import 'dart:io';
import 'package:path/path.dart';
import 'package:mnemo_cards_telegram_bot/bot_config.dart';
import 'package:mnemo_cards_telegram_bot/image_generator.dart';

import 'package:process_run/process_run.dart';
import 'package:teledart/teledart.dart';
import 'package:teledart/telegram.dart';
import 'package:mnemo_cards_telegram_bot/backend_client.dart';

const String version = '0.0.1';

void main() async {
  return _run();
}

String? _extractCodeFromText(String? rawText) {
  if (rawText == null) {
    return null;
  }

  final text = rawText.trim();
  if (text.isEmpty) {
    return null;
  }

  if (text.startsWith('/start')) {
    final parts = text.split(' ');
    if (parts.length > 1) {
      final payload = parts.sublist(1).join(' ').trim();
      return _extractCodeFromPayload(payload);
    }
    return null;
  }

  return _extractCodeFromPayload(text);
}

String? _extractCodeFromPayload(String payload) {
  final sanitized = payload.trim();
  if (sanitized.isEmpty) {
    return null;
  }

  final match = RegExp(r'(\d{6})$').firstMatch(sanitized);
  if (match == null) {
    return null;
  }

  final code = match.group(1);
  if (code == null) {
    return null;
  }

  return RegExp(r'^\d{6}$').hasMatch(code) ? code : null;
}

Future<void> _handleCodeClaim({
  required BackendClient backendClient,
  required TeleDart teledartInstance,
  required dynamic message,
  required String code,
}) async {
  final from = message.from;
  if (from == null) {
    return;
  }

  final claimed = await backendClient.claimWebAuthCode(
    code: code,
    telegramUserId: from.id.toString(),
    telegramUsername: from.username,
    firstName: from.firstName,
    lastName: from.lastName,
  );

  if (claimed) {
    await teledartInstance.sendMessage(
      message.chat.id,
      'Код подтверждён ✅\n'
      'Вернись на сайт и нажми «Войти» в течение 5 минут.',
      replyToMessageId: message.messageId,
    );
  } else {
    await teledartInstance.sendMessage(
      message.chat.id,
      'Не удалось подтвердить код 😔\n'
      'Возможно он уже использован или истёк. Сгенерируй новый код на сайте.',
      replyToMessageId: message.messageId,
    );
  }
}

Future<void> _run() async {
  print('[BOT] Starting bot version $version');
  BackendClient? backendClient;
  TeleDart? teledart;

  try {
    final config = BotConfig.fromEnvironment();

    final lines = File('admins').readAsLinesSync();

    final adminIds = lines.map((e) => e.trim()).toList();
    if (adminIds.isEmpty) {
      print('[BOT] ERROR: No admins found in admins file');
      return;
    }

    final username = (await Telegram(config.botToken).getMe()).username;
    teledart = TeleDart(config.botToken, Event(username!));

    Future<void> notifyAdmins(String message) async {
      for (final admin in adminIds) {
        try {
          await teledart!.sendMessage(admin, message);
        } catch (e) {
          print('[BOT] ERROR: Failed to notify admin $admin: $e');
        }
      }
    }

    print('[BOT] Using backend API at ${config.backendUrl}');

    backendClient = BackendClient(
      backendUrl: config.backendUrl,
      apiKey: config.apiKey,
    );

    // At this point all variables are initialized and non-null
    final teledartInstance = teledart;
    final backendClientInstance = backendClient;

    teledartInstance.onCommand('logs').listen(
      (message) async {
        String result;
        try {
          final r = await Process.run(
            'journalctl',
            ['-u', 'mnemo_cards_backend', '--since', "5min ago"],
          );
          result = '${r.stdout.toString()} ${r.stderr}';
        } catch (e) {
          result = 'Error: $e';
        }
        message.reply(result);
      },
    );

    teledart.onCommand('start').listen(
      (message) async {
        final from = message.from;
        if (from == null) {
          return;
        }

        final payloadCode = _extractCodeFromText(message.text);
        if (payloadCode != null) {
          await _handleCodeClaim(
            backendClient: backendClientInstance,
            teledartInstance: teledartInstance,
            message: message,
            code: payloadCode,
          );
          return;
        }

