// File: contracts/Diplomat.sol



//SPDX-License-Identifier: MIT
/**                                                                              
                                            ..                                  
                                          ,*.                                   
                                        .**,                                    
                                       ,***.                                    
                                 .,.   ,***,                                    
                               .**,    *****.                                   
                             .****.    ,*****,                                  
                           .******,     ,******,                                
                         .*******.       .********,              .              
                       ,******.            .*************,,*****.               
                     ,*****.        ,,.        ,************,.                  
                  .,****.         ,*****,                                       
                 ,***,          ,*******,.              ..                      
               ,**,          .*******,.       ,********.                        
                           .******,.       .********,                           
                         .*****,         .*******,                              
                       ,****,          .******,                                 
                     ,***,.          .*****,                                    
                   ,**,.           ./***,                                       
                  ,,             .***,                                          
                               .**,                                 
            __  _______  ____  _   _______ __  ______  ______         
           /  |/  / __ \/ __ \/ | / / ___// / / / __ \/_  __/         
          / /|_/ / / / / / / /  |/ /\__ \/ /_/ / / / / / /            
         / /  / / /_/ / /_/ / /|  /___/ / __  / /_/ / / /             
        /_/  /_/\____/\____/_/_|_//____/_/_/_/\____/_/_/__    ________
          / ____/ __ \/ /   / /   / ____/ ____/_  __/  _/ |  / / ____/
         / /   / / / / /   / /   / __/ / /     / /  / / | | / / __/   
        / /___/ /_/ / /___/ /___/ /___/ /___  / / _/ /  | |/ / /___   
        \____/\____/_____/_____/_____/\____/ /_/ /___/  |___/_____/                                                           
*/
pragma solidity ^0.8.9;

import "@openzeppelin/contracts/access/AccessControl.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "./ElectionFactory.sol";
import "./EIP712MetaTransaction.sol";

contract Diplomat is AccessControl, ElectionFactory, EIP712MetaTransaction("Diplomat", "1") {

    bytes32 public constant VOTER_ROLE = 
        keccak256("VOTER_ROLE");
    
    uint256 public currentElectionStartBlock;
    uint256 public electionCount;

    constructor() {
        _setupRole(DEFAULT_ADMIN_ROLE, msg.sender);
    }

    modifier onlyAdmin() {
        require(hasRole(DEFAULT_ADMIN_ROLE, msg.sender), "NOT ADMIN");
        _;
    }

    function admin(address wallet, bool value) public onlyAdmin {
        if (value) {
            grantRole(DEFAULT_ADMIN_ROLE, wallet);
        } else {
            revokeRole(DEFAULT_ADMIN_ROLE, wallet);
        }
    }

    function createElection(
        string memory electionId
    ) public returns (string memory){
        // NOTE: Using electionCount as ID
       return _createElection(electionId);
    }

    function getElections() public view returns (string[] memory){
       return elections;
    }

    function endElection(string memory electionId) public {
        _endElection(electionId);
    }

    function payElection(string memory electionId, address[] memory _adrs, uint256[] memory _shares, address _token) public payable {
        _payElection(electionId, _adrs, _shares, _token);
    }

    function deposit() public payable {}

    // payable fallback function
    receive() external payable {}

    fallback() external payable {}
}

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



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "./IAccessControl.sol";
import "../utils/Context.sol";
import "../utils/Strings.sol";
import "../utils/introspection/ERC165.sol";

/**
 * @dev Contract module that allows children to implement role-based access
 * control mechanisms. This is a lightweight version that doesn't allow enumerating role
 * members except through off-chain means by accessing the contract event logs. Some
 * applications may benefit from on-chain enumerability, for those cases see
 * {AccessControlEnumerable}.
 *
 * Roles are referred to by their `bytes32` identifier. These should be exposed
 * in the external API and be unique. The best way to achieve this is by
 * using `public constant` hash digests:
 *
 * ```
 * bytes32 public constant MY_ROLE = keccak256("MY_ROLE");
 * ```
 *
 * Roles can be used to represent a set of permissions. To restrict access to a
 * function call, use {hasRole}:
 *
 * ```
 * function foo() public {
 *     require(hasRole(MY_ROLE, msg.sender));
 *     ...
 * }
 * ```
 *
 * Roles can be granted and revoked dynamically via the {grantRole} and
 * {revokeRole} functions. Each role has an associated admin role, and only
 * accounts that have a role's admin role can call {grantRole} and {revokeRole}.
 *
 * By default, the admin role for all roles is `DEFAULT_ADMIN_ROLE`, which means
 * that only accounts with this role will be able to grant or revoke other
 * roles. More complex role relationships can be created by using
 * {_setRoleAdmin}.
 *
 * WARNING: The `DEFAULT_ADMIN_ROLE` is also its own admin: it has permission to
 * grant and revoke this role. Extra precautions should be taken to secure
 * accounts that have been granted it.
 */
abstract contract AccessControl is Context, IAccessControl, ERC165 {
    struct RoleData {
        mapping(address => bool) members;
        bytes32 adminRole;
    }

