// КругСвоих Bot SDK for Dart / Flutter
// https://krugsvoih.ru/bots.html
//
// Add to pubspec.yaml:
//   dependencies:
//     http: ^1.2.0
//
// Quick start:
//
//   final bot = KSBot('YOUR_TOKEN');
//
//   bot.onCommand('start', (msg) async {
//     await bot.sendMessage(msg.chatId, 'Привет! 👋');
//   });
//
//   await bot.runPolling();

library ksbot;

import 'dart:async';
import 'dart:convert';
import 'dart:io';
import 'package:http/http.dart' as http;

const _baseUrl = 'https://v.krugsvoih.ru/bot';

// ── Types ──────────────────────────────────────────────────────────────────────

class BotError implements Exception {
  final String description;
  const BotError(this.description);

  @override
  String toString() => 'BotError: $description';
}

class BotInfo {
  final String id, username, displayName;
  final String? avatarUrl;
  final bool isBot;

  BotInfo.fromJson(Map<String, dynamic> j)
      : id = j['id'] as String,
        username = j['username'] as String,
        displayName = j['displayName'] as String,
        avatarUrl = j['avatarUrl'] as String?,
        isBot = (j['isBot'] as bool?) ?? false;
}

class Message {
  final String id, chatId, senderId, senderUsername, content;
  final DateTime sentAt;
  final bool isEdited;

  Message.fromJson(Map<String, dynamic> j)
      : id = j['id'] as String,
        chatId = j['chatId'] as String,
        senderId = j['senderId'] as String,
        senderUsername = j['senderUsername'] as String,
        content = j['content'] as String,
        sentAt = DateTime.parse(j['sentAt'] as String),
        isEdited = (j['isEdited'] as bool?) ?? false;
}

class CallbackQuery {
  final String id, fromUserId, fromUsername, chatId, messageId, data;

  CallbackQuery.fromJson(Map<String, dynamic> j)
      : id = j['id'] as String,
        fromUserId = j['fromUserId'] as String,
        fromUsername = j['fromUsername'] as String,
        chatId = j['chatId'] as String,
        messageId = j['messageId'] as String,
        data = j['data'] as String;
}

class Update {
  final int updateId;
  final String type;
  final Message? message;
  final CallbackQuery? callbackQuery;

  Update.fromJson(Map<String, dynamic> j)
      : updateId = j['updateId'] as int,
        type = j['type'] as String,
        message = j['message'] != null
            ? Message.fromJson(j['message'] as Map<String, dynamic>)
            : null,
        callbackQuery = j['callbackQuery'] != null
            ? CallbackQuery.fromJson(j['callbackQuery'] as Map<String, dynamic>)
            : null;
}

class ChatInfo {
  final String id, name, type;

  ChatInfo.fromJson(Map<String, dynamic> j)
      : id = j['id'] as String,
        name = j['name'] as String,
        type = j['type'] as String;
}

class ChatMember {
  final String userId, username, displayName, role;
  final String? avatarUrl;
  final bool isBot;

  ChatMember.fromJson(Map<String, dynamic> j)
      : userId = j['userId'] as String,
        username = j['username'] as String,
        displayName = j['displayName'] as String,
        avatarUrl = j['avatarUrl'] as String?,
        role = j['role'] as String,
        isBot = (j['isBot'] as bool?) ?? false;
}

class WebhookInfo {
  final String? url;
  final int pendingUpdateCount;

  WebhookInfo.fromJson(Map<String, dynamic> j)
      : url = j['url'] as String?,
        pendingUpdateCount = (j['pendingUpdateCount'] as int?) ?? 0;
}

class BotCommand {
  final String command, description;
  const BotCommand(this.command, this.description);

  Map<String, dynamic> toJson() => {'command': command, 'description': description};
}

/// Helper: builds an inline keyboard button.
Map<String, dynamic> kbButton(String text, {String? callbackData, String? url}) {
  final btn = <String, dynamic>{'text': text};
  if (callbackData != null) btn['callbackData'] = callbackData;
  if (url != null) btn['url'] = url;
  return btn;
}

/// Helper: builds an inline keyboard markup.
///
/// Example:
/// ```dart
/// final markup = inlineKeyboard([
///   [kbButton('✅ Да', callbackData: 'yes'), kbButton('❌ Нет', callbackData: 'no')],
///   [kbButton('🌐 Сайт', url: 'https://krugsvoih.ru')],
/// ]);
/// ```
Map<String, dynamic> inlineKeyboard(List<List<Map<String, dynamic>>> rows) =>
    {'inlineKeyboard': rows};

// ── Client ─────────────────────────────────────────────────────────────────────

class KSBot {
  final String token;
  late final String _base;
  int _offset = 0;
  bool _running = false;

  final _messageHandlers = <Future<void> Function(Message)>[];
  final _commandHandlers = <String, Future<void> Function(Message)>{};
  final _callbackHandlers = <Future<void> Function(CallbackQuery)>[];

