TRC20 智能合约：USDT 与 TRX 兑换功能

以下是一个具备 USDT 与 TRX 兑换功能的 TRC20 智能合约示例代码，它允许用户将 USDT 兑换为 TRX，并使用 Chainlink 获取实时兑换价格。

pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "@chainlink/contracts/src/v0.8/interfaces/AggregatorV3Interface.sol";

contract TRC20Token is ERC20 {
    address private owner;
    AggregatorV3Interface private priceFeed;
    uint private exchangeRate;

    constructor() ERC20('TRC20Token', 'TRC20') {
        owner = msg.sender;
        priceFeed = AggregatorV3Interface(0x5f4eC3Df9cbd43714FE2740f5E3616155c5b8419); // Chainlink ETH/USD Price Feed Address
        exchangeRate = 100; // Initial exchange rate between USDT and TRX
    }

    function transferTRX() external payable {
        _mint(msg.sender, msg.value);
    }

    function convertUSDTToTRX(uint usdtAmount) external {
        uint trxAmount = usdtAmount * exchangeRate;
        require(balanceOf(address(this)) >= trxAmount, 'Insufficient TRX balance in contract');
        _burn(address(this), trxAmount);
        payable(msg.sender).transfer(trxAmount);
    }

    function getContractBalance() external view returns (uint trxBalance, uint usdtBalance) {
        trxBalance = balanceOf(address(this));
        usdtBalance = address(this).balance;
    }

    function withdrawTRX(uint amount, address recipient) external onlyOwner {
        require(balanceOf(address(this)) >= amount, 'Insufficient TRX balance in contract');
        _transfer(address(this), recipient, amount);
    }

    function withdrawUSDT(uint amount, address recipient) external onlyOwner {
        require(address(this).balance >= amount, 'Insufficient USDT balance in contract');
        payable(recipient).transfer(amount);
    }

    function setExchangeRate(uint rate) external onlyOwner {
        exchangeRate = rate;
    }

    modifier onlyOwner() {
        require(msg.sender == owner, 'Only contract owner can call this function');
        _;
    }
}

请注意，此示例代码假设已经安装了 OpenZeppelin 和 Chainlink 的相应库，并且正确地引入了它们。