tg_exporter/internal/client_channel.go

package internal

import (
	"context"
	"mime"

	"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 *DBChannel, modeHistory bool) error {
	inputPeer := &tg.InputPeerChannel{ChannelID: channel.ID, AccessHash: channel.AccessHash}

	request := &tg.MessagesGetHistoryRequest{
		Peer:  inputPeer,
		Limit: 10,
	}

	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
	}

	request.Limit = 1
	request.OffsetID = 3753

	messages, err := t.Client.API().MessagesGetHistory(ctx, request)
	if err != nil {
		return errors.Wrap(err, "messages.getHistory")
	}
	if len(messages.(*tg.MessagesChannelMessages).GetMessages()) == 0 {
		t.logger.Info("no new message")
		return errors.New("no new message")
	}

	downloader := downloader.NewDownloader()
	lo.ForEach(messages.(*tg.MessagesChannelMessages).GetMessages(), func(item tg.MessageClass, index int) {
		defer func() {
			t.logger.Info("update config", zap.Int("offset", cfg.Offset))
			if err := cfg.Update(ctx, item.GetID()); err != nil {
				t.logger.Error("update config failed", zap.Error(err))
			}
		}()

		switch item.(type) {
		case *tg.MessageEmpty:
			return
		case *tg.MessageService:
			return
		}

		msg, ok := item.(*tg.Message)
		if !ok {
			t.logger.Error("convert msg to *tg.Message failed")
			return
		}

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

		channelMessage.WithMessage(msg.GetMessage())
		if grpID, ok := msg.GetGroupedID(); ok {
			channelMessage.WithGroupID(grpID)
		}

		if mediaClass, ok := msg.GetMedia(); ok {
			switch mediaClass.(type) {
			case *tg.MessageMediaDocument:
				if docClass, ok := mediaClass.(*tg.MessageMediaDocument).GetDocument(); ok {
					t.logger.Warn("document",
						zap.Int("msg_id", msg.ID),
						zap.String("file_name", docClass.String()),
					)

					doc := docClass.(*tg.Document)
					if doc.GetSize() > 1024*1024*10 {
						t.logger.Warn("document size too large", zap.Int64("size", doc.GetSize()))
						return
					}

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

					location := &tg.InputDocumentFileLocation{
						ID:            doc.GetID(),
						AccessHash:    doc.GetAccessHash(),
						FileReference: doc.GetFileReference(),
						ThumbSize:     thumbSize,
					}
					exts, err := mime.ExtensionsByType(doc.GetMimeType())
					if err != nil {
						t.logger.Error("get extension failed", zap.Error(err), zap.String("mime_type", doc.GetMimeType()))
						return
					}

					saveTo := cfg.Asset(doc.GetID(), exts[0])
					_, err = downloader.Download(t.Client.API(), location).ToPath(ctx, saveTo)
					if err != nil {
						t.logger.Error("download failed", zap.Error(err))
						return
					}
					channelMessage.WithDoc(doc.GetID(), exts[0])
					t.logger.Info("download photo success", zap.String("location", saveTo))
					return
				}
			case *tg.MessageMediaWebPage:
				if page, ok := mediaClass.(*tg.MessageMediaWebPage).GetWebpage().(*tg.WebPage); ok {
					channelMessage.WithWebPage(page.Title, page.URL)
					return
				}
				t.logger.Warn("web_page", zap.String("url", mediaClass.(*tg.MessageMediaWebPage).GetWebpage().String()))
			case *tg.MessageMediaPhoto:
				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 photo success", zap.String("location", saveTo))
				}
			}
		}
	})

	return nil
}