// 看起來(lái)很"Hack"
private static final ThreadLocal<Long> currentUser = new ThreadLocal<>();

// 看起來(lái)很"丑"
@GetMapping("/me")
public User getMyProfile(HttpServletRequest request) {
    Long userId = (Long) request.getAttribute("currentUserId");
    return userService.getById(userId);
}

@Target(ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
public @interface CurrentUser {
}

@Component
public class CurrentUserArgumentResolver implements HandlerMethodArgumentResolver {

    @Override
    public boolean supportsParameter(MethodParameter parameter) {
        // 只解析被 @CurrentUser 標(biāo)記的參數(shù)
        return parameter.hasParameterAnnotation(CurrentUser.class);
    }

    @Override
    public Object resolveArgument(MethodParameter parameter,
                                 ModelAndViewContainer mavContainer,
                                 NativeWebRequest webRequest,
                                 WebDataBinderFactory binderFactory) throws Exception {
        // 從 request 中獲取之前設(shè)置的用戶ID
        return webRequest.getAttribute("currentUserId", WebRequest.SCOPE_REQUEST);
    }
}

@Configuration
public class WebMvcConfig implements WebMvcConfigurer {

    @Autowired
    private CurrentUserArgumentResolver currentUserArgumentResolver;

    @Override
    public void addArgumentResolvers(List<HandlerMethodArgumentResolver> resolvers) {
        resolvers.add(currentUserArgumentResolver);
    }
}

@Component
public class JwtAuthenticationFilter extends OncePerRequestFilter {

    @Autowired
    private JwtService jwtService;

    @Override
    protected void doFilterInternal(HttpServletRequest request,
                                   HttpServletResponse response,
                                   FilterChain filterChain) throws ServletException, IOException {

        String authorizationHeader = request.getHeader("Authorization");

        if (authorizationHeader != null && authorizationHeader.startsWith("Bearer ")) {
            String token = authorizationHeader.substring(7);
            try {
                Long userId = jwtService.extractUserId(token);
                // 標(biāo)準(zhǔn)：使用 request.setAttribute 設(shè)置
                request.setAttribute("currentUserId", userId);
            } catch (Exception e) {
                // token 無(wú)效，繼續(xù)執(zhí)行后續(xù)邏輯
            }
        }

        filterChain.doFilter(request, response);
    }
}

@RestController
@RequestMapping("/api/users")
public class UserController {

    @Autowired
    private UserService userService;

    @GetMapping("/me")
    public ResponseEntity<User> getCurrentUser(@CurrentUser Long userId) {
        // userId 被"魔法般"地自動(dòng)注入了！
        User user = userService.findById(userId);
        return ResponseEntity.ok(user);
    }

    @PutMapping("/me")
    public ResponseEntity<User> updateCurrentUser(@CurrentUser Long userId,
                                                 @RequestBody UserUpdateRequest request) {
        // 每個(gè) Controller 方法都可以直接使用 @CurrentUser
        User updatedUser = userService.updateUser(userId, request);
        return ResponseEntity.ok(updatedUser);
    }

    @GetMapping("/permissions")
    public ResponseEntity<List<Permission>> getUserPermissions(@CurrentUser Long userId) {
        // 完全類(lèi)型安全，無(wú)需手動(dòng)類(lèi)型轉(zhuǎn)換
        List<Permission> permissions = userService.getUserPermissions(userId);
        return ResponseEntity.ok(permissions);
    }
}

@Component
public class CurrentUserArgumentResolver implements HandlerMethodArgumentResolver {

    @Autowired
    private UserService userService;

    @Override
    public boolean supportsParameter(MethodParameter parameter) {
        return parameter.hasParameterAnnotation(CurrentUser.class);
    }

    @Override
    public Object resolveArgument(MethodParameter parameter,
                                 ModelAndViewContainer mavContainer,
                                 NativeWebRequest webRequest,
                                 WebDataBinderFactory binderFactory) throws Exception {

        Long userId = (Long) webRequest.getAttribute("currentUserId", WebRequest.SCOPE_REQUEST);

        if (userId == null) {
            return null; // 或者拋出異常
        }

        // 根據(jù)參數(shù)類(lèi)型決定返回什么
        Class<?> parameterType = parameter.getParameterType();

        if (parameterType == Long.class || parameterType == long.class) {
            return userId;
        } else if (parameterType == User.class) {
            return userService.findById(userId);
        } else if (parameterType == UserProfile.class) {
            return userService.getUserProfile(userId);
        }

        throw new IllegalArgumentException("Unsupported parameter type: " + parameterType);
    }
}

@RestController
@RequestMapping("/api")
public class AdvancedUserController {

    @GetMapping("/user/id")
    public ResponseEntity<String> getUserId(@CurrentUser Long userId) {
        return ResponseEntity.ok("User ID: " + userId);
    }

    @GetMapping("/user/info")
    public ResponseEntity<User> getUserInfo(@CurrentUser User user) {
        return ResponseEntity.ok(user);
    }

    @GetMapping("/user/profile")
    public ResponseEntity<UserProfile> getUserProfile(@CurrentUser UserProfile profile) {
        return ResponseEntity.ok(profile);
    }
}

@Component
public class CurrentUserArgumentResolver implements HandlerMethodArgumentResolver {

    @Override
    public Object resolveArgument(...) throws Exception {
        Long userId = (Long) webRequest.getAttribute("currentUserId", WebRequest.SCOPE_REQUEST);

        if (userId == null) {
            throw new UnauthorizedException("用戶未登錄");
        }

        return userId;
    }
}

@ControllerAdvice
public class GlobalExceptionHandler {

    @ExceptionHandler(UnauthorizedException.class)
    public ResponseEntity<String> handleUnauthorized(UnauthorizedException e) {
        return ResponseEntity.status(401).body(e.getMessage());
    }
}

@Component
public class CurrentUserArgumentResolver implements HandlerMethodArgumentResolver {

    @Override
    public Object resolveArgument(...) throws Exception {
        Authentication authentication = SecurityContextHolder.getContext().getAuthentication();

        if (authentication != null && authentication.isAuthenticated()) {
            UserDetails userDetails = (UserDetails) authentication.getPrincipal();
            return Long.parseLong(userDetails.getUsername()); // 假設(shè)username存儲(chǔ)的是userId
        }

        return null;
    }
}

@Target(ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
public @interface CurrentTenant {
}

@Component
public class CurrentTenantArgumentResolver implements HandlerMethodArgumentResolver {

    @Override
    public boolean supportsParameter(MethodParameter parameter) {
        return parameter.hasParameterAnnotation(CurrentTenant.class);
    }

    @Override
    public Object resolveArgument(...) throws Exception {
        return webRequest.getAttribute("currentTenantId", WebRequest.SCOPE_REQUEST);
    }
}

@GetMapping("/tenant/data")
public ResponseEntity<List<Data>> getTenantData(@CurrentUser Long userId,
                                               @CurrentTenant Long tenantId) {
    // 同時(shí)獲取當(dāng)前用戶和租戶信息
    List<Data> data = dataService.findByUserAndTenant(userId, tenantId);
    return ResponseEntity.ok(data);
}