import 'dart:async';
import 'dart:math';
import 'dart:ui' as ui;
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:google_maps_flutter/google_maps_flutter.dart';
import 'package:geolocator/geolocator.dart';
import '../constants/app_colors.dart';
import '../constants/app_strings.dart';

class GoogleMapScreen extends StatefulWidget {
  const GoogleMapScreen({super.key});

  @override
  State<GoogleMapScreen> createState() => _GoogleMapScreenState();
}

class _GoogleMapScreenState extends State<GoogleMapScreen> {
  GoogleMapController? _mapController;
  StreamSubscription<Position>? _positionStreamSubscription;
  Timer? _simulationTimer;
  
  // Controle de frequência de atualização para evitar sobrecarga e crashes
  DateTime? _lastUpdate;
  
  final List<LatLng> _routePoints = [];
  final Set<Polyline> _polylines = {};
  final Set<Marker> _markers = {};
  
  LatLng? _plannedStart;
  LatLng? _plannedEnd;
  bool _isPlanningMode = false;
  bool _isRunning = false;

  double _currentSpeed = 0.0;
  double _totalDistance = 0.0;
  LatLng _currentPosition = const LatLng(38.7223, -9.1393);
  bool _isLoading = true;
  bool _isSimulating = false;

  BitmapDescriptor? _startIcon;
  BitmapDescriptor? _arrowIcon;
  BitmapDescriptor? _finishIcon;

  @override
  void initState() {
    super.initState();
    _setupIconsAndTracking();
  }

  Future<void> _setupIconsAndTracking() async {
    // Marcadores premium: tamanho ideal para visibilidade e estética
    _startIcon = await _createPremiumMarker(Colors.greenAccent, Icons.play_arrow_rounded, 85);
    _finishIcon = await _createPremiumMarker(AppColors.coral, Icons.flag_rounded, 85);
    _arrowIcon = await _createArrowMarker(Colors.black, Colors.white, 95);
    await _initTracking();
  }

  Future<BitmapDescriptor> _createPremiumMarker(Color color, IconData icon, double size) async {
    final ui.PictureRecorder recorder = ui.PictureRecorder();
    final Canvas canvas = Canvas(recorder);
    final Paint shadowPaint = Paint()..color = Colors.black.withOpacity(0.4)..maskFilter = const MaskFilter.blur(BlurStyle.normal, 6);
    canvas.drawCircle(Offset(size / 2, size / 2 + 3), size / 2, shadowPaint);
    canvas.drawCircle(Offset(size / 2, size / 2), size / 2, Paint()..color = Colors.white);
    canvas.drawCircle(Offset(size / 2, size / 2), size / 2 - 5, Paint()..color = color);
    TextPainter textPainter = TextPainter(textDirection: TextDirection.ltr);
    textPainter.text = TextSpan(text: String.fromCharCode(icon.codePoint), style: TextStyle(fontSize: size * 0.6, fontFamily: icon.fontFamily, color: Colors.white, fontWeight: FontWeight.bold));
    textPainter.layout();
    textPainter.paint(canvas, Offset((size - textPainter.width) / 2, (size - textPainter.height) / 2));
    final ui.Image image = await recorder.endRecording().toImage(size.toInt(), size.toInt() + 6);
    final ByteData? byteData = await image.toByteData(format: ui.ImageByteFormat.png);
    return BitmapDescriptor.fromBytes(byteData!.buffer.asUint8List());
  }

  Future<BitmapDescriptor> _createArrowMarker(Color color, Color borderColor, double size) async {
    final ui.PictureRecorder recorder = ui.PictureRecorder();
    final Canvas canvas = Canvas(recorder);
    final Path path = Path();
    path.moveTo(size / 2, 0);
    path.lineTo(size * 0.9, size);
    path.lineTo(size / 2, size * 0.7);
    path.lineTo(size * 0.1, size);
    path.close();
    canvas.drawPath(path.shift(const Offset(0, 4)), Paint()..color = Colors.black38..maskFilter = const MaskFilter.blur(BlurStyle.normal, 4));
    canvas.drawPath(path, Paint()..color = color);
    canvas.drawPath(path, Paint()..color = borderColor..style = ui.PaintingStyle.stroke..strokeWidth = 7);
    final ui.Image image = await recorder.endRecording().toImage(size.toInt(), size.toInt() + 6);
    final ByteData? byteData = await image.toByteData(format: ui.ImageByteFormat.png);
    return BitmapDescriptor.fromBytes(byteData!.buffer.asUint8List());
  }

  @override
  void dispose() {
    _positionStreamSubscription?.cancel();
    _simulationTimer?.cancel();
    _mapController?.dispose();
    super.dispose();
  }

