Program_SecretChats.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
using TL;
using WTelegram;

namespace WTelegramClientTest
{
	static class Program_SecretChats
	{
		static Client Client;
		static SecretChats Secrets;
		static ISecretChat ActiveChat; // the secret chat currently selected
		static readonly Dictionary<long, User> Users = [];
		static readonly Dictionary<long, ChatBase> Chats = [];

		// go to Project Properties > Debug > Launch Profiles > Environment variables and add at least these: api_id, api_hash, phone_number
		static async Task Main()
		{
			Helpers.Log = (l, s) => System.Diagnostics.Debug.WriteLine(s);
			Client = new Client(Environment.GetEnvironmentVariable);
			Secrets = new SecretChats(Client, "Secrets.bin");
			AppDomain.CurrentDomain.ProcessExit += (s, e) => { Secrets.Dispose(); Client.Dispose(); };
			SelectActiveChat();

			Client.OnUpdates += Client_OnUpdates;
			var myself = await Client.LoginUserIfNeeded();
			Users[myself.id] = myself;
			Console.WriteLine($"We are logged-in as {myself}");
				
			var dialogs = await Client.Messages_GetAllDialogs(); // load the list of users/chats
			dialogs.CollectUsersChats(Users, Chats);
			Console.WriteLine(@"Available commands:
/request <UserID>   Initiate Secret Chat with user (see /users)
/discard [delete]   Terminate active secret chat [and delete history]
/select <ChatID>    Select another Secret Chat
/photo filename.jpg Send a JPEG photo
/read               Mark active discussion as read
/users              List collected users and their IDs
Type a command, or a message to send to the active secret chat:");
			do
			{
				try
				{
					var line = Console.ReadLine();
					if (line.StartsWith('/'))
					{
						if (line == "/discard delete") { await Secrets.Discard(ActiveChat.ChatId, true); SelectActiveChat(); }
						else if (line == "/discard") { await Secrets.Discard(ActiveChat.ChatId, false); SelectActiveChat(); }
						else if (line == "/read") await Client.Messages_ReadEncryptedHistory(ActiveChat.Peer, DateTime.UtcNow);
						else if (line == "/users") foreach (var user in Users.Values) Console.WriteLine($"{user.id,-10} {user}");
						else if (line.StartsWith("/select ")) SelectActiveChat(int.Parse(line[8..]));
						else if (line.StartsWith("/request "))
							if (Users.TryGetValue(long.Parse(line[9..]), out var user))
								SelectActiveChat(await Secrets.Request(user));
							else
								Console.WriteLine("User not found");
						else if (line.StartsWith("/photo "))
						{
							var media = new TL.Layer46.DecryptedMessageMediaPhoto { caption = line[7..] };
							var file = await Secrets.UploadFile(File.OpenRead(line[7..]), media);
							var sent = await Secrets.SendMessage(ActiveChat.ChatId, new TL.Layer73.DecryptedMessage { random_id = Helpers.RandomLong(),
								media = media, flags = TL.Layer73.DecryptedMessage.Flags.has_media }, file: file);
						}
						else Console.WriteLine("Unrecognized command");
					}
					else if (ActiveChat == null) Console.WriteLine("No active secret chat");
					else await Secrets.SendMessage(ActiveChat.ChatId, new TL.Layer73.DecryptedMessage { message = line, random_id = Helpers.RandomLong() });
				}
				catch (Exception ex)
				{
					Console.WriteLine(ex);
				}
			} while (true);
		}

		private static async Task Client_OnUpdates(UpdatesBase updates)
		{
			updates.CollectUsersChats(Users, Chats);
			foreach (var update in updates.UpdateList)
				switch (update)
				{
					case UpdateEncryption ue: // Change in Secret Chat status
						await Secrets.HandleUpdate(ue);
						break;
					case UpdateNewEncryptedMessage unem: // Encrypted message or service message:
						if (unem.message.ChatId != ActiveChat?.ChatId) SelectActiveChat(unem.message.ChatId);
						foreach (var msg in Secrets.DecryptMessage(unem.message))
						{
							if (msg.Media != null && unem.message is EncryptedMessage { file: EncryptedFile ef })
							{
								int slash = msg.Media.MimeType?.IndexOf('/') ?? 0; // quick & dirty conversion from MIME type to file extension
								var filename = $"{DateTime.Now:yyyy-MM-dd_HH-mm-ss}.{(slash > 0 ? msg.Media.MimeType[(slash + 1)..] : "bin")}";
								Console.WriteLine($"{unem.message.ChatId}> {msg.Message} [attached file downloaded to {filename}]");
								using var output = File.Create(filename);
								await Secrets.DownloadFile(ef, msg.Media, output);
							}
							else if (msg.Action == null) Console.WriteLine($"{unem.message.ChatId}> {msg.Message}");
							else Console.WriteLine($"{unem.message.ChatId}> Service Message {msg.Action.GetType().Name[22..]}");
						}
						break;
					case UpdateEncryptedChatTyping:
					case UpdateEncryptedMessagesRead:
						//Console.WriteLine(update.GetType().Name);
						break;
				}
		}

		private static void SelectActiveChat(int newActiveChat = 0)
		{
			ActiveChat = Secrets.Chats.FirstOrDefault(sc => newActiveChat == 0 || sc.ChatId == newActiveChat);
			Console.WriteLine("Active secret chat ID: " + ActiveChat?.ChatId);
		}
	}
}