    mapping(bytes32 => RoleData) private _roles;

    bytes32 public constant DEFAULT_ADMIN_ROLE = 0x00;

    /**
     * @dev Modifier that checks that an account has a specific role. Reverts
     * with a standardized message including the required role.
     *
     * The format of the revert reason is given by the following regular expression:
     *
     *  /^AccessControl: account (0x[0-9a-f]{40}) is missing role (0x[0-9a-f]{64})$/
     *
     * _Available since v4.1._
     */
    modifier onlyRole(bytes32 role) {
        _checkRole(role, _msgSender());
        _;
    }

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

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

    /**
     * @dev Revert with a standard message if `account` is missing `role`.
     *
     * The format of the revert reason is given by the following regular expression:
     *
     *  /^AccessControl: account (0x[0-9a-f]{40}) is missing role (0x[0-9a-f]{64})$/
     */
    function _checkRole(bytes32 role, address account) internal view {
        if (!hasRole(role, account)) {
            revert(
                string(
                    abi.encodePacked(
                        "AccessControl: account ",
                        Strings.toHexString(uint160(account), 20),
                        " is missing role ",
                        Strings.toHexString(uint256(role), 32)
                    )
                )
            );
        }
    }

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

    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function grantRole(bytes32 role, address account) public virtual override onlyRole(getRoleAdmin(role)) {
        _grantRole(role, account);
    }

    /**
     * @dev Revokes `role` from `account`.
     *
     * If `account` had been granted `role`, emits a {RoleRevoked} event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function revokeRole(bytes32 role, address account) public virtual override onlyRole(getRoleAdmin(role)) {
        _revokeRole(role, account);
    }

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

        _revokeRole(role, account);
    }

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

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

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

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

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



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

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

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

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

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

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

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

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

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

// File: contracts/ElectionFactory.sol



//SPDX-License-Identifier: MIT
/**
                                            ..
                                          ,*.
                                        .**,
                                       ,***.
                                 .,.   ,***,
                               .**,    *****.
                             .****.    ,*****,
                           .******,     ,******,
                         .*******.       .********,              .
                       ,******.            .*************,,*****.
                     ,*****.        ,,.        ,************,.
                  .,****.         ,*****,
                 ,***,          ,*******,.              ..
               ,**,          .*******,.       ,********.
                           .******,.       .********,
                         .*****,         .*******,
                       ,****,          .******,
                     ,***,.          .*****,
                   ,**,.           ./***,
                  ,,             .***,
                               .**,
            __  _______  ____  _   _______ __  ______  ______
           /  |/  / __ \/ __ \/ | / / ___// / / / __ \/_  __/
          / /|_/ / / / / / / /  |/ /\__ \/ /_/ / / / / / /
         / /  / / /_/ / /_/ / /|  /___/ / __  / /_/ / / /
        /_/  /_/\____/\____/_/_|_//____/_/_/_/\____/_/_/__    ________
          / ____/ __ \/ /   / /   / ____/ ____/_  __/  _/ |  / / ____/
         / /   / / / / /   / /   / __/ / /     / /  / / | | / / __/
        / /___/ /_/ / /___/ /___/ /___/ /___  / / _/ /  | |/ / /___
        \____/\____/_____/_____/_____/\____/ /_/ /___/  |___/_____/
*/
pragma solidity ^0.8.9;

import "./Distributor.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";

contract ElectionFactory is Distributor {
    event NewElection(string electionId, address sender);
    event EndedElection(string electionId, address sender);
    event PaidElection(string electionId, address sender);

    string[] public elections;
    mapping(string => mapping(address => bool)) isElectionAdmin;

