package validator

import (
	"fmt"
	"strings"

	"github.com/go-kratos/kratos/v2/errors"
)

// ValidationError 验证错误
type ValidationError struct {
	FieldPath string            // 字段路径 如 "user.email"
	RuleID    string            // 规则ID
	Message   string            // 错误消息(中文)
	MessageEN string            // 错误消息(英文)
	Value     interface{}       // 失败的值
	Metadata  map[string]string // 附加信息
}

// Error 实现 error 接口
func (e *ValidationError) Error() string {
	if e.FieldPath != "" {
		return fmt.Sprintf("%s: %s", e.FieldPath, e.Message)
	}
	return e.Message
}

// ValidationErrors 多个验证错误的集合
type ValidationErrors struct {
	Errors   []*ValidationError // 错误列表
	Warnings []*ValidationError // 警告列表(非阻塞)
}

// Error 实现 error 接口
func (e *ValidationErrors) Error() string {
	if len(e.Errors) == 0 {
		return ""
	}

	var messages []string
	for _, err := range e.Errors {
		messages = append(messages, err.Error())
	}
	return strings.Join(messages, "; ")
}

// Add 添加错误
func (e *ValidationErrors) Add(err *ValidationError) {
	if e.Errors == nil {
		e.Errors = make([]*ValidationError, 0)
	}
	e.Errors = append(e.Errors, err)
}

// AddWarning 添加警告
func (e *ValidationErrors) AddWarning(err *ValidationError) {
	if e.Warnings == nil {
		e.Warnings = make([]*ValidationError, 0)
	}
	e.Warnings = append(e.Warnings, err)
}

// HasErrors 是否有错误
func (e *ValidationErrors) HasErrors() bool {
	return len(e.Errors) > 0
}

// IsEmpty 是否为空
func (e *ValidationErrors) IsEmpty() bool {
	return len(e.Errors) == 0 && len(e.Warnings) == 0
}

// Count 错误数量
func (e *ValidationErrors) Count() int {
	return len(e.Errors)
}

// ToKratosError 转换为 Kratos 错误
func (e *ValidationErrors) ToKratosError() error {
	if !e.HasErrors() {
		return nil
	}

	// 构建详细的错误消息
	var messages []string
	for _, err := range e.Errors {
		messages = append(messages, err.Error())
	}

	// 使用 Kratos 的 BadRequest 错误
	kratosErr := errors.BadRequest(
		"VALIDATION_FAILED",
		strings.Join(messages, "; "),
	)

	// 添加错误元数据
	metadata := make(map[string]string)
	for i, err := range e.Errors {
		prefix := fmt.Sprintf("error_%d", i)
		metadata[prefix+"_field"] = err.FieldPath
		metadata[prefix+"_rule"] = err.RuleID
		metadata[prefix+"_message"] = err.Message
	}

	return kratosErr.WithMetadata(metadata)
}

// NewValidationError 创建验证错误
func NewValidationError(fieldPath, ruleID, message string) *ValidationError {
	return &ValidationError{
		FieldPath: fieldPath,
		RuleID:    ruleID,
		Message:   message,
	}
}

// NewValidationErrorWithValue 创建带值的验证错误
func NewValidationErrorWithValue(fieldPath, ruleID, message string, value interface{}) *ValidationError {
	return &ValidationError{
		FieldPath: fieldPath,
		RuleID:    ruleID,
		Message:   message,
		Value:     value,
	}
}

// 预定义错误代码
const (
	ErrCodeInvalidValue   = "INVALID_VALUE"
	ErrCodeRequired       = "REQUIRED_FIELD"
	ErrCodeInvalidFormat  = "INVALID_FORMAT"
	ErrCodeOutOfRange     = "OUT_OF_RANGE"
	ErrCodeInvalidLength  = "INVALID_LENGTH"
	ErrCodeInvalidPattern = "INVALID_PATTERN"
	ErrCodeCELExecution   = "CEL_EXECUTION_ERROR"
)