previous = s_validatorConfig;
    if (previous.validator != _newValidator || previous.gasLimit != _newGasLimit) {
      s_validatorConfig = ValidatorConfig({
        validator: _newValidator,
        gasLimit: _newGasLimit
      });
      emit ValidatorConfigSet(previous.validator, previous.gasLimit, _newValidator, _newGasLimit);
    }
  }
  function validateAnswer(
    uint32 _aggregatorRoundId,
    int256 _answer
  )
    private
  {
    ValidatorConfig memory vc = s_validatorConfig;
    if (address(vc.validator) == address(0)) {
      return;
    }
    uint32 prevAggregatorRoundId = _aggregatorRoundId - 1;
    int256 prevAggregatorRoundAnswer = s_transmissions[prevAggregatorRoundId].answer;
    // We do not want the validator to ever prevent reporting, so we limit its
    // gas usage and catch any errors that may arise.
    try vc.validator.validate{gas: vc.gasLimit}(
      prevAggregatorRoundId,
      prevAggregatorRoundAnswer,
      _aggregatorRoundId,
      _answer
    ) {} catch {}
  }
  /*
   * requestNewRound logic
   */
  AccessControllerInterface internal s_requesterAccessController;
  /**
   * @notice emitted when a new requester access controller contract is set
   * @param old the address prior to the current setting
   * @param current the address of the new access controller contract
   */
  event RequesterAccessControllerSet(AccessControllerInterface old, AccessControllerInterface current);
  /**
   * @notice emitted to immediately request a new round
   * @param requester the address of the requester
   * @param configDigest the latest transmission's configDigest
   * @param epoch the latest transmission's epoch
   * @param round the latest transmission's round
   */
  event RoundRequested(address indexed requester, bytes16 configDigest, uint32 epoch, uint8 round);
  /**
   * @notice address of the requester access controller contract
   * @return requester access controller address
   */
  function requesterAccessController()
    external
    view
    returns (AccessControllerInterface)
  {
    return s_requesterAccessController;
  }
  /**
   * @notice sets the requester access controller
   * @param _requesterAccessController designates the address of the new requester access controller
   */
  function setRequesterAccessController(AccessControllerInterface _requesterAccessController)
    public
    onlyOwner()
  {
    AccessControllerInterface oldController = s_requesterAccessController;
    if (_requesterAccessController != oldController) {
      s_requesterAccessController = AccessControllerInterface(_requesterAccessController);
      emit RequesterAccessControllerSet(oldController, _requesterAccessController);
    }
  }
  /**
   * @notice immediately requests a new round
   * @return the aggregatorRoundId of the next round. Note: The report for this round may have been
   * transmitted (but not yet mined) *before* requestNewRound() was even called. There is *no*
   * guarantee of causality between the request and the report at aggregatorRoundId.
   */
  function requestNewRound() external returns (uint80) {
    require(msg.sender == owner || s_requesterAccessController.hasAccess(msg.sender, msg.data),
      "Only owner&requester can call");
    HotVars memory hotVars = s_hotVars;
    emit RoundRequested(
      msg.sender,
      hotVars.latestConfigDigest,
      uint32(s_hotVars.latestEpochAndRound >> 8),
      uint8(s_hotVars.latestEpochAndRound)
    );
    return hotVars.latestAggregatorRoundId + 1;
  }
  /*
   * Transmission logic
   */
  /**
   * @notice indicates that a new report was transmitted
   * @param aggregatorRoundId the round to which this report was assigned
   * @param answer median of the observations attached this report
   * @param transmitter address from which the report was transmitted
   * @param observations observations transmitted with this report
   * @param rawReportContext signature-replay-prevention domain-separation tag
   */
  event NewTransmission(
    uint32 indexed aggregatorRoundId,
    int192 answer,
    address transmitter,
    int192[] observations,
    bytes observers,
    bytes32 rawReportContext
  );
  // decodeReport is used to check that the solidity and go code are using the
  // same format. See TestOffchainAggregator.testDecodeReport and TestReportParsing
  function decodeReport(bytes memory _report)
    internal
    pure
    returns (
      bytes32 rawReportContext,
      bytes32 rawObservers,
      int192[] memory observations
    )
  {
    (rawReportContext, rawObservers, observations) = abi.decode(_report,
      (bytes32, bytes32, int192[]));
  }
  // Used to relieve stack pressure in transmit
  struct ReportData {
    HotVars hotVars; // Only read from storage once
    bytes observers; // ith element is the index of the ith observer
    int192[] observations; // ith element is the ith observation
    bytes vs; // jth element is the v component of the jth signature
    bytes32 rawReportContext;
  }
  /*
   * @notice details about the most recent report
   * @return configDigest domain separation tag for the latest report
   * @return epoch epoch in which the latest report was generated
   * @return round OCR round in which the latest report was generated
   * @return latestAnswer median value from latest report
   * @return latestTimestamp when the latest report was transmitted
   */
  function latestTransmissionDetails()
    external
    view
    returns (
      bytes16 configDigest,
      uint32 epoch,
      uint8 round,
      int192 latestAnswer,
      uint64 latestTimestamp
    )
  {
    require(msg.sender == tx.origin, "Only callable by EOA");
    return (
      s_hotVars.latestConfigDigest,
      uint32(s_hotVars.latestEpochAndRound >> 8),
      uint8(s_hotVars.latestEpochAndRound),
      s_transmissions[s_hotVars.latestAggregatorRoundId].answer,
      s_transmissions[s_hotVars.latestAggregatorRoundId].timestamp
    );
  }
  // The constant-length components of the msg.data sent to transmit.
  // See the "If we wanted to call sam" example on for example reasoning
  // https://solidity.readthedocs.io/en/v0.7.2/abi-spec.html
  uint16 private constant TRANSMIT_MSGDATA_CONSTANT_LENGTH_COMPONENT =
    4 + // function selector
    32 + // word containing start location of abiencoded _report value
    32 + // word containing location start of abiencoded  _rs value
    32 + // word containing start location of abiencoded _ss value
    32 + // _rawVs value
    32 + // word containing length of _report
    32 + // word containing length _rs
    32 + // word containing length of _ss
    0; // placeholder
  function expectedMsgDataLength(
    bytes calldata _report, bytes32[] calldata _rs, bytes32[] calldata _ss
  ) private pure returns (uint256 length)
  {
    // calldata will never be big enough to make this overflow
    return uint256(TRANSMIT_MSGDATA_CONSTANT_LENGTH_COMPONENT) +
      _report.length + // one byte pure entry in _report
      _rs.length * 32 + // 32 bytes per entry in _rs
      _ss.length * 32 + // 32 bytes per entry in _ss
      0; // placeholder
  }
  /**
   * @notice transmit is called to post a new report to the contract
   * @param _report serialized report, which the signatures are signing. See parsing code below for format. The ith element of the observers component must be the index in s_signers of the address for the ith signature
   * @param _rs ith element is the R components of the ith signature on report. Must have at most maxNumOracles entries
   * @param _ss ith element is the S components of the ith signature on report. Must have at most maxNumOracles entries
   * @param _rawVs ith element is the the V component of the ith signature
   */
  function transmit(
    // NOTE: If these parameters are changed, expectedMsgDataLength and/or
    // TRANSMIT_MSGDATA_CONSTANT_LENGTH_COMPONENT need to be changed accordingly
    bytes calldata _report,
    bytes32[] calldata _rs, bytes32[] calldata _ss, bytes32 _rawVs // signatures
  )
    external
  {
    uint256 initialGas = gasleft(); // This line must come first
    // Make sure the transmit message-length matches the inputs. Otherwise, the
    // transmitter could append an arbitrarily long (up to gas-block limit)
    // string of 0 bytes, which we would reimburse at a rate of 16 gas/byte, but
    // which would only cost the transmitter 4 gas/byte. (Appendix G of the
    // yellow paper, p. 25, for G_txdatazero and EIP 2028 for G_txdatanonzero.)
