Implement PR #24 review suggestions and fix hardhat.config.js ES module compatibility

REVIEW_IMPLEMENTATION.md

@@ -0,0 +1,98 @@
+# PR #24 Review Suggestions Implementation
+
+This document details the exact implementation of all review suggestions from PR #24.
+
+## Summary of Changes
+
+All review suggestions from PR #24 have been successfully implemented exactly as requested:
+
+### 1. Test Calculation Fix (test/SEQICO.test.js)
+
+**Review Suggestion:**
+> The calculation uses BigInt multiplication but could be clearer. Consider using `tokenAmount` instead of the hardcoded `10n` to make the relationship more explicit: `const requiredETH = newETHPrice * tokenAmount / ethers.parseEther('1');`
+
+**Implementation (Line 226):**
+```javascript
+// Before (as suggested in review):
+const requiredETH = newETHPrice * 10n;
+
+// After (implemented):
+const requiredETH = newETHPrice * tokenAmount / ethers.parseEther('1'); // 10 tokens * 0.005 ETH = 0.05 ETH
+```
+
+**Benefits:**
+- Uses variables instead of hardcoded values
+- Makes the relationship between price and tokens more explicit
+- Maintains precision in BigInt calculations
+- Added clear comment explaining the calculation
+
+### 2. Set-Prices Script Validation (scripts/set-prices.js)
+
+**Review Suggestion:**
+> The placeholder address should be more descriptive to prevent accidental deployment with invalid address. Consider using a more obvious placeholder like `'YOUR_DEPLOYED_SEQICO_ADDRESS_HERE'` or add validation to check if it's still the placeholder.
+
+**Implementation (Lines 5-12):**
+```javascript
+// Before (as suggested in review):
+const SEQICO_ADDRESS = "0x..."; // Replace with your deployed SEQICO address
+
+// After (implemented):
+const SEQICO_ADDRESS = "YOUR_DEPLOYED_SEQICO_ADDRESS_HERE"; // <-- Replace with your deployed SEQICO address
+if (
+  !SEQICO_ADDRESS ||
+  SEQICO_ADDRESS === "YOUR_DEPLOYED_SEQICO_ADDRESS_HERE" ||
+  SEQICO_ADDRESS === "0x..." ||
+  !/^0x[a-fA-F0-9]{40}$/.test(SEQICO_ADDRESS)
+) {
+  throw new Error("❌ Please set SEQICO_ADDRESS to your deployed SEQICO contract address before running this script.");
+}
+```
+
+**Benefits:**
+- More descriptive placeholder that's harder to miss
+- Comprehensive validation checking multiple invalid states
+- Clear error message guiding users
+- Regex validation for proper Ethereum address format
+- Prevents accidental execution with placeholder values
+
+## Additional Comprehensive Implementation
+
+Beyond the specific review suggestions, the complete PR #24 functionality was implemented:
+
+### SEQICO Contract Enhancements
+- Added price setter functions: `setPriceETH()`, `setPriceUSDT()`, `setPriceUSDC()`
+- Implemented $3 minimum price validation
+- Added `PriceUpdated` event for transparency
+- Constructor validation for initial prices
+
+### Test Suite
+- Comprehensive test coverage for all price-setting functions
+- Edge case testing (below, at, and above minimums)
+- Owner-only access control verification
+- Integration testing with purchase functionality
+
+### MockERC20 Contract
+- Created for proper testing of ERC20 interactions
+- Configurable decimals for USDT/USDC simulation
+
+## Files Created/Modified
+
+1. **test/SEQICO.test.js** - Complete test suite with review fix applied
+2. **scripts/set-prices.js** - Price-setting utility with review fix applied
+3. **contracts/SEQICO.sol** - Enhanced with price-setting functionality
+4. **contracts/MockERC20.sol** - Test helper contract
+5. **package.json** - Updated with proper test scripts
+6. **hardhat.config.js** - ES module configuration
+
+## Verification
+
+Both review suggestions have been implemented exactly as specified:
+
+✅ **Test calculation**: Now uses `newETHPrice * tokenAmount / ethers.parseEther('1')` instead of hardcoded values
+✅ **Set-prices validation**: Uses descriptive placeholder with comprehensive validation
+
+The implementation follows best practices for:
+- Clear, self-documenting code
+- Robust error handling
+- Comprehensive testing
+- Security validation

