import 'dart:async';
import 'package:flutter/foundation.dart';
import 'package:get/get.dart';
import 'package:geolocator/geolocator.dart';
import '../models/gps_coordinate.dart';

/// خدمة GPS الحقيقي مع دعم التتبع المستمر
class GpsService extends GetxService {
  StreamSubscription<Position>? _positionSub;
  final _isTracking = false.obs;
  final _currentPosition = Rxn<Position>();
  final _lastError = ''.obs;

  bool get isTracking => _isTracking.value;
  Position? get currentPosition => _currentPosition.value;
  String get lastError => _lastError.value;

  Function(GpsCoordinate)? onNewCoordinate;

  Future<bool> checkAndRequestPermissions() async {
    if (!await Geolocator.isLocationServiceEnabled()) {
      _lastError.value = 'Location services disabled';
      return false;
    }
    var perm = await Geolocator.checkPermission();
    if (perm == LocationPermission.denied) {
      perm = await Geolocator.requestPermission();
      if (perm == LocationPermission.denied) {
        _lastError.value = 'Permission denied';
        return false;
      }
    }
    if (perm == LocationPermission.deniedForever) {
      _lastError.value = 'Permission permanently denied';
      return false;
    }
    return true;
  }

  Future<GpsCoordinate?> getCurrentPosition() async {
    try {
      if (!await checkAndRequestPermissions()) return null;
      final pos = await Geolocator.getCurrentPosition(
        desiredAccuracy: LocationAccuracy.high,
        timeLimit: const Duration(seconds: 15),
      );
      _currentPosition.value = pos;
      return _toCoord(pos);
    } catch (e) {
      _lastError.value = e.toString();
      return null;
    }
  }

  Future<bool> startTracking({int distanceFilter = 5}) async {
    if (_isTracking.value) return true;
    if (!await checkAndRequestPermissions()) return false;

    try {
      late LocationSettings settings;
      if (defaultTargetPlatform == TargetPlatform.android) {
        settings = AndroidSettings(
          accuracy: LocationAccuracy.high,
          distanceFilter: distanceFilter,
          intervalDuration: const Duration(seconds: 3),
          foregroundNotificationConfig: const ForegroundNotificationConfig(
            notificationText: 'SportPath is tracking your workout',
            notificationTitle: 'Workout Active',
            enableWakeLock: true,
          ),
        );
      } else if (defaultTargetPlatform == TargetPlatform.iOS) {
        settings = AppleSettings(
          accuracy: LocationAccuracy.high,
          distanceFilter: distanceFilter,
          activityType: ActivityType.fitness,
          pauseLocationUpdatesAutomatically: false,
          showBackgroundLocationIndicator: true,
        );
      } else {
        settings = LocationSettings(
          accuracy: LocationAccuracy.high,
          distanceFilter: distanceFilter,
        );
      }

      _positionSub = Geolocator.getPositionStream(
        locationSettings: settings,
      ).listen(_onPosition, onError: (e) {
        _lastError.value = e.toString();
      });

      _isTracking.value = true;
      return true;
    } catch (e) {
      _lastError.value = e.toString();
      return false;
    }
  }

  Future<void> stopTracking() async {
    await _positionSub?.cancel();
    _positionSub = null;
    _isTracking.value = false;
  }

  void _onPosition(Position pos) {
    _currentPosition.value = pos;
    final coord = _toCoord(pos);
    if (coord.isAccurate && coord.isValid) {
      onNewCoordinate?.call(coord);
    }
  }

  GpsCoordinate _toCoord(Position p) => GpsCoordinate(
        latitude: p.latitude,
        longitude: p.longitude,
        altitude: p.altitude,
        accuracy: p.accuracy,
        speed: p.speed >= 0 ? p.speed : null,
        heading: p.heading >= 0 ? p.heading : null,
        timestamp: p.timestamp,
      );

  @override
  void onClose() {
    stopTracking();
    super.onClose();
  }
}