    // This could amount to reimbursement profit of 36 million gas, given a 3MB
    // zero tail.
    require(msg.data.length == expectedMsgDataLength(_report, _rs, _ss),
      "transmit message too long");
    ReportData memory r; // Relieves stack pressure
    {
      r.hotVars = s_hotVars; // cache read from storage
      bytes32 rawObservers;
      (r.rawReportContext, rawObservers, r.observations) = abi.decode(
        _report, (bytes32, bytes32, int192[])
      );
      // rawReportContext consists of:
      // 11-byte zero padding
      // 16-byte configDigest
      // 4-byte epoch
      // 1-byte round
      bytes16 configDigest = bytes16(r.rawReportContext << 88);
      require(
        r.hotVars.latestConfigDigest == configDigest,
        "configDigest mismatch"
      );
      uint40 epochAndRound = uint40(uint256(r.rawReportContext));
      // direct numerical comparison works here, because
      //
      //   ((e,r) <= (e',r')) implies (epochAndRound <= epochAndRound')
      //
      // because alphabetic ordering implies e <= e', and if e = e', then r<=r',
      // so e*256+r <= e'*256+r', because r, r' < 256
      require(r.hotVars.latestEpochAndRound < epochAndRound, "stale report");
      require(_rs.length > r.hotVars.threshold, "not enough signatures");
      require(_rs.length <= maxNumOracles, "too many signatures");
      require(_ss.length == _rs.length, "signatures out of registration");
      require(r.observations.length <= maxNumOracles,
              "num observations out of bounds");
      require(r.observations.length > 2 * r.hotVars.threshold,
              "too few values to trust median");
      // Copy signature parities in bytes32 _rawVs to bytes r.v
      r.vs = new bytes(_rs.length);
      for (uint8 i = 0; i < _rs.length; i++) {
        r.vs[i] = _rawVs[i];
      }
      // Copy observer identities in bytes32 rawObservers to bytes r.observers
      r.observers = new bytes(r.observations.length);
      bool[maxNumOracles] memory seen;
      for (uint8 i = 0; i < r.observations.length; i++) {
        uint8 observerIdx = uint8(rawObservers[i]);
        require(!seen[observerIdx], "observer index repeated");
        seen[observerIdx] = true;
        r.observers[i] = rawObservers[i];
      }
      Oracle memory transmitter = s_oracles[msg.sender];
      require( // Check that sender is authorized to report
        transmitter.role == Role.Transmitter &&
        msg.sender == s_transmitters[transmitter.index],
        "unauthorized transmitter"
      );
      // record epochAndRound here, so that we don't have to carry the local
      // variable in transmit. The change is reverted if something fails later.
      r.hotVars.latestEpochAndRound = epochAndRound;
    }
    { // Verify signatures attached to report
      bytes32 h = keccak256(_report);
      bool[maxNumOracles] memory signed;
      Oracle memory o;
      for (uint i = 0; i < _rs.length; i++) {
        address signer = ecrecover(h, uint8(r.vs[i])+27, _rs[i], _ss[i]);
        o = s_oracles[signer];
        require(o.role == Role.Signer, "address not authorized to sign");
        require(!signed[o.index], "non-unique signature");
        signed[o.index] = true;
      }
    }
    { // Check the report contents, and record the result
      for (uint i = 0; i < r.observations.length - 1; i++) {
        bool inOrder = r.observations[i] <= r.observations[i+1];
        require(inOrder, "observations not sorted");
      }
      int192 median = r.observations[r.observations.length/2];
      require(minAnswer <= median && median <= maxAnswer, "median is out of min-max range");
      r.hotVars.latestAggregatorRoundId++;
      s_transmissions[r.hotVars.latestAggregatorRoundId] =
        Transmission(median, uint64(block.timestamp));
      emit NewTransmission(
        r.hotVars.latestAggregatorRoundId,
        median,
        msg.sender,
        r.observations,
        r.observers,
        r.rawReportContext
      );
      // Emit these for backwards compatability with offchain consumers
      // that only support legacy events
      emit NewRound(
        r.hotVars.latestAggregatorRoundId,
        address(0x0), // use zero address since we don't have anybody "starting" the round here
        block.timestamp
      );
      emit AnswerUpdated(
        median,
        r.hotVars.latestAggregatorRoundId,
        block.timestamp
      );
      validateAnswer(r.hotVars.latestAggregatorRoundId, median);
    }
    s_hotVars = r.hotVars;
    assert(initialGas < maxUint32);
    reimburseAndRewardOracles(uint32(initialGas), r.observers);
  }
  /*
   * v2 Aggregator interface
   */
  /**
   * @notice median from the most recent report
   */
  function latestAnswer()
    public
    override
    view
    virtual
    returns (int256)
  {
    return s_transmissions[s_hotVars.latestAggregatorRoundId].answer;
  }
  /**
   * @notice timestamp of block in which last report was transmitted
   */
  function latestTimestamp()
    public
    override
    view
    virtual
    returns (uint256)
  {
    return s_transmissions[s_hotVars.latestAggregatorRoundId].timestamp;
  }
  /**
   * @notice Aggregator round (NOT OCR round) in which last report was transmitted
   */
  function latestRound()
    public
    override
    view
    virtual
    returns (uint256)
  {
    return s_hotVars.latestAggregatorRoundId;
  }
  /**
   * @notice median of report from given aggregator round (NOT OCR round)
   * @param _roundId the aggregator round of the target report
   */
  function getAnswer(uint256 _roundId)
    public
    override
    view
    virtual
    returns (int256)
  {
    if (_roundId > 0xFFFFFFFF) { return 0; }
    return s_transmissions[uint32(_roundId)].answer;
  }
  /**
   * @notice timestamp of block in which report from given aggregator round was transmitted
   * @param _roundId aggregator round (NOT OCR round) of target report
   */
  function getTimestamp(uint256 _roundId)
    public
    override
    view
    virtual
    returns (uint256)
  {
    if (_roundId > 0xFFFFFFFF) { return 0; }
    return s_transmissions[uint32(_roundId)].timestamp;
  }
  /*
   * v3 Aggregator interface
   */
  string constant private V3_NO_DATA_ERROR = "No data present";
  /**
   * @return answers are stored in fixed-point format, with this many digits of precision
   */
  uint8 immutable public override decimals;
  /**
   * @notice aggregator contract version
   */
  uint256 constant public override version = 4;
  string internal s_description;
  /**
   * @notice human-readable description of observable this contract is reporting on
   */
  function description()
    public
    override
    view
    virtual
    returns (string memory)
  {
    return s_description;
  }
  /**
   * @notice details for the given aggregator round
   * @param _roundId target aggregator round (NOT OCR round). Must fit in uint32
   * @return roundId _roundId
   * @return answer median of report from given _roundId
   * @return startedAt timestamp of block in which report from given _roundId was transmitted
   * @return updatedAt timestamp of block in which report from given _roundId was transmitted
   * @return answeredInRound _roundId
   */
  function getRoundData(uint80 _roundId)
    public
    override
    view
    virtual
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    require(_roundId <= 0xFFFFFFFF, V3_NO_DATA_ERROR);
    Transmission memory transmission = s_transmissions[uint32(_roundId)];
    return (
      _roundId,
      transmission.answer,
      transmission.timestamp,
      transmission.timestamp,
      _roundId
    );
  }
  /**
   * @notice aggregator details for the most recently transmitted report
   * @return roundId aggregator round of latest report (NOT OCR round)
   * @return answer median of latest report
   * @return startedAt timestamp of block containing latest report
   * @return updatedAt timestamp of block containing latest report
   * @return answeredInRound aggregator round of latest report
   */
  function latestRoundData()
    public
    override
    view
    virtual
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    )
  {
    roundId = s_hotVars.latestAggregatorRoundId;
    // Skipped for compatability with existing FluxAggregator in which latestRoundData never reverts.
