first commit

.eslintignore

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+node_modules
+artifacts
+cache
+coverage

.eslintrc.js

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+module.exports = {
+  settings: {
+    node: {
+      allowModules: ["electron"],
+      resolvePaths: [__dirname],
+      tryExtensions: [".js", ".json", ".node", ".ts", ".d.ts"],
+    },
+  },
+  env: {
+    browser: false,
+    es2021: true,
+    mocha: true,
+    node: true,
+  },
+  plugins: ["@typescript-eslint"],
+  extends: [
+    "standard",
+    "plugin:prettier/recommended",
+    "plugin:node/recommended",
+  ],
+  parser: "@typescript-eslint/parser",
+  parserOptions: {
+    ecmaVersion: 12,
+  },
+  rules: {
+    "node/no-unsupported-features/es-syntax": [
+      "error",
+      { ignores: ["modules"] },
+    ],
+  },
+};

.gitignore

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+node_modules
+.env
+coverage
+coverage.json
+typechain
+
+#Hardhat files
+cache
+artifacts

.npmignore

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+hardhat.config.ts
+scripts
+test

.prettierignore

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+node_modules
+artifacts
+cache
+coverage*
+gasReporterOutput.json

.prettierrc

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+{}

.solhint.json

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+{
+  "extends": "solhint:recommended",
+  "rules": {
+    "compiler-version": ["error", "^0.8.0"],
+    "func-visibility": ["warn", { "ignoreConstructors": true }]
+  }
+}

.solhintignore

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+node_modules

.vscode/settings.json

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+{
+    "solidity.compileUsingRemoteVersion": "v0.8.10+commit.fc410830"
+}

README.md

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+# Advanced Sample Hardhat Project
+
+This project demonstrates an advanced Hardhat use case, integrating other tools commonly used alongside Hardhat in the ecosystem.
+
+The project comes with a sample contract, a test for that contract, a sample script that deploys that contract, and an example of a task implementation, which simply lists the available accounts. It also comes with a variety of other tools, preconfigured to work with the project code.
+
+Try running some of the following tasks:
+
+```shell
+npx hardhat accounts
+npx hardhat compile
+npx hardhat clean
+npx hardhat test
+npx hardhat node
+npx hardhat help
+REPORT_GAS=true npx hardhat test
+npx hardhat coverage
+npx hardhat run scripts/deploy.ts
+TS_NODE_FILES=true npx ts-node scripts/deploy.ts
+npx eslint '**/*.{js,ts}'
+npx eslint '**/*.{js,ts}' --fix
+npx prettier '**/*.{json,sol,md}' --check
+npx prettier '**/*.{json,sol,md}' --write
+npx solhint 'contracts/**/*.sol'
+npx solhint 'contracts/**/*.sol' --fix
+```
+
+# Etherscan verification
+
+To try out Etherscan verification, you first need to deploy a contract to an Ethereum network that's supported by Etherscan, such as Ropsten.
+
+In this project, copy the .env.example file to a file named .env, and then edit it to fill in the details. Enter your Etherscan API key, your Ropsten node URL (eg from Alchemy), and the private key of the account which will send the deployment transaction. With a valid .env file in place, first deploy your contract:
+
+```shell
+hardhat run --network ropsten scripts/deploy.ts
+```
+
+Then, copy the deployment address and paste it in to replace `DEPLOYED_CONTRACT_ADDRESS` in this command:
+
+```shell
+npx hardhat verify --network ropsten DEPLOYED_CONTRACT_ADDRESS "Hello, Hardhat!"
+```
+
+# Performance optimizations
+
+For faster runs of your tests and scripts, consider skipping ts-node's type checking by setting the environment variable `TS_NODE_TRANSPILE_ONLY` to `1` in hardhat's environment. For more details see [the documentation](https://hardhat.org/guides/typescript.html#performance-optimizations).

contracts/FlashLoan.sol

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+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8;
+pragma abicoder v2;
+
+import "./interfaces/DydxFlashloanBase.sol";
+import "./interfaces/ICallee.sol";
+
+contract FlashLoan is ICallee, DydxFlashloanBase {
+  //main 0x1E0447b19BB6EcFdAe1e4AE1694b0C3659614e4e
+  address private constant SOLO = 0x1E0447b19BB6EcFdAe1e4AE1694b0C3659614e4e;
+
+  // JUST FOR TESTING - ITS OKAY TO REMOVE ALL OF THESE VARS
+  address public flashUser;
+
+  event Log(string message, uint val);
+
+  struct MyCustomData {
+    address token;
+    uint repayAmount;
+  }
+
+  function initiateFlashLoan(address _token, uint _amount) external {
+    ISoloMargin solo = ISoloMargin(SOLO);
+
+    // Get marketId from token address
+    /*
+    0	WETH
+    1	SAI
+    2	USDC
+    3	DAI
+    */
+    uint marketId = _getMarketIdFromTokenAddress(SOLO, _token);
+
+    // Calculate repay amount (_amount + (2 wei))
+    uint repayAmount = _getRepaymentAmountInternal(_amount);
+    IERC20(_token).approve(SOLO, repayAmount);
+
+    /*
+    1. Withdraw
+    2. Call callFunction()
+    3. Deposit back
+    */
+
+    Actions.ActionArgs[] memory operations = new Actions.ActionArgs[](3);
+
+    operations[0] = _getWithdrawAction(marketId, _amount);
+    operations[1] = _getCallAction(
+      abi.encode(MyCustomData({token: _token, repayAmount: repayAmount}))
+    );
+    operations[2] = _getDepositAction(marketId, repayAmount);
+
+    Account.Info[] memory accountInfos = new Account.Info[](1);
+    accountInfos[0] = _getAccountInfo();
+
+    solo.operate(accountInfos, operations);
+  }
+
+  function callFunction(
+    address sender,
+    Account.Info memory account,
+    bytes memory data
+  ) public override {
+    require(msg.sender == SOLO, "!solo");
+    require(sender == address(this), "!this contract");
+
+    MyCustomData memory mcd = abi.decode(data, (MyCustomData));
+    uint repayAmount = mcd.repayAmount;
+
+    uint bal = IERC20(mcd.token).balanceOf(address(this));
+    require(bal >= repayAmount, "bal < repay");
+
+    // More code here...
+    flashUser = sender;
+    emit Log("bal", bal);
+    emit Log("repay", repayAmount);
+    emit Log("bal - repay", bal - repayAmount);
+  }
+}
+// Solo margin contract mainnet - 0x1e0447b19bb6ecfdae1e4ae1694b0c3659614e4e
+// payable proxy - 0xa8b39829cE2246f89B31C013b8Cde15506Fb9A76
+
+// https://etherscan.io/tx/0xda79adea5cdd8cb069feb43952ea0fc510e4b6df4a270edc8130d8118d19e3f4

