Add cream compound protocol

contracts/strategies/StrategyCompoundCreamLendingPool.sol

@@ -0,0 +1,225 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity >=0.6.0 <0.8.0;
+
+import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+import "@openzeppelin/contracts/math/SafeMath.sol";
+import "@openzeppelin/contracts/utils/Address.sol";
+import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
+import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
+import "@openzeppelin/contracts/access/Ownable.sol";
+
+import "./interfaces/IStrategy.sol";
+import "./interfaces/compound/ICErc20.sol";
+import "./interfaces/compound/IComptroller.sol";
+import "./interfaces/uniswap/IUniswapV2.sol";
+
+/**
+ * Deposits ERC20 token into Compound or Cream Lending Pool based on interest rate and issues stCreamLendingToken(e.g. stCreamLendingDAI) in L2. Holds cToken (Cream interest-bearing tokens).
+ */
+contract StrategyCreamLendingPool is IStrategy, Ownable {
+    using SafeERC20 for IERC20;
+    using Address for address;
+    using SafeMath for uint256;
+
+    // Info of supplying erc20 token to Cream lending pool
+    // The symbol of the supplying token
+    string public symbol;
+    // The address of supplying token (e.g. DAI, USDT)
+    address public supplyToken;
+
+    // The address of Compound interest-bearing token (e.g. cDAI, cUSDT)
+    address public cErc20;
+
+    // The address of Cream interest-bearing token (e.g. crDAI, crUSDT)
+    address public crErc20;
+
+    // The address is used for claim COMP token
+    address public comptroller;
+
+    // The address is used for claim CREAM token
+    address public creamtroller;
+
+    // The address of COMP token
+    address public comp;
+
+    // The address of CREAM token
+    address public cream;
+
+    address public uniswap;
+    // The address of WETH token
+    address public weth;
+
+    address public controller;
+
+    constructor(
+        string memory _symbol,
+        address _supplyToken,
+        address _cErc20,
+        address _crErc20,
+        address _comptroller,
+        address _creamtroller,
+        address _comp,
+        address _cream,
+        address _uniswap,
+        address _weth,
+        address _controller
+    ) {
+        symbol = _symbol;
+        supplyToken = _supplyToken;
+        cErc20 = _cErc20;
+        crErc20 = _crErc20;
+        comptroller = _comptroller;
+        creamtroller = _creamtroller;
+        comp = _comp;
+        cream = _cream;
+        uniswap = _uniswap;
+        weth = _weth;
+        controller = _controller;
+    }
+
+    /**
+     * @dev Require that the caller must be an EOA account to avoid flash loans.
+     */
+    modifier onlyEOA() {
+        require(msg.sender == tx.origin, "Not EOA");
+        _;
+    }
+
+    function getAssetAddress() external view override returns (address) {
+        return supplyToken;
+    }
+
+    function syncBalance() external override returns (uint256) {
+        // Supplying token(e.g. DAI, USDT) balance of this contract.
+        // supplyTokenBalance is equal to the cToken balance multiplied by the Exchange Rate.
+        uint256 supplyTokenBalance =
+            ICErc20(cErc20).balanceOfUnderlying(address(this)) + ICErc20(crErc20).balanceOfUnderlying(address(this));
+        return supplyTokenBalance;
+    }
+
+    function harvest() external override onlyEOA {
+        // Claim COMP token.
+        IComptroller(comptroller).claimComp(address(this));
+        uint256 compBalance = IERC20(comp).balanceOf(address(this));
+        if (compBalance > 0) {
+            // Sell COMP token for obtain more supplying token(e.g. DAI, USDT)
+            IERC20(comp).safeIncreaseAllowance(uniswap, compBalance);
+
+            address[] memory paths = new address[](3);
+            paths[0] = comp;
+            paths[1] = weth;
+            paths[2] = supplyToken;
+
+            IUniswapV2(uniswap).swapExactTokensForTokens(
+                compBalance,
+                uint256(0),
+                paths,
+                address(this),
+                block.timestamp.add(1800)
+            );
+        }
+
+        // Claim CREAM token.
+        IComptroller(creamtroller).claimComp(address(this));
