split compound in 2 lectures

defi-development-mastery/2-integrating-defi-protocols/3-compound/contracts/MyDeFiProject.sol

@@ -30,7 +30,11 @@ contract MyDeFiProject {
 
   function redeem(address cTokenAddress, uint cTokenAmount) external {
     CTokenInterface cToken = CTokenInterface(cTokenAddress);
-    cToken.redeem(cTokenAmount);
+    uint result = cToken.redeem(cTokenAmount);
+    require(
+      result == 0,
+      'cToken#redeem() failed. see Compound ErrorReporter.sol for more details'
+    );
   }
 
   function enterMarket(address cTokenAddress) external {
@@ -56,7 +60,6 @@ contract MyDeFiProject {
   function repayBorrow(address cTokenAddress, uint underlyingAmount) external {
     CTokenInterface cToken = CTokenInterface(cTokenAddress);
     address underlyingAddress = cToken.underlying(); 
-    //bat.approve(address(cBat), underlyingAmount);
     IERC20(underlyingAddress).approve(cTokenAddress, underlyingAmount);
     uint result = cToken.repayBorrow(underlyingAmount);
     require(
@@ -76,7 +79,6 @@ contract MyDeFiProject {
     require(liquidity > 0, 'account does not have collateral');
     uint underlyingPrice = priceOracle.getUnderlyingPrice(cTokenAddress);
     return liquidity / underlyingPrice;
-    //require(borrowAmount <= maxBorrowUnderlying, 'not enough collateral');
   }
 
 }

defi-development-mastery/2-integrating-defi-protocols/3-compound/package.json

@@ -12,8 +12,7 @@
   "author": "",
   "license": "ISC",
   "dependencies": {
-    "@openzeppelin/contracts": "^3.2.1-solc-0.7",
-    "@truffle/hdwallet-provider": "^1.2.0"
+    "@openzeppelin/contracts": "^3.2.1-solc-0.7"
   },
   "devDependencies": {},
   "description": ""

defi-development-mastery/2-integrating-defi-protocols/3-compound/truffle-config.js

@@ -1,7 +1,3 @@
-const HDWalletProvider = require('@truffle/hdwallet-provider');
-
-const privateKey = '';
-const infuraUrl = '';
 /**
  * Use this file to configure your truffle project. It's seeded with some
  * common settings for different networks and features like migrations,
@@ -62,16 +58,6 @@ module.exports = {
     // },
     // Useful for deploying to a public network.
     // NB: It's important to wrap the provider as a function.
-    rinkeby: {
-      timeoutBlocks: 200000,
-      networkCheckTimeout: 10000, 
-      provider: () => new HDWalletProvider(
-        privateKey,
-        infuraUrl
-      ),
-      network_id: 4,
-      skipDryRun: true
-    },
     // Useful for private networks
     // private: {
     // provider: () => new HDWalletProvider(mnemonic, `https://network.io`),

defi-development-mastery/2-integrating-defi-protocols/4-homework/contracts/CTokenInterface.sol

@@ -0,0 +1,10 @@
+pragma solidity ^0.7.3;
+
+interface CTokenInterface {
+  function mint(uint mintAmount) external returns (uint);
+  function redeem(uint redeemTokens) external returns (uint);
+  function redeemUnderlying(uint redeemAmount) external returns (uint);
+  function borrow(uint borrowAmount) external returns (uint);
+  function repayBorrow(uint repayAmount) external returns (uint);
+  function underlying() external view returns(address);
+}

defi-development-mastery/2-integrating-defi-protocols/4-homework/contracts/ComptrollerInterface.sol

@@ -0,0 +1,10 @@
+pragma solidity ^0.7.3;
+
+interface ComptrollerInterface {
+  function enterMarkets(address[] calldata cTokens) external returns (uint[] memory);
+  function getAccountLiquidity(address owner) external view returns(uint, uint, uint);
+}
+
+
+
+

defi-development-mastery/2-integrating-defi-protocols/4-homework/contracts/MyDeFiProject.sol

@@ -0,0 +1,84 @@
+pragma solidity ^0.7.3;
+
+import '@openzeppelin/contracts/token/ERC20/IERC20.sol';
+import './CTokenInterface.sol';
+import './ComptrollerInterface.sol';
+import './PriceOracleInterface.sol';
+
+contract MyDeFiProject {
+  ComptrollerInterface public comptroller;
+  PriceOracleInterface public priceOracle;
+
+  constructor(
+    address _comptroller,
+    address _priceOracle
+  ) {
+    comptroller = ComptrollerInterface(_comptroller);
+    priceOracle = PriceOracleInterface(_priceOracle);
+  }
+
+  function supply(address cTokenAddress, uint underlyingAmount ) public {
+    CTokenInterface cToken = CTokenInterface(cTokenAddress);
+    address underlyingAddress = cToken.underlying(); 
+    IERC20(underlyingAddress).approve(cTokenAddress, underlyingAmount);
+    uint result = cToken.mint(underlyingAmount);
+    require(
+      result == 0, 
+      'cToken#mint() failed. see Compound ErrorReporter.sol for details'
+    );
+  }
+
+  function redeem(address cTokenAddress, uint cTokenAmount) external {
+    CTokenInterface cToken = CTokenInterface(cTokenAddress);
+    uint result = cToken.redeem(cTokenAmount);
+    require(
+      result == 0,
+      'cToken#redeem() failed. see Compound ErrorReporter.sol for more details'
+    );
+  }
+
+  function enterMarket(address cTokenAddress) external {
+    address[] memory markets = new address[](1);
+    markets[0] = cTokenAddress; 
+    uint[] memory results = comptroller.enterMarkets(markets);
+    require(
+      results[0] == 0, 
+      'comptroller#enterMarket() failed. see Compound ErrorReporter.sol for details'
+    ); 
+  }
+
+  function borrow(address cTokenAddress, uint borrowAmount) external {
+    CTokenInterface cToken = CTokenInterface(cTokenAddress);
+    address underlyingAddress = cToken.underlying(); 
+    uint result = cToken.borrow(borrowAmount);
+    require(
+      result == 0, 
+      'cToken#borrow() failed. see Compound ErrorReporter.sol for details'
+    ); 
+  }
+
+  function repayBorrow(address cTokenAddress, uint underlyingAmount) external {
+    CTokenInterface cToken = CTokenInterface(cTokenAddress);
+    address underlyingAddress = cToken.underlying(); 
+    IERC20(underlyingAddress).approve(cTokenAddress, underlyingAmount);
+    uint result = cToken.repayBorrow(underlyingAmount);
+    require(
+      result == 0, 
+      'cToken#borrow() failed. see Compound ErrorReporter.sol for details'
+    ); 
+  }
+
+  function getMaxBorrow(address cTokenAddress) external view returns(uint) {
+    (uint result, uint liquidity, uint shortfall) = comptroller
+      .getAccountLiquidity(address(this));
+    require(
+      result == 0, 
+      'comptroller#getAccountLiquidity() failed. see Compound ErrorReporter.sol for details'
+    ); 
+    require(shortfall == 0, 'account underwater');
+    require(liquidity > 0, 'account does not have collateral');
+    uint underlyingPrice = priceOracle.getUnderlyingPrice(cTokenAddress);
+    return liquidity / underlyingPrice;
+  }
+
+}

defi-development-mastery/2-integrating-defi-protocols/4-homework/contracts/PriceOracleInterface.sol

@@ -0,0 +1,5 @@
+pragma solidity ^0.7.3;
+
+interface PriceOracleInterface {
+  function getUnderlyingPrice(address asset) external view returns(uint);
+}