package middleware

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"net/http"
	"os"
	"path"
	"path/filepath"
	"strings"

	"gitee.com/xuyiping_admin/pkg/logger/zaplog"
	"gitee.com/xuyiping_admin/pkg/xerr"
	"github.com/gin-gonic/gin"
	"github.com/nicksnyder/go-i18n/v2/i18n"
	"go.uber.org/zap"
	"golang.org/x/text/language"
)

var (
	localesDir      = "./locales"
	bundle          *i18n.Bundle
	defaultLanguage = language.Chinese
	supported       = map[string]bool{ // 支持的语言列表
		"zh": true, // 中文
		"en": true, // 英文
		// 添加其他支持的语言...
	}
)

// I18N 初始化国际化中间件
func I18N() gin.HandlerFunc {
	bundle = i18n.NewBundle(defaultLanguage)
	bundle.RegisterUnmarshalFunc("json", json.Unmarshal)

	// 加载翻译文件
	if err := loadTranslations(); err != nil {
		zaplog.Error("Failed to load translations", zap.Error(err))
	}

	return func(c *gin.Context) {
		lang := detectLanguage(c.Request)
		localize := i18n.NewLocalizer(bundle, lang)
		c.Set(LanguageContent, localize)
		c.Set(Language, lang)
		c.Next()
	}
}

// loadTranslations 加载所有翻译文件
func loadTranslations() error {
	absPath, err := filepath.Abs(localesDir)
	if err != nil {
		return xerr.WithStack(err)
	}

	files, err := ioutil.ReadDir(absPath)
	if err != nil {
		return xerr.WithStack(fmt.Errorf("failed to read files dir: %w", err))
	}

	if len(files) == 0 {
		return xerr.Custom("no found in files directory")
	}

	loaded := false
	for _, entry := range files {
		if entry.IsDir() || !strings.HasSuffix(entry.Name(), ".json") {
			continue
		}

		filePath := path.Join(absPath, entry.Name())
		data, err := os.ReadFile(filePath)
		if err != nil {
			zaplog.Error("Failed to read translation file",
				zap.String("file", filePath),
				zap.Error(err))
			continue
		}

		messageFile, err := bundle.ParseMessageFileBytes(data, filePath)
		if err != nil {
			zaplog.Error("Failed to parse translation file",
				zap.String("file", filePath),
				zap.Error(err))
			continue
		}

		zaplog.Info("Loaded translation",
			zap.String("language", messageFile.Tag.String()),
			zap.Any("messageFile", messageFile))
		loaded = true
	}

	if !loaded {
		return xerr.Custom("no valid translation files were loaded")
	}
	return nil
}

// detectLanguage 检测客户端语言偏好
func detectLanguage(r *http.Request) string {
	// 1. 检查查询参数
	if lang := r.URL.Query().Get("language"); lang != "" {
		return normalizeLanguage(lang)
	}

	// 2. 检查 Cookie
	if langCookie, err := r.Cookie("language"); err == nil && langCookie.Value != "" {
		return normalizeLanguage(langCookie.Value)
	}

	// 3. 检查 Accept-Language 头
	if acceptLang := r.Header.Get("Accept-Language"); acceptLang != "" {
		if langs := strings.Split(acceptLang, ","); len(langs) > 0 {
			return normalizeLanguage(langs[0])
		}
	}
	// 默认返回中文
	return defaultLanguage.String()
}

// normalizeLanguage 规范化语言代码
func normalizeLanguage(lang string) string {
	// 去除权重值 (如 en;q=0.9 -> en)
	if parts := strings.Split(lang, ";"); len(parts) > 0 {
		lang = parts[0]
	}

	// 转换为小写并去除地区代码 (en-US -> en)
	lang = strings.ToLower(strings.Split(lang, "-")[0])

	if supported[lang] {
		return lang
	}
	return defaultLanguage.String()
}