  KSBot(this.token) {
    _base = '$_baseUrl/$token';
  }

  // ── Low-level request ──────────────────────────────────────────────────────

  Future<dynamic> _request(String method, [Map<String, dynamic>? data]) async {
    final url = Uri.parse('$_base/$method');
    late http.Response resp;

    if (data == null) {
      resp = await http.get(url);
    } else {
      resp = await http.post(url,
          headers: {'Content-Type': 'application/json'},
          body: jsonEncode(data));
    }

    final body = jsonDecode(resp.body) as Map<String, dynamic>;
    if (!(body['ok'] as bool)) {
      throw BotError(body['description'] as String? ?? 'Unknown error');
    }
    return body['result'];
  }

  // ── Bot info ───────────────────────────────────────────────────────────────

  Future<BotInfo> getMe() async =>
      BotInfo.fromJson((await _request('getMe')) as Map<String, dynamic>);

  // ── Sending messages ───────────────────────────────────────────────────────

  Future<Message> sendMessage(
    String chatId,
    String text, {
    String? replyToMessageId,
    Map<String, dynamic>? replyMarkup,
  }) async {
    final payload = <String, dynamic>{'chatId': chatId, 'text': text};
    if (replyToMessageId != null) payload['replyToMessageId'] = replyToMessageId;
    if (replyMarkup != null) payload['replyMarkup'] = replyMarkup;
    return Message.fromJson((await _request('sendMessage', payload)) as Map<String, dynamic>);
  }

  Future<Message> sendPhoto(
    String chatId,
    String photoUrl, {
    String? caption,
    Map<String, dynamic>? replyMarkup,
  }) async {
    final payload = <String, dynamic>{'chatId': chatId, 'photoUrl': photoUrl};
    if (caption != null) payload['caption'] = caption;
    if (replyMarkup != null) payload['replyMarkup'] = replyMarkup;
    return Message.fromJson((await _request('sendPhoto', payload)) as Map<String, dynamic>);
  }

  Future<Message> sendDocument(
    String chatId,
    String documentUrl,
    String fileName, {
    String? caption,
    Map<String, dynamic>? replyMarkup,
  }) async {
    final payload = <String, dynamic>{
      'chatId': chatId,
      'documentUrl': documentUrl,
      'fileName': fileName,
    };
    if (caption != null) payload['caption'] = caption;
    if (replyMarkup != null) payload['replyMarkup'] = replyMarkup;
    return Message.fromJson((await _request('sendDocument', payload)) as Map<String, dynamic>);
  }

  /// Upload and send a photo file directly (no external hosting needed).
  Future<Message> uploadPhoto(
    String chatId,
    File photo, {
    String? caption,
  }) async {
    final url = Uri.parse('$_base/sendPhoto/upload');
    final req = http.MultipartRequest('POST', url);
    req.fields['chatId'] = chatId;
    if (caption != null) req.fields['caption'] = caption;
    req.files.add(await http.MultipartFile.fromPath('photo', photo.path));
    final streamed = await req.send();
    final resp = await http.Response.fromStream(streamed);
    final body = jsonDecode(resp.body) as Map<String, dynamic>;
    if (!(body['ok'] as bool)) throw BotError(body['description'] as String? ?? 'Unknown error');
    return Message.fromJson(body['result'] as Map<String, dynamic>);
  }

  /// Upload and send any file directly (no external hosting needed).
  Future<Message> uploadDocument(
    String chatId,
    File document, {
    String? caption,
  }) async {
    final url = Uri.parse('$_base/sendDocument/upload');
    final req = http.MultipartRequest('POST', url);
    req.fields['chatId'] = chatId;
    if (caption != null) req.fields['caption'] = caption;
    req.files.add(await http.MultipartFile.fromPath('document', document.path));
    final streamed = await req.send();
    final resp = await http.Response.fromStream(streamed);
    final body = jsonDecode(resp.body) as Map<String, dynamic>;
    if (!(body['ok'] as bool)) throw BotError(body['description'] as String? ?? 'Unknown error');
    return Message.fromJson(body['result'] as Map<String, dynamic>);
  }

  Future<Message> forwardMessage(
      String fromChatId, String messageId, String toChatId) async =>
      Message.fromJson((await _request('forwardMessage', {
        'fromChatId': fromChatId,
        'messageId': messageId,
        'toChatId': toChatId,
      })) as Map<String, dynamic>);

  // ── Editing and deleting ───────────────────────────────────────────────────

  Future<Message> editMessageText(
      String chatId, String messageId, String sentAt, String text) async =>
      Message.fromJson((await _request('editMessageText', {
        'chatId': chatId,
        'messageId': messageId,
        'sentAt': sentAt,
        'text': text,
      })) as Map<String, dynamic>);

  Future<void> deleteMessage(
      String chatId, String messageId, String sentAt) async =>
      _request('deleteMessage', {'chatId': chatId, 'messageId': messageId, 'sentAt': sentAt});

  // ── Chat management ────────────────────────────────────────────────────────

  Future<ChatInfo> getChat(String chatId) async =>
      ChatInfo.fromJson((await _request('getChat', {'chatId': chatId})) as Map<String, dynamic>);