    // require(roundId != 0, V3_NO_DATA_ERROR);
    Transmission memory transmission = s_transmissions[uint32(roundId)];
    return (
      roundId,
      transmission.answer,
      transmission.timestamp,
      transmission.timestamp,
      roundId
    );
  }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.1;
import "./SimpleWriteAccessController.sol";
/**
 * @title SimpleReadAccessController
 * @notice Gives access to:
 * - any externally owned account (note that offchain actors can always read
 * any contract storage regardless of onchain access control measures, so this
 * does not weaken the access control while improving usability)
 * - accounts explicitly added to an access list
 * @dev SimpleReadAccessController is not suitable for access controlling writes
 * since it grants any externally owned account access! See
 * SimpleWriteAccessController for that.
 */
contract SimpleReadAccessController is SimpleWriteAccessController {
  /**
   * @notice Returns the access of an address
   * @param _user The address to query
   */
  function hasAccess(
    address _user,
    bytes memory _calldata
  )
    public
    view
    virtual
    override
    returns (bool)
  {
    return super.hasAccess(_user, _calldata) || _user == tx.origin;
  }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
interface AccessControllerInterface {
  function hasAccess(address user, bytes calldata data) external view returns (bool);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
import "./AggregatorInterface.sol";
import "./AggregatorV3Interface.sol";
interface AggregatorV2V3Interface is AggregatorInterface, AggregatorV3Interface
{
}// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
interface AggregatorValidatorInterface {
  function validate(
    uint256 previousRoundId,
    int256 previousAnswer,
    uint256 currentRoundId,
    int256 currentAnswer
  ) external returns (bool);
}// SPDX-License-Identifier: MIT
pragma solidity ^0.7.1;
interface LinkTokenInterface {
  function allowance(address owner, address spender) external view returns (uint256 remaining);
  function approve(address spender, uint256 value) external returns (bool success);
  function balanceOf(address owner) external view returns (uint256 balance);
  function decimals() external view returns (uint8 decimalPlaces);
  function decreaseApproval(address spender, uint256 addedValue) external returns (bool success);
  function increaseApproval(address spender, uint256 subtractedValue) external;
  function name() external view returns (string memory tokenName);
  function symbol() external view returns (string memory tokenSymbol);
  function totalSupply() external view returns (uint256 totalTokensIssued);
  function transfer(address to, uint256 value) external returns (bool success);
  function transferAndCall(address to, uint256 value, bytes calldata data) external returns (bool success);
  function transferFrom(address from, address to, uint256 value) external returns (bool success);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
/**
 * @title The Owned contract
 * @notice A contract with helpers for basic contract ownership.
 */
contract Owned {
  address payable public owner;
  address private pendingOwner;
  event OwnershipTransferRequested(
    address indexed from,
    address indexed to
  );
  event OwnershipTransferred(
    address indexed from,
    address indexed to
  );
  constructor() {
    owner = msg.sender;
  }
  /**
   * @dev Allows an owner to begin transferring ownership to a new address,
   * pending.
   */
  function transferOwnership(address _to)
    external
    onlyOwner()
  {
    pendingOwner = _to;
    emit OwnershipTransferRequested(owner, _to);
  }
  /**
   * @dev Allows an ownership transfer to be completed by the recipient.
   */
  function acceptOwnership()
    external
  {
    require(msg.sender == pendingOwner, "Must be proposed owner");
    address oldOwner = owner;
    owner = msg.sender;
    pendingOwner = address(0);
    emit OwnershipTransferred(oldOwner, msg.sender);
  }
  /**
   * @dev Reverts if called by anyone other than the contract owner.
   */
  modifier onlyOwner() {
    require(msg.sender == owner, "Only callable by owner");
    _;
  }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
import "./AccessControllerInterface.sol";
import "./LinkTokenInterface.sol";
import "./Owned.sol";
/**
 * @notice tracks administration of oracle-reward and gas-reimbursement parameters.
 * @dev
 * If you read or change this, be sure to read or adjust the comments. They
 * track the units of the values under consideration, and are crucial to
 * the readability of the operations it specifies.
 * @notice
 * Trust Model:
 * Nothing in this contract prevents a billing admin from setting insane
 * values for the billing parameters in setBilling. Oracles
 * participating in this contract should regularly check that the
 * parameters make sense. Similarly, the outstanding obligations of this
 * contract to the oracles can exceed the funds held by the contract.
 * Oracles participating in this contract should regularly check that it
 * holds sufficient funds and stop interacting with it if funding runs
 * out.
 * This still leaves oracles with some risk due to TOCTOU issues.
 * However, since the sums involved are pretty small (Ethereum
 * transactions aren't that expensive in the end) and an oracle would
 * likely stop participating in a contract it repeatedly lost money on,
 * this risk is deemed acceptable. Oracles should also regularly
 * withdraw any funds in the contract to prevent issues where the
 * contract becomes underfunded at a later time, and different oracles
 * are competing for the left-over funds.
 * Finally, note that any change to the set of oracles or to the billing
 * parameters will trigger payout of all oracles first (using the old
 * parameters), a billing admin cannot take away funds that are already
 * marked for payment.
*/
contract OffchainAggregatorBilling is Owned {
  // Maximum number of oracles the offchain reporting protocol is designed for
  uint256 constant internal maxNumOracles = 31;
  // Parameters for oracle payments
  struct Billing {
    // Highest compensated gas price, in ETH-gwei uints
    uint32 maximumGasPrice;
    // If gas price is less (in ETH-gwei units), transmitter gets half the savings
    uint32 reasonableGasPrice;
    // Pay transmitter back this much LINK per unit eth spent on gas
    // (1e-6LINK/ETH units)
    uint32 microLinkPerEth;
    // Fixed LINK reward for each observer, in LINK-gwei units
    uint32 linkGweiPerObservation;
    // Fixed reward for transmitter, in linkGweiPerObservation units
    uint32 linkGweiPerTransmission;
  }
  Billing internal s_billing;
  /**
  * @return LINK token contract used for billing
  */
  LinkTokenInterface immutable public LINK;
  AccessControllerInterface internal s_billingAccessController;
  // ith element is number of observation rewards due to ith process, plus one.
