@Service
public class UserService {

    @Autowired
    private UserMapper userMapper;

    // 聲明事務(wù)：傳播行為REQUIRED，對(duì)所有Exception回滾，超時(shí)30秒
    @Transactional(propagation = Propagation.REQUIRED, 
                   rollbackFor = Exception.class, 
                   timeout = 30)
    public void transferMoney(Long fromId, Long toId, BigDecimal amount) throws Exception {
        // 扣錢
        userMapper.decreaseBalance(fromId, amount);
        // 模擬異常（如網(wǎng)絡(luò)波動(dòng)）
        if (amount.compareTo(new BigDecimal("10000")) > 0) {
            throw new Exception("轉(zhuǎn)賬金額過大"); // 觸發(fā)回滾
        }
        // 加錢
        userMapper.increaseBalance(toId, amount);
    }
}

// 訂單實(shí)體
@Data
public class Order {
    private Long id;
    private Long userId;
    private Long productId;
    private Integer quantity; // 購買數(shù)量
    private LocalDateTime createTime;
}

// 商品實(shí)體（庫存）
@Data
public class Product {
    private Long id;
    private String name;
    private Integer stock; // 庫存數(shù)量
}

// 操作日志實(shí)體
@Data
public class OperateLog {
    private Long id;
    private String content; // 日志內(nèi)容
    private LocalDateTime createTime;
}

// 訂單Mapper
@Mapper
public interface OrderMapper {
    // 插入訂單
    @Insert("INSERT INTO `order`(user_id, product_id, quantity, create_time) " +
            "VALUES(#{userId}, #{productId}, #{quantity}, #{createTime})")
    void insert(Order order);
}

// 商品Mapper
@Mapper
public interface ProductMapper {
    // 扣減庫存（where條件確保庫存充足時(shí)才扣減）
    @Update("UPDATE product SET stock = stock - #{quantity} " +
            "WHERE id = #{productId} AND stock >= #{quantity}")
    int decreaseStock(@Param("productId") Long productId, @Param("quantity") Integer quantity);

    // 查詢商品
    @Select("SELECT * FROM product WHERE id = #{id}")
    Product selectById(Long id);
}

// 日志Mapper
@Mapper
public interface OperateLogMapper {
    @Insert("INSERT INTO operate_log(content, create_time) VALUES(#{content}, #{createTime})")
    void insert(OperateLog log);
}

@Service
public class ProductService {

    @Autowired
    private ProductMapper productMapper;

    /**
     * 扣減庫存（事務(wù)傳播行為：REQUIRED，默認(rèn)）
     * 若庫存不足，拋出異常觸發(fā)回滾
     */
    @Transactional
    public void decreaseStock(Long productId, Integer quantity) {
        // 扣減庫存（返回影響行數(shù)，0表示庫存不足）
        int rows = productMapper.decreaseStock(productId, quantity);
        if (rows == 0) {
            // 庫存不足，拋出異常（會(huì)被上層事務(wù)捕獲并觸發(fā)回滾）
            throw new RuntimeException("商品庫存不足");
        }
    }
}

@Service
public class LogService {

    @Autowired
    private OperateLogMapper logMapper;

    /**
     * 記錄日志（事務(wù)傳播行為：REQUIRES_NEW，獨(dú)立事務(wù)）
     */
    @Transactional(propagation = Propagation.REQUIRES_NEW)
    public void recordLog(String content) {
        OperateLog log = new OperateLog();
        log.setContent(content);
        log.setCreateTime(LocalDateTime.now());
        logMapper.insert(log);
    }
}

@Service
public class OrderService {

    @Autowired
    private OrderMapper orderMapper;

    @Autowired
    private ProductService productService; // 注入庫存服務(wù)（事務(wù)協(xié)同）

    @Autowired
    private LogService logService; // 注入日志服務(wù)（獨(dú)立事務(wù)）

    /**
     * 創(chuàng)建訂單（主事務(wù)：REQUIRED）
     * 流程：扣減庫存 -> 創(chuàng)建訂單 -> 記錄日志（成功/失敗）
     */
    @Transactional(rollbackFor = Exception.class) // 對(duì)所有異常回滾
    public void createOrder(Long userId, Long productId, Integer quantity) {
        String logContent;
        try {
            // 1. 扣減庫存（調(diào)用ProductService，加入當(dāng)前事務(wù)）
            productService.decreaseStock(productId, quantity);

            // 2. 創(chuàng)建訂單（與扣減庫存同事務(wù)）
            Order order = new Order();
            order.setUserId(userId);
            order.setProductId(productId);
            order.setQuantity(quantity);
            order.setCreateTime(LocalDateTime.now());
            orderMapper.insert(order);

            logContent = "訂單創(chuàng)建成功：用戶" + userId + "購買商品" + productId + "，數(shù)量" + quantity;
        } catch (Exception e) {
            // 3. 若異常（如庫存不足），記錄失敗日志
            logContent = "訂單創(chuàng)建失敗：" + e.getMessage();
            throw e; // 關(guān)鍵：必須重新拋出異常，否則主事務(wù)不會(huì)回滾！
        } finally {
            // 4. 記錄日志（調(diào)用LogService，獨(dú)立事務(wù)，無論成敗都會(huì)執(zhí)行）
            logService.recordLog(logContent);
        }
    }
}

@RestController
@RequestMapping("/orders")
public class OrderController {

    @Autowired
    private OrderService orderService;

    @PostMapping
    public String createOrder(
            @RequestParam Long userId,
            @RequestParam Long productId,
            @RequestParam Integer quantity) {
        try {
            orderService.createOrder(userId, productId, quantity);
            return "訂單創(chuàng)建成功";
        } catch (Exception e) {
            return "訂單創(chuàng)建失敗：" + e.getMessage();
        }
    }
}