+        uint256 creamBalance = IERC20(cream).balanceOf(address(this));
+        if (creamBalance > 0) {
+            // Sell CREAM token for obtain more supplying token(e.g. DAI, USDT)
+            IERC20(cream).safeIncreaseAllowance(uniswap, creamBalance);
+
+            address[] memory paths = new address[](3);
+            paths[0] = cream;
+            paths[1] = weth;
+            paths[2] = supplyToken;
+
+            IUniswapV2(uniswap).swapExactTokensForTokens(
+                creamBalance,
+                uint256(0),
+                paths,
+                address(this),
+                block.timestamp.add(1800)
+            );
+        }
+
+        reditribute();
+    }
+
+    function aggregateCommit(uint256 _commitAmount) external override {
+        require(msg.sender == controller, "Not controller");
+        require(_commitAmount > 0, "Nothing to commit");
+
+        // Pull supplying token(e.g. DAI, USDT) from Controller
+        IERC20(supplyToken).safeTransferFrom(msg.sender, address(this), _commitAmount);
+        uint256 mintResult;
+
+        if (ICErc20(cErc20).supplyRatePerBlock() > ICErc20(crErc20).supplyRatePerBlock()) {
+            // Deposit supplying token to Compound Erc20 Lending Pool and mint cErc20.
+            IERC20(supplyToken).safeIncreaseAllowance(cErc20, _commitAmount);
+            mintResult = ICErc20(cErc20).mint(_commitAmount);
+        } else {
+            // Deposit supplying token to Cream Erc20 Lending Pool and mint crErc20.
+            IERC20(supplyToken).safeIncreaseAllowance(crErc20, _commitAmount);
+            mintResult = ICErc20(crErc20).mint(_commitAmount);
+        }
+
+        require(mintResult == 0, "Couldn't mint cToken/crToken");
+
+        emit Committed(_commitAmount);
+    }
+
+    function aggregateUncommit(uint256 _uncommitAmount) external override {
+        require(msg.sender == controller, "Not controller");
+        require(_uncommitAmount > 0, "Nothing to uncommit");
+
+        ICErc20 lowRateProtocol = ICErc20(cErc20);
+        ICErc20 highRateProtocol = ICErc20(crErc20);
+        if (lowRateProtocol.supplyRatePerBlock() > highRateProtocol.supplyRatePerBlock()) {
+            lowRateProtocol = ICErc20(crErc20);
+            highRateProtocol = ICErc20(cErc20);
+        }
+
+        uint256 redeemResult;
+        uint256 lowRateBalance = lowRateProtocol.balanceOfUnderlying(address(this));
+        if (_uncommitAmount < lowRateBalance) {
+            lowRateBalance = _uncommitAmount;
+        } else {
+            redeemResult = highRateProtocol.redeemUnderlying(_uncommitAmount - lowRateBalance);
+            require(redeemResult == 0, "Couldn't redeem cToken");
+        }
+
+        redeemResult = lowRateProtocol.redeemUnderlying(lowRateBalance);
+        require(redeemResult == 0, "Couldn't redeem cToken");
+
+        // Transfer supplying token(e.g. DAI, USDT) to Controller
+        uint256 supplyTokenBalance = IERC20(supplyToken).balanceOf(address(this));
+        IERC20(supplyToken).safeTransfer(msg.sender, supplyTokenBalance);
+
+        emit UnCommitted(_uncommitAmount);
+    }
+
+    function reditribute() public {
+        require(msg.sender == controller, "Not controller");
+
+        ICErc20 lowRateProtocol = ICErc20(cErc20);
+        ICErc20 highRateProtocol = ICErc20(crErc20);
+        if (lowRateProtocol.supplyRatePerBlock() > highRateProtocol.supplyRatePerBlock()) {
+            lowRateProtocol = ICErc20(crErc20);
+            highRateProtocol = ICErc20(cErc20);
+        }
+
+        uint256 lowRateBalance = lowRateProtocol.balanceOfUnderlying(address(this));
+
+        uint256 redeemResult = lowRateProtocol.redeemUnderlying(lowRateBalance);
+        require(redeemResult == 0, "Couldn't redeem cToken/crToken");
+
+        uint256 supplyTokenBalance = IERC20(supplyToken).balanceOf(address(this));
+        IERC20(supplyToken).safeIncreaseAllowance(address(highRateProtocol), supplyTokenBalance);
+        uint256 mintResult = highRateProtocol.mint(supplyTokenBalance);
+        require(mintResult == 0, "Couldn't mint cToken/crToken");
+    }
+
+    function setController(address _controller) external onlyOwner {
+        emit ControllerChanged(controller, _controller);
+        controller = _controller;
+    }
+}