contracts/FlashLoanArbitrage.sol

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+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8;
+pragma abicoder v2;
+
+import "./interfaces/DydxFlashloanBase.sol";
+import "./interfaces/ICallee.sol";
+import "@uniswap/v2-periphery/contracts/interfaces/IUniswapV2Router02.sol";
+import "@uniswap/lib/contracts/libraries/TransferHelper.sol";
+
+contract FlashLoanArbitrage is ICallee, DydxFlashloanBase {
+    //main net
+    address private constant SOLO = 0x1E0447b19BB6EcFdAe1e4AE1694b0C3659614e4e;
+    address private constant DAI = 0x6B175474E89094C44Da98b954EedeAC495271d0F;
+
+    IUniswapV2Router02 public swapRouter1;
+    IUniswapV2Router02 public swapRouter2;
+
+    struct MyCustomData {
+        address token;
+        uint256 repayAmount;
+    }
+
+    function initiateFlashLoan(
+        address _token,
+        uint256 _amount,
+        address _swapRouter1,
+        address _swapRouter2
+    ) external {
+        ISoloMargin solo = ISoloMargin(SOLO);
+
+        swapRouter1 = IUniswapV2Router02(_swapRouter1);
+        swapRouter2 = IUniswapV2Router02(_swapRouter2);
+
+        // Get marketId from token address
+        /*
+    0	WETH
+    1	SAI
+    2	USDC
+    3	DAI
+    */
+        uint256 marketId = _getMarketIdFromTokenAddress(SOLO, _token);
+
+        // Calculate repay amount (_amount + (2 wei))
+        uint256 repayAmount = _getRepaymentAmountInternal(_amount);
+        IERC20(_token).approve(SOLO, repayAmount);
+
+        /*
+    1. Withdraw
+    2. Call callFunction()
+    3. Deposit back
+    */
+
+        Actions.ActionArgs[] memory operations = new Actions.ActionArgs[](3);
+
+        operations[0] = _getWithdrawAction(marketId, _amount);
+        operations[1] = _getCallAction(
+            abi.encode(MyCustomData({token: _token, repayAmount: repayAmount}))
+        );
+        operations[2] = _getDepositAction(marketId, repayAmount);
+
+        Account.Info[] memory accountInfos = new Account.Info[](1);
+        accountInfos[0] = _getAccountInfo();
+
+        solo.operate(accountInfos, operations);
+    }
+
+    function callFunction(
+        address sender,
+        Account.Info memory account,
+        bytes memory data
+    ) public override {
+        require(msg.sender == SOLO, "!solo");
+        require(sender == address(this), "!this contract");
+
+        MyCustomData memory mcd = abi.decode(data, (MyCustomData));
+        uint256 repayAmount = mcd.repayAmount;
+
+        uint256 bal = IERC20(mcd.token).balanceOf(address(this));
+        require(bal >= repayAmount, "bal < repay");
+
+        uint256 amountOut = swapExactInputSingle(bal, mcd.token, DAI, true);
+        swapExactInputSingle(amountOut, DAI, mcd.token, false);
+
+        IERC20(mcd.token).transfer(msg.sender, bal - repayAmount);
+
+        uint256 profit = IERC20(mcd.token).balanceOf(address(this));
+        require(profit >= repayAmount, "profit < repay");
+    }
+
+    function swapExactInputSingle(
+        uint256 amountIn,
+        address from,
+        address to,
+        bool first
+    ) private returns (uint256 amountOut) {
+        TransferHelper.safeApprove(
+            from,
+            address(first ? swapRouter1 : swapRouter2),
+            amountIn
+        );
+
+        address[] memory path = new address[](2);
+        path[0] = from;
+        path[1] = to;
+
+        uint256[] memory amountOuts = (first ? swapRouter1 : swapRouter2)
+            .swapExactTokensForTokens(
+                amountIn,
+                0,
+                path,
+                msg.sender,
+                block.timestamp
+            );
+
+        amountOut = amountOuts[0];
+    }
+}