// Spring Validation依賴配置
/*
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-validation</artifactId>
</dependency>
*/

// 啟用驗(yàn)證的基本配置
@Configuration
public class ValidationConfig {
    
    @Bean
    public Validator validator() {
        return Validation.buildDefaultValidatorFactory().getValidator();
    }
    
    @Bean
    public MethodValidationPostProcessor methodValidationPostProcessor() {
        return new MethodValidationPostProcessor();
    }
}

// 手動(dòng)校驗(yàn)示例
@Service
public class ValidationService {
    
    @Autowired
    private Validator validator;
    
    public <T> ValidationResult validate(T object) {
        ValidationResult result = new ValidationResult();
        Set<ConstraintViolation<T>> violations = validator.validate(object);
        
        if (!violations.isEmpty()) {
            result.setValid(false);
            
            Map<String, String> errorMap = violations.stream()
                .collect(Collectors.toMap(
                    v -> v.getPropertyPath().toString(),
                    ConstraintViolation::getMessage,
                    (msg1, msg2) -> msg1 + "; " + msg2
                ));
                
            result.setErrorMessages(errorMap);
        }
        
        return result;
    }
}

// 校驗(yàn)結(jié)果封裝
public class ValidationResult {
    private boolean valid = true;
    private Map<String, String> errorMessages = new HashMap<>();
    
    // Getters and setters
    
    public boolean hasErrors() {
        return !valid;
    }
}

// 內(nèi)置約束注解使用示例
@Entity
public class Product {
    
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    
    @NotBlank(message = "產(chǎn)品名稱不能為空")
    @Size(min = 2, max = 50, message = "產(chǎn)品名稱長(zhǎng)度必須在2-50之間")
    private String name;
    
    @NotNull(message = "價(jià)格不能為空")
    @Positive(message = "價(jià)格必須是正數(shù)")
    @Digits(integer = 6, fraction = 2, message = "價(jià)格格式不正確")
    private BigDecimal price;
    
    @Min(value = 0, message = "庫(kù)存不能為負(fù)數(shù)")
    private Integer stock;
    
    @NotEmpty(message = "產(chǎn)品分類不能為空")
    private List<@NotBlank(message = "分類名稱不能為空") String> categories;
    
    @Pattern(regexp = "^[A-Z]{2}\\d{6}$", message = "產(chǎn)品編碼格式不正確，應(yīng)為2個(gè)大寫(xiě)字母+6位數(shù)字")
    private String productCode;
    
    @Email(message = "聯(lián)系郵箱格式不正確")
    private String contactEmail;
    
    @Past(message = "創(chuàng)建日期必須是過(guò)去的時(shí)間")
    private LocalDate createdDate;
    
    // Getters and setters
}

// 自定義約束注解示例 - 中國(guó)手機(jī)號(hào)驗(yàn)證
@Documented
@Constraint(validatedBy = ChinesePhoneValidator.class)
@Target({ ElementType.FIELD, ElementType.PARAMETER })
@Retention(RetentionPolicy.RUNTIME)
public @interface ChinesePhone {
    
    String message() default "手機(jī)號(hào)格式不正確";
    
    Class<?>[] groups() default {};
    
    Class<? extends Payload>[] payload() default {};
}

// 約束驗(yàn)證器實(shí)現(xiàn)
public class ChinesePhoneValidator implements ConstraintValidator<ChinesePhone, String> {
    
    private static final Pattern PHONE_PATTERN = Pattern.compile("^1[3-9]\\d{9}$");
    
    @Override
    public void initialize(ChinesePhone annotation) {
        // 初始化邏輯，如果需要
    }
    
    @Override
    public boolean isValid(String value, ConstraintValidatorContext context) {
        if (value == null) {
            return true; // 如果需要非空校驗(yàn)，應(yīng)該額外使用@NotNull
        }
        
        return PHONE_PATTERN.matcher(value).matches();
    }
}

// 使用自定義約束
public class User {
    
    @NotNull(message = "姓名不能為空")
    private String name;
    
