package handlers

import (
	"fmt"
	"regexp"
	"strings"

	"github.com/celestix/gotgproto/dispatcher"
	"github.com/celestix/gotgproto/ext"
	"github.com/charmbracelet/log"
	"github.com/gotd/td/tg"
	"github.com/krau/SaveAny-Bot/common/utils/tgutil"
	"github.com/krau/SaveAny-Bot/config"
	storconfig "github.com/krau/SaveAny-Bot/config/storage"
	"github.com/krau/SaveAny-Bot/core"
	"github.com/krau/SaveAny-Bot/core/tasks/batchimport"
	"github.com/krau/SaveAny-Bot/pkg/storagetypes"
	"github.com/krau/SaveAny-Bot/storage"
	"github.com/rs/xid"
)

func handleImportCmd(ctx *ext.Context, update *ext.Update) error {
	logger := log.FromContext(ctx)
	args := strings.Split(update.EffectiveMessage.Text, " ")

	if len(args) < 3 {
		ctx.Reply(update, ext.ReplyTextString("用法: /import <storage_name> <dir_path> [target_chat_id] [filter]\n\n"+
			"示例:\n"+
			"/import 本机1 /downloads\n"+
			"/import MyAlist /media/photos -1001234567890\n"+
			"/import MyLocal /backup \".*\\\\.mp4$\""), nil)
		return dispatcher.EndGroups
	}

	storageName := args[1]
	dirPath := args[2]

	userID := update.GetUserChat().GetID()

	// 1. 获取源存储端
	stor, err := storage.GetStorageByUserIDAndName(ctx, userID, storageName)
	if err != nil {
		logger.Errorf("Failed to get storage by user ID and name: %s", err)
		ctx.Reply(update, ext.ReplyTextString(fmt.Sprintf("存储端 '%s' 不存在或您无权访问: %v", storageName, err)), nil)
		return dispatcher.EndGroups
	}

	// 2. 检查是否支持列举
	listable, ok := stor.(storage.StorageListable)
	if !ok {
		ctx.Reply(update, ext.ReplyTextString(fmt.Sprintf("存储端 '%s' 不支持列举文件功能", storageName)), nil)
		return dispatcher.EndGroups
	}

	// 3. 检查是否支持读取
	_, ok = stor.(storage.StorageReadable)
	if !ok {
		ctx.Reply(update, ext.ReplyTextString(fmt.Sprintf("存储端 '%s' 不支持读取文件功能", storageName)), nil)
		return dispatcher.EndGroups
	}

	// 4. 获取目标 Telegram 存储
	telegramStorage, err := storage.GetTelegramStorageByUserID(ctx, userID)
	if err != nil {
		ctx.Reply(update, ext.ReplyTextString(fmt.Sprintf("未找到可用的 Telegram 存储: %v", err)), nil)
		return dispatcher.EndGroups
	}

	// 5. 列举目录文件
	replied, err := ctx.Reply(update, ext.ReplyTextString("正在获取文件列表..."), nil)
	if err != nil {
		logger.Errorf("Failed to reply: %s", err)
		return dispatcher.EndGroups
	}

	files, err := listable.ListFiles(ctx, dirPath)
	if err != nil {
		ctx.EditMessage(update.EffectiveChat().GetID(), &tg.MessagesEditMessageRequest{
			ID:      replied.ID,
			Message: fmt.Sprintf("获取文件列表失败: %v", err),
		})
		return dispatcher.EndGroups
	}

	// 6. 过滤文件
	var filter *regexp.Regexp
	if len(args) >= 5 {
		filter, err = regexp.Compile(args[4])
		if err != nil {
			ctx.EditMessage(update.EffectiveChat().GetID(), &tg.MessagesEditMessageRequest{
				ID:      replied.ID,
				Message: fmt.Sprintf("正则表达式无效: %v", err),
			})
			return dispatcher.EndGroups
		}
	}

	filteredFiles := make([]storagetypes.FileInfo, 0)
	for _, file := range files {
		if file.IsDir {
			continue
		}
		if filter != nil && !filter.MatchString(file.Name) {
			continue
		}
		filteredFiles = append(filteredFiles, file)
	}

	if len(filteredFiles) == 0 {
		ctx.EditMessage(update.EffectiveChat().GetID(), &tg.MessagesEditMessageRequest{
			ID:      replied.ID,
			Message: "目录中没有可导入的文件",
		})
		return dispatcher.EndGroups
	}

	// 7. 解析目标 Chat ID
	// Get default chat_id from Telegram storage config
	targetChatID := int64(0)
	if telegramCfg := config.C().GetStorageByName(telegramStorage.Name()); telegramCfg != nil {
		if tgCfg, ok := telegramCfg.(*storconfig.TelegramStorageConfig); ok {
			targetChatID = tgCfg.ChatID
		}
	}

	if len(args) >= 4 {
		parsedChatID, err := tgutil.ParseChatID(ctx, args[3])
		if err != nil {
			ctx.EditMessage(update.EffectiveChat().GetID(), &tg.MessagesEditMessageRequest{
				ID:      replied.ID,
				Message: fmt.Sprintf("无效的 Chat ID: %v", err),
			})
			return dispatcher.EndGroups
		}
		targetChatID = parsedChatID
	}

	if targetChatID == 0 {
		ctx.EditMessage(update.EffectiveChat().GetID(), &tg.MessagesEditMessageRequest{
			ID:      replied.ID,
			Message: "未指定目标频道 ID，且 Telegram 存储未配置默认 chat_id",
		})
		return dispatcher.EndGroups
	}

	// 8. 创建任务元素
	elems := make([]batchimport.TaskElement, 0, len(filteredFiles))
	var totalSize int64
	for _, file := range filteredFiles {
		elem := batchimport.NewTaskElement(stor, file, telegramStorage, targetChatID)
		elems = append(elems, *elem)
		totalSize += file.Size
	}

	// 9. 创建并添加任务
	taskID := xid.New().String()
	injectCtx := tgutil.ExtWithContext(ctx.Context, ctx)
	task := batchimport.NewBatchImportTask(
		taskID,
		injectCtx,
		elems,
		batchimport.NewProgressTracker(replied.ID, userID),
		true, // IgnoreErrors
	)

	if err := core.AddTask(injectCtx, task); err != nil {
		ctx.EditMessage(update.EffectiveChat().GetID(), &tg.MessagesEditMessageRequest{
			ID:      replied.ID,
			Message: fmt.Sprintf("添加任务失败: %v", err),
		})
		return dispatcher.EndGroups
	}

	ctx.EditMessage(update.EffectiveChat().GetID(), &tg.MessagesEditMessageRequest{
		ID:      replied.ID,
		Message: fmt.Sprintf("✅ 已添加 %d 个文件到导入队列\n总大小: %.2f MB\n任务 ID: %s", len(elems), float64(totalSize)/(1024*1024), taskID),
	})

	return dispatcher.EndGroups
}