pragma solidity 0.4.18;

interface ConversionRatesInterface {

    function recordImbalance(
        ERC20 token,
        int buyAmount,
        uint rateUpdateBlock,
        uint currentBlock
    )
        public;

    function getRate(ERC20 token, uint currentBlockNumber, bool buy, uint qty) public view returns(uint);
}

interface ERC20 {
    function totalSupply() public view returns (uint supply);
    function balanceOf(address _owner) public view returns (uint balance);
    function transfer(address _to, uint _value) public returns (bool success);
    function transferFrom(address _from, address _to, uint _value) public returns (bool success);
    function approve(address _spender, uint _value) public returns (bool success);
    function allowance(address _owner, address _spender) public view returns (uint remaining);
    function decimals() public view returns(uint digits);
    event Approval(address indexed _owner, address indexed _spender, uint _value);
}

interface KyberReserveInterface {

    function trade(
        ERC20 srcToken,
        uint srcAmount,
        ERC20 destToken,
        address destAddress,
        uint conversionRate,
        bool validate
    )
        public
        payable
        returns(bool);

    function getConversionRate(ERC20 src, ERC20 dest, uint srcQty, uint blockNumber) public view returns(uint);
}

contract PermissionGroups {

    address public admin;
    address public pendingAdmin;
    mapping(address=>bool) internal operators;
    mapping(address=>bool) internal alerters;
    address[] internal operatorsGroup;
    address[] internal alertersGroup;
    uint constant internal MAX_GROUP_SIZE = 50;

    function PermissionGroups() public {
        admin = msg.sender;
    }

    modifier onlyAdmin() {
        require(msg.sender == admin);
        _;
    }

    modifier onlyOperator() {
        require(operators[msg.sender]);
        _;
    }

    modifier onlyAlerter() {
        require(alerters[msg.sender]);
        _;
    }

    function getOperators () external view returns(address[]) {
        return operatorsGroup;
    }

    function getAlerters () external view returns(address[]) {
        return alertersGroup;
    }

    event TransferAdminPending(address pendingAdmin);

    /**
     * @dev Allows the current admin to set the pendingAdmin address.
     * @param newAdmin The address to transfer ownership to.
     */
    function transferAdmin(address newAdmin) public onlyAdmin {
        require(newAdmin != address(0));
        TransferAdminPending(pendingAdmin);
        pendingAdmin = newAdmin;
    }

    /**
     * @dev Allows the current admin to set the admin in one tx. Useful initial deployment.
     * @param newAdmin The address to transfer ownership to.
     */
    function transferAdminQuickly(address newAdmin) public onlyAdmin {
        require(newAdmin != address(0));
        TransferAdminPending(newAdmin);
        AdminClaimed(newAdmin, admin);
        admin = newAdmin;
    }

    event AdminClaimed( address newAdmin, address previousAdmin);

    /**
     * @dev Allows the pendingAdmin address to finalize the change admin process.
     */
    function claimAdmin() public {
        require(pendingAdmin == msg.sender);
        AdminClaimed(pendingAdmin, admin);
        admin = pendingAdmin;
        pendingAdmin = address(0);
    }

    event AlerterAdded (address newAlerter, bool isAdd);

    function addAlerter(address newAlerter) public onlyAdmin {
        require(!alerters[newAlerter]); // prevent duplicates.
        require(alertersGroup.length < MAX_GROUP_SIZE);

        AlerterAdded(newAlerter, true);
        alerters[newAlerter] = true;
        alertersGroup.push(newAlerter);
    }

    function removeAlerter (address alerter) public onlyAdmin {
        require(alerters[alerter]);
        alerters[alerter] = false;

        for (uint i = 0; i < alertersGroup.length; ++i) {
            if (alertersGroup[i] == alerter) {
                alertersGroup[i] = alertersGroup[alertersGroup.length - 1];
                alertersGroup.length--;
                AlerterAdded(alerter, false);
                break;
            }
        }
    }

    event OperatorAdded(address newOperator, bool isAdd);

    function addOperator(address newOperator) public onlyAdmin {
        require(!operators[newOperator]); // prevent duplicates.
        require(operatorsGroup.length < MAX_GROUP_SIZE);