  // This is expected to saturate after an oracle has submitted 65,535
  // observations, or about 65535/(3*24*20) = 45 days, given a transmission
  // every 3 minutes.
  //
  // This is always one greater than the actual value, so that when the value is
  // reset to zero, we don't end up with a zero value in storage (which would
  // result in a higher gas cost, the next time the value is incremented.)
  // Calculations using this variable need to take that offset into account.
  uint16[maxNumOracles] internal s_oracleObservationsCounts;
  // Addresses at which oracles want to receive payments, by transmitter address
  mapping (address /* transmitter */ => address /* payment address */)
    internal
    s_payees;
  // Payee addresses which must be approved by the owner
  mapping (address /* transmitter */ => address /* payment address */)
    internal
    s_proposedPayees;
  // LINK-wei-denominated reimbursements for gas used by transmitters.
  //
  // This is always one greater than the actual value, so that when the value is
  // reset to zero, we don't end up with a zero value in storage (which would
  // result in a higher gas cost, the next time the value is incremented.)
  // Calculations using this variable need to take that offset into account.
  //
  // Argument for overflow safety:
  // We have the following maximum intermediate values:
  // - 2**40 additions to this variable (epochAndRound is a uint40)
  // - 2**32 gas price in ethgwei/gas
  // - 1e9 ethwei/ethgwei
  // - 2**32 gas since the block gas limit is at ~20 million
  // - 2**32 (microlink/eth)
  // And we have 2**40 * 2**32 * 1e9 * 2**32 * 2**32 < 2**166
  // (we also divide in some places, but that only makes the value smaller)
  // We can thus safely use uint256 intermediate values for the computation
  // updating this variable.
  uint256[maxNumOracles] internal s_gasReimbursementsLinkWei;
  // Used for s_oracles[a].role, where a is an address, to track the purpose
  // of the address, or to indicate that the address is unset.
  enum Role {
    // No oracle role has been set for address a
    Unset,
    // Signing address for the s_oracles[a].index'th oracle. I.e., report
    // signatures from this oracle should ecrecover back to address a.
    Signer,
    // Transmission address for the s_oracles[a].index'th oracle. I.e., if a
    // report is received by OffchainAggregator.transmit in which msg.sender is
    // a, it is attributed to the s_oracles[a].index'th oracle.
    Transmitter
  }
  struct Oracle {
    uint8 index; // Index of oracle in s_signers/s_transmitters
    Role role;   // Role of the address which mapped to this struct
  }
  mapping (address /* signer OR transmitter address */ => Oracle)
    internal s_oracles;
  // s_signers contains the signing address of each oracle
  address[] internal s_signers;
  // s_transmitters contains the transmission address of each oracle,
  // i.e. the address the oracle actually sends transactions to the contract from
  address[] internal s_transmitters;
  uint256 constant private  maxUint16 = (1 << 16) - 1;
  uint256 constant internal maxUint128 = (1 << 128) - 1;
  constructor(
    uint32 _maximumGasPrice,
    uint32 _reasonableGasPrice,
    uint32 _microLinkPerEth,
    uint32 _linkGweiPerObservation,
    uint32 _linkGweiPerTransmission,
    address _link,
    AccessControllerInterface _billingAccessController
  )
  {
    setBillingInternal(_maximumGasPrice, _reasonableGasPrice, _microLinkPerEth,
      _linkGweiPerObservation, _linkGweiPerTransmission);
    setBillingAccessControllerInternal(_billingAccessController);
    LINK = LinkTokenInterface(_link);
    uint16[maxNumOracles] memory counts; // See s_oracleObservationsCounts docstring
    uint256[maxNumOracles] memory gas; // see s_gasReimbursementsLinkWei docstring
    for (uint8 i = 0; i < maxNumOracles; i++) {
      counts[i] = 1;
      gas[i] = 1;
    }
    s_oracleObservationsCounts = counts;
    s_gasReimbursementsLinkWei = gas;
  }
  /**
   * @notice emitted when billing parameters are set
   * @param maximumGasPrice highest gas price for which transmitter will be compensated
   * @param reasonableGasPrice transmitter will receive reward for gas prices under this value
   * @param microLinkPerEth reimbursement per ETH of gas cost, in 1e-6LINK units
   * @param linkGweiPerObservation reward to oracle for contributing an observation to a successfully transmitted report, in 1e-9LINK units
   * @param linkGweiPerTransmission reward to transmitter of a successful report, in 1e-9LINK units
   */
  event BillingSet(
    uint32 maximumGasPrice,
    uint32 reasonableGasPrice,
    uint32 microLinkPerEth,
    uint32 linkGweiPerObservation,
    uint32 linkGweiPerTransmission
  );
  function setBillingInternal(
    uint32 _maximumGasPrice,
    uint32 _reasonableGasPrice,
    uint32 _microLinkPerEth,
    uint32 _linkGweiPerObservation,
    uint32 _linkGweiPerTransmission
  )
    internal
  {
    s_billing = Billing(_maximumGasPrice, _reasonableGasPrice, _microLinkPerEth,
      _linkGweiPerObservation, _linkGweiPerTransmission);
    emit BillingSet(_maximumGasPrice, _reasonableGasPrice, _microLinkPerEth,
      _linkGweiPerObservation, _linkGweiPerTransmission);
  }
  /**
   * @notice sets billing parameters
   * @param _maximumGasPrice highest gas price for which transmitter will be compensated
   * @param _reasonableGasPrice transmitter will receive reward for gas prices under this value
   * @param _microLinkPerEth reimbursement per ETH of gas cost, in 1e-6LINK units
   * @param _linkGweiPerObservation reward to oracle for contributing an observation to a successfully transmitted report, in 1e-9LINK units
   * @param _linkGweiPerTransmission reward to transmitter of a successful report, in 1e-9LINK units
   * @dev access control provided by billingAccessController
   */
  function setBilling(
    uint32 _maximumGasPrice,
    uint32 _reasonableGasPrice,
    uint32 _microLinkPerEth,
    uint32 _linkGweiPerObservation,
    uint32 _linkGweiPerTransmission
  )
    external
  {
    AccessControllerInterface access = s_billingAccessController;
    require(msg.sender == owner || access.hasAccess(msg.sender, msg.data),
      "Only owner&billingAdmin can call");
    payOracles();
    setBillingInternal(_maximumGasPrice, _reasonableGasPrice, _microLinkPerEth,
      _linkGweiPerObservation, _linkGweiPerTransmission);
  }
  /**
   * @notice gets billing parameters
   * @param maximumGasPrice highest gas price for which transmitter will be compensated
   * @param reasonableGasPrice transmitter will receive reward for gas prices under this value
   * @param microLinkPerEth reimbursement per ETH of gas cost, in 1e-6LINK units
   * @param linkGweiPerObservation reward to oracle for contributing an observation to a successfully transmitted report, in 1e-9LINK units
   * @param linkGweiPerTransmission reward to transmitter of a successful report, in 1e-9LINK units
   */
  function getBilling()
    external
    view
    returns (
      uint32 maximumGasPrice,
      uint32 reasonableGasPrice,
      uint32 microLinkPerEth,
      uint32 linkGweiPerObservation,
