From f2219a1e062a7e9f21403bb913fe463a29e9060c Mon Sep 17 00:00:00 2001
From: Sumner Evans <sumner.evans@automattic.com>
Date: Wed, 15 May 2024 16:54:34 -0600
Subject: [PATCH] cmd/directdl: add experimental direct download handler

Signed-off-by: Sumner Evans <sumner.evans@automattic.com>
---
 cmd/directdl/main.go | 129 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 129 insertions(+)
 create mode 100644 cmd/directdl/main.go

diff --git a/cmd/directdl/main.go b/cmd/directdl/main.go
new file mode 100644
index 00000000..63565c5b
--- /dev/null
+++ b/cmd/directdl/main.go
@@ -0,0 +1,129 @@
+package main
+
+import (
+	"bufio"
+	"bytes"
+	"context"
+	"encoding/base64"
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+
+	"github.com/gotd/td/session"
+	"github.com/gotd/td/telegram"
+	"github.com/gotd/td/telegram/downloader"
+	"github.com/gotd/td/tg"
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/log"
+	"go.mau.fi/zerozap"
+	"go.uber.org/zap"
+	"maunium.net/go/mautrix/id"
+)
+
+type FileSession struct{}
+
+func (s *FileSession) LoadSession(context.Context) ([]byte, error) {
+	if data, err := os.ReadFile("session"); err != nil {
+		return nil, session.ErrNotFound
+	} else {
+		return data, nil
+	}
+}
+
+func (s *FileSession) StoreSession(ctx context.Context, data []byte) error {
+	return os.WriteFile("session", data, 0600)
+}
+
+func main() {
+	apiID, err := strconv.ParseInt(os.Args[1], 10, 32)
+	if err != nil {
+		panic(err)
+	}
+	apiHash := os.Args[2]
+
+	log.Logger = log.Output(zerolog.ConsoleWriter{Out: os.Stderr})
+
+	zaplog := zap.New(zerozap.New(log.Logger))
+
+	var sessionStorage FileSession
+	// https://core.telegram.org/api/obtaining_api_id
+	client := telegram.NewClient(int(apiID), apiHash, telegram.Options{
+		SessionStorage: &sessionStorage,
+		Logger:         zaplog,
+	})
+
+	reader := bufio.NewReader(os.Stdin)
+	if err := client.Run(context.Background(), func(ctx context.Context) error {
+		for {
+			fmt.Printf("enter the URI here: ")
+			raw, err := reader.ReadString('\n')
+			if err != nil {
+				panic(err)
+			}
+			uri, err := id.ParseContentURI(strings.TrimSpace(raw))
+			if err != nil {
+				panic(err)
+			}
+			fmt.Printf("uri: %s\n", uri)
+			fmt.Printf("fid: %s\n", uri.FileID)
+			fmt.Printf("hs: %s\n", uri.Homeserver)
+
+			isPhoto := false
+			var id, accessHash int64
+			var fileReference []byte
+			var thumbSize string
+			for _, part := range strings.Split(uri.FileID, ".") {
+				if len(part) == 1 && part == "p" {
+					isPhoto = true
+				} else if len(part) > 1 {
+					switch part[0] {
+					case 'i':
+						id, err = strconv.ParseInt(part[1:], 10, 64)
+						if err != nil {
+							panic(err)
+						}
+					case 'a':
+						accessHash, err = strconv.ParseInt(part[1:], 10, 64)
+						if err != nil {
+							panic(err)
+						}
+					case 'f':
+						fileReference, err = base64.RawURLEncoding.DecodeString(part[1:])
+						if err != nil {
+							panic(err)
+						}
+					case 't':
+						thumbSize = part[1:]
+					}
+				} else {
+					panic("invalid file id")
+				}
+			}
+
+			if isPhoto {
+				file := tg.InputPhotoFileLocation{
+					ID:            id,
+					AccessHash:    accessHash,
+					FileReference: fileReference,
+					ThumbSize:     thumbSize,
+				}
+
+				fmt.Printf("4\n")
+				var buf bytes.Buffer
+				if _, err := downloader.NewDownloader().Download(client.API(), &file).Stream(context.TODO(), &buf); err != nil {
+					panic(err)
+				}
+				fmt.Printf("2\n")
+				if err := os.WriteFile("/home/sumner/tmp/test.jpg", buf.Bytes(), 0666); err != nil {
+					panic(err)
+				}
+			} else {
+				panic("not a photo")
+			}
+		}
+	}); err != nil {
+		panic(err)
+	}
+
+}