package pkg

import (
	"encoding/json"
	"fmt"
	"io"
	"math/rand/v2"
	"net/http"
	"os"
	"path/filepath"
	"reflect"
	"strings"
	"time"

	"github.com/go-viper/mapstructure/v2"
	"github.com/google/uuid"
)

func GetModuleDir() (string, error) {
	dir, err := os.Getwd()
	if err != nil {
		return "", err
	}

	for {
		modPath := filepath.Join(dir, "go.mod")
		if _, err := os.Stat(modPath); err == nil {
			return dir, nil // 找到 go.mod
		}

		// 向上查找父目录
		parent := filepath.Dir(dir)
		if parent == dir {
			break // 到达根目录，未找到
		}
		dir = parent
	}

	return "", fmt.Errorf("go.mod not found in current directory or parents")
}

// GetCacheDir 用于获取缓存目录路径
// 如果缓存目录不存在，则会自动创建
// 返回值:
//   - string: 缓存目录的路径
//   - error: 如果获取模块目录失败或创建缓存目录失败，则返回错误信息
func GetCacheDir() (string, error) {
	// 获取模块目录
	modDir, err := GetModuleDir()
	if err != nil {
		return "", err
	}
	// 拼接缓存目录路径
	path := fmt.Sprintf("%s/cache", modDir)
	// 创建目录（包括所有必要的父目录），权限设置为0755
	err = os.MkdirAll(path, 0755)
	if err != nil {
		return "", fmt.Errorf("创建目录失败: %w", err)
	}
	// 返回成功创建的缓存目录路径
	return path, nil
}

func GetTmplDir() (string, error) {
	modDir, err := GetModuleDir()
	if err != nil {
		return "", err
	}
	path := fmt.Sprintf("%s/tmpl", modDir)
	err = os.MkdirAll(path, 0755)
	if err != nil {
		return "", fmt.Errorf("创建目录失败: %w", err)
	}
	return path, nil
}

func ReverseSliceNew[T any](s []T) []T {
	result := make([]T, len(s))
	for i := 0; i < len(s); i++ {
		result[i] = s[len(s)-1-i]
	}
	return result
}

func JsonStringIgonErr(data interface{}) string {
	return string(JsonByteIgonErr(data))
}

func JsonByteIgonErr(data interface{}) []byte {
	dataByte, _ := json.Marshal(data)
	return dataByte
}

func IntersectionGeneric[T comparable](slice1, slice2 []T) []T {
	m := make(map[T]bool)
	result := []T{}

	for _, v := range slice1 {
		m[v] = true
	}

	for _, v := range slice2 {
		if m[v] {
			result = append(result, v)
			delete(m, v) // 避免重复
		}
	}

	return result
}

func CreateOrderNum(prefix string) string {
	code := fmt.Sprintf("%04d", rand.IntN(10000))
	fmt.Println("4位随机数字:", code) // 输出示例: "0837"
	return prefix + time.Now().Format("20060102150405") + code
}

func BuildUpdateMap(obj interface{}, omitFields ...string) map[string]interface{} {
	result := make(map[string]interface{})
	omitMap := make(map[string]bool)
	for _, f := range omitFields {
		omitMap[f] = true
	}

	v := reflect.ValueOf(obj)
	if v.Kind() == reflect.Ptr {
		v = v.Elem()
	}
	t := v.Type()

	for i := 0; i < v.NumField(); i++ {
		field := v.Field(i)
		fieldName := t.Field(i).Name

		if omitMap[fieldName] {
			continue
		}

		// 只处理非 nil 的指针字段
		if field.Kind() == reflect.Ptr && !field.IsNil() {
			// 将驼峰转为下划线（可选的，根据你的数据库列名决定）
			colName := CamelToSnake(fieldName)
			result[colName] = field.Elem().Interface()
		}
	}
	return result
}

func CamelToSnake(s string) string {
	var result []rune
	for i, r := range s {
		if i > 0 && r >= 'A' && r <= 'Z' {
			result = append(result, '_')
		}
		result = append(result, r)
	}
	return string(result)
}

func CopyNonNilFields(src, dst interface{}) error {
	config := &mapstructure.DecoderConfig{
		Result:     dst,
		TagName:    "json",
		ZeroFields: false, // 重要：不清零目标字段
		Squash:     false,
	}

	decoder, err := mapstructure.NewDecoder(config)
	if err != nil {
		return err
	}

	return decoder.Decode(src)
}

func DownloadFile(url string, saveDir string, filename string) (string, error) {
	os.MkdirAll(saveDir, 0755)

	if filename == "" {
		filename = uuid.New().String() + ".docx"
	}

	filePath := filepath.Join(saveDir, filename)

	resp, err := http.Get(url)
	if err != nil {
		return "", err
	}
	defer resp.Body.Close()

	out, err := os.Create(filePath)
	if err != nil {
		return "", err
	}
	defer out.Close()

	_, err = io.Copy(out, resp.Body)
	if err != nil {
		return "", err
	}

	absPath, _ := filepath.Abs(filePath)
	return absPath, nil
}

func DownloadImage(url string, requestID string, dir string) (string, error) {
	os.MkdirAll(dir, 0755)

	ext := filepath.Ext(url)
	if ext == "" {
		ext = ".jpg"
	}
	filename := requestID + "_" + uuid.New().String() + ext
	filePath := filepath.Join(dir, filename)

	resp, err := http.Get(url)
	if err != nil {
		return "", err
	}
	defer resp.Body.Close()

	out, err := os.Create(filePath)
	if err != nil {
		return "", err
	}
	defer out.Close()

	_, err = io.Copy(out, resp.Body)
	if err != nil {
		return "", err
	}

	return filepath.Abs(filePath)
}

func DeleteFile(path string) {
	if path != "" {
		os.Remove(path)
	}
}

func GenerateUUID() string {
	return uuid.New().String()
}

func GenerateUserIndex() string {
	return uuid.New().String()[:20]
}

func GetString(m map[string]interface{}, key string) string {
	if v, ok := m[key]; ok {
		switch v.(type) {
		case []uint8:
			return string(v.([]uint8))
		case string:
			return v.(string)
		case int64:
			return fmt.Sprintf("%d", v)
		default:
			return fmt.Sprintf("%v", v)
		}

	}
	return ""
}

func ParseTags(tagStr string) []string {
	if tagStr == "" {
		return []string{}
	}
	tags := strings.Split(tagStr, ",")
	result := make([]string, 0)
	for _, t := range tags {
		trimmed := strings.TrimSpace(t)
		if trimmed != "" {
			result = append(result, trimmed)
		}
	}
	return result
}