library SafeMath {
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "");
        return c;
    }
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "");
    }
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;
        return c;
    }
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        }
        uint256 c = a * b;
        require(c / a == b, "");
        return c;
    }
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "");
    }
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        uint256 c = a / b;
        return c;
    }
}

interface IERC20 {
    function totalSupply() external view returns (uint256);
    function decimals() external view returns (uint8);
    function symbol() external view returns (string memory);
    function name() external view returns (string memory);
    function getOwner() external view returns (address);
    function balanceOf(address account) external view returns (uint256);
    function transfer(address recipient, uint256 amount) external returns (bool);
    function allowance(address _owner, address spender) external view returns (uint256);
    function approve(address spender, uint256 amount) external returns (bool);
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

abstract contract Auth {
    address internal owner;
    mapping (address => bool) internal authorizations;
    constructor(address _owner) {
        owner = _owner;
        authorizations[_owner] = true;
    }
    modifier onlyOwner() {
        require(isOwner(msg.sender), ""); _;
    }
    modifier authorized() {
        require(isAuthorized(msg.sender), ""); _;
    }
    function authorize(address adr) public onlyOwner {
        authorizations[adr] = true;
    }
    function unauthorize(address adr) public onlyOwner {
        authorizations[adr] = false;
    }
    function isOwner(address account) private view returns (bool) {
        return account == owner;
    }
    function isAuthorized(address adr) public view returns (bool) {
        return authorizations[adr];
    }
    function transferOwnership(address payable adr) public onlyOwner {
        owner = adr;
        authorizations[adr] = true;
        emit OwnershipTransferred(adr);
    }
    event OwnershipTransferred(address owner);
}

interface IUniswapV2Factory {
    function createPair(address tokenA, address tokenB) external returns (address pair);
}

interface UniRouter {
    function factory() external pure returns (address);
    function WETH() external pure returns (address);
    function addLiquidity(address tokenA, address tokenB, uint amountADesired, uint amountBDesired, uint amountAMin, uint amountBMin, address to, uint deadline) external returns (uint amountA, uint amountB, uint liquidity);
    function addLiquidityETH(address token, uint amountTokenDesired, uint amountTokenMin, uint amountETHMin, address to, uint deadline) external payable returns (uint amountToken, uint amountETH, uint liquidity);
    function swapExactTokensForTokensSupportingFeeOnTransferTokens(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline) external;
    function swapExactETHForTokensSupportingFeeOnTransferTokens(uint amountOutMin, address[] calldata path, address to, uint deadline) external payable;
    function swapExactTokensForETHSupportingFeeOnTransferTokens(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline) external;
}

interface IWBTCDistributor {
    function setDistributionCriteria(uint256 _minPeriod, uint256 _minDistribution) external;
    function setShare(address shareholder, uint256 amount) external;
    function deposit() external payable;
    function process(uint256 gas) external;
}

contract WBTCDistributor is IWBTCDistributor {
    using SafeMath for uint256;
    address _token;
    struct Share {
        uint256 amount;
        uint256 totalExcluded;
        uint256 totalRealised;
    }
    IERC20 RWRD = IERC20(0x2260FAC5E5542a773Aa44fBCfeDf7C193bc2C599); // WBTC
    address WETH = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2; // WETH
    UniRouter router;

    address[] shareholders;
    mapping (address => uint256) shareholderIndexes;
    mapping (address => uint256) shareholderClaims;
    mapping (address => Share) public shares;

    uint256 public totalShares;
    uint256 public totalDividends;
    uint256 public totalDistributed;
    uint256 public dividendsPerShare;
    uint256 public dividendsPerShareAccuracyFactor = 10 ** 36;
    uint256 public minPeriod = 45 * 60;
    uint256 public minDistribution = 1 * (10 ** 18);
    uint256 currentIndex;

    bool initialized;
    modifier initialization() {
        require(!initialized);
        _;
        initialized = true;
    }

    modifier onlyToken() {
        require(msg.sender == _token); _;
    }

    constructor (address _router) {
        router = _router != address(0)
        ? UniRouter(_router)
        : UniRouter(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);
        _token = msg.sender;
    }