        OperatorAdded(newOperator, true);
        operators[newOperator] = true;
        operatorsGroup.push(newOperator);
    }

    function removeOperator (address operator) public onlyAdmin {
        require(operators[operator]);
        operators[operator] = false;

        for (uint i = 0; i < operatorsGroup.length; ++i) {
            if (operatorsGroup[i] == operator) {
                operatorsGroup[i] = operatorsGroup[operatorsGroup.length - 1];
                operatorsGroup.length -= 1;
                OperatorAdded(operator, false);
                break;
            }
        }
    }
}

interface SanityRatesInterface {
    function getSanityRate(ERC20 src, ERC20 dest) public view returns(uint);
}

contract Utils {

    ERC20 constant internal ETH_TOKEN_ADDRESS = ERC20(0x00eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee);
    uint  constant internal PRECISION = (10**18);
    uint  constant internal MAX_QTY   = (10**28); // 10B tokens
    uint  constant internal MAX_RATE  = (PRECISION * 10**6); // up to 1M tokens per ETH
    uint  constant internal MAX_DECIMALS = 18;
    uint  constant internal ETH_DECIMALS = 18;
    mapping(address=>uint) internal decimals;

    function setDecimals(ERC20 token) internal {
        if (token == ETH_TOKEN_ADDRESS) decimals[token] = ETH_DECIMALS;
        else decimals[token] = token.decimals();
    }

    function getDecimals(ERC20 token) internal view returns(uint) {
        if (token == ETH_TOKEN_ADDRESS) return ETH_DECIMALS; // save storage access
        uint tokenDecimals = decimals[token];
        // technically, there might be token with decimals 0
        // moreover, very possible that old tokens have decimals 0
        // these tokens will just have higher gas fees.
        if(tokenDecimals == 0) return token.decimals();

        return tokenDecimals;
    }

    function calcDstQty(uint srcQty, uint srcDecimals, uint dstDecimals, uint rate) internal pure returns(uint) {
        require(srcQty <= MAX_QTY);
        require(rate <= MAX_RATE);

        if (dstDecimals >= srcDecimals) {
            require((dstDecimals - srcDecimals) <= MAX_DECIMALS);
            return (srcQty * rate * (10**(dstDecimals - srcDecimals))) / PRECISION;
        } else {
            require((srcDecimals - dstDecimals) <= MAX_DECIMALS);
            return (srcQty * rate) / (PRECISION * (10**(srcDecimals - dstDecimals)));
        }
    }

    function calcSrcQty(uint dstQty, uint srcDecimals, uint dstDecimals, uint rate) internal pure returns(uint) {
        require(dstQty <= MAX_QTY);
        require(rate <= MAX_RATE);
        
        //source quantity is rounded up. to avoid dest quantity being too low.
        uint numerator;
        uint denominator;
        if (srcDecimals >= dstDecimals) {
            require((srcDecimals - dstDecimals) <= MAX_DECIMALS);
            numerator = (PRECISION * dstQty * (10**(srcDecimals - dstDecimals)));
            denominator = rate;
        } else {
            require((dstDecimals - srcDecimals) <= MAX_DECIMALS);
            numerator = (PRECISION * dstQty);
            denominator = (rate * (10**(dstDecimals - srcDecimals)));
        }
        return (numerator + denominator - 1) / denominator; //avoid rounding down errors
    }
}

contract Withdrawable is PermissionGroups {

    event TokenWithdraw(ERC20 token, uint amount, address sendTo);

    /**
     * @dev Withdraw all ERC20 compatible tokens
     * @param token ERC20 The address of the token contract
     */
    function withdrawToken(ERC20 token, uint amount, address sendTo) external onlyAdmin {
        require(token.transfer(sendTo, amount));
        TokenWithdraw(token, amount, sendTo);
    }

    event EtherWithdraw(uint amount, address sendTo);

