tg_exporter/internal/client.go

package internal

import (
	"context"
	"fmt"
	"path/filepath"

	"exporter/config"

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

type TClient struct {
	Config *config.Config
	Client *telegram.Client
	logger *zap.Logger
	api    *tg.Client

	waitLogin chan error
	block     chan struct{}
}

// func (t *TClient) Close() {
// 	t.block <- struct{}{}
// }

func NewClient(config *config.Config) *TClient {
	c := &TClient{
		Config: config,
		Client: telegram.NewClient(config.AppID, config.AppHash, telegram.Options{
			Logger:        logger,
			UpdateHandler: nil,
			SessionStorage: &telegram.FileSessionStorage{
				Path: lo.Must(filepath.Abs(config.SessionFile)),
			},
		}),
	}

	return c
}

// func (t *TClient) Run(ctx context.Context) {
// 	err := t.Client.Run(ctx, func(ctx context.Context) error {
// 		flow := auth.NewFlow(Terminal{PhoneNumber: t.Config.Phone}, auth.SendCodeOptions{})
// 		if err := t.Client.Auth().IfNecessary(ctx, flow); err != nil {
// 			return errors.Wrap(err, "auth")
// 		}
// 		t.api = t.Client.API()

// 		t.waitLogin <- nil
// 		<-t.block
// 		return nil
// 	})
// 	if err != nil {
// 		t.waitLogin <- err
// 	}
// }

// func (t *TClient) Wait() <-chan error {
// 	return t.waitLogin
// }

func (t *TClient) Login(ctx context.Context) error {
	flow := auth.NewFlow(Terminal{PhoneNumber: client.Config.Phone}, auth.SendCodeOptions{})
	if err := t.Client.Auth().IfNecessary(context.Background(), flow); err != nil {
		return errors.Wrap(err, "auth")
	}

	self, err := t.Client.Self(ctx)
	if err != nil {
		return errors.Wrap(err, "call self")
	}

	logger.Info("Login",
		zap.String("first_name", self.FirstName),
		zap.String("last_name", self.LastName),
		zap.String("username", self.Username),
		zap.Int64("id", self.ID),
	)

	return nil
}

// ChannelInfo
func (t *TClient) ChannelInfoByAlias(ctx context.Context, channelAlias string) (*tg.Channel, error) {
	p, err := t.Client.API().ContactsResolveUsername(ctx, channelAlias)
	if err != nil {
		return nil, errors.Wrap(err, "contacts.resolveUsername")
	}
	chats := p.GetChats()
	if len(chats) == 0 {
		return nil, errors.New("chat not found")
	}
	channel := chats[0].(*tg.Channel)
	return channel, nil
}

func (t *TClient) ChannelInfoByID(ctx context.Context, channelID int64) (*tg.Channel, error) {
	p, err := t.Client.API().ChannelsGetChannels(ctx, []tg.InputChannelClass{
		&tg.InputChannel{ChannelID: channelID},
	})
	if err != nil {
		return nil, errors.Wrap(err, "contacts.resolveUsername")
	}
	chats := p.GetChats()
	if len(chats) == 0 {
		return nil, errors.New("chat not found")
	}
	channel := chats[0].(*tg.Channel)
	return channel, nil
}

func (t *TClient) Channel(ctx context.Context, channel *tg.Channel, offset int) error {
	inputPeer := &tg.InputPeerChannel{ChannelID: channel.ID, AccessHash: channel.AccessHash}
	messages, err := t.api.MessagesGetHistory(ctx, &tg.MessagesGetHistoryRequest{
		Peer:     inputPeer,
		Limit:    10,
		OffsetID: offset,
	})
	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 {
			fmt.Println("ID: get failed")
			return
		}

		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 := lo.Must(filepath.Abs(fmt.Sprintf("./photos/%d.jpg", photo.GetID())))
				storage, err := downloader.Download(t.api, location).ToPath(ctx, saveTo)

				if err != nil {
					fmt.Println(err)
				} else {
					fmt.Println("Downloaded : ", storage)
				}
			}
		}

		fmt.Println("")
		fmt.Println("------------------------------------------------------------------------------------------------------")
		fmt.Println("")
	})

	return nil
}