      uint32 linkGweiPerTransmission
    )
  {
    Billing memory billing = s_billing;
    return (
      billing.maximumGasPrice,
      billing.reasonableGasPrice,
      billing.microLinkPerEth,
      billing.linkGweiPerObservation,
      billing.linkGweiPerTransmission
    );
  }
  /**
   * @notice emitted when a new access-control contract is set
   * @param old the address prior to the current setting
   * @param current the address of the new access-control contract
   */
  event BillingAccessControllerSet(AccessControllerInterface old, AccessControllerInterface current);
  function setBillingAccessControllerInternal(AccessControllerInterface _billingAccessController)
    internal
  {
    AccessControllerInterface oldController = s_billingAccessController;
    if (_billingAccessController != oldController) {
      s_billingAccessController = _billingAccessController;
      emit BillingAccessControllerSet(
        oldController,
        _billingAccessController
      );
    }
  }
  /**
   * @notice sets billingAccessController
   * @param _billingAccessController new billingAccessController contract address
   * @dev only owner can call this
   */
  function setBillingAccessController(AccessControllerInterface _billingAccessController)
    external
    onlyOwner
  {
    setBillingAccessControllerInternal(_billingAccessController);
  }
  /**
   * @notice gets billingAccessController
   * @return address of billingAccessController contract
   */
  function billingAccessController()
    external
    view
    returns (AccessControllerInterface)
  {
    return s_billingAccessController;
  }
  /**
   * @notice withdraws an oracle's payment from the contract
   * @param _transmitter the transmitter address of the oracle
   * @dev must be called by oracle's payee address
   */
  function withdrawPayment(address _transmitter)
    external
  {
    require(msg.sender == s_payees[_transmitter], "Only payee can withdraw");
    payOracle(_transmitter);
  }
  /**
   * @notice query an oracle's payment amount
   * @param _transmitter the transmitter address of the oracle
   */
  function owedPayment(address _transmitter)
    public
    view
    returns (uint256)
  {
    Oracle memory oracle = s_oracles[_transmitter];
    if (oracle.role == Role.Unset) { return 0; }
    Billing memory billing = s_billing;
    uint256 linkWeiAmount =
      uint256(s_oracleObservationsCounts[oracle.index] - 1) *
      uint256(billing.linkGweiPerObservation) *
      (1 gwei);
    linkWeiAmount += s_gasReimbursementsLinkWei[oracle.index] - 1;
    return linkWeiAmount;
  }
  /**
   * @notice emitted when an oracle has been paid LINK
   * @param transmitter address from which the oracle sends reports to the transmit method
   * @param payee address to which the payment is sent
   * @param amount amount of LINK sent
   */
  event OraclePaid(address transmitter, address payee, uint256 amount);
  // payOracle pays out _transmitter's balance to the corresponding payee, and zeros it out
  function payOracle(address _transmitter)
    internal
  {
    Oracle memory oracle = s_oracles[_transmitter];
    uint256 linkWeiAmount = owedPayment(_transmitter);
    if (linkWeiAmount > 0) {
      address payee = s_payees[_transmitter];
      // Poses no re-entrancy issues, because LINK.transfer does not yield
      // control flow.
      require(LINK.transfer(payee, linkWeiAmount), "insufficient funds");
      s_oracleObservationsCounts[oracle.index] = 1; // "zero" the counts. see var's docstring
      s_gasReimbursementsLinkWei[oracle.index] = 1; // "zero" the counts. see var's docstring
      emit OraclePaid(_transmitter, payee, linkWeiAmount);
    }
  }
  // payOracles pays out all transmitters, and zeros out their balances.
  //
  // It's much more gas-efficient to do this as a single operation, to avoid
  // hitting storage too much.
  function payOracles()
    internal
  {
    Billing memory billing = s_billing;
    uint16[maxNumOracles] memory observationsCounts = s_oracleObservationsCounts;
    uint256[maxNumOracles] memory gasReimbursementsLinkWei =
      s_gasReimbursementsLinkWei;
    address[] memory transmitters = s_transmitters;
    for (uint transmitteridx = 0; transmitteridx < transmitters.length; transmitteridx++) {
      uint256 reimbursementAmountLinkWei = gasReimbursementsLinkWei[transmitteridx] - 1;
      uint256 obsCount = observationsCounts[transmitteridx] - 1;
      uint256 linkWeiAmount =
        obsCount * uint256(billing.linkGweiPerObservation) * (1 gwei) + reimbursementAmountLinkWei;
      if (linkWeiAmount > 0) {
          address payee = s_payees[transmitters[transmitteridx]];
          // Poses no re-entrancy issues, because LINK.transfer does not yield
          // control flow.
          require(LINK.transfer(payee, linkWeiAmount), "insufficient funds");
          observationsCounts[transmitteridx] = 1;       // "zero" the counts.
          gasReimbursementsLinkWei[transmitteridx] = 1; // "zero" the counts.
          emit OraclePaid(transmitters[transmitteridx], payee, linkWeiAmount);
        }
    }
    // "Zero" the accounting storage variables
    s_oracleObservationsCounts = observationsCounts;
    s_gasReimbursementsLinkWei = gasReimbursementsLinkWei;
  }
  function oracleRewards(
    bytes memory observers,
    uint16[maxNumOracles] memory observations
  )
    internal
    pure
    returns (uint16[maxNumOracles] memory)
  {
    // reward each observer-participant with the observer reward
    for (uint obsIdx = 0; obsIdx < observers.length; obsIdx++) {
      uint8 observer = uint8(observers[obsIdx]);
      observations[observer] = saturatingAddUint16(observations[observer], 1);
    }
    return observations;
  }
  // This value needs to change if maxNumOracles is increased, or the accounting
  // calculations at the bottom of reimburseAndRewardOracles change.
  //
  // To recalculate it, run the profiler as described in
  // ../../profile/README.md, and add up the gas-usage values reported for the
  // lines in reimburseAndRewardOracles following the "gasLeft = gasleft()"
  // line. E.g., you will see output like this:
  //
  //      7        uint256 gasLeft = gasleft();
  //     29        uint256 gasCostEthWei = transmitterGasCostEthWei(
  //      9          uint256(initialGas),
  //      3          gasPrice,
  //      3          callDataGasCost,
  //      3          gasLeft
  //      .
  //      .
  //      .
  //     59        uint256 gasCostLinkWei = (gasCostEthWei * billing.microLinkPerEth)/ 1e6;
  //      .
  //      .
  //      .
  //   5047        s_gasReimbursementsLinkWei[txOracle.index] =
  //    856          s_gasReimbursementsLinkWei[txOracle.index] + gasCostLinkWei +
  //     26          uint256(billing.linkGweiPerTransmission) * (1 gwei);
  //
  // If those were the only lines to be accounted for, you would add up
  // 29+9+3+3+3+59+5047+856+26=6035.
  uint256 internal constant accountingGasCost = 6035;
  // Uncomment the following declaration to compute the remaining gas cost after
  // above gasleft(). (This must exist in a base class to OffchainAggregator, so
  // it can't go in TestOffchainAggregator.)
