contract MintHelper is Ownable {
   using SafeMath for uint;

    string public name;
    address public mintableToken;
    mapping(bytes32 => bool) successfulPayments;

    constructor(address mToken, string memory mName)
    public
    {
      mintableToken = mToken;
      name = mName;
    }

    function setMintableToken(address mToken)
    public onlyOwner
    returns (bool)
    {
      mintableToken = mToken;
      return true;
    }

    function paymentSuccessful(bytes32 paymentId) public view returns (bool){
        return (successfulPayments[paymentId] == true);
    }
    
    function proxyMint(uint256 nonce, bytes32 challenge_digest )
    public
    returns (bool)
    {
      require(ERC918Interface(mintableToken).mint(nonce, challenge_digest), "Could not mint token");
      return true;
    }

    //withdraw any eth inside
    function withdraw()
    public onlyOwner
    {
        msg.sender.transfer(address(this).balance);
    }

    //send tokens out
    function send(address _tokenAddr, address dest, uint value)
    public onlyOwner
    returns (bool)
    {
     return ERC20Interface(_tokenAddr).transfer(dest, value);
    }

    //batch send tokens
    function multisend(address _tokenAddr, bytes32 paymentId, address[] memory dests, uint256[] memory values)
    public onlyOwner
    returns (uint256)
    {
        require(dests.length > 0, "Must have more than 1 destination address");
        require(values.length >= dests.length, "Address to Value array size mismatch");
        require(successfulPayments[paymentId] != true, "Payment ID already exists and was successful");

        uint256 i = 0;
        while (i < dests.length) {
           require(ERC20Interface(_tokenAddr).transfer(dests[i], values[i]));
           i += 1;
        }

        successfulPayments[paymentId] = true;
        return (i);
    }
}
/*
 The owner (or anyone) will deposit tokens in here
 The owner calls the multisend method to send out payments
 */
function multisend(address _tokenAddr, bytes32 paymentId, address[] memory dests, uint256[] memory values)
    public onlyOwner
    returns (uint256)
    {
        require(dests.length > 0, "Must have more than 1 destination address");
        require(values.length >= dests.length, "Address to Value array size mismatch");
        require(successfulPayments[paymentId] != true, "Payment ID already exists and was successful");

        uint256 i = 0;
        while (i < dests.length) {
           require(ERC20Interface(_tokenAddr).transfer(dests[i], values[i]));
           i += 1;
        }

        successfulPayments[paymentId] = true;
        return (i);
    }
//batch send tokens