pragma solidity ^0.6.0;
pragma experimental ABIEncoderV2;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);
    function deposit() external payable;
    function withdraw(uint256 amount) external;

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, "SafeMath: modulo by zero");
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
        // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
        // for accounts without code, i.e. `keccak256('')`
        bytes32 codehash;
        bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        // solhint-disable-next-line no-inline-assembly
        assembly { codehash := extcodehash(account) }
        return (codehash != accountHash && codehash != 0x0);
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (bool success, ) = recipient.call.value(amount)("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain`call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
      return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        return _functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        return _functionCallWithValue(target, data, value, errorMessage);
    }

    function _functionCallWithValue(address target, bytes memory data, uint256 weiValue, string memory errorMessage) private returns (bytes memory) {
        require(isContract(target), "Address: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.call.value(weiValue)(data);
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                // solhint-disable-next-line no-inline-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using SafeMath for uint256;
    using Address for address;

    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(IERC20 token, address spender, uint256 value) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        // solhint-disable-next-line max-line-length
        require((value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).add(value);
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        if (returndata.length > 0) { // Return data is optional
            // solhint-disable-next-line max-line-length
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

interface InstaFlashV2Interface {
    function initiateFlashLoan(address[] calldata tokens, uint256[] calldata amts, uint route, bytes calldata data) external;
    function fee() external view returns(uint);
}

interface TokenInterface {
    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);
}

interface MemoryInterface {
    function getUint(uint _id) external returns (uint _num);
    function setUint(uint _id, uint _val) external;
}

interface AccountInterface {
    function enable(address) external;
    function disable(address) external;
}

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");
    }

    function sub(uint x, uint y) internal pure returns (uint z) {
        require((z = x - y) <= x, "sub-overflow");
    }

    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 {

    using SafeERC20 for IERC20;

    /**
     * @dev Return ethereum address
     */
    function getAddressETH() internal pure returns (address) {
        return 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE; // ETH Address
    }

    /**
     * @dev Return Memory Variable Address
     */
    function getMemoryAddr() internal pure returns (address) {
        return 0x8a5419CfC711B2343c17a6ABf4B2bAFaBb06957F; // InstaMemory Address
    }

    /**
     * @dev Get Uint value from InstaMemory Contract.
    */
    function getUint(uint getId, uint val) internal returns (uint returnVal) {
        returnVal = getId == 0 ? val : MemoryInterface(getMemoryAddr()).getUint(getId);
    }

    /**
     * @dev Set Uint value in InstaMemory Contract.
    */
    function setUint(uint setId, uint val) internal {
        if (setId != 0) MemoryInterface(getMemoryAddr()).setUint(setId, val);
    }

    /**
     * @dev Connector Details.
    */
    function connectorID() public pure returns(uint _type, uint _id) {
        (_type, _id) = (1, 56);
    }

    function _transfer(address payable to, IERC20 token, uint _amt) internal {
        address(token) == getAddressETH() ?
            to.transfer(_amt) :
            token.safeTransfer(to, _amt);
    }

    function _getBalance(IERC20 token) internal view returns (uint256) {
        return address(token) == getAddressETH() ?
            address(this).balance :
            token.balanceOf(address(this));
    }
}


contract DydxFlashHelpers is Helpers {
    /**
     * @dev Return Instapool address
     */
    function getInstaFlashV2Addr() internal pure returns (address) {
        return 0x691d4172331a11912c6D0e6D1A002E3d7CED6a66;
    }

    function calculateTotalFeeAmt(InstaFlashV2Interface instapoolContract, uint amt) internal view returns (uint totalAmt) {
        uint fee = instapoolContract.fee();
        if (fee == 0) {
            totalAmt = amt;
        } else {
            uint feeAmt = wmul(amt, fee);
            totalAmt = add(amt, feeAmt);
        }
    }

    function calculateFlashFeeAmt(InstaFlashV2Interface instapoolContract, uint flashAmt, uint amt) internal view returns (uint totalAmt) {
        uint fee = instapoolContract.fee();
        if (fee == 0) {
            totalAmt = amt;
        } else {
            uint feeAmt = wmul(flashAmt, fee);
            totalAmt = add(amt, feeAmt);
        }
    }
}

contract LiquidityAccessHelper is DydxFlashHelpers {
    /**
     * @dev Add Fee Amount to borrowed flashloan/
     * @param amt Get token amount at this ID from `InstaMemory` Contract.
     * @param getId Get token amount at this ID from `InstaMemory` Contract.
     * @param setId Set token amount at this ID in `InstaMemory` Contract.
    */
    function addFeeAmount(uint flashAmt, uint amt, uint getId, uint setId) external payable {
        uint _amt = getUint(getId, amt);
        require(_amt != 0, "amt-is-0");
        InstaFlashV2Interface instapoolContract = InstaFlashV2Interface(getInstaFlashV2Addr());

        uint totalFee = calculateFlashFeeAmt(instapoolContract, flashAmt, _amt);

        setUint(setId, totalFee);
    }

}

contract LiquidityAccess is LiquidityAccessHelper {

    event LogFlashBorrow(address[] token, uint256[] tokenAmt);
    event LogFlashPayback(address[] token, uint256[] tokenAmt, uint256[] totalAmtFee);