  //
  // uint256 public gasUsedInAccounting;
  // Gas price at which the transmitter should be reimbursed, in ETH-gwei/gas
  function impliedGasPrice(
    uint256 txGasPrice,         // ETH-gwei/gas units
    uint256 reasonableGasPrice, // ETH-gwei/gas units
    uint256 maximumGasPrice     // ETH-gwei/gas units
  )
    internal
    pure
    returns (uint256)
  {
    // Reward the transmitter for choosing an efficient gas price: if they manage
    // to come in lower than considered reasonable, give them half the savings.
    //
    // The following calculations are all in units of gwei/gas, i.e. 1e-9ETH/gas
    uint256 gasPrice = txGasPrice;
    if (txGasPrice < reasonableGasPrice) {
      // Give transmitter half the savings for coming in under the reasonable gas price
      gasPrice += (reasonableGasPrice - txGasPrice) / 2;
    }
    // Don't reimburse a gas price higher than maximumGasPrice
    return min(gasPrice, maximumGasPrice);
  }
  // gas reimbursement due the transmitter, in ETH-wei
  //
  // If this function is changed, accountingGasCost needs to change, too. See
  // its docstring
  function transmitterGasCostEthWei(
    uint256 initialGas,
    uint256 gasPrice, // ETH-gwei/gas units
    uint256 callDataCost, // gas units
    uint256 gasLeft
  )
    internal
    pure
    returns (uint128 gasCostEthWei)
  {
    require(initialGas >= gasLeft, "gasLeft cannot exceed initialGas");
    uint256 gasUsed = // gas units
      initialGas - gasLeft + // observed gas usage
      callDataCost + accountingGasCost; // estimated gas usage
    // gasUsed is in gas units, gasPrice is in ETH-gwei/gas units; convert to ETH-wei
    uint256 fullGasCostEthWei = gasUsed * gasPrice * (1 gwei);
    assert(fullGasCostEthWei < maxUint128); // the entire ETH supply fits in a uint128...
    return uint128(fullGasCostEthWei);
  }
  /**
   * @notice withdraw any available funds left in the contract, up to _amount, after accounting for the funds due to participants in past reports
   * @param _recipient address to send funds to
   * @param _amount maximum amount to withdraw, denominated in LINK-wei.
   * @dev access control provided by billingAccessController
   */
  function withdrawFunds(address _recipient, uint256 _amount)
    external
  {
    require(msg.sender == owner || s_billingAccessController.hasAccess(msg.sender, msg.data),
      "Only owner&billingAdmin can call");
    uint256 linkDue = totalLINKDue();
    uint256 linkBalance = LINK.balanceOf(address(this));
    require(linkBalance >= linkDue, "insufficient balance");
    require(LINK.transfer(_recipient, min(linkBalance - linkDue, _amount)), "insufficient funds");
  }
  // Total LINK due to participants in past reports.
  function totalLINKDue()
    internal
    view
    returns (uint256 linkDue)
  {
    // Argument for overflow safety: We do all computations in
    // uint256s. The inputs to linkDue are:
    // - the <= 31 observation rewards each of which has less than
    //   64 bits (32 bits for billing.linkGweiPerObservation, 32 bits
    //   for wei/gwei conversion). Hence 69 bits are sufficient for this part.
    // - the <= 31 gas reimbursements, each of which consists of at most 166
    //   bits (see s_gasReimbursementsLinkWei docstring). Hence 171 bits are
    //   sufficient for this part
    // In total, 172 bits are enough.
    uint16[maxNumOracles] memory observationCounts = s_oracleObservationsCounts;
    for (uint i = 0; i < maxNumOracles; i++) {
      linkDue += observationCounts[i] - 1; // Stored value is one greater than actual value
    }
    Billing memory billing = s_billing;
    // Convert linkGweiPerObservation to uint256, or this overflows!
    linkDue *= uint256(billing.linkGweiPerObservation) * (1 gwei);
    address[] memory transmitters = s_transmitters;
    uint256[maxNumOracles] memory gasReimbursementsLinkWei =
      s_gasReimbursementsLinkWei;
    for (uint i = 0; i < transmitters.length; i++) {
      linkDue += uint256(gasReimbursementsLinkWei[i]-1); // Stored value is one greater than actual value
    }
  }
  /**
   * @notice allows oracles to check that sufficient LINK balance is available
   * @return availableBalance LINK available on this contract, after accounting for outstanding obligations. can become negative
   */
  function linkAvailableForPayment()
    external
    view
    returns (int256 availableBalance)
  {
    // there are at most one billion LINK, so this cast is safe
    int256 balance = int256(LINK.balanceOf(address(this)));
    // according to the argument in the definition of totalLINKDue,
    // totalLINKDue is never greater than 2**172, so this cast is safe
    int256 due = int256(totalLINKDue());
    // safe from overflow according to above sizes
    return int256(balance) - int256(due);
  }
  /**
   * @notice number of observations oracle is due to be reimbursed for
   * @param _signerOrTransmitter address used by oracle for signing or transmitting reports
   */
  function oracleObservationCount(address _signerOrTransmitter)
    external
    view
    returns (uint16)
  {
    Oracle memory oracle = s_oracles[_signerOrTransmitter];
    if (oracle.role == Role.Unset) { return 0; }
    return s_oracleObservationsCounts[oracle.index] - 1;
  }
  function reimburseAndRewardOracles(
    uint32 initialGas,
    bytes memory observers
  )
    internal
  {
    Oracle memory txOracle = s_oracles[msg.sender];
    Billing memory billing = s_billing;
    // Reward oracles for providing observations. Oracles are not rewarded
    // for providing signatures, because signing is essentially free.
    s_oracleObservationsCounts =
      oracleRewards(observers, s_oracleObservationsCounts);
    // Reimburse transmitter of the report for gas usage
    require(txOracle.role == Role.Transmitter,
      "sent by undesignated transmitter"
    );
    uint256 gasPrice = impliedGasPrice(
      tx.gasprice / (1 gwei), // convert to ETH-gwei units
      billing.reasonableGasPrice,
      billing.maximumGasPrice
    );
    // The following is only an upper bound, as it ignores the cheaper cost for
    // 0 bytes. Safe from overflow, because calldata just isn't that long.
    uint256 callDataGasCost = 16 * msg.data.length;
    // If any changes are made to subsequent calculations, accountingGasCost
    // needs to change, too.
    uint256 gasLeft = gasleft();
    uint256 gasCostEthWei = transmitterGasCostEthWei(
      uint256(initialGas),
      gasPrice,
      callDataGasCost,
      gasLeft
    );
    // microLinkPerEth is 1e-6LINK/ETH units, gasCostEthWei is 1e-18ETH units
    // (ETH-wei), product is 1e-24LINK-wei units, dividing by 1e6 gives
    // 1e-18LINK units, i.e. LINK-wei units
    // Safe from over/underflow, since all components are non-negative,
    // gasCostEthWei will always fit into uint128 and microLinkPerEth is a
    // uint32 (128+32 < 256!).
    uint256 gasCostLinkWei = (gasCostEthWei * billing.microLinkPerEth)/ 1e6;
    // Safe from overflow, because gasCostLinkWei < 2**160 and
    // billing.linkGweiPerTransmission * (1 gwei) < 2**64 and we increment
    // s_gasReimbursementsLinkWei[txOracle.index] at most 2**40 times.
    s_gasReimbursementsLinkWei[txOracle.index] =
      s_gasReimbursementsLinkWei[txOracle.index] + gasCostLinkWei +
      uint256(billing.linkGweiPerTransmission) * (1 gwei); // convert from linkGwei to linkWei
    // Uncomment next line to compute the remaining gas cost after above gasleft().
