//
// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2020
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//

using Td = Telegram.Td;
using TdApi = Telegram.Td.Api;

using System;
using System.Threading;

namespace TdExample
{
 /// <summary>
 /// Example class for TDLib usage from C#.
 /// </summary>
 class Example
 {
 private static Td.Client _client = null;
 private readonly static Td.ClientResultHandler _defaultHandler = new DefaultHandler();

 private static TdApi.AuthorizationState _authorizationState = null;
 private static volatile bool _haveAuthorization = false;
 private static volatile bool _quiting = false;

 private static volatile AutoResetEvent _gotAuthorization = new AutoResetEvent(false);

 private static readonly string _newLine = Environment.NewLine;
 private static readonly string _commandsLine = "Enter command (gc <chatId> - GetChat, me - GetMe, sm <chatId> <message> - SendMessage, lo - LogOut, r - Restart, q - Quit): ";
 private static volatile string _currentPrompt = null;

 private static Td.Client CreateTdClient()
 {
 Td.Client result = Td.Client.Create(new UpdatesHandler());
 new Thread(() =>
 {
 Thread.CurrentThread.IsBackground = true;
 result.Run();
 }).Start();
 return result;
 }

 private static void Print(string str)
 {
 if (_currentPrompt != null)
 {
 Console.WriteLine();
 }
 Console.WriteLine(str);
 if (_currentPrompt != null)
 {
 Console.Write(_currentPrompt);
 }
 }

 private static string ReadLine(string str)
 {
 Console.Write(str);
 _currentPrompt = str;
 var result = Console.ReadLine();
 _currentPrompt = null;
 return result;
 }

 private static void OnAuthorizationStateUpdated(TdApi.AuthorizationState authorizationState)
 {
 if (authorizationState != null)
 {
 _authorizationState = authorizationState;
 }
 if (_authorizationState is TdApi.AuthorizationStateWaitTdlibParameters)
 {
 TdApi.TdlibParameters parameters = new TdApi.TdlibParameters();
 parameters.DatabaseDirectory = "tdlib";
 parameters.UseMessageDatabase = true;
 parameters.UseSecretChats = true;
 parameters.ApiId = 94575;
 parameters.ApiHash = "a3406de8d171bb422bb6ddf3bbd800e2";
 parameters.SystemLanguageCode = "en";
 parameters.DeviceModel = "Desktop";
 parameters.SystemVersion = "Unknown";
 parameters.ApplicationVersion = "1.0";
 parameters.EnableStorageOptimizer = true;

 _client.Send(new TdApi.SetTdlibParameters(parameters), new AuthorizationRequestHandler());
 }
 else if (_authorizationState is TdApi.AuthorizationStateWaitEncryptionKey)
 {
 _client.Send(new TdApi.CheckDatabaseEncryptionKey(), new AuthorizationRequestHandler());
 }
 else if (_authorizationState is TdApi.AuthorizationStateWaitPhoneNumber)
 {
 string phoneNumber = ReadLine("Please enter phone number: ");
 _client.Send(new TdApi.SetAuthenticationPhoneNumber(phoneNumber, null), new AuthorizationRequestHandler());
 }
 else if (_authorizationState is TdApi.AuthorizationStateWaitOtherDeviceConfirmation state)
 {
 Console.WriteLine("Please confirm this login link on another device: " + state.Link);
 }
 else if (_authorizationState is TdApi.AuthorizationStateWaitCode)
 {
 string code = ReadLine("Please enter authentication code: ");
 _client.Send(new TdApi.CheckAuthenticationCode(code), new AuthorizationRequestHandler());
 }
 else if (_authorizationState is TdApi.AuthorizationStateWaitRegistration)
 {
 string firstName = ReadLine("Please enter your first name: ");
 string lastName = ReadLine("Please enter your last name: ");
 _client.Send(new TdApi.RegisterUser(firstName, lastName), new AuthorizationRequestHandler());
 }
 else if (_authorizationState is TdApi.AuthorizationStateWaitPassword)
 {
 string password = ReadLine("Please enter password: ");
 _client.Send(new TdApi.CheckAuthenticationPassword(password), new AuthorizationRequestHandler());
 }
 else if (_authorizationState is TdApi.AuthorizationStateReady)
 {
 _haveAuthorization = true;
 _gotAuthorization.Set();
 }
 else if (_authorizationState is TdApi.AuthorizationStateLoggingOut)
 {
 _haveAuthorization = false;
 Print("Logging out");
 }
 else if (_authorizationState is TdApi.AuthorizationStateClosing)
 {
 _haveAuthorization = false;
 Print("Closing");
 }
 else if (_authorizationState is TdApi.AuthorizationStateClosed)
 {
 Print("Closed");
 _client.Dispose(); // _client is closed and native resources can be disposed now
 if (!_quiting)
 {
 _client = CreateTdClient(); // recreate _client after previous has closed
 }
 }
 else
 {
 Print("Unsupported authorization state:" + _newLine + _authorizationState);
 }
 }