    @ChinesePhone
    private String phoneNumber;
    
    // 其他字段和方法
}

// 分組校驗(yàn)的基本使用
// 定義驗(yàn)證分組
public interface Create {}
public interface Update {}
public interface Delete {}

// 使用分組約束
@Entity
public class Customer {
    
    @NotNull(groups = {Update.class, Delete.class}, message = "ID不能為空")
    @Null(groups = Create.class, message = "創(chuàng)建時(shí)不應(yīng)指定ID")
    private Long id;
    
    @NotBlank(groups = {Create.class, Update.class}, message = "名稱不能為空")
    private String name;
    
    @NotBlank(groups = Create.class, message = "創(chuàng)建時(shí)密碼不能為空")
    private String password;
    
    @Email(groups = {Create.class, Update.class}, message = "郵箱格式不正確")
    private String email;
    
    // Getters and setters
}

// 在控制器中使用分組校驗(yàn)
@RestController
@RequestMapping("/customers")
public class CustomerController {
    
    @PostMapping
    public ResponseEntity<Customer> createCustomer(
            @Validated(Create.class) @RequestBody Customer customer) {
        // 創(chuàng)建客戶邏輯
        return ResponseEntity.ok(customerService.create(customer));
    }
    
    @PutMapping("/{id}")
    public ResponseEntity<Customer> updateCustomer(
            @PathVariable Long id,
            @Validated(Update.class) @RequestBody Customer customer) {
        // 更新客戶邏輯
        return ResponseEntity.ok(customerService.update(id, customer));
    }
}

// 分組序列示例
// 定義基礎(chǔ)分組
public interface BasicCheck {}
public interface AdvancedCheck {}
public interface BusinessCheck {}

// 定義分組序列
@GroupSequence({BasicCheck.class, AdvancedCheck.class, BusinessCheck.class})
public interface OrderedChecks {}

// 使用分組序列
@Entity
public class Order {
    
    @NotNull(groups = BasicCheck.class, message = "訂單號(hào)不能為空")
    private String orderNumber;
    
    @NotEmpty(groups = BasicCheck.class, message = "訂單項(xiàng)不能為空")
    private List<OrderItem> items;
    
    @Valid // 級(jí)聯(lián)驗(yàn)證
    private Customer customer;
    
    @AssertTrue(groups = AdvancedCheck.class, message = "總價(jià)必須匹配訂單項(xiàng)金額")
    public boolean isPriceValid() {
        if (items == null || items.isEmpty()) {
            return true; // 基礎(chǔ)檢查會(huì)捕獲此問(wèn)題
        }
        
        BigDecimal calculatedTotal = items.stream()
            .map(item -> item.getPrice().multiply(new BigDecimal(item.getQuantity())))
            .reduce(BigDecimal.ZERO, BigDecimal::add);
            
        return totalPrice.compareTo(calculatedTotal) == 0;
    }
    
    @AssertTrue(groups = BusinessCheck.class, message = "庫(kù)存不足")
    public boolean isStockSufficient() {
        // 庫(kù)存檢查邏輯
        return inventoryService.checkStock(this);
    }
    
    // 其他字段和方法
}

// 使用分組序列驗(yàn)證
@Service
public class OrderService {
    
    @Autowired
    private Validator validator;
    
    public ValidationResult validateOrder(Order order) {
        Set<ConstraintViolation<Order>> violations = 
            validator.validate(order, OrderedChecks.class);
            
        // 處理驗(yàn)證結(jié)果
        return processValidationResult(violations);
    }
}

// 自定義類級(jí)約束注解
@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Constraint(validatedBy = DateRangeValidator.class)
public @interface ValidDateRange {
    
    String message() default "結(jié)束日期必須晚于開(kāi)始日期";
    
    Class<?>[] groups() default {};
    
    Class<? extends Payload>[] payload() default {};
    
    String startDateField();
    
