setup hardhat folder

_hardhat/.eslintignore

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+node_modules
+artifacts
+cache
+coverage

_hardhat/.eslintrc.js

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+module.exports = {
+  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"] },
+    ],
+  },
+};

_hardhat/.gitignore

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

_hardhat/.npmignore

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+hardhat.config.ts
+scripts
+test

_hardhat/.prettierignore

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

_hardhat/.prettierrc

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+{}

_hardhat/.solhint.json

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

_hardhat/.solhintignore

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+node_modules

_hardhat/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).

_hardhat/contracts/Greeter.sol

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+//SPDX-License-Identifier: Unlicense
+pragma solidity ^0.8.0;
+
+import "hardhat/console.sol";
+
+contract Greeter {
+    string private greeting;
+
+    constructor(string memory _greeting) {
+        console.log("Deploying a Greeter with greeting:", _greeting);
+        greeting = _greeting;
+    }
+
+    function greet() public view returns (string memory) {
+        return greeting;
+    }
+
+    function setGreeting(string memory _greeting) public {
+        console.log("Changing greeting from '%s' to '%s'", greeting, _greeting);
+        greeting = _greeting;
+    }
+}

_hardhat/contracts/Musit.sol

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+// SPDX-License-Identifier: MIT
+pragma solidity >=0.8.0 <0.9.0;
+
+import "./Ownable.sol";
+
+contract Musit is Ownable {
+
+}

_hardhat/contracts/Ownable.sol

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+// SPDX-License-Identifier: MIT
+pragma solidity >=0.8.0 <0.9.0;
+
+contract Ownable {
+  address internal _owner;  // owner : 배포자 
+
+  event OwnershipTransferred(address oldOwner,address newOwner);
+
+  constructor () {
+    _transferOwnership(msg.sender);
+  }
+
+  modifier onlyOwner {
+    require(msg.sender == _owner, "Ownable: This is for only owner!");
+    _;
+  }
+
+  // 컨트랙트 주소에 담긴 이더를 소유자에게 출금 
+  function withdraw () onlyOwner external {
+    payable(_owner).transfer(address(this).balance);
+  }
+
+  // 소유권 출력 함수
+  function owner() public view returns(address) {
+    return _owner;
+  }
+
+  // 소유권 포기 함수
+  function _renounceOwnership() public onlyOwner {
+    _transferOwnership(address(this));
+  }
+
+  // 소유자 이전 함수 (소유자가 address(0)가 아닌 경우)
+  function transferOwnership(address _newOwner) public onlyOwner {
+    require(_newOwner != address(0), "Ownable: new owner is the zero address");
+    _transferOwnership(_newOwner);
+  }
+
+  // 소유자 이전 함수
+  function _transferOwnership(address _newOwner) internal {
+    address oldOwner = _owner;
+    _owner = _newOwner;
+    emit OwnershipTransferred(oldOwner, _newOwner);
+  }
+}

_hardhat/contracts/SongNFT.sol

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+// SPDX-License-Identifier: MIT
+pragma solidity >=0.8.0 <0.9.0;
+
+// TODO: ERC721, Ownable 컨트랙트 불러오기
+
+contract SongNFT { // 불러온 컨트랙트들 상속하기
+  /**
+    TODO: 
+    1. variables : 민팅가격, 발행 총 수량, 현재까지 발행된 민팅 수량, 민팅 가능 여부 State, 토큰 uri, 자금 회수용 지갑(?), 주소 당 최대 민팅 수량, 트랜잭션 당 최대 민팅 수량 
+    2. mapping : 주소 당 민팅 총 수량
+    3. constructor : payable, ERC721을 통해서 토큰 이름 및 심볼 적기
+    4. function : 민팅 가능 여부 설정 함수, 토큰 uri 설정 함수, 토큰 uri 출력 함수, 출금 함수, 민팅 함수
+  */
+
+}

_hardhat/hardhat.config.ts

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+import * as dotenv from "dotenv";
+
+import { HardhatUserConfig, task } from "hardhat/config";
+import "@nomiclabs/hardhat-etherscan";
+import "@nomiclabs/hardhat-waffle";
+import "@typechain/hardhat";
+import "hardhat-gas-reporter";
+import "solidity-coverage";
+
+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 (taskArgs, hre) => {
+  const accounts = await hre.ethers.getSigners();
+
+  for (const account of accounts) {
+    console.log(account.address);
+  }
+});
+
+// You need to export an object to set up your config
+// Go to https://hardhat.org/config/ to learn more
+
+const config: HardhatUserConfig = {
+  solidity: "0.8.4",
+  networks: {
+    ropsten: {
+      url: process.env.ROPSTEN_URL || "",
+      accounts:
+        process.env.PRIVATE_KEY !== undefined ? [process.env.PRIVATE_KEY] : [],
+    },
+  },
+  gasReporter: {
+    enabled: process.env.REPORT_GAS !== undefined,
+    currency: "USD",
+  },
+  etherscan: {
+    apiKey: process.env.ETHERSCAN_API_KEY,
+  },
+};
+
+export default config;