  Future<List<ChatMember>> getChatMembers(String chatId) async {
    final list = (await _request('getChatMembers', {'chatId': chatId})) as List;
    return list.map((e) => ChatMember.fromJson(e as Map<String, dynamic>)).toList();
  }

  Future<ChatMember> getChatMember(String chatId, String userId) async =>
      ChatMember.fromJson((await _request('getChatMember', {
        'chatId': chatId,
        'userId': userId,
      })) as Map<String, dynamic>);

  Future<void> banChatMember(String chatId, String userId) =>
      _request('banChatMember', {'chatId': chatId, 'userId': userId});

  Future<void> unbanChatMember(String chatId, String userId) =>
      _request('unbanChatMember', {'chatId': chatId, 'userId': userId});

  Future<void> leaveChat(String chatId) =>
      _request('leaveChat', {'chatId': chatId});

  // ── Pinning messages ───────────────────────────────────────────────────────

  Future<void> pinMessage(String chatId, String messageId, String sentAt) =>
      _request('pinChatMessage', {
        'chatId': chatId,
        'messageId': messageId,
        'sentAt': sentAt,
      });

  Future<void> unpinMessage(String chatId) =>
      _request('unpinChatMessage', {'chatId': chatId});

  // ── Updates ────────────────────────────────────────────────────────────────

  Future<List<Update>> getUpdates({
    int offset = 0,
    int limit = 100,
    int timeout = 0,
  }) async {
    final list = (await _request('getUpdates', {
      'offset': offset,
      'limit': limit,
      'timeout': timeout,
    })) as List;
    return list.map((e) => Update.fromJson(e as Map<String, dynamic>)).toList();
  }

  // ── Webhooks ───────────────────────────────────────────────────────────────

  Future<void> setWebhook(String url) => _request('setWebhook', {'url': url});

  Future<void> deleteWebhook() => _request('deleteWebhook');

  Future<WebhookInfo> getWebhookInfo() async =>
      WebhookInfo.fromJson((await _request('getWebhookInfo')) as Map<String, dynamic>);

  // ── Commands ───────────────────────────────────────────────────────────────

  Future<void> setMyCommands(List<BotCommand> commands) =>
      _request('setMyCommands', {'commands': commands.map((c) => c.toJson()).toList()});

  Future<List<BotCommand>> getMyCommands() async {
    final list = (await _request('getMyCommands')) as List;
    return list.map((e) {
      final m = e as Map<String, dynamic>;
      return BotCommand(m['command'] as String, m['description'] as String);
    }).toList();
  }

  // ── Callback queries ───────────────────────────────────────────────────────

  Future<void> answerCallbackQuery(
    String callbackQueryId, {
    String? text,
    bool showAlert = false,
  }) {
    final payload = <String, dynamic>{
      'callbackQueryId': callbackQueryId,
      'showAlert': showAlert,
    };
    if (text != null) payload['text'] = text;
    return _request('answerCallbackQuery', payload);
  }

  // ── Handler registration ───────────────────────────────────────────────────

  void onMessage(FutureOr<void> Function(Message) handler) {
    _messageHandlers.add((msg) async => handler(msg));
  }

  void onCommand(String command, FutureOr<void> Function(Message) handler) {
    _commandHandlers[command.replaceFirst(RegExp(r'^/'), '')] =
        (msg) async => handler(msg);
  }

  void onCallback(FutureOr<void> Function(CallbackQuery) handler) {
    _callbackHandlers.add((cb) async => handler(cb));
  }

  // ── Dispatch ───────────────────────────────────────────────────────────────

  Future<void> _dispatch(Update update) async {
    if (update.message != null) {
      final msg = update.message!;
      final text = msg.content;
      if (text.startsWith('/')) {
        final parts = text.trim().split(RegExp(r'\s+'));
        final cmd = parts[0].replaceFirst('/', '').split('@')[0].toLowerCase();
        final handler = _commandHandlers[cmd];
        if (handler != null) {
          await handler(msg);
          return;
        }
      }
      for (final h in _messageHandlers) {
        await h(msg);
      }
    }
    if (update.callbackQuery != null) {
      for (final h in _callbackHandlers) {
        await h(update.callbackQuery!);
      }
    }
  }

  // ── Polling loop ───────────────────────────────────────────────────────────

  Future<void> runPolling({int pollTimeout = 30}) async {
    final me = await getMe();
    print('Bot @${me.username} started. Press Ctrl+C to stop.');

    _running = true;
    while (_running) {
      try {
        final updates = await getUpdates(offset: _offset, timeout: pollTimeout);
        for (final u in updates) {
          try {
            await _dispatch(u);
          } catch (e) {
            print('[handler error] $e');
          }
          _offset = u.updateId + 1;
        }
      } on BotError catch (e) {
        print('[bot error] $e');
        await Future.delayed(const Duration(seconds: 5));
      } catch (e) {
        if (!_running) break;
        print('[error] $e');
        await Future.delayed(const Duration(seconds: 5));
      }
    }
  }

  void stop() => _running = false;
}