import 'dart:async';

import 'package:flutter/material.dart';
import 'package:firebase_database/firebase_database.dart';

import '../models/sensor_model.dart';
import '../services/firebase_service.dart';

class SensorProvider extends ChangeNotifier {
  SensorModel? _sensor;

  SensorModel? get sensor => _sensor;

  bool _isLoading = true;

  bool get isLoading => _isLoading;

  String? _errorMessage;

  String? get errorMessage => _errorMessage;

  StreamSubscription<DatabaseEvent>? _subscription;

  void startListening() {
    _subscription?.cancel();
    _isLoading = true;
    _errorMessage = null;

    _subscription = FirebaseService.currentRef.onValue.listen((event) {
      if (event.snapshot.value == null) {
        _sensor = null;
        _isLoading = false;
        notifyListeners();
        return;
      }

      try {
        final data = Map<dynamic, dynamic>.from(event.snapshot.value as Map);
        _sensor = SensorModel.fromMap(data);
        _errorMessage = null;
      } catch (e) {
        _sensor = null;
        _errorMessage = 'Parsing Error: $e';
      }

      _isLoading = false;
      notifyListeners();
    }, onError: (error) {
      _sensor = null;
      _errorMessage = 'Firebase Error: $error';
      _isLoading = false;
      notifyListeners();
    });
  }

  void stopListening() {
    _subscription?.cancel();
  }

  @override
  void dispose() {
    _subscription?.cancel();
    super.dispose();
  }
}