    function setDistributionCriteria(uint256 _minPeriod, uint256 _minDistribution) external override onlyToken {
        minPeriod = _minPeriod;
        minDistribution = _minDistribution;
    }

    function setShare(address shareholder, uint256 amount) external override onlyToken {
        if(shares[shareholder].amount > 0){
            distributeDividend(shareholder);
        }

        if(amount > 0 && shares[shareholder].amount == 0){
            addShareholder(shareholder);
        }else if(amount == 0 && shares[shareholder].amount > 0){
            removeShareholder(shareholder);
        }

        totalShares = totalShares.sub(shares[shareholder].amount).add(amount);
        shares[shareholder].amount = amount;
        shares[shareholder].totalExcluded = getCumulativeDividends(shares[shareholder].amount);
    }
 
    function deposit() external payable override onlyToken {
        uint256 balanceBefore = RWRD.balanceOf(address(this));

        address[] memory path = new address[](2);
        path[0] = WETH;
        path[1] = address(RWRD);

        router.swapExactETHForTokensSupportingFeeOnTransferTokens{value: msg.value}(0, path, address(this), block.timestamp);
        uint256 amount = RWRD.balanceOf(address(this)).sub(balanceBefore);
        totalDividends = totalDividends.add(amount);
        dividendsPerShare = dividendsPerShare.add(dividendsPerShareAccuracyFactor.mul(amount).div(totalShares));
    }

    function process(uint256 gas) external override onlyToken {
        uint256 shareholderCount = shareholders.length;

        if(shareholderCount == 0) { return; }

        uint256 gasUsed = 0;
        uint256 gasLeft = gasleft();
        uint256 iterations = 0;

        while(gasUsed < gas && iterations < shareholderCount) {
            if(currentIndex >= shareholderCount){
                currentIndex = 0;
            }

            if(shouldDistribute(shareholders[currentIndex])){
                distributeDividend(shareholders[currentIndex]);
            }

            gasUsed = gasUsed.add(gasLeft.sub(gasleft()));
            gasLeft = gasleft();
            currentIndex++;
            iterations++;
        }
    }

    function shouldDistribute(address shareholder) internal view returns (bool) {
        return shareholderClaims[shareholder] + minPeriod < block.timestamp && getUnpaidEarnings(shareholder) > minDistribution;
    }

    function distributeDividend(address shareholder) internal {
        if(shares[shareholder].amount == 0){ return; }

        uint256 amount = getUnpaidEarnings(shareholder);
        if(amount > 0){
            totalDistributed = totalDistributed.add(amount);
            RWRD.transfer(shareholder, amount);
            shareholderClaims[shareholder] = block.timestamp;
            shares[shareholder].totalRealised = shares[shareholder].totalRealised.add(amount);
            shares[shareholder].totalExcluded = getCumulativeDividends(shares[shareholder].amount);
        }
    }

    function claimDividend() external {
        distributeDividend(msg.sender);
    }

    function getUnpaidEarnings(address shareholder) public view returns (uint256) {
        if(shares[shareholder].amount == 0){ return 0; }

        uint256 shareholderTotalDividends = getCumulativeDividends(shares[shareholder].amount);
        uint256 shareholderTotalExcluded = shares[shareholder].totalExcluded;

        if(shareholderTotalDividends <= shareholderTotalExcluded){ return 0; }

        return shareholderTotalDividends.sub(shareholderTotalExcluded);
    }

    function getCumulativeDividends(uint256 share) internal view returns (uint256) {
        return share.mul(dividendsPerShare).div(dividendsPerShareAccuracyFactor);
    }

    function addShareholder(address shareholder) internal {
        shareholderIndexes[shareholder] = shareholders.length;
        shareholders.push(shareholder);
    }

    function removeShareholder(address shareholder) internal {
        shareholders[shareholderIndexes[shareholder]] = shareholders[shareholders.length-1];
        shareholderIndexes[shareholders[shareholders.length-1]] = shareholderIndexes[shareholder];
        shareholders.pop();
    }
}

{
  "compilationTarget": {
    "WBTCDistributor.sol": "WBTCDistributor"
  },
  "evmVersion": "istanbul",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs"
  },
  "optimizer": {
    "enabled": true,
    "runs": 200
  },
  "remappings": []
}