# **CrytoCamp Homework3**
###### tags: `Solidity`
## 1. <基礎作業>

1. 透過 remix JavaScript VM 部署合約
2. 部署任一自訂 ERC20 Token
3. 部署質押合約
- Deposit（存入）
- Reward（回饋）
- TimeLock（固定鎖倉期）

### ERC20

// contracts/GLDToken.sol
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";

contract MyToken is ERC20 {
    constructor() ERC20("MyToken", "MT") {
        _mint(msg.sender, 100000);
    }
}

### Bank

// contracts/GLDToken.sol
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";

contract Bank {
    
    IERC20 public stakingToken;

    mapping(address => uint256) public balanceOf;

    // 池中總量
    uint256 public totalSupply;

    // 鎖倉時間
    uint256 public lockRcord;
    mapping(address => uint256) public lockStartOf;
    mapping(address => uint256) public lockEndOf;

    // 獎勵
    uint256 public rewardRate = 1;
    mapping(address => uint256) public rewardOf;

    constructor(IERC20 _stakingToken) {
        stakingToken = _stakingToken;
    }

    // 質押
    function deposit(uint256 _amount, uint256 _lockTime) external {
        require(_lockTime > 5, "Please enter a longer time");
        lockRcord = _lockTime;
        stakingToken.transferFrom(msg.sender, address(this), _amount); // 轉移代幣
        totalSupply += _amount; // 紀錄質押數量
        balanceOf[msg.sender] += _amount; // 紀錄個人質押數量

        // 紀錄鎖倉時間
        lockStartOf[msg.sender] = block.timestamp;
        lockEndOf[msg.sender] = block.timestamp + _lockTime;
    }
    
    //  贖回
    function withdraw(uint256 _amount) public {
        require(block.timestamp > lockEndOf[msg.sender], "withdraw too soon");
        require(_amount <= balanceOf[msg.sender], "insufficient token");

        // 獲得獎勵
        rewardOf[msg.sender] += getReward();

        stakingToken.transfer(msg.sender, _amount);
        totalSupply -= _amount;
        balanceOf[msg.sender] -= _amount;
    }

    // 獎勵
    function getReward() public view returns (uint256) {
        uint256 duration = block.timestamp - lockStartOf[msg.sender];

        //Rewaord scale
        if (lockRcord <= 20) {
            return duration * (rewardRate * 5) * balanceOf[msg.sender];
        }else if (lockRcord > 20 && lockRcord <= 40) {
            return duration * (rewardRate * 10) * balanceOf[msg.sender];
        }else {
            return duration * (rewardRate * 20) * balanceOf[msg.sender];
        }
    }
}

### 功能說明
存入時需要輸入存放金額與時間
一開始決定存放的時間，會影響到結算Reward金額

## 2. <進階作業>
### ERC20

// contracts/GLDToken.sol
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";

contract MyToken is ERC20 {
    constructor() ERC20("MyToken", "MT") {
        _mint(msg.sender, 100000);
    }
}

### 會找時間補上 X﹏X

## 3. <進階作業>
### ERC20

// contracts/GLDToken.sol
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";

contract MyToken is ERC20 {
    constructor() ERC20("MyToken", "MT") {
        _mint(msg.sender, 100000);
    }
}

### 會找時間補上 X﹏X