contract RandomNumberConsumer is VRFConsumerBase {
    bytes32 internal keyHash;
    uint256 internal fee;

    bool private progress = false;
    uint256 private winner = 0;
    address private distributer;

    modifier onlyDistributer() {
        require(distributer == msg.sender, "Ownable: caller is not the owner");
        _;
    }

    /**
     * Constructor inherits VRFConsumerBase
     *
     * Network: Mainnet
     * Chainlink VRF Coordinator address: 0xf0d54349aDdcf704F77AE15b96510dEA15cb7952
     * LINK token address:                0x514910771AF9Ca656af840dff83E8264EcF986CA
     * Key Hash: 0xAA77729D3466CA35AE8D28B3BBAC7CC36A5031EFDC430821C02BC31A238AF445
     */
    constructor(address _distributer)
        VRFConsumerBase(
            0xf0d54349aDdcf704F77AE15b96510dEA15cb7952,
            0x514910771AF9Ca656af840dff83E8264EcF986CA
        )
    {
        keyHash = 0xAA77729D3466CA35AE8D28B3BBAC7CC36A5031EFDC430821C02BC31A238AF445;
        fee = 2 * 10**18; // 2 LINK
        distributer = _distributer;
    }

    /**
     * Requests randomness from a user-provided seed
     */
    function getRandomNumber(uint256 userProvidedSeed)
        public
        onlyDistributer
        returns (bytes32 requestId)
    {
        require(
            LINK.balanceOf(address(this)) >= fee,
            "Not enough LINK"
        );
        require(!progress, "now getting an random number.");
        winner = 0;
        progress = true;
        return requestRandomness(keyHash, fee, userProvidedSeed);
    }

    /**
     * Callback function used by VRF Coordinator
     */
    function fulfillRandomness(bytes32 requestId, uint256 randomness)
        internal
        override
    {
        requestId = 0;
        progress = false;
        winner = randomness;
    }

    function getWinner() external view onlyDistributer returns (uint256) {
        if(progress)
            return 0;
        return winner;
    }
}
function fulfillRandomness(bytes32 requestId, uint256 randomness)
    internal
    override
{
    requestId = 0;
    progress = false;
    winner = randomness;
}

/**
 * Callback function used by VRF Coordinator
 */