pragma solidity ^0.5.8;
pragma experimental ABIEncoderV2;

interface ERC20Interface {
    function allowance(address, address) external view returns (uint);
    function balanceOf(address) external view returns (uint);
    function approve(address, uint) external;
    function transfer(address, uint) external returns (bool);
    function transferFrom(address, address, uint) external returns (bool);
    function deposit() external payable;
    function withdraw(uint) external;
}


contract SoloMarginContract {

    struct Info {
        address owner;  // The address that owns the account
        uint256 number; // A nonce that allows a single address to control many accounts
    }

    enum ActionType {
        Deposit,   // supply tokens
        Withdraw,  // borrow tokens
        Transfer,  // transfer balance between accounts
        Buy,       // buy an amount of some token (externally)
        Sell,      // sell an amount of some token (externally)
        Trade,     // trade tokens against another account
        Liquidate, // liquidate an undercollateralized or expiring account
        Vaporize,  // use excess tokens to zero-out a completely negative account
        Call       // send arbitrary data to an address
    }

    enum AssetDenomination {
        Wei, // the amount is denominated in wei
        Par  // the amount is denominated in par
    }

    enum AssetReference {
        Delta, // the amount is given as a delta from the current value
        Target // the amount is given as an exact number to end up at
    }

    struct AssetAmount {
        bool sign; // true if positive
        AssetDenomination denomination;
        AssetReference ref;
        uint256 value;
    }

    struct ActionArgs {
        ActionType actionType;
        uint256 accountId;
        AssetAmount amount;
        uint256 primaryMarketId;
        uint256 secondaryMarketId;
        address otherAddress;
        uint256 otherAccountId;
        bytes data;
    }

    struct Wei {
        bool sign; // true if positive
        uint256 value;
    }

    function operate(Info[] memory accounts, ActionArgs[] memory actions) public;
    function getAccountWei(Info memory account, uint256 marketId) public returns (Wei memory);

}


contract DSMath {

    function add(uint x, uint y) internal pure returns (uint z) {
        require((z = x + y) >= x, "math-not-safe");
    }

    function mul(uint x, uint y) internal pure returns (uint z) {
        require(y == 0 || (z = x * y) / y == x, "math-not-safe");
    }

    uint constant WAD = 10 ** 18;

    function wmul(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, y), WAD / 2) / WAD;
    }

    function wdiv(uint x, uint y) internal pure returns (uint z) {
        z = add(mul(x, WAD), y / 2) / y;
    }

}


contract Helpers is DSMath {

    /**
     * @dev get ethereum address
     */
    function getAddressETH() public pure returns (address eth) {
        eth = 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE;
    }

        /**
     * @dev get WETH address
     */
    function getAddressWETH() public pure returns (address weth) {
        weth = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;
    }

    /**
     * @dev get Dydx Solo Address
     */
    function getSoloAddress() public pure returns (address addr) {
        addr = 0x1E0447b19BB6EcFdAe1e4AE1694b0C3659614e4e;
    }

    /**
     * @dev setting allowance to dydx for the "user proxy" if required
     */
    function setApproval(address erc20, uint srcAmt, address to) internal {
        ERC20Interface erc20Contract = ERC20Interface(erc20);
        uint tokenAllowance = erc20Contract.allowance(address(this), to);
        if (srcAmt > tokenAllowance) {
            erc20Contract.approve(to, uint(-1));
        }
    }

    /**
    * @dev getting actions arg
    */
    function getActionsArgs(uint256 marketId, uint256 tokenAmt, bool sign) internal view returns (SoloMarginContract.ActionArgs[] memory) {
        SoloMarginContract.ActionArgs[] memory actions = new SoloMarginContract.ActionArgs[](1);
        SoloMarginContract.AssetAmount memory amount = SoloMarginContract.AssetAmount(
            sign,
            SoloMarginContract.AssetDenomination.Wei,
            SoloMarginContract.AssetReference.Delta,
            tokenAmt
        );
        bytes memory empty;
        // address otherAddr = (marketId == 0 && sign) ? getSoloPayableAddress() : address(this);
        SoloMarginContract.ActionType action = sign ? SoloMarginContract.ActionType.Deposit : SoloMarginContract.ActionType.Withdraw;
        actions[0] = SoloMarginContract.ActionArgs(
            action,
            0,
            amount,
            marketId,
            0,
            address(this),
            0,
            empty
        );
        return actions;
    }

    /**
    * @dev getting acccount arg
    */
    function getAccountArgs() internal view returns (SoloMarginContract.Info[] memory) {
        SoloMarginContract.Info[] memory accounts = new SoloMarginContract.Info[](1);
        accounts[0] = (SoloMarginContract.Info(address(this), 0));
        return accounts;
    }