contracts/strategies/StrategyCreamLendingPool.sol

@@ -0,0 +1,148 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity >=0.6.0 <0.8.0;
+
+import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+import "@openzeppelin/contracts/math/SafeMath.sol";
+import "@openzeppelin/contracts/utils/Address.sol";
+import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
+import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
+import "@openzeppelin/contracts/access/Ownable.sol";
+
+import "./interfaces/IStrategy.sol";
+import "./interfaces/compound/ICErc20.sol";
+import "./interfaces/compound/IComptroller.sol";
+import "./interfaces/uniswap/IUniswapV2.sol";
+
+/**
+ * Deposits ERC20 token into Cream Lending Pool and issues stCreamLendingToken(e.g. stCreamLendingDAI) in L2. Holds cToken (Cream interest-bearing tokens).
+ */
+contract StrategyCreamLendingPool is IStrategy, Ownable {
+    using SafeERC20 for IERC20;
+    using Address for address;
+    using SafeMath for uint256;
+
+    // Info of supplying erc20 token to Cream lending pool
+    // The symbol of the supplying token
+    string public symbol;
+    // The address of supplying token (e.g. DAI, USDT)
+    address public supplyToken;
+
+    // The address of Cream interest-bearing token (e.g. crDAI, crUSDT)
+    address public crErc20;
+
+    // The address is used for claim CREAM token
+    address public creamtroller;
+    // The address of CREAM token
+    address public cream;
+
+    address public uniswap;
+    // The address of WETH token
+    address public weth;
+
+    address public controller;
+
+    constructor(
+        string memory _symbol,
+        address _supplyToken,
+        address _crErc20,
+        address _creamtroller,
+        address _cream,
+        address _uniswap,
+        address _weth,
+        address _controller
+    ) {
+        symbol = _symbol;
+        supplyToken = _supplyToken;
+        crErc20 = _crErc20;
+        creamtroller = _creamtroller;
+        cream = _cream;
+        uniswap = _uniswap;
+        weth = _weth;
+        controller = _controller;
+    }
+
+    /**
+     * @dev Require that the caller must be an EOA account to avoid flash loans.
+     */
+    modifier onlyEOA() {
+        require(msg.sender == tx.origin, "Not EOA");
+        _;
+    }
+
+    function getAssetAddress() external view override returns (address) {
+        return supplyToken;
+    }
+
+    function syncBalance() external override returns (uint256) {
+        // Supplying token(e.g. DAI, USDT) balance of this contract.
+        // supplyTokenBalance is equal to the cToken balance multiplied by the Exchange Rate.
+        uint256 supplyTokenBalance = ICErc20(crErc20).balanceOfUnderlying(address(this));
+        return supplyTokenBalance;
+    }
+
+    function harvest() external override onlyEOA {
+        // Claim CREAM token.
+        IComptroller(creamtroller).claimComp(address(this));
+        uint256 creamBalance = IERC20(cream).balanceOf(address(this));
+        if (creamBalance > 0) {
+            // Sell CREAM token for obtain more supplying token(e.g. DAI, USDT)
+            IERC20(cream).safeIncreaseAllowance(uniswap, creamBalance);
+
+            address[] memory paths = new address[](3);
+            paths[0] = cream;
+            paths[1] = weth;
+            paths[2] = supplyToken;
+
+            IUniswapV2(uniswap).swapExactTokensForTokens(
+                creamBalance,
+                uint256(0),
+                paths,
+                address(this),
+                block.timestamp.add(1800)
+            );
+
+            // Deposit supplying token to Cream Erc20 Lending Pool and mint cToken.
+            uint256 obtainedSupplyTokenAmount = IERC20(supplyToken).balanceOf(address(this));
+            IERC20(supplyToken).safeIncreaseAllowance(crErc20, obtainedSupplyTokenAmount);
+            uint256 mintResult = ICErc20(crErc20).mint(obtainedSupplyTokenAmount);
+            require(mintResult == 0, "Couldn't mint crToken");
+        }
+    }
+
+    function aggregateCommit(uint256 _commitAmount) external override {
+        require(msg.sender == controller, "Not controller");
+        require(_commitAmount > 0, "Nothing to commit");
+
+        // Pull supplying token(e.g. DAI, USDT) from Controller
+        IERC20(supplyToken).safeTransferFrom(msg.sender, address(this), _commitAmount);
+
+        // Deposit supplying token to Cream Erc20 Lending Pool and mint crErc20.
+        IERC20(supplyToken).safeIncreaseAllowance(crErc20, _commitAmount);
+        uint256 mintResult = ICErc20(crErc20).mint(_commitAmount);
+        require(mintResult == 0, "Couldn't mint cToken");
+
+        emit Committed(_commitAmount);
+    }
+
+    function aggregateUncommit(uint256 _uncommitAmount) external override {
+        require(msg.sender == controller, "Not controller");
+        require(_uncommitAmount > 0, "Nothing to uncommit");
+
+        // Withdraw supplying token from Cream Erc20 Lending Pool
+        // based on an amount of the supplying token(e.g. DAI, USDT).
+        uint256 redeemResult = ICErc20(crErc20).redeemUnderlying(_uncommitAmount);
+        require(redeemResult == 0, "Couldn't redeem cToken");
+
+        // Transfer supplying token(e.g. DAI, USDT) to Controller
+        uint256 supplyTokenBalance = IERC20(supplyToken).balanceOf(address(this));
+        IERC20(supplyToken).safeTransfer(msg.sender, supplyTokenBalance);
+
+        emit UnCommitted(_uncommitAmount);
+    }
+
+    function setController(address _controller) external onlyOwner {
+        emit ControllerChanged(controller, _controller);
+        controller = _controller;
+    }
+}

contracts/strategies/interfaces/compound/ICErc20.sol

@@ -26,4 +26,10 @@ interface ICErc20 {
      * @return 0 = success, otherwise a failure
      */
     function redeemUnderlying(uint256 redeemAmount) external returns (uint256);
+
+    /**
+     * @notice Returns the current per-block supply interest rate for this cToken
+     * @return The supply interest rate per block, scaled by 1e18
+     */
+    function supplyRatePerBlock() external view returns (uint256);
 }