// Dependency file: contracts/token/IERC20.sol

// pragma solidity ^0.5.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP. Does not include
 * the optional functions; to access them see {ERC20Detailed}.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount)
        external
        returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender)
        external
        view
        returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(
        address indexed owner,
        address indexed spender,
        uint256 value
    );
}


// Dependency file: contracts/IToken.sol

// pragma solidity ^0.5.0;

interface IToken {
    function mint(address to, uint256 amount) external;

    function updateAdmin(address newAdmin) external;
}


// Dependency file: contracts/GSN/Context.sol

// pragma solidity ^0.5.0;

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
contract Context {
    // Empty internal constructor, to prevent people from mistakenly deploying
    // an instance of this contract, which should be used via inheritance.
    constructor() internal {}

    // solhint-disable-previous-line no-empty-blocks

    function _msgSender() internal view returns (address payable) {
        return msg.sender;
    }

    function _msgData() internal view returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}


// Dependency file: contracts/BridgeBase.sol

// pragma solidity ^0.5.0;

// import 'contracts/token/IERC20.sol';
// import 'contracts/IToken.sol';
// import 'contracts/GSN/Context.sol';

contract BridgeBase is Context {
    address public admin;
    IToken public token;
    mapping(uint256 => bool) public processedNonces;

    enum Step {Burn, Mint}
    event CrossTransfer(
        address from,
        address to,
        uint256 amount,
        uint256 date,
        uint256 nonce,
        Step indexed step
    );

    constructor(address _token) public {
        admin = _msgSender();
        token = IToken(_token);
    }

    modifier onlyAdmin() {
        require(
            _msgSender() == admin,
            'Only admin is allowed to execute this operation.'
        );
        _;
    }

    function updateAdmin(address newAdmin) external onlyAdmin {
        admin = newAdmin;
    }

    function updateTokenAdmin(address newAdmin) external onlyAdmin {
        token.updateAdmin(newAdmin);
    }

    function isProcessed(uint256 _nonce) external view returns (bool) {
        return processedNonces[_nonce];
    }

    function mint(
        address to,
        uint256 amount,
        uint256 otherChainNonce
    ) external onlyAdmin {
        require(
            processedNonces[otherChainNonce] == false,
            'transfer already processed'
        );
        processedNonces[otherChainNonce] = true;
        token.mint(to, amount);
        emit CrossTransfer(
            _msgSender(),
            to,
            amount,
            block.timestamp,
            otherChainNonce,
            Step.Mint
        );
    }
}


// Root file: contracts/BridgeEth.sol

pragma solidity ^0.5.0;

// import "contracts/BridgeBase.sol";

contract BridgeEth is BridgeBase {
    constructor(address token) public BridgeBase(token) {}
}