  Future<void> _initTracking() async {
    bool serviceEnabled = await Geolocator.isLocationServiceEnabled();
    if (!serviceEnabled) return;
    LocationPermission permission = await Geolocator.checkPermission();
    if (permission == LocationPermission.denied) {
      permission = await Geolocator.requestPermission();
      if (permission == LocationPermission.denied) return;
    }
    Position position = await Geolocator.getCurrentPosition(desiredAccuracy: LocationAccuracy.bestForNavigation);
    _currentPosition = LatLng(position.latitude, position.longitude);
    setState(() => _isLoading = false);
    _startLocationStream();
  }

  void _startLocationStream() {
    _positionStreamSubscription = Geolocator.getPositionStream(
        locationSettings: const LocationSettings(
            accuracy: LocationAccuracy.bestForNavigation,
            distanceFilter: 0
        )
    ).listen((Position position) {
      if (!_isSimulating) {
        final now = DateTime.now();
        if (_lastUpdate == null || now.difference(_lastUpdate!).inMilliseconds > 500) {
          _lastUpdate = now;
          _updatePosition(LatLng(position.latitude, position.longitude), position.speed);
        }
      }
    }, onError: (error) {
      debugPrint("${AppStrings.unknownDevice}: $error");
    });
  }

  void _updatePosition(LatLng newPoint, double speed) {
    if (!mounted) return;
    setState(() {
      if (_routePoints.isNotEmpty) {
        _totalDistance += Geolocator.distanceBetween(_currentPosition.latitude, _currentPosition.longitude, newPoint.latitude, newPoint.longitude);
      }
      _currentSpeed = speed >= 0 ? speed : 0;
      _routePoints.add(newPoint);
      _currentPosition = newPoint;
      _updateMarkers(); 

      if (_routePoints.length > 1) {
        _polylines.removeWhere((p) => p.polylineId.value == 'route' || p.polylineId.value == 'route_glow');
        _polylines.add(Polyline(
          polylineId: const PolylineId('route_glow'),
          points: List.from(_routePoints),
          color: Colors.cyanAccent.withOpacity(0.3),
          width: 14,
          zIndex: 9,
        ));
        _polylines.add(Polyline(
          polylineId: const PolylineId('route'),
          points: List.from(_routePoints),
          color: Colors.white,
          width: 6,
          patterns: [PatternItem.dot, PatternItem.gap(15)],
          jointType: JointType.round,
          zIndex: 10,
        ));
      }
    });

    if (_mapController != null) {
      _mapController!.animateCamera(CameraUpdate.newLatLng(newPoint));
    }
  }

  void _updateMarkers() {
    _markers.removeWhere((m) => m.markerId.value == 'follower');
    _markers.add(Marker(
      markerId: const MarkerId('follower'),
      position: _currentPosition,
      rotation: _calculateRotation(_routePoints),
      flat: true,
      anchor: const Offset(0.5, 0.5),
      icon: _arrowIcon ?? BitmapDescriptor.defaultMarker,
      zIndex: 12,
    ));
  }

  double _calculateRotation(List<LatLng> points) {
    if (points.length < 2) return 0;
    LatLng p1 = points[points.length - 2];
    LatLng p2 = points.last;
    return Geolocator.bearingBetween(p1.latitude, p1.longitude, p2.latitude, p2.longitude);
  }

  void _onMapTap(LatLng point) {
    if (!_isPlanningMode) return;
    setState(() {
      if (_plannedStart == null) {
        _plannedStart = point;
        _markers.add(Marker(markerId: const MarkerId('planned_start'), position: point, icon: _startIcon ?? BitmapDescriptor.defaultMarker, zIndex: 5, infoWindow: const InfoWindow(title: AppStrings.startPoint)));
      } else if (_plannedEnd == null) {
        _plannedEnd = point;
        _markers.add(Marker(markerId: const MarkerId('planned_end'), position: point, icon: _finishIcon ?? BitmapDescriptor.defaultMarker, zIndex: 5, infoWindow: const InfoWindow(title: AppStrings.finishPoint)));
        _polylines.add(Polyline(polylineId: const PolylineId('planned_route'), points: [_plannedStart!, _plannedEnd!], color: Colors.white.withOpacity(0.1), width: 2, zIndex: 1));
      } else {
        _plannedStart = point;
        _plannedEnd = null;
        _markers.removeWhere((m) => m.markerId.value.startsWith('planned'));
        _polylines.removeWhere((p) => p.polylineId.value == 'planned_route');
        _markers.add(Marker(markerId: const MarkerId('planned_start'), position: point, icon: _startIcon ?? BitmapDescriptor.defaultMarker, zIndex: 5, infoWindow: const InfoWindow(title: AppStrings.startPoint)));
      }
    });
  }

  void _toggleSimulation() {
    if (_isSimulating) {
      _simulationTimer?.cancel();
      setState(() => _isSimulating = false);
    } else {
      setState(() {
        _isSimulating = true;
        _isPlanningMode = false;
        _routePoints.clear();
        _polylines.removeWhere((p) => p.polylineId.value == 'route' || p.polylineId.value == 'route_glow');
        _totalDistance = 0.0;
        _currentPosition = _plannedStart ?? _currentPosition;
        _routePoints.add(_currentPosition);
        _updateMarkers();
      });

