package internal

import (
	"context"

	"github.com/gotd/td/telegram/downloader"
	"github.com/gotd/td/tg"
	"github.com/pkg/errors"
	"github.com/samber/lo"
	"go.uber.org/zap"
)

func (t *TClient) Channel(ctx context.Context, channel *tg.Channel, cfg *ChannelConfig, modeHistory bool) error {
	inputPeer := &tg.InputPeerChannel{ChannelID: channel.ID, AccessHash: channel.AccessHash}

	request := &tg.MessagesGetHistoryRequest{
		Peer:  inputPeer,
		Limit: 1,
	}

	if modeHistory { // 提供此ID供遍历历史消息
		request.OffsetID = cfg.Offset
	} else {
		request.MinID = cfg.MinID // 提供此ID供新增加的消息
	}

	messages, err := t.Client.API().MessagesGetHistory(ctx, request)
	if err != nil {
		return errors.Wrap(err, "messages.getHistory")
	}

	downloader := downloader.NewDownloader()
	lo.ForEach(messages.(*tg.MessagesChannelMessages).GetMessages(), func(item tg.MessageClass, index int) {
		msg, ok := item.(*tg.Message)
		if !ok {
			t.logger.Error("convert msg to *tg.Message failed")
			return
		}
		defer func() {
			if err := cfg.Update(ctx, msg.ID); err != nil {
				t.logger.Error("update config failed", zap.Error(err))
			}
		}()

		channelMessage := NewChannelMessage(msg.ID)
		defer cfg.SaveMessage(channelMessage)

		channelMessage.WithMessage(msg.GetMessage())

		if mediaClass, ok := msg.GetMedia(); ok {
			if photoClass, ok := mediaClass.(*tg.MessageMediaPhoto).GetPhoto(); ok {
				photo := photoClass.(*tg.Photo)

				thumbSize := ""
				if len(photo.Sizes) > 1 {
					thumbSize = photo.Sizes[len(photo.Sizes)-1].GetType()
				}

				location := &tg.InputPhotoFileLocation{
					ID:            photo.GetID(),
					AccessHash:    photo.GetAccessHash(),
					FileReference: photo.GetFileReference(),
					ThumbSize:     thumbSize,
				}

				saveTo := cfg.Asset(photo.GetID(), "jpg")
				_, err := downloader.Download(t.Client.API(), location).ToPath(ctx, saveTo)
				if err != nil {
					t.logger.Error("download failed", zap.Error(err))
					return
				}
				channelMessage.WithPhoto(photo.GetID(), "jpg")
				t.logger.Info("download failed", zap.String("asset", saveTo))
			}
		}
	})

	return nil
}