    /**
     * @dev Withdraw Ethers
     */
    function withdrawEther(uint amount, address sendTo) external onlyAdmin {
        sendTo.transfer(amount);
        EtherWithdraw(amount, sendTo);
    }
}

interface FundWalletInterface {
    function() public payable;
    function pullToken(ERC20 token, uint amount) external returns (bool);
    function pullEther(uint amount) external returns (bool);
    function checkBalance(ERC20 token) public view returns (uint);
}

/// @title Kyber Fund Reserve contract
contract KyberFundReserve is KyberReserveInterface, Withdrawable, Utils {

    address public kyberNetwork;
    bool public tradeEnabled;
    ConversionRatesInterface public conversionRatesContract;
    SanityRatesInterface public sanityRatesContract;
    FundWalletInterface public fundWalletContract;
    mapping(bytes32=>bool) public approvedWithdrawAddresses; // sha3(token,address)=>bool

    function KyberFundReserve(address _kyberNetwork, ConversionRatesInterface _ratesContract, FundWalletInterface _fundWallet, address _admin) public {
        require(_admin != address(0));
        require(_ratesContract != address(0));
        require(_kyberNetwork != address(0));
        require(_fundWallet != address(0));
        kyberNetwork = _kyberNetwork;
        conversionRatesContract = _ratesContract;
        fundWalletContract = _fundWallet;
        admin = _admin;
        tradeEnabled = true;
    }

    event DepositToken(ERC20 token, uint amount);

    function() public payable {
        DepositToken(ETH_TOKEN_ADDRESS, msg.value);
    }

    event TradeExecute(
        address indexed origin,
        address src,
        uint srcAmount,
        address destToken,
        uint destAmount,
        address destAddress
    );

    function trade(
        ERC20 srcToken,
        uint srcAmount,
        ERC20 destToken,
        address destAddress,
        uint conversionRate,
        bool validate
    )
        public
        payable
        returns(bool)
    {
        require(tradeEnabled);
        require(msg.sender == kyberNetwork);

        require(doTrade(srcToken, srcAmount, destToken, destAddress, conversionRate, validate));

        return true;
    }

    event TradeEnabled(bool enable);

    function enableTrade() public onlyAdmin returns(bool) {
        tradeEnabled = true;
        TradeEnabled(true);

        return true;
    }

    function disableTrade() public onlyAlerter returns(bool) {
        tradeEnabled = false;
        TradeEnabled(false);

        return true;
    }

    event WithdrawAddressApproved(ERC20 token, address addr, bool approve);

    function approveWithdrawAddress(ERC20 token, address addr, bool approve) public onlyAdmin {
        approvedWithdrawAddresses[keccak256(token, addr)] = approve;
        WithdrawAddressApproved(token, addr, approve);

        setDecimals(token);
    }

    function setFundWallet(FundWalletInterface _fundWallet) public onlyAdmin {
        require(_fundWallet != address(0x0));
        fundWalletContract = _fundWallet;
    }

    event WithdrawFunds(ERC20 token, uint amount, address destination);

    function withdraw(ERC20 token, uint amount, address destination) public onlyOperator returns(bool) {
        require(approvedWithdrawAddresses[keccak256(token, destination)]);

        if (token == ETH_TOKEN_ADDRESS) {
            require(ethPuller(amount));
            destination.transfer(amount);
        } else {
            require(tokenPuller(token, amount));
            require(token.transfer(destination, amount));
        }

        WithdrawFunds(token, amount, destination);

        return true;
    }

    event SetContractAddresses(address network, address rate, address sanity);

    function setContracts(
        address _kyberNetwork,
        ConversionRatesInterface _conversionRates,
        SanityRatesInterface _sanityRates
    )
        public
        onlyAdmin
    {
        require(_kyberNetwork != address(0));
        require(_conversionRates != address(0));

        kyberNetwork = _kyberNetwork;
        conversionRatesContract = _conversionRates;
        sanityRatesContract = _sanityRates;

        SetContractAddresses(kyberNetwork, conversionRatesContract, sanityRatesContract);
    }