    String endDateField();
}

// 類級(jí)約束驗(yàn)證器
public class DateRangeValidator implements ConstraintValidator<ValidDateRange, Object> {
    
    private String startDateField;
    private String endDateField;
    
    @Override
    public void initialize(ValidDateRange constraintAnnotation) {
        this.startDateField = constraintAnnotation.startDateField();
        this.endDateField = constraintAnnotation.endDateField();
    }
    
    @Override
    public boolean isValid(Object value, ConstraintValidatorContext context) {
        try {
            LocalDate startDate = (LocalDate) BeanUtils.getPropertyValue(value, startDateField);
            LocalDate endDate = (LocalDate) BeanUtils.getPropertyValue(value, endDateField);
            
            if (startDate == null || endDate == null) {
                return true; // 空值驗(yàn)證交給@NotNull處理
            }
            
            return !endDate.isBefore(startDate);
        } catch (Exception e) {
            return false;
        }
    }
}

// 應(yīng)用類級(jí)約束
@ValidDateRange(
    startDateField = "startDate",
    endDateField = "endDate",
    groups = BusinessCheck.class
)
public class EventSchedule {
    
    @NotNull(groups = BasicCheck.class)
    private String eventName;
    
    @NotNull(groups = BasicCheck.class)
    private LocalDate startDate;
    
    @NotNull(groups = BasicCheck.class)
    private LocalDate endDate;
    
    // 其他字段和方法
}

// 控制器參數(shù)校驗(yàn)示例
@RestController
@RequestMapping("/api/products")
public class ProductController {
    
    @Autowired
    private ProductService productService;
    
    // 請(qǐng)求體驗(yàn)證
    @PostMapping
    public ResponseEntity<?> createProduct(
            @Validated(Create.class) @RequestBody Product product,
            BindingResult bindingResult) {
        
        if (bindingResult.hasErrors()) {
            Map<String, String> errors = bindingResult.getFieldErrors().stream()
                .collect(Collectors.toMap(
                    FieldError::getField,
                    FieldError::getDefaultMessage,
                    (msg1, msg2) -> msg1 + "; " + msg2
                ));
                
            return ResponseEntity.badRequest().body(errors);
        }
        
        return ResponseEntity.ok(productService.createProduct(product));
    }
    
    // 路徑變量和請(qǐng)求參數(shù)驗(yàn)證
    @GetMapping("/search")
    public ResponseEntity<?> searchProducts(
            @RequestParam @NotBlank String category,
            @RequestParam @Positive Integer minPrice,
            @RequestParam @Positive Integer maxPrice) {
        
        return ResponseEntity.ok(
            productService.searchProducts(category, minPrice, maxPrice)
        );
    }
}

// 全局異常處理
@RestControllerAdvice
public class ValidationExceptionHandler {
    
    @ExceptionHandler(MethodArgumentNotValidException.class)
    public ResponseEntity<Object> handleValidationExceptions(
            MethodArgumentNotValidException ex) {
        
        Map<String, String> errors = ex.getBindingResult().getFieldErrors().stream()
            .collect(Collectors.toMap(
                FieldError::getField,
                FieldError::getDefaultMessage,
                (msg1, msg2) -> msg1 + "; " + msg2
            ));
            
        return ResponseEntity
            .status(HttpStatus.BAD_REQUEST)
            .body(new ApiError("Validation Failed", errors));
    }
    
    @ExceptionHandler(ConstraintViolationException.class)
    public ResponseEntity<Object> handleConstraintViolation(
            ConstraintViolationException ex) {
        
        Map<String, String> errors = ex.getConstraintViolations().stream()
            .collect(Collectors.toMap(
                violation -> violation.getPropertyPath().toString(),
                ConstraintViolation::getMessage,
                (msg1, msg2) -> msg1 + "; " + msg2
            ));
            
        return ResponseEntity
            .status(HttpStatus.BAD_REQUEST)
            .body(new ApiError("Validation Failed", errors));
    }
}