import 'dart:async';

import 'package:flutter_bloc/flutter_bloc.dart';

import '../../../core/api/api_exception.dart';
import '../../../core/ui/view_status.dart';
import '../data/chat_repository.dart';

class ChatState {
  const ChatState({
    this.status = ViewStatus.idle,
    this.messages = const [],
    this.sending = false,
    this.error,
  });

  final ViewStatus status;
  final List<ChatMessage> messages;
  final bool sending;
  final String? error;
}

class ChatCubit extends Cubit<ChatState> {
  ChatCubit(this._repo) : super(const ChatState());

  final ChatRepository _repo;
  Timer? _poll;
  String? _tripId;

  @override
  Future<void> close() {
    _poll?.cancel();
    return super.close();
  }

  /// استطلاع كل خمس ثوانٍ — الخادم لا يبثّ الرسائل عبر السوكت
  /// (راجع `ChatRepository`). يتوقّف مع إغلاق الشاشة.
  Future<void> open(String tripId) async {
    _tripId = tripId;
    emit(const ChatState(status: ViewStatus.loading));
    await _refresh();
    _poll = Timer.periodic(const Duration(seconds: 5), (_) => _refresh());
  }

  Future<void> _refresh() async {
    final tripId = _tripId;
    if (tripId == null || isClosed) return;
    try {
      final messages = await _repo.messages(tripId);
      if (isClosed) return;
      emit(ChatState(
        status: ViewStatus.success,
        messages: messages,
        sending: state.sending,
      ));
    } on ApiException catch (e) {
      // فشل الاستطلاع لا يمسح ما وصل: الرسائل المعروضة تبقى.
      if (!isClosed && state.messages.isEmpty) {
        emit(ChatState(status: ViewStatus.error, error: e.message));
      }
    }
  }

  Future<void> send(String body) async {
    final tripId = _tripId;
    if (tripId == null || body.trim().isEmpty) return;
    emit(ChatState(
      status: state.status,
      messages: state.messages,
      sending: true,
    ));
    try {
      await _repo.send(tripId, body.trim());
      await _refresh();
    } on ApiException {
      if (!isClosed) {
        emit(ChatState(status: state.status, messages: state.messages));
      }
    }
  }
}