    modifier onlyElectionAdmin(string memory electionId) {
        require(
            !isElectionAdmin[electionId][msg.sender],
            "Sender Not Election Admin!"
        );
        _;
    }

    function _emitNewElection(string memory electionId) internal {
        emit NewElection(electionId, msg.sender);
    }

    function _emitEndedElection(string memory electionId) internal {
        emit EndedElection(electionId, msg.sender);
    }

    function _emitPaidElection(string memory electionId) internal {
        emit PaidElection(electionId, msg.sender);
    }

    function _createElection(string memory electionId)
        internal
        returns (string memory)
    {
        elections.push(electionId);
        isElectionAdmin[electionId][msg.sender] = true;
        _emitNewElection(electionId);
        return electionId;
    }

    function _endElection(string memory electionId)
        internal
        onlyElectionAdmin(electionId)
    {
        _emitEndedElection(electionId);
    }

    // TODO: Implement Chainlink to check pay validity
    function _payElection(
        string memory electionId,
        address[] memory candidates,
        uint256[] memory shares,
        address token
    ) internal onlyElectionAdmin(electionId) {
        // NOTE: Not Escrow Version
        if (token == address(0)) {
            _sharePayedETH(candidates, shares);
        } else {
            _sharePayedToken(candidates, shares, IERC20(token), msg.sender); // Token needs to IERC20
        }
        _emitPaidElection(electionId);
    }
}

// File: contracts/EIP712MetaTransaction.sol



//SPDX-License-Identifier: MIT
pragma solidity ^0.8.9;

import "./EIP712Base.sol";

contract EIP712MetaTransaction is EIP712Base {
    bytes32 private constant META_TRANSACTION_TYPEHASH = keccak256(bytes("MetaTransaction(uint256 nonce,address from,bytes functionSignature)"));

    event MetaTransactionExecuted(address userAddress, address payable relayerAddress, bytes functionSignature);
    mapping(address => uint256) private nonces;

    /*
     * Meta transaction structure.
     * No point of including value field here as if user is doing value transfer then he has the funds to pay for gas
     * He should call the desired function directly in that case.
     */
    struct MetaTransaction {
        uint256 nonce;
        address from;
        bytes functionSignature;
    }

    constructor(string memory name, string memory version) EIP712Base(name, version) {}

    function convertBytesToBytes4(bytes memory inBytes) internal pure returns (bytes4 outBytes4) {
        if (inBytes.length == 0) {
            return 0x0;
        }

        assembly {
            outBytes4 := mload(add(inBytes, 32))
        }
    }

    function executeMetaTransaction(address userAddress,
        bytes memory functionSignature, bytes32 sigR, bytes32 sigS, uint8 sigV) public payable returns(bytes memory) {
        bytes4 destinationFunctionSig = convertBytesToBytes4(functionSignature);
        require(destinationFunctionSig != msg.sig, "functionSignature can not be of executeMetaTransaction method");
        MetaTransaction memory metaTx = MetaTransaction({
            nonce: nonces[userAddress],
            from: userAddress,
            functionSignature: functionSignature
        });
        require(verify(userAddress, metaTx, sigR, sigS, sigV), "Signer and signature do not match");
        nonces[userAddress]++;
        // Append userAddress at the end to extract it from calling context
        (bool success, bytes memory returnData) = address(this).call(abi.encodePacked(functionSignature, userAddress));

        require(success, "Function call not successful");
        emit MetaTransactionExecuted(userAddress, payable(msg.sender), functionSignature);
        return returnData;
    }

    function hashMetaTransaction(MetaTransaction memory metaTx) internal pure returns (bytes32) {
        return keccak256(abi.encode(
            META_TRANSACTION_TYPEHASH,
            metaTx.nonce,
            metaTx.from,
            keccak256(metaTx.functionSignature)
        ));
    }

    function getNonce(address user) external view returns(uint256 nonce) {
        nonce = nonces[user];
    }

    function verify(address user, MetaTransaction memory metaTx, bytes32 sigR, bytes32 sigS, uint8 sigV) internal view returns (bool) {
        address signer = ecrecover(toTypedMessageHash(hashMetaTransaction(metaTx)), sigV, sigR, sigS);
        require(signer != address(0), "Invalid signature");
        return signer == user;
    }

    function msgSender() internal view returns(address sender) {
        if(msg.sender == address(this)) {
            bytes memory array = msg.data;
            uint256 index = msg.data.length;
            assembly {
                // Load the 32 bytes word from memory with the address on the lower 20 bytes, and mask those.
                sender := and(mload(add(array, index)), 0xffffffffffffffffffffffffffffffffffffffff)
            }
        } else {
            sender = msg.sender;
        }
        return sender;
    }
}