    /**
     * @dev getting dydx balance
     */
    function getDydxBal(uint256 marketId) internal returns (uint tokenBal, bool tokenSign) {
        SoloMarginContract solo = SoloMarginContract(getSoloAddress());
        SoloMarginContract.Wei memory tokenWeiBal = solo.getAccountWei(getAccountArgs()[0], marketId);
        tokenBal = tokenWeiBal.value;
        tokenSign = tokenWeiBal.sign;
    }

}


contract DydxResolver is Helpers {

    event LogDeposit(address erc20Addr, uint tokenAmt, address owner);
    event LogWithdraw(address erc20Addr, uint tokenAmt, address owner);
    event LogBorrow(address erc20Addr, uint tokenAmt, address owner);
    event LogPayback(address erc20Addr, uint tokenAmt, address owner);

    /**
     * @dev Deposit ETH/ERC20
     */
    function deposit(uint256 marketId, address erc20Addr, uint256 tokenAmt) public payable {
        if (erc20Addr == getAddressETH()) {
            ERC20Interface(getAddressWETH()).deposit.value(msg.value)();
            setApproval(getAddressWETH(), tokenAmt, getSoloAddress());
        } else {
            require(ERC20Interface(erc20Addr).transferFrom(msg.sender, address(this), tokenAmt), "Allowance or not enough bal");
            setApproval(erc20Addr, tokenAmt, getSoloAddress());
        }
        SoloMarginContract(getSoloAddress()).operate(getAccountArgs(), getActionsArgs(marketId, tokenAmt, true));
        emit LogDeposit(erc20Addr, tokenAmt, address(this));
    }

    /**
     * @dev Payback ETH/ERC20
     */
    function payback(uint256 marketId, address erc20Addr, uint256 tokenAmt) public payable {
        (uint toPayback, bool tokenSign) = getDydxBal(marketId);
        require(!tokenSign, "No debt to payback");
        toPayback = toPayback > tokenAmt ? tokenAmt : toPayback;
        if (erc20Addr == getAddressETH()) {
            ERC20Interface(getAddressWETH()).deposit.value(toPayback)();
            setApproval(getAddressWETH(), toPayback, getSoloAddress());
            msg.sender.transfer(address(this).balance);
        } else {
            require(ERC20Interface(erc20Addr).transferFrom(msg.sender, address(this), toPayback), "Allowance or not enough bal");
            setApproval(erc20Addr, toPayback, getSoloAddress());
        }
        SoloMarginContract(getSoloAddress()).operate(getAccountArgs(), getActionsArgs(marketId, toPayback, true));
        emit LogPayback(erc20Addr, toPayback, address(this));
    }

    /**
     * @dev Withdraw ETH/ERC20
     */
    function withdraw(uint256 marketId, address erc20Addr, uint256 tokenAmt) public {
        (uint toWithdraw, bool tokenSign) = getDydxBal(marketId);
        require(tokenSign, "token not deposited");
        toWithdraw = toWithdraw > tokenAmt ? tokenAmt : toWithdraw;
        SoloMarginContract solo = SoloMarginContract(getSoloAddress());
        solo.operate(getAccountArgs(), getActionsArgs(marketId, toWithdraw, false));
        if (erc20Addr == getAddressETH()) {
            ERC20Interface wethContract = ERC20Interface(getAddressWETH());
            uint wethBal = wethContract.balanceOf(address(this));
            toWithdraw = toWithdraw < wethBal ? wethBal : toWithdraw;
            setApproval(getAddressWETH(), toWithdraw, getAddressWETH());
            ERC20Interface(getAddressWETH()).withdraw(toWithdraw);
            msg.sender.transfer(toWithdraw);
        } else {
            require(ERC20Interface(erc20Addr).transfer(msg.sender, toWithdraw), "Allowance or not enough bal");
        }
        emit LogWithdraw(erc20Addr, toWithdraw, address(this));
    }

    /**
    * @dev Borrow ETH/ERC20
    */
    function borrow(uint256 marketId, address erc20Addr, uint256 tokenAmt) public {
        SoloMarginContract(getSoloAddress()).operate(getAccountArgs(), getActionsArgs(marketId, tokenAmt, false));
        if (erc20Addr == getAddressETH()) {
            setApproval(getAddressWETH(), tokenAmt, getAddressWETH());
            ERC20Interface(getAddressWETH()).withdraw(tokenAmt);
            msg.sender.transfer(tokenAmt);
        } else {
            require(ERC20Interface(erc20Addr).transfer(msg.sender, tokenAmt), "Allowance or not enough bal");
        }
        emit LogBorrow(erc20Addr, tokenAmt, address(this));
    }

}


contract InstaDydx is DydxResolver {
    function() external payable {}
}