        // Generate auth code for the user (legacy flow)
        final code = await backendClientInstance.generateAuthCode(
          telegramUserId: from.id.toString(),
          telegramUsername: from.username,
          firstName: from.firstName,
          lastName: from.lastName,
        );

        if (code == null) {
          await message.reply(
            'Ошибка при генерации кода. Попробуй позже.',
          );
        } else {
          await message.reply(
            'Привет! Для авторизации на сайте используй этот код:\n\n'
            '**$code**\n\n'
            'Код действителен 5 минут.',
          );
        }
      },
    );

    teledart.onCommand('login').listen(
      (message) async {
        final from = message.from;
        if (from == null) {
          return;
        }

        // Generate auth code for the user
        final code = await backendClientInstance.generateAuthCode(
          telegramUserId: from.id.toString(),
          telegramUsername: from.username,
          firstName: from.firstName,
          lastName: from.lastName,
        );

        if (code == null) {
          await message.reply(
            'Ошибка при генерации кода. Попробуй позже.',
          );
        } else {
          await message.reply(
            'Код для авторизации на сайте:\n\n'
            '**$code**\n\n'
            'Код действителен 5 минут.\n'
            'Введи его на сайте для входа.',
          );
        }
      },
    );

    teledart.onCommand('code').listen(
      (message) async {
        final from = message.from;
        if (from == null) {
          return;
        }

        // Generate auth code for the user
        final code = await backendClientInstance.generateAuthCode(
          telegramUserId: from.id.toString(),
          telegramUsername: from.username,
          firstName: from.firstName,
          lastName: from.lastName,
        );

        if (code == null) {
          await message.reply(
            'Ошибка при генерации кода. Попробуй позже.',
          );
        } else {
          await message.reply(
            'Твой код авторизации:\n\n'
            '**$code**\n\n'
            '⏱ Действителен 5 минут',
          );
        }
      },
    );

    teledartInstance.onCommand('app').listen((message) {
      try {
        final file = File('apks/app.apk');
        final t = file.lastModifiedSync();
        teledartInstance.sendMessage(message.chat.id, 'Загрузка apk...');
        message.replyDocument(file, caption: t.simpleString);
      } on Object catch (e, s) {
        if (adminIds.contains(message.from?.id.toString())) {
          message.reply(e.toString());
        } else {
          message.reply('Что-то пошло не так');
        }
        print('[BOT] ERROR: app error: $e\n$s');
      }
    });

    teledartInstance.onCommand('info').listen((message) async {
      if (adminIds.contains(message.from?.id.toString())) {
        final info = await backendClientInstance.info();
        message.reply(info);
      }
    });

    teledartInstance.onCommand('user').listen((message) async {
      if (adminIds.contains(message.from?.id.toString())) {
        final userId = message.text?.replaceFirst('/user', '').trim() ?? '';
        final info = await backendClientInstance.userInfo(userId);
        message.reply(info);
      }
    });

    teledartInstance.onCommand('words').listen((message) async {
      if (adminIds.contains(message.from?.id.toString())) {
        final separator = message.text?.replaceFirst('/words', '').trim() ?? '';
        final words = await backendClientInstance.words();
        message.reply(words.join(separator.isEmpty ? ',\n' : separator));
      }
    });

    teledartInstance.onCommand('admin_app').listen((message) {
      if (adminIds.contains(message.from?.id.toString())) {
        try {
          final file = File('apks/admin_app.apk');
          final t = file.lastModifiedSync();
          teledartInstance.sendMessage(message.chat.id, 'Загрузка apk...');
          message.replyDocument(file, caption: t.simpleString);
        } on Object catch (e, s) {
          print('[BOT] ERROR: app error: $e\n$s');
          message.reply(e.toString());
        }
      }
    });

    teledartInstance.onCommand('clear_cache').listen((message) async {
      var answer = StringBuffer();
      if (adminIds.contains(message.from?.id.toString())) {
        final types = ['images', 'cards'];
        final sizes = ['big', 'small', 'medium', 'extraSmall'];
        for (final type in types) {
          for (final size in sizes) {
            final dir = Directory('../mnemo_cards_backend/data/$type/$size');
            if (await dir.exists()) {
              try {
                await dir.delete(recursive: true);
                answer.write('$type/$size - ok\n');
              } catch (e, s) {
                answer.write('$type/$size - error\n');
                print('[BOT] ERROR: clear cache error $dir: $e\n$s');
              }
            } else {
              answer.write('$type/$size - not exists\n');
            }
          }
        }
        message.reply(answer.toString());
      }
    });