 private static long GetChatId(string arg)
 {
 long chatId = 0;
 try
 {
 chatId = Convert.ToInt64(arg);
 }
 catch (FormatException)
 {
 }
 catch (OverflowException)
 {
 }
 return chatId;
 }

 private static void GetCommand()
 {
 string command = ReadLine(_commandsLine);
 string[] commands = command.Split(new char[] { ' ' }, 2);
 try
 {
 switch (commands[0])
 {
 case "gc":
 _client.Send(new TdApi.GetChat(GetChatId(commands[1])), _defaultHandler);
 break;
 case "me":
 _client.Send(new TdApi.GetMe(), _defaultHandler);
 break;
 case "sm":
 string[] args = commands[1].Split(new char[] { ' ' }, 2);
 sendMessage(GetChatId(args[0]), args[1]);
 break;
 case "lo":
 _haveAuthorization = false;
 _client.Send(new TdApi.LogOut(), _defaultHandler);
 break;
 case "r":
 _haveAuthorization = false;
 _client.Send(new TdApi.Close(), _defaultHandler);
 break;
 case "q":
 _quiting = true;
 _haveAuthorization = false;
 _client.Send(new TdApi.Close(), _defaultHandler);
 break;
 default:
 Print("Unsupported command: " + command);
 break;
 }
 }
 catch (IndexOutOfRangeException)
 {
 Print("Not enough arguments");
 }
 }

 private static void sendMessage(long chatId, string message)
 {
 // initialize reply markup just for testing
 TdApi.InlineKeyboardButton[] row = { new TdApi.InlineKeyboardButton("https://telegram.org?1", new TdApi.InlineKeyboardButtonTypeUrl()), new TdApi.InlineKeyboardButton("https://telegram.org?2", new TdApi.InlineKeyboardButtonTypeUrl()), new TdApi.InlineKeyboardButton("https://telegram.org?3", new TdApi.InlineKeyboardButtonTypeUrl()) };
 TdApi.ReplyMarkup replyMarkup = new TdApi.ReplyMarkupInlineKeyboard(new TdApi.InlineKeyboardButton[][] { row, row, row });

 TdApi.InputMessageContent content = new TdApi.InputMessageText(new TdApi.FormattedText(message, null), false, true);
 _client.Send(new TdApi.SendMessage(chatId, 0, null, replyMarkup, content), _defaultHandler);
 }

 static void Main()
 {
 // disable TDLib log
 Td.Client.Execute(new TdApi.SetLogVerbosityLevel(0));
 if (Td.Client.Execute(new TdApi.SetLogStream(new TdApi.LogStreamFile("tdlib.log", 1 << 27))) is TdApi.Error)
 {
 throw new System.IO.IOException("Write access to the current directory is required");
 }

 // create Td.Client
 _client = CreateTdClient();

 // test Client.Execute
 _defaultHandler.OnResult(Td.Client.Execute(new TdApi.GetTextEntities("@telegram /test_command https://telegram.org telegram.me @gif @test")));

 // main loop
 while (!_quiting)
 {
 // await authorization
 _gotAuthorization.Reset();
 _gotAuthorization.WaitOne();

 _client.Send(new TdApi.GetChats(null, Int64.MaxValue, 0, 100), _defaultHandler); // preload main chat list
 while (_haveAuthorization)
 {
 GetCommand();
 }
 }
 }

 private class DefaultHandler : Td.ClientResultHandler
 {
 void Td.ClientResultHandler.OnResult(TdApi.BaseObject @object)
 {
 Print(@object.ToString());
 }
 }

 private class UpdatesHandler : Td.ClientResultHandler
 {
 void Td.ClientResultHandler.OnResult(TdApi.BaseObject @object)
 {
 if (@object is TdApi.UpdateAuthorizationState)
 {
 OnAuthorizationStateUpdated((@object as TdApi.UpdateAuthorizationState).AuthorizationState);
 }
 else
 {
 // Print("Unsupported update: " + @object);
 }
 }
 }

 private class AuthorizationRequestHandler : Td.ClientResultHandler
 {
 void Td.ClientResultHandler.OnResult(TdApi.BaseObject @object)
 {
 if (@object is TdApi.Error)
 {
 Print("Receive an error:" + _newLine + @object);
 OnAuthorizationStateUpdated(null); // repeat last action
 }
 else
 {
 // result is already received through UpdateAuthorizationState, nothing to do
 }
 }
 }
 }
}