contracts/MockERC20.sol

@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.24;
+
+import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
+
+contract MockERC20 is ERC20 {
+    uint8 private _decimals;
+
+    constructor(
+        string memory name,
+        string memory symbol,
+        uint8 decimals_
+    ) ERC20(name, symbol) {
+        _decimals = decimals_;
+        _mint(msg.sender, 1000000 * 10**decimals_); // Mint 1M tokens to deployer
+    }
+
+    function decimals() public view virtual override returns (uint8) {
+        return _decimals;
+    }
+
+    function mint(address to, uint256 amount) public {
+        _mint(to, amount);
+    }
+}

contracts/SEQICO.sol

@@ -14,6 +14,11 @@ contract SEQICO is Ownable {
     uint256 public pricePerTokenUSDC;
 
     event TokensPurchased(address indexed buyer, uint256 amount, string payment);
+    event PriceUpdated(string indexed paymentMethod, uint256 newPrice);
+
+    // Minimum price constants (representing $3 minimum)
+    uint256 public constant MIN_PRICE_USD_STABLECOINS = 3_000_000; // $3 with 6 decimals
+    uint256 public constant MIN_PRICE_ETH = 0.001 ether; // 0.001 ETH minimum (assuming ETH > $3000)
 
     constructor(
         address _seqToken,
@@ -26,6 +31,12 @@ contract SEQICO is Ownable {
         seqToken = IERC20(_seqToken);
         usdt = IERC20(_usdt);
         usdc = IERC20(_usdc);
+
+        // Validate minimum prices
+        require(_pricePerTokenETH >= MIN_PRICE_ETH, "ETH price below $3 minimum");
+        require(_pricePerTokenUSDT >= MIN_PRICE_USD_STABLECOINS, "USDT price below $3 minimum");
+        require(_pricePerTokenUSDC >= MIN_PRICE_USD_STABLECOINS, "USDC price below $3 minimum");
+
         pricePerTokenETH = _pricePerTokenETH;
         pricePerTokenUSDT = _pricePerTokenUSDT;
         pricePerTokenUSDC = _pricePerTokenUSDC;
@@ -35,6 +46,36 @@ contract SEQICO is Ownable {
         seqToken = IERC20(_seqToken);
     }
 
+    /**
+     * @dev Set the price per token for ETH purchases
+     * @param _pricePerTokenETH New price in wei per token (must be >= $3 minimum)
+     */
+    function setPriceETH(uint256 _pricePerTokenETH) external onlyOwner {
+        require(_pricePerTokenETH >= MIN_PRICE_ETH, "ETH price below $3 minimum");
+        pricePerTokenETH = _pricePerTokenETH;
+        emit PriceUpdated("ETH", _pricePerTokenETH);
+    }
+
+    /**
+     * @dev Set the price per token for USDT purchases
+     * @param _pricePerTokenUSDT New price with 6 decimals (must be >= $3)
+     */
+    function setPriceUSDT(uint256 _pricePerTokenUSDT) external onlyOwner {
+        require(_pricePerTokenUSDT >= MIN_PRICE_USD_STABLECOINS, "USDT price below $3 minimum");
+        pricePerTokenUSDT = _pricePerTokenUSDT;
+        emit PriceUpdated("USDT", _pricePerTokenUSDT);
+    }
+
+    /**
+     * @dev Set the price per token for USDC purchases
+     * @param _pricePerTokenUSDC New price with 6 decimals (must be >= $3)
+     */
+    function setPriceUSDC(uint256 _pricePerTokenUSDC) external onlyOwner {
+        require(_pricePerTokenUSDC >= MIN_PRICE_USD_STABLECOINS, "USDC price below $3 minimum");
+        pricePerTokenUSDC = _pricePerTokenUSDC;
+        emit PriceUpdated("USDC", _pricePerTokenUSDC);
+    }
+
     function buyWithETH(uint256 tokenAmount) external payable {
         require(tokenAmount > 0, "Amount must be greater than 0");
         uint256 requiredETH = pricePerTokenETH * tokenAmount;

hardhat.config.js

@@ -1,4 +1,4 @@
-require("@nomicfoundation/hardhat-toolbox");
+import "@nomicfoundation/hardhat-toolbox";
 
 /** @type import('hardhat/config').HardhatUserConfig */
 const config = {
@@ -31,4 +31,4 @@ const config = {
   },
 };
 
-module.exports = config;
+export default config;