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



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev External interface of AccessControl declared to support ERC165 detection.
 */
interface IAccessControl {
    /**
     * @dev Emitted when `newAdminRole` is set as ``role``'s admin role, replacing `previousAdminRole`
     *
     * `DEFAULT_ADMIN_ROLE` is the starting admin for all roles, despite
     * {RoleAdminChanged} not being emitted signaling this.
     *
     * _Available since v3.1._
     */
    event RoleAdminChanged(bytes32 indexed role, bytes32 indexed previousAdminRole, bytes32 indexed newAdminRole);

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

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

    /**
     * @dev Returns `true` if `account` has been granted `role`.
     */
    function hasRole(bytes32 role, address account) external view returns (bool);

    /**
     * @dev Returns the admin role that controls `role`. See {grantRole} and
     * {revokeRole}.
     *
     * To change a role's admin, use {AccessControl-_setRoleAdmin}.
     */
    function getRoleAdmin(bytes32 role) external view returns (bytes32);

    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function grantRole(bytes32 role, address account) external;

    /**
     * @dev Revokes `role` from `account`.
     *
     * If `account` had been granted `role`, emits a {RoleRevoked} event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function revokeRole(bytes32 role, address account) external;

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

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



// SPDX-License-Identifier: MIT

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/Strings.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

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

    /**
     * @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);
    }
}

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



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "./IERC165.sol";

/**
 * @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/utils/introspection/IERC165.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

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

// File: contracts/Distributor.sol



//SPDX-License-Identifier: MIT
/**
                                            ..
                                          ,*.
                                        .**,
                                       ,***.
                                 .,.   ,***,
                               .**,    *****.
                             .****.    ,*****,
                           .******,     ,******,
                         .*******.       .********,              .
                       ,******.            .*************,,*****.
                     ,*****.        ,,.        ,************,.
                  .,****.         ,*****,
                 ,***,          ,*******,.              ..
               ,**,          .*******,.       ,********.
                           .******,.       .********,
                         .*****,         .*******,
                       ,****,          .******,
                     ,***,.          .*****,
                   ,**,.           ./***,
                  ,,             .***,
                               .**,
            __  _______  ____  _   _______ __  ______  ______
           /  |/  / __ \/ __ \/ | / / ___// / / / __ \/_  __/
          / /|_/ / / / / / / /  |/ /\__ \/ /_/ / / / / / /
         / /  / / /_/ / /_/ / /|  /___/ / __  / /_/ / / /
        /_/  /_/\____/\____/_/_|_//____/_/_/_/\____/_/_/__    ________
          / ____/ __ \/ /   / /   / ____/ ____/_  __/  _/ |  / / ____/
         / /   / / / / /   / /   / __/ / /     / /  / / | | / / __/
        / /___/ /_/ / /___/ /___/ /___/ /___  / / _/ /  | |/ / /___
        \____/\____/_____/_____/_____/\____/ /_/ /___/  |___/_____/
*/
pragma solidity ^0.8.9;

import "@openzeppelin/contracts/utils/math/SafeMath.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";

contract Distributor {
    // utilize safemath for solidity <0.8.0
    using SafeMath for uint256;
    using SafeERC20 for IERC20;

    // validate 1-1 relationship between users and shares
    modifier accurateUserSharesRatio(
        address[] memory users,
        uint256[] memory shares
    ) {
        require(users.length == shares.length, "Incorrect distribution ratio");
        _;
    }

    // check provided balance >= total number of shares to distribute
    modifier hasEnoughBalance(uint256[] memory shares, uint256 balance) {
        uint256 totalShares;
        for (uint256 i = 0; i < shares.length; i++) {
            totalShares = totalShares.add(shares[i]);
        }
        // make sure specified balance is greater than totalShares specified
        require(balance >= totalShares, "Not enough eth for distribution");
        _;
    }

    // escrow management functions
    // share ETH from contract account balance
    function _shareETH(address[] memory users, uint256[] memory shares)
        internal
        accurateUserSharesRatio(users, shares)
        hasEnoughBalance(shares, address(this).balance)
    {
        _distribute(users, shares, address(0), address(0));
    }