    /**
     * @dev Borrow Flashloan and Cast spells.
     * @param token Token Address.
     * @param amt Token Amount.
     * @param data targets & data for cast.
     */
    function flashBorrowAndCast(address token, uint amt, uint route, bytes memory data) public payable {
        AccountInterface(address(this)).enable(getInstaFlashV2Addr());

        address[] memory tokens = new address[](1);
        uint[] memory amts = new uint[](1);
        tokens[0] = token;
        amts[0] = amt;

        emit LogFlashBorrow(tokens, amts);

        InstaFlashV2Interface(getInstaFlashV2Addr()).initiateFlashLoan(tokens, amts, route, data);

        AccountInterface(address(this)).disable(getInstaFlashV2Addr());

    }

    /**
     * @dev Return token to InstaPool.
     * @param token token address.(For ETH: 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE)
     * @param amt token amt.(For ETH: 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE)
     * @param getId Get token amount at this ID from `InstaMemory` Contract.
     * @param setId Set token amount at this ID in `InstaMemory` Contract.
    */
    function flashPayback(address token, uint amt, uint getId, uint setId) external payable {
        uint _amt = getUint(getId, amt);
        
        InstaFlashV2Interface instapoolContract = InstaFlashV2Interface(getInstaFlashV2Addr());
        IERC20 tokenContract = IERC20(token);

        (uint totalFeeAmt) = calculateTotalFeeAmt(instapoolContract, _amt);

        _transfer(payable(address(getInstaFlashV2Addr())), tokenContract, totalFeeAmt);

        setUint(setId, totalFeeAmt);

        address[] memory tokens = new address[](1);
        uint[] memory amts = new uint[](1);
        uint[] memory totalFeeAmts = new uint[](1);
        tokens[0] = token;
        amts[0] = amt;
        totalFeeAmts[0] = totalFeeAmt;

        emit LogFlashPayback(tokens, amts, totalFeeAmts);
    }
}

contract LiquidityAccessMulti is LiquidityAccess {
    /**
     * @dev Borrow Flashloan and Cast spells.
     * @param tokens Array of token Addresses.
     * @param amts Array of token Amounts.
     * @param route Route to borrow.
     * @param data targets & data for cast.
     */
    function flashMultiBorrowAndCast(address[] calldata tokens, uint[] calldata amts, uint route, bytes calldata data) external payable {
        AccountInterface(address(this)).enable(getInstaFlashV2Addr());

        emit LogFlashBorrow(tokens, amts);

        InstaFlashV2Interface(getInstaFlashV2Addr()).initiateFlashLoan(tokens, amts, route, data);

        AccountInterface(address(this)).disable(getInstaFlashV2Addr());

    }

    /**
     * @dev Return Multiple token liquidity to InstaPool.
     * @param tokens Array of token addresses.(For ETH: 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE)
     * @param amts Array of token amounts.
     * @param getId get token amounts at this IDs from `InstaMemory` Contract.
     * @param setId set token amounts at this IDs in `InstaMemory` Contract.
    */
    function flashMultiPayback(address[] calldata tokens, uint[] calldata amts, uint[] calldata getId, uint[] calldata setId) external payable {
        uint _length = tokens.length;
        InstaFlashV2Interface instapoolContract = InstaFlashV2Interface(getInstaFlashV2Addr());

        uint[] memory totalAmtFees = new uint[](_length);
        for (uint i = 0; i < _length; i++) {
            uint _amt = getUint(getId[i], amts[i]);
            IERC20 tokenContract = IERC20(tokens[i]);

            
            (totalAmtFees[i]) = calculateTotalFeeAmt(instapoolContract, _amt);

            _transfer(payable(address(getInstaFlashV2Addr())), tokenContract, totalAmtFees[i]);

            setUint(setId[i], totalAmtFees[i]);
        }

        emit LogFlashPayback(tokens, amts, totalAmtFees);
    }

}

contract ConnectInstaPoolV2 is LiquidityAccessMulti {
    string public name = "Instapool-v2.2";
}