    ////////////////////////////////////////////////////////////////////////////
    /// status functions ///////////////////////////////////////////////////////
    ////////////////////////////////////////////////////////////////////////////
    function getBalance(ERC20 token) public view returns(uint) {
        return fetchBalance(token);
    }

    function fetchBalance(ERC20 token) public view returns(uint) {
        return fundWalletContract.checkBalance(token);
    }

    function getDestQty(ERC20 src, ERC20 dest, uint srcQty, uint rate) public view returns(uint) {
        uint dstDecimals = getDecimals(dest);
        uint srcDecimals = getDecimals(src);

        return calcDstQty(srcQty, srcDecimals, dstDecimals, rate);
    }

    function getSrcQty(ERC20 src, ERC20 dest, uint dstQty, uint rate) public view returns(uint) {
        uint dstDecimals = getDecimals(dest);
        uint srcDecimals = getDecimals(src);

        return calcSrcQty(dstQty, srcDecimals, dstDecimals, rate);
    }

    function getConversionRate(ERC20 src, ERC20 dest, uint srcQty, uint blockNumber) public view returns(uint) {
        ERC20 token;
        bool  isBuy;

        if (!tradeEnabled) return 0;

        if (ETH_TOKEN_ADDRESS == src) {
            isBuy = true;
            token = dest;
        } else if (ETH_TOKEN_ADDRESS == dest) {
            isBuy = false;
            token = src;
        } else {
            return 0; // pair is not listed
        }

        uint rate = conversionRatesContract.getRate(token, blockNumber, isBuy, srcQty);
        uint destQty = getDestQty(src, dest, srcQty, rate);

        if (getBalance(dest) < destQty) return 0;

        if (sanityRatesContract != address(0)) {
            uint sanityRate = sanityRatesContract.getSanityRate(src, dest);
            if (rate > sanityRate) return 0;
        }

        return rate;
    }

    /// @dev do a trade
    /// @param srcToken Src token
    /// @param srcAmount Amount of src token
    /// @param destToken Destination token
    /// @param destAddress Destination address to send tokens to
    /// @param validate If true, additional validations are applicable
    /// @return true iff trade is successful
    function doTrade(
        ERC20 srcToken,
        uint srcAmount,
        ERC20 destToken,
        address destAddress,
        uint conversionRate,
        bool validate
    )
        internal
        returns(bool)
    {
        // can skip validation if done at kyber network level
        if (validate) {
            require(conversionRate > 0);
            if (srcToken == ETH_TOKEN_ADDRESS)
                require(msg.value == srcAmount);
            else
                require(msg.value == 0);
        }

        uint destAmount = getDestQty(srcToken, destToken, srcAmount, conversionRate);
        // sanity check
        require(destAmount > 0);

        // add to imbalance
        ERC20 token;
        int tradeAmount;
        if (srcToken == ETH_TOKEN_ADDRESS) {
            tradeAmount = int(destAmount);
            token = destToken;
        } else {
            tradeAmount = -1 * int(srcAmount);
            token = srcToken;
        }

        conversionRatesContract.recordImbalance(
            token,
            tradeAmount,
            0,
            block.number
        );


        // collect src tokens (if eth forward to fund Wallet)
        if (srcToken == ETH_TOKEN_ADDRESS) {
            //require push eth function
            require(ethPusher(srcAmount));
        } else {
            require(srcToken.transferFrom(msg.sender, fundWalletContract, srcAmount));
        }

        // send dest tokens
        if (destToken == ETH_TOKEN_ADDRESS) {
          //require pull eth function then send eth to dest address;
          require(ethPuller(destAmount));
          destAddress.transfer(destAmount);
        } else {
          //require pull token function then send token to dest address;
          require(tokenPuller(destToken, destAmount));
          require(destToken.transfer(destAddress, destAmount));
        }

        TradeExecute(msg.sender, srcToken, srcAmount, destToken, destAmount, destAddress);

        return true;
    }

    //push eth function
    function ethPusher(uint srcAmount) internal returns(bool) {
        fundWalletContract.transfer(srcAmount);
        return true;
    }

    //pull eth functions
    function ethPuller(uint destAmount) internal returns(bool) {
        require(fundWalletContract.pullEther(destAmount));
        return true;
    }

    //pull token function
    function tokenPuller(ERC20 token, uint destAmount) internal returns(bool) {
        require(fundWalletContract.pullToken(token, destAmount));
        return true;
    }
}