// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "@openzeppelin/contracts-upgradeable/token/ERC20/ERC20Upgradeable.sol";
import "@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";
import "@openzeppelin/contracts-upgradeable/proxy/utils/UUPSUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";

/**
 * @title WUSD
 * @notice Wrapped USD - 简单的ERC20代币
 */
contract WUSD is Initializable, ERC20Upgradeable, UUPSUpgradeable, OwnableUpgradeable {
    
    /// @custom:oz-upgrades-unsafe-allow constructor
    constructor() {
        _disableInitializers();
    }
    
    /**
     * @notice 初始化合约
     * @param _name 代币名称
     * @param _symbol 代币符号
     */
    function initialize(string memory _name, string memory _symbol) external initializer {
        __ERC20_init(_name, _symbol);
        __UUPSUpgradeable_init();
        __Ownable_init(msg.sender);
    }
    
    /**
     * @notice 授权升级（仅owner可调用）
     * @param newImplementation 新实现合约地址
     */
    function _authorizeUpgrade(address newImplementation) internal override onlyOwner {}
    
    /**
     * @notice 铸造代币
     * @param _to 接收地址
     * @param _amount 铸造数量
     */
    function mint(address _to, uint256 _amount) external onlyOwner {
        _mint(_to, _amount);
    }
    
    /**
     * @notice 销毁代币
     * @param _from 销毁地址
     * @param _amount 销毁数量
     */
    function burn(address _from, uint256 _amount) external onlyOwner {
        _burn(_from, _amount);
    }
    
    /**
     * @dev 预留存储空间，用于未来升级时添加新的状态变量
     */
    uint256[50] private __gap;
}