    // share ERC-20 token from contract balance
    function _shareToken(
        address[] memory users,
        uint256[] memory shares,
        IERC20 token
    )
        internal
        accurateUserSharesRatio(users, shares)
        hasEnoughBalance(shares, token.balanceOf(address(this)))
    {
        _distribute(users, shares, address(token), address(this));
    }

    // user balance management functions
    // share ETH from amount payed by user
    function _sharePayedETH(address[] memory users, uint256[] memory shares)
        internal
        accurateUserSharesRatio(users, shares)
      
    {
        _distribute(users, shares, address(0), address(0));
    }

    // share tokens from approved spender account
    function _sharePayedToken(
        address[] memory users,
        uint256[] memory shares,
        IERC20 token,
        address spender
    )
        internal
        accurateUserSharesRatio(users, shares)
        hasEnoughBalance(shares, msg.sender.balance)
    {
        require(
            spender == msg.sender,
            "You can't distribute someone else's token balance"
        );
        require(
            spender != address(this),
            "Use other shareToken method for contract token distribution"
        );

        _distribute(users, shares, address(token), spender);
    }

    function _distribute(
        address[] memory users,
        uint256[] memory shares,
        address token,
        address spender
    ) internal {
        bool isToken = token != address(0) && spender != address(0);
        bool spenderIsContract = address(this) == spender;

        for (uint256 i = 0; i < users.length; i++) {
            // make sure user is not genesis account and shares is greater than 0
            if (users[i] != address(0) && shares[i] > 0) {
                if (isToken) {
                    // send ERC20 token
                    if (spenderIsContract) {
                        // from contract if spender is contract
                        IERC20(token).safeTransfer(users[i], shares[i]);
                    } else {
                        // from spender if spender is not contract
                        IERC20(token).safeTransferFrom(
                            spender,
                            users[i],
                            shares[i]
                        );
                    }
                } else {
                    // transfer ETH otherwise (we do not care if the transfer is successful 
                    // or not, as this would block all other transfers)
                    // NOTE: add re-entrancy guard for this ^ 
                    users[i].call{value: shares[i]}("");
                }
            }
        }
    }
}

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



// SPDX-License-Identifier: MIT

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 no longer needed starting with Solidity 0.8. 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 substraction 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/token/ERC20/utils/SafeERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "../IERC20.sol";
import "../../../utils/Address.sol";

/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using Address for address;

    function safeTransfer(
        IERC20 token,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(
        IERC20 token,
        address from,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        require(
            (value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        uint256 newAllowance = token.allowance(address(this), spender) + value;
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        unchecked {
            uint256 oldAllowance = token.allowance(address(this), spender);
            require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
            uint256 newAllowance = oldAllowance - value;
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
        }
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        if (returndata.length > 0) {
            // Return data is optional
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

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



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        assembly {
            size := extcodesize(account)
        }
        return size > 0;
    }

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

        (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

                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

// File: contracts/EIP712Base.sol



//SPDX-License-Identifier: MIT
pragma solidity ^0.8.9;

contract EIP712Base {

    struct EIP712Domain {
        string name;
        string version;
        address verifyingContract;
        bytes32 salt;
    }

    bytes32 internal constant EIP712_DOMAIN_TYPEHASH = keccak256(bytes("EIP712Domain(string name,string version,address verifyingContract,bytes32 salt)"));

    bytes32 internal domainSeparator;

    constructor(string memory name, string memory version) {
        domainSeparator = keccak256(abi.encode(
            EIP712_DOMAIN_TYPEHASH,
            keccak256(bytes(name)),
            keccak256(bytes(version)),
            address(this),
            bytes32(getChainID())
        ));
    }

    function getChainID() internal view returns (uint256 id) {
        assembly {
            id := chainid()
        }
    }

    function getDomainSeparator() private view returns(bytes32) {
        return domainSeparator;
    }

    /**
    * Accept message hash and returns hash message in EIP712 compatible form
    * So that it can be used to recover signer from signature signed using EIP712 formatted data
    * https://eips.ethereum.org/EIPS/eip-712
    * "\\x19" makes the encoding deterministic
    * "\\x01" is the version byte to make it compatible to EIP-191
    */
    function toTypedMessageHash(bytes32 messageHash) internal view returns(bytes32) {
        return keccak256(abi.encodePacked("\x19\x01", getDomainSeparator(), messageHash));
    }

}