ICO contract and tests

ico/.env.example

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+ALCHEMY_API_KEY=
+ROPSTEN_PRIVATE_KEY=

ico/.gitignore

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+node_modules
+.env
+
+#Hardhat files
+cache
+artifacts
+dist

ico/.prettierrc

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+{
+  "overrides": [
+    {
+      "files": "*.sol",
+      "options": {
+        "printWidth": 120,
+        "tabWidth": 2,
+        "useTabs": false,
+        "singleQuote": false,
+        "bracketSpacing": false,
+        "explicitTypes": "always",
+        "semi": true
+      }
+    }
+  ]
+}

ico/contracts/ICO.sol

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+// SPDX-License-Identifier: GPL-3.0
+
+/*
+Requirements:
+
+  - Must receive eth in exchange for an ERC20 token
+  - There is a recipient address that receives all incoming eth.
+  - Exchange rate is fixed. 1 eth = 1000 tokens
+  - Minimum investment is 0.01 eth and maximum is 5 eth.
+  - The ICO hardcap is 300 eth.
+  - An admin decides when the ICO starts and ends.
+  - The ICO ends when the hardcap is reached or end time is reached.
+  - The token will be tradeable only after a specific time set by the admin
+
+*/
+
+pragma solidity ^0.8.7;
+
+import "@openzeppelin/contracts/access/Ownable.sol";
+import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
+import "./Token.sol";
+
+uint256 constant TOKENS_PER_ETH = 1000;
+uint256 constant HARDCAP = 10 ether;
+uint256 constant MIN_INVESTMENT = 0.01 ether;
+uint256 constant MAX_INVESTMENT = 5 ether;
+
+contract ICO is Ownable {
+  address payable recipient; // address that will receive all invested eth
+  uint256 totalRaised; // keep track of raised eth
+  uint256 public startBlock; // block after which investment is allowed
+  uint256 public endBlock; // block until which investment is allowed
+  Token public token; // ERC20 token minted from this ICO
+
+  event Invested(address indexed investor, uint256 etherValue, uint256 tokensReceived);
+
+  constructor(
+    address payable _recipient,
+    uint256 _startBlock,
+    uint256 _endBlock,
+    uint256 _tradeableAfterBlock
+  ) {
+    recipient = _recipient;
+    startBlock = _startBlock;
+    endBlock = _endBlock;
+    token = new Token(_tradeableAfterBlock);
+  }
+
+  modifier notFinished() {
+    require(block.number >= startBlock, "ICO not started yet");
+    require(block.number <= endBlock, "ICO already finished");
+    _;
+  }
+
+  function invest() public payable notFinished {
+    require(msg.value >= MIN_INVESTMENT, "Minimum investment is 0.01 eth");
+    require(msg.value <= MAX_INVESTMENT, "Maximum investment is 5 eth");
+
+    // Ensure hardcap is not passed even with current investment
+    totalRaised += msg.value;
+    require(totalRaised <= HARDCAP, "Hardcap exceeded");
+
+    // Send eth to the contract's recipient
+    recipient.transfer(msg.value);
+
+    // Mint tokens for the investor
+    uint256 tokens = msg.value * TOKENS_PER_ETH;
+    token.mint(msg.sender, tokens);
+
+    emit Invested(msg.sender, msg.value, tokens);
+  }
+
+  function setBlocks(uint256 _startBlock, uint256 _endBlock) public onlyOwner {
+    startBlock = _startBlock;
+    endBlock = _endBlock;
+  }
+}

ico/contracts/Token.sol

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+// SPDX-License-Identifier: GPL-3.0
+
+// ICO Token
+
+pragma solidity ^0.8.7;
+
+import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
+import "@openzeppelin/contracts/access/Ownable.sol";
+
+contract Token is ERC20('Terra Vision', 'TVI'), Ownable {
+  uint tradeableAfterBlock;
+
+  constructor(uint _tradeableAfterBlock){
+    tradeableAfterBlock = _tradeableAfterBlock;
+  }
+
+  function mint(address account, uint amount) public onlyOwner {
+    _mint(account, amount);
+  }
+
+  function _transfer(address sender, address recipient, uint amount) internal override {
+    require(block.number >= tradeableAfterBlock, "Token is not tradeable yet");
+    ERC20._transfer(sender, recipient, amount);
+  }
+
+  function setTradeableAfterBlock(uint _tradeableAfterBlock) public onlyOwner {
+    tradeableAfterBlock = _tradeableAfterBlock;
+  }
+}

ico/hardhat.config.ts

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+import { task } from "hardhat/config";
+import "@nomiclabs/hardhat-waffle";
+import "hardhat-gas-reporter"
+import "hardhat-tracer"
+import "@atixlabs/hardhat-time-n-mine"
+import "@atixlabs/hardhat-time-n-mine/dist/src/type-extensions";
+
+import dotenv from 'dotenv'
+dotenv.config()
+
+// This is a sample Hardhat task. To learn how to create your own go to
+// https://hardhat.org/guides/create-task.html
+task("accounts", "Prints the list of accounts", async (args, hre) => {
+  const accounts = await hre.ethers.getSigners();
+
+  for (const account of accounts) {
+    console.log(await account.address);
+  }
+});
+
+// You need to export an object to set up your config
+// Go to https://hardhat.org/config/ to learn more
+
+export default {
+  solidity: {
+    version: '0.8.7',
+    settings: {
+      outputSelection: {
+        "*": {
+            "*": ["storageLayout"],
+        },
+      },
+    }
+  },
+  networks: {
+    ropsten: {
+      url: `https://eth-ropsten.alchemyapi.io/v2/${process.env.ALCHEMY_API_KEY}`,
+      accounts: [`0x${process.env.ROPSTEN_PRIVATE_KEY}`],
+    },
+  },
+};