package errors

import (
	"errors"
	"fmt"
)

// 错误类型定义
var (
	ErrNotFound         = errors.New("resource not found")
	ErrInvalidInput     = errors.New("invalid input")
	ErrInternalServer   = errors.New("internal server error")
	ErrUnauthorized     = errors.New("unauthorized")
	ErrForbidden        = errors.New("forbidden")
	ErrConflict         = errors.New("conflict")
	ErrBadRequest       = errors.New("bad request")
	ErrTimeout          = errors.New("timeout")
	ErrServiceUnavailable = errors.New("service unavailable")
)

// AppError 应用错误结构
type AppError struct {
	Err     error
	Message string
	Code    int
}

func (e *AppError) Error() string {
	if e.Message != "" {
		return e.Message
	}
	return e.Err.Error()
}

func (e *AppError) Unwrap() error {
	return e.Err
}

// NewAppError 创建新的应用错误
func NewAppError(err error, message string, code int) *AppError {
	return &AppError{
		Err:     err,
		Message: message,
		Code:    code,
	}
}

// WrapError 包装错误
func WrapError(err error, message string) error {
	return fmt.Errorf("%s: %w", message, err)
}

// IsNotFound 检查是否为资源未找到错误
func IsNotFound(err error) bool {
	return errors.Is(err, ErrNotFound)
}

// IsInvalidInput 检查是否为无效输入错误
func IsInvalidInput(err error) bool {
	return errors.Is(err, ErrInvalidInput)
}

// IsInternalServer 检查是否为内部服务器错误
func IsInternalServer(err error) bool {
	return errors.Is(err, ErrInternalServer)
}

// IsUnauthorized 检查是否为未授权错误
func IsUnauthorized(err error) bool {
	return errors.Is(err, ErrUnauthorized)
}

// IsForbidden 检查是否为禁止访问错误
func IsForbidden(err error) bool {
	return errors.Is(err, ErrForbidden)
}

// IsConflict 检查是否为冲突错误
func IsConflict(err error) bool {
	return errors.Is(err, ErrConflict)
}

// IsBadRequest 检查是否为请求错误
func IsBadRequest(err error) bool {
	return errors.Is(err, ErrBadRequest)
}

// IsTimeout 检查是否为超时错误
func IsTimeout(err error) bool {
	return errors.Is(err, ErrTimeout)
}

// IsServiceUnavailable 检查是否为服务不可用错误
func IsServiceUnavailable(err error) bool {
	return errors.Is(err, ErrServiceUnavailable)
}