@RestController
@RequestMapping("/api/users")
public class UserController {
    
    @GetMapping("/{id}")
    public ResponseEntity<?> getUser(@PathVariable Long id) {
        try {
            User user = userService.findById(id);
            if (user == null) {
                return ResponseEntity.notFound().build();
            }
            return ResponseEntity.ok(user);
        } catch (Exception e) {
            return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR)
                .body("獲取用戶信息失?。? + e.getMessage());
        }
    }
    
    @PostMapping
    public ResponseEntity<User> createUser(@RequestBody User user) {
        User createdUser = userService.save(user);
        URI location = ServletUriComponentsBuilder
            .fromCurrentRequest()
            .path("/{id}")
            .buildAndExpand(createdUser.getId())
            .toUri();
        
        return ResponseEntity.created(location).body(createdUser);
    }
}

@Controller
@RequestMapping("/api/products")
public class ProductController {
    
    @GetMapping("/{id}")
    @ResponseBody
    public Product getProduct(@PathVariable Long id) {
        return productService.findById(id);
    }
    
    @GetMapping("/count")
    @ResponseBody
    public Integer getProductCount() {
        return productService.count();
    }
    
    @GetMapping("/available")
    @ResponseBody
    public boolean isProductAvailable(@RequestParam String sku) {
        return productService.checkAvailability(sku);
    }
    
    @GetMapping("/message")
    @ResponseBody
    public String getMessage() {
        return "這是一條簡單的文本消息";
    }
}

@Controller
@RequestMapping("/web")
public class WebController {
    
    @GetMapping("/users")
    public String listUsers(Model model) {
        List<User> users = userService.findAll();
        model.addAttribute("users", users);
        model.addAttribute("title", "用戶列表");
        return "user/list";  // 返回視圖名，對應 templates/user/list.html
    }
    
    @GetMapping("/dashboard")
    public ModelAndView dashboard() {
        ModelAndView mav = new ModelAndView("dashboard");
        mav.addObject("stats", statisticsService.getSummary());
        mav.addObject("lastLogin", new Date());
        return mav;
    }
    
    // 重定向示例
    @PostMapping("/users/save")
    public String saveUser(User user) {
        userService.save(user);
        return "redirect:/web/users";  // 重定向到用戶列表
    }
}

// 統(tǒng)一響應實體類
@Data
public class ApiResponse<T> {
    private Integer code;
    private String message;
    private T data;
    private long timestamp;
    
    public static <T> ApiResponse<T> success(T data) {
        ApiResponse<T> response = new ApiResponse<>();
        response.setCode(200);
        response.setMessage("操作成功");
        response.setData(data);
        response.setTimestamp(System.currentTimeMillis());
        return response;
    }
    
    public static <T> ApiResponse<T> error(Integer code, String message) {
        ApiResponse<T> response = new ApiResponse<>();
        response.setCode(code);
        response.setMessage(message);
        response.setTimestamp(System.currentTimeMillis());
        return response;
    }
}

// 全局響應處理（可選方式）
@RestControllerAdvice
public class GlobalResponseHandler implements ResponseBodyAdvice<Object> {
    
    @Override
    public boolean supports(MethodParameter returnType, Class<? extends HttpMessageConverter<?>> converterType) {
        // 決定哪些方法需要處理
        return true;
    }
    
    @Override
    public Object beforeBodyWrite(Object body, MethodParameter returnType, 
                                 MediaType selectedContentType, 
                                 Class<? extends HttpMessageConverter<?>> selectedConverterType, 
                                 ServerHttpRequest request, ServerHttpResponse response) {
        // 已經(jīng)是ApiResponse類型則不再包裝
        if (body instanceof ApiResponse) {
            return body;
        }
        // 包裝成功響應
        return ApiResponse.success(body);
    }
}

// 控制器使用示例
@RestController
@RequestMapping("/api/v1")
public class ModernApiController {
    
    @GetMapping("/orders")
    public ApiResponse<List<Order>> getOrders() {
        List<Order> orders = orderService.findAll();
        return ApiResponse.success(orders);
    }
    
    @GetMapping("/customers/{id}")
    public ApiResponse<Customer> getCustomer(@PathVariable Long id) {
        try {
            Customer customer = customerService.findById(id);
            if (customer == null) {
                return ApiResponse.error(404, "客戶不存在");
            }
            return ApiResponse.success(customer);
        } catch (Exception e) {
            return ApiResponse.error(500, "服務器錯誤：" + e.getMessage());
        }
    }
}