    teledartInstance.onCommand('images').listen((message) async {
      if (adminIds.contains(message.from?.id.toString())) {
        try {
          final loadingMessage = await teledartInstance.sendMessage(
            message.chat.id,
            'Загрузка...',
          );
          final cardsDir = Directory('../mnemo_cards_backend/data/cards/');
          final dir = Directory('zips');
          if (dir.existsSync()) {
            dir.deleteSync(recursive: true);
          }
          dir.createSync();
          var shell = Shell();
          await shell.run(
              'zip -s 49m -vr ${join(dir.path, 'images.zip')} ${cardsDir.path}');
          final zips = dir.listSync().whereType<File>();
          int i = 0;

          print('Will send ${zips.length} zip files:');
          print('${zips.map((e) => e.path).toList()}');
          teledartInstance.deleteMessage(
            loadingMessage.chat.id,
            loadingMessage.messageId,
          );
          for (final zip in zips) {
            i++;
            await teledartInstance.sendDocument(
              message.chat.id,
              zip,
              caption: '$i/${zips.length}',
            );
          }
        } on Object catch (e, s) {
          print('[BOT] ERROR: app error: $e\n$s');
          message.reply(e.toString());
        }
      }
    });

    teledartInstance.onCommand('cards').listen((message) async {
      if (adminIds.contains(message.from?.id.toString())) {
        try {
          final cardsDir = Directory('../mnemo_cards_backend/data/cards/');
          final names = cardsDir
              .listSync()
              .whereType<File>()
              .map((f) => basename(f.path))
              .toList()
            ..sort((p, n) {
              final pParts = p.split('_');
              final nParts = n.split('_');
              return (int.tryParse(pParts.isNotEmpty ? pParts.first : '') ??
                      99999)
                  .compareTo(
                      int.tryParse(nParts.isNotEmpty ? nParts.first : '') ??
                          9999);
            });
          message.reply(
            names.take(50).join('\n'),
          );
          if (names.length > 50) {
            message.reply(
              names.sublist(50).join('\n'),
            );
          }
        } on Object catch (e, s) {
          print('[BOT] ERROR: app error: $e\n$s');
          message.reply(e.toString());
        }
      }
    });

    teledartInstance.onCommand('backup').listen((message) async {
      if (adminIds.contains(message.from?.id.toString())) {
        try {
          final dir = Directory('backups/');
          if (!dir.existsSync()) {
            message.reply('No backups');
          }
          final files = dir.listSync().whereType<File>().toList();
          files.sort(
              (a, b) => b.lastModifiedSync().compareTo(a.lastModifiedSync()));
          if (files.isNotEmpty) {
            teledartInstance.sendMessage(message.chat.id, 'Загрузка backup...');
            var shell = Shell();
            final file = files.first;
            final name = basename(file.path).split('.').first;
            final dir = Directory('zips');
            if (dir.existsSync()) {
              dir.deleteSync(recursive: true);
            }
            dir.createSync();
            await shell
                .run('zip -s 49m ${join(dir.path, '$name.zip')} ${file.path}');
            final zips = dir.listSync().whereType<File>();
            int i = 0;
            print('Will send ${zips.length} zip files:');
            print('${zips.map((e) => e.path).toList()}');
            for (final zip in zips) {
              i++;
              await teledartInstance.sendDocument(
                message.chat.id,
                zip,
                caption: '$i/${zips.length}',
              );
            }
            // dir.deleteSync();
          } else {
            message.reply('No backups');
          }
        } on Object catch (e, s) {
          print('[BOT] ERROR: backup error: $e\n$s');
          message.reply(e.toString());
        }
      }
    });

    teledartInstance.onCommand('share').listen((message) async {
      try {
        final from = message.from;
        if (from == null) {
          await message.reply('Ошибка: не удалось определить пользователя');
          return;
        }

        final telegramUserId = from.id.toString();
        print('[SHARE_CMD] User $telegramUserId requested /share command');

        // Check rate limit
        if (!await backendClientInstance.canShareToday(
          telegramUserId,
          config.shareDailyLimit,
        )) {
          print('[SHARE_BLOCKED] User $telegramUserId reached daily limit');
          await message.reply(
            'Ты уже поделился сегодня. Попробуй завтра! '
            '(Лимит: ${config.shareDailyLimit} раз в день)',
          );
          return;
        }