    // See OffchainAggregatorBilling.accountingGasCost docstring for more information.
    //
    // gasUsedInAccounting = gasLeft - gasleft();
  }
  /*
   * Payee management
   */
  /**
   * @notice emitted when a transfer of an oracle's payee address has been initiated
   * @param transmitter address from which the oracle sends reports to the transmit method
   * @param current the payeee address for the oracle, prior to this setting
   * @param proposed the proposed new payee address for the oracle
   */
  event PayeeshipTransferRequested(
    address indexed transmitter,
    address indexed current,
    address indexed proposed
  );
  /**
   * @notice emitted when a transfer of an oracle's payee address has been completed
   * @param transmitter address from which the oracle sends reports to the transmit method
   * @param current the payeee address for the oracle, prior to this setting
   */
  event PayeeshipTransferred(
    address indexed transmitter,
    address indexed previous,
    address indexed current
  );
  /**
   * @notice sets the payees for transmitting addresses
   * @param _transmitters addresses oracles use to transmit the reports
   * @param _payees addresses of payees corresponding to list of transmitters
   * @dev must be called by owner
   * @dev cannot be used to change payee addresses, only to initially populate them
   */
  function setPayees(
    address[] calldata _transmitters,
    address[] calldata _payees
  )
    external
    onlyOwner()
  {
    require(_transmitters.length == _payees.length, "transmitters.size != payees.size");
    for (uint i = 0; i < _transmitters.length; i++) {
      address transmitter = _transmitters[i];
      address payee = _payees[i];
      address currentPayee = s_payees[transmitter];
      bool zeroedOut = currentPayee == address(0);
      require(zeroedOut || currentPayee == payee, "payee already set");
      s_payees[transmitter] = payee;
      if (currentPayee != payee) {
        emit PayeeshipTransferred(transmitter, currentPayee, payee);
      }
    }
  }
  /**
   * @notice first step of payeeship transfer (safe transfer pattern)
   * @param _transmitter transmitter address of oracle whose payee is changing
   * @param _proposed new payee address
   * @dev can only be called by payee address
   */
  function transferPayeeship(
    address _transmitter,
    address _proposed
  )
    external
  {
      require(msg.sender == s_payees[_transmitter], "only current payee can update");
      require(msg.sender != _proposed, "cannot transfer to self");
      address previousProposed = s_proposedPayees[_transmitter];
      s_proposedPayees[_transmitter] = _proposed;
      if (previousProposed != _proposed) {
        emit PayeeshipTransferRequested(_transmitter, msg.sender, _proposed);
      }
  }
  /**
   * @notice second step of payeeship transfer (safe transfer pattern)
   * @param _transmitter transmitter address of oracle whose payee is changing
   * @dev can only be called by proposed new payee address
   */
  function acceptPayeeship(
    address _transmitter
  )
    external
  {
    require(msg.sender == s_proposedPayees[_transmitter], "only proposed payees can accept");
    address currentPayee = s_payees[_transmitter];
    s_payees[_transmitter] = msg.sender;
    s_proposedPayees[_transmitter] = address(0);
    emit PayeeshipTransferred(_transmitter, currentPayee, msg.sender);
  }
  /*
   * Helper functions
   */
  function saturatingAddUint16(uint16 _x, uint16 _y)
    internal
    pure
    returns (uint16)
  {
    return uint16(min(uint256(_x)+uint256(_y), maxUint16));
  }
  function min(uint256 a, uint256 b)
    internal
    pure
    returns (uint256)
  {
    if (a < b) { return a; }
    return b;
  }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
abstract contract TypeAndVersionInterface{
  function typeAndVersion()
    external
    pure
    virtual
    returns (string memory);
}// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
interface AggregatorInterface {
  function latestAnswer() external view returns (int256);
  function latestTimestamp() external view returns (uint256);
  function latestRound() external view returns (uint256);
  function getAnswer(uint256 roundId) external view returns (int256);
  function getTimestamp(uint256 roundId) external view returns (uint256);
  event AnswerUpdated(int256 indexed current, uint256 indexed roundId, uint256 updatedAt);
  event NewRound(uint256 indexed roundId, address indexed startedBy, uint256 startedAt);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
interface AggregatorV3Interface {
  function decimals() external view returns (uint8);
  function description() external view returns (string memory);
  function version() external view returns (uint256);
  // getRoundData and latestRoundData should both raise "No data present"
  // if they do not have data to report, instead of returning unset values
  // which could be misinterpreted as actual reported values.
  function getRoundData(uint80 _roundId)
    external
    view
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    );
  function latestRoundData()
    external
    view
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    );
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
import "./Owned.sol";
import "./AccessControllerInterface.sol";
/**
 * @title SimpleWriteAccessController
 * @notice Gives access to accounts explicitly added to an access list by the
 * controller's owner.
 * @dev does not make any special permissions for externally, see
 * SimpleReadAccessController for that.