        // Send loading message
        final loadingMsg = await teledartInstance.sendMessage(
          message.chat.id,
          'Готовлю красивое сообщение...',
        );

        // Get random card
        final card = await backendClientInstance.getRandomCard();
        if (card == null) {
          try {
            await teledartInstance.editMessageText(
              'К сожалению, карточки недоступны. Попробуй позже.',
              chatId: loadingMsg.chat.id.toString(),
              messageId: loadingMsg.messageId,
            );
          } catch (e) {
            print('Error editing message: $e');
          }
          return;
        }

        // Generate image
        final imageGenerator = ImageGenerator();
        final imageBytes = await imageGenerator.generateShareImage(card);

        if (imageBytes == null || imageBytes.isEmpty) {
          try {
            await teledartInstance.editMessageText(
              'Не удалось создать изображение. Попробуй позже.',
              chatId: loadingMsg.chat.id.toString(),
              messageId: loadingMsg.messageId,
              
            );
          } catch (e) {
            print('Error editing message: $e');
          }
          return;
        }

        // Prepare share message
        final shareMessage = 'Приветствую! Я тестирую приложение mnemo cards '
            'для изучения языков.\n\n'
            'Присоединяйся и начни учиться вместе со мной!';

        // Delete loading message
        try {
          await teledartInstance.deleteMessage(
            loadingMsg.chat.id,
            loadingMsg.messageId,
          );
        } catch (e) {
          print('Error deleting loading message: $e');
        }

        // Send image with caption
        message.reply('Sending image...');
        File? temp;
        try {
          final dir = await Directory.systemTemp.createTemp('share_image');
          temp = await File("${dir.path}/${DateTime.now().millisecondsSinceEpoch}.png").create();
          await temp.writeAsBytes(imageBytes);

        await message.replyPhoto(
          temp,
          caption: shareMessage,
        );
        print('[SHARE_SUCCESS] Image sent to user $telegramUserId');
        } catch (e) {
          message.reply('Error sending image: $e');
          print('Error sending image: $e');
        } finally {
          await temp?.delete();
        }
        

        // Record the share request
        await backendClientInstance.recordShareRequest(
          telegramUserId: telegramUserId,
          telegramUsername: from.username,
          sharedCardId: card.id,
        );
        print('[SHARE_COMPLETE] User $telegramUserId completed share flow');
      } catch (e, s) {
        print('Error in /share command: $e');
        print('Stack trace: $s');
        await message.reply(
          'Ошибка при создании сообщения. Пожалуйста, попробуй позже.',
        );
      }
    });

    teledartInstance.onMessage().listen((message) async {
      final text = message.text?.trim();

      // Skip command updates - handled by command listeners
      if (text != null && text.startsWith('/')) {
        return;
      }

      final code = _extractCodeFromText(text);
      if (code != null) {
        await _handleCodeClaim(
          backendClient: backendClientInstance,
          teledartInstance: teledartInstance,
          message: message,
          code: code,
        );
        return;
      }

      await message.reply('Спасибо, переслал.');
      teledartInstance.forwardMessage(
        adminIds.first,
        message.chat.id,
        message.messageId,
        messageThreadId: message.messageThreadId,
      );
    });

    teledartInstance.start();
    print('[BOT] Bot started successfully');
  } on Exception catch (e, s) {
    print('[BOT] ERROR: Error: $e\n$s');
    print('[BOT] Error while starting bot: $e');
    print('Stack trace: $s');
    print('');
    print('Required environment variables:');
    print('  - TELEGRAM_BOT_TOKEN (required)');
    print('  - TELEGRAM_BOT_API_KEY (required)');
    print('  - BACKEND_URL or MNEMO_BACKEND_URL (optional, default: https://api.mnemo-cards.online)');
    print('  - BOT_SHARE_DAILY_LIMIT (optional, default: 1)');

    // Cleanup resources before restart
    try {
      backendClient?.dispose();
    } catch (_) {
      // Ignore cleanup errors
    }

    print('Restarting in 5 seconds...');
    await Future.delayed(const Duration(seconds: 5));
    return _run();
  }
}

extension on DateTime {
  String get simpleString =>
      '${year}.${month.toString().padLeft(2, '0')}.${day.toString().padLeft(2, '0')} '
      '${hour.toString().padLeft(2, '0')}:${minute.toString().padLeft(2, '0')}';
}