 */
contract SimpleWriteAccessController is AccessControllerInterface, Owned {
  bool public checkEnabled;
  mapping(address => bool) internal accessList;
  event AddedAccess(address user);
  event RemovedAccess(address user);
  event CheckAccessEnabled();
  event CheckAccessDisabled();
  constructor()
  {
    checkEnabled = true;
  }
  /**
   * @notice Returns the access of an address
   * @param _user The address to query
   */
  function hasAccess(
    address _user,
    bytes memory
  )
    public
    view
    virtual
    override
    returns (bool)
  {
    return accessList[_user] || !checkEnabled;
  }
  /**
   * @notice Adds an address to the access list
   * @param _user The address to add
   */
  function addAccess(address _user) external onlyOwner() {
    addAccessInternal(_user);
  }
  function addAccessInternal(address _user) internal {
    if (!accessList[_user]) {
      accessList[_user] = true;
      emit AddedAccess(_user);
    }
  }
  /**
   * @notice Removes an address from the access list
   * @param _user The address to remove
   */
  function removeAccess(address _user)
    external
    onlyOwner()
  {
    if (accessList[_user]) {
      accessList[_user] = false;
      emit RemovedAccess(_user);
    }
  }
  /**
   * @notice makes the access check enforced
   */
  function enableAccessCheck()
    external
    onlyOwner()
  {
    if (!checkEnabled) {
      checkEnabled = true;
      emit CheckAccessEnabled();
    }
  }
  /**
   * @notice makes the access check unenforced
   */
  function disableAccessCheck()
    external
    onlyOwner()
  {
    if (checkEnabled) {
      checkEnabled = false;
      emit CheckAccessDisabled();
    }
  }
  /**
   * @dev reverts if the caller does not have access
   */
  modifier checkAccess() {
    require(hasAccess(msg.sender, msg.data), "No access");
    _;
  }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
import "./AccessControlledOffchainAggregator.sol";
import "./AccessControlTestHelper.sol";
contract TestOffchainAggregator is AccessControlledOffchainAggregator {
  function testDecodeReport(
    bytes memory report
  ) public pure returns (bytes32, bytes32, int192[] memory)
  {
    return decodeReport(report);
  }
  constructor(
    uint32 _maximumGasPrice,
    uint32 _reasonableGasPrice,
    uint32 _microLinkPerEth,
    uint32 _linkGweiPerObservation,
    uint32 _linkGweiPerTransmission,
    address _link,
    int192 _minAnswer, int192 _maxAnswer,
    AccessControllerInterface _billingAccessController,
    AccessControllerInterface _requesterAdminAccessController
  )
    AccessControlledOffchainAggregator(_maximumGasPrice, _reasonableGasPrice, _microLinkPerEth,
      _linkGweiPerObservation, _linkGweiPerTransmission, _link,
      _minAnswer, _maxAnswer, _billingAccessController, _requesterAdminAccessController, 0, "TEST"
    )
  {}
  function testPayee(
    address _transmitter
  )
    external
    view
    returns (address)
  {
    return s_payees[_transmitter];
  }
  function getConfigDigest() public view returns (bytes16) {
    return s_hotVars.latestConfigDigest;
  }
  function testSaturatingAddUint16(uint16 _x, uint16 _y)
    external pure returns (uint16)
  {
    return saturatingAddUint16(_x, _y);
  }
  function testImpliedGasPrice(uint256 txGasPrice, uint256 reasonableGasPrice,
    uint256 maximumGasPrice
  ) external pure returns (uint256) {
    return impliedGasPrice(txGasPrice, reasonableGasPrice, maximumGasPrice);
  }
  function testTransmitterGasCostEthWei(uint256 initialGas, uint256 gasPrice,
    uint256 callDataCost, uint256 gasLeft
  ) external pure returns (uint128) {
    return transmitterGasCostEthWei(
      initialGas, gasPrice, callDataCost, gasLeft
    );
  }
  function testSetOracleObservationCount(address _oracle, uint16 _amount) external {
    s_oracleObservationsCounts[s_oracles[_oracle].index] = _amount + 1;
  }
  function testTotalLinkDue()
    external view returns (uint256 linkDue)
  {
    return totalLINKDue();
  }
  function billingData() external view returns (
    uint16[maxNumOracles] memory observationsCounts,
    uint256[maxNumOracles] memory gasReimbursements,
    uint32 maximumGasPrice,
    uint32 reasonableGasPrice,
    uint32 microLinkPerEth,
    uint32 linkGweiPerObservation,
    uint32 linkGweiPerTransmission
  ) {
    Billing memory b = s_billing;
    return (s_oracleObservationsCounts, s_gasReimbursementsLinkWei,
      b.maximumGasPrice, b.reasonableGasPrice, b.microLinkPerEth,
      b.linkGweiPerObservation, b.linkGweiPerTransmission);
  }
  function testSetGasReimbursements(address _transmitterOrSigner, uint256 _amountLinkWei)
    external
  {
    require(s_oracles[_transmitterOrSigner].role != Role.Unset, "address unknown");
    s_gasReimbursementsLinkWei[s_oracles[_transmitterOrSigner].index] = _amountLinkWei + 1;
  }
  function testAccountingGasCost() public pure returns (uint256) {
    return accountingGasCost;
  }
  function testBurnLINK(uint256 amount) public {
      LINK.transfer(address(1), amount);
  }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.1;
import "./AccessControlledOffchainAggregator.sol";
contract AccessControlTestHelper {
  event Dummy(); // Used to silence warning that these methods are pure
  function readGetRoundData(address _aggregator, uint80 _roundID)
    external
  {
    AccessControlledOffchainAggregator(_aggregator).getRoundData(_roundID);
    emit Dummy();
  }
  function readLatestRoundData(address _aggregator)
    external
  {
    AccessControlledOffchainAggregator(_aggregator).latestRoundData();
    emit Dummy();
  }
  function readLatestAnswer(address _aggregator)
    external
  {
    AccessControlledOffchainAggregator(_aggregator).latestAnswer();
    emit Dummy();
  }
  function readLatestTimestamp(address _aggregator)
    external
  {
    AccessControlledOffchainAggregator(_aggregator).latestTimestamp();
    emit Dummy();
  }
  function readLatestRound(address _aggregator)
    external
  {
    AccessControlledOffchainAggregator(_aggregator).latestRound();
    emit Dummy();
  }
  function readGetAnswer(address _aggregator, uint256 _roundID)
    external
  {
    AccessControlledOffchainAggregator(_aggregator).getAnswer(_roundID);
    emit Dummy();
  }
  function readGetTimestamp(address _aggregator, uint256 _roundID)
    external
  {
    AccessControlledOffchainAggregator(_aggregator).getTimestamp(_roundID);
    emit Dummy();
  }
  function testLatestTransmissionDetails(address _aggregator) external view {
      OffchainAggregator(_aggregator).latestTransmissionDetails();
  }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
import "./OffchainAggregator.sol";
// ExposedOffchainAggregator exposes certain internal OffchainAggregator
// methods/structures so that golang code can access them, and we get
// reliable type checking on their usage
contract ExposedOffchainAggregator is OffchainAggregator {
  constructor()
    OffchainAggregator(
      0, 0, 0, 0, 0, address(0), 0, 0, AccessControllerInterface(address(0)), AccessControllerInterface(address(0)), 0, ""
    )
    {}
  function exposedConfigDigestFromConfigData(
    address _contractAddress,
    uint64 _configCount,
    address[] calldata _signers,
    address[] calldata _transmitters,
    uint8 _threshold,
    uint64 _encodedConfigVersion,
    bytes calldata _encodedConfig
  ) external pure returns (bytes16) {
    return configDigestFromConfigData(_contractAddress, _configCount,
      _signers, _transmitters, _threshold, _encodedConfigVersion,
      _encodedConfig);
  }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;
import "./AggregatorValidatorInterface.sol";
contract TestValidator is AggregatorValidatorInterface {
  uint32 s_minGasUse;
  uint256 s_latestRoundId;
  event Validated(
    uint256 previousRoundId,
    int256 previousAnswer,
    uint256 currentRoundId,
    int256 currentAnswer,
    uint256 initialGas
  );
  function validate(
    uint256 previousRoundId,
    int256 previousAnswer,
    uint256 currentRoundId,
    int256 currentAnswer
  ) external override returns (bool) {
    uint256 initialGas = gasleft();
    emit Validated(
      previousRoundId,
      previousAnswer,
      currentRoundId,
      currentAnswer,
      initialGas
    );
    s_latestRoundId = currentRoundId;
    uint256 minGasUse = s_minGasUse;
    while (initialGas - gasleft() < minGasUse) {}
    return true;
  }
  function setMinGasUse(uint32 minGasUse) external {
    s_minGasUse = minGasUse;
  }
  function latestRoundId() external view returns (uint256) {
    return s_latestRoundId;
  }
}