      _simulationTimer = Timer.periodic(const Duration(milliseconds: 100), (timer) {
        double latStep = 0.000025;
        double lngStep = 0.000025;

        if (_plannedEnd != null) {
          double dist = Geolocator.distanceBetween(_currentPosition.latitude, _currentPosition.longitude, _plannedEnd!.latitude, _plannedEnd!.longitude);
          if (dist < 2) {
            _updatePosition(_plannedEnd!, 0.0);
            _toggleSimulation();
            return;
          }
          latStep = (_plannedEnd!.latitude - _currentPosition.latitude) / (max(dist / 0.8, 1));
          lngStep = (_plannedEnd!.longitude - _currentPosition.longitude) / (max(dist / 0.8, 1));
        }

        LatLng nextPoint = LatLng(_currentPosition.latitude + latStep, _currentPosition.longitude + lngStep);
        _updatePosition(nextPoint, 3.5 + Random().nextDouble() * 0.5);
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: AppColors.background,
      appBar: AppBar(title: Text(_isPlanningMode ? AppStrings.mapTitlePlanning : AppStrings.mapTitleRunning, style: const TextStyle(fontWeight: FontWeight.w900, color: Colors.white, letterSpacing: 2)), centerTitle: true, backgroundColor: Colors.transparent, elevation: 0, leading: IconButton(icon: const Icon(Icons.arrow_back_ios_new, color: Colors.white), onPressed: () => Navigator.pop(context)), actions: [IconButton(icon: Icon(_isPlanningMode ? Icons.check_circle_rounded : Icons.add_location_alt_rounded, color: AppColors.coral, size: 30), onPressed: () => setState(() => _isPlanningMode = !_isPlanningMode))]),
      extendBodyBehindAppBar: true,
      body: Stack(children: [Center(child: Container(width: MediaQuery.of(context).size.width * 0.94, height: MediaQuery.of(context).size.height * 0.7, decoration: BoxDecoration(color: AppColors.backgroundGrey, borderRadius: BorderRadius.circular(55), border: Border.all(color: Colors.white.withOpacity(0.1), width: 3), boxShadow: [BoxShadow(color: Colors.black.withOpacity(0.7), blurRadius: 50, offset: const Offset(0, 30))]), child: ClipRRect(borderRadius: BorderRadius.circular(52), child: _isLoading ? const Center(child: CircularProgressIndicator(color: AppColors.coral)) : GoogleMap(initialCameraPosition: CameraPosition(target: _currentPosition, zoom: 17.5), onMapCreated: (controller) => _mapController = controller, onTap: _onMapTap, markers: _markers, polylines: _polylines, zoomControlsEnabled: false, myLocationButtonEnabled: false, compassEnabled: false, mapToolbarEnabled: false)))), Positioned(top: 115, left: 45, right: 45, child: Container(padding: const EdgeInsets.symmetric(vertical: 20, horizontal: 25), decoration: BoxDecoration(color: AppColors.background.withOpacity(0.95), borderRadius: BorderRadius.circular(25), border: Border.all(color: Colors.white10), boxShadow: [BoxShadow(color: Colors.black26, blurRadius: 10)]), child: Row(mainAxisAlignment: MainAxisAlignment.spaceAround, children: [_buildStat(AppStrings.mapPace, "${(_currentSpeed * 3.6).toStringAsFixed(1)}", AppStrings.kmhUnit), Container(width: 1, height: 35, color: Colors.white10), _buildStat(AppStrings.mapRoute, (_totalDistance / 1000).toStringAsFixed(2), AppStrings.kmUnit)]))), if (_isPlanningMode) Positioned(bottom: 140, left: 60, right: 60, child: Container(padding: const EdgeInsets.all(12), decoration: BoxDecoration(color: Colors.black.withOpacity(0.85), borderRadius: BorderRadius.circular(20), border: Border.all(color: AppColors.coral.withOpacity(0.5))), child: const Text(AppStrings.planningInstruction, textAlign: TextAlign.center, style: TextStyle(color: Colors.white, fontSize: 13, fontWeight: FontWeight.bold))))]),
      floatingActionButton: FloatingActionButton.extended(onPressed: _toggleSimulation, label: Text(_isSimulating ? AppStrings.btnStop : AppStrings.btnStartRun, style: const TextStyle(fontWeight: FontWeight.w900, letterSpacing: 1.5)), icon: Icon(_isSimulating ? Icons.stop_rounded : Icons.play_arrow_rounded, size: 32), backgroundColor: _isSimulating ? AppColors.coral : Colors.white, foregroundColor: _isSimulating ? Colors.white : AppColors.background, elevation: 15),
      floatingActionButtonLocation: FloatingActionButtonLocation.centerFloat,
    );
  }

  Widget _buildStat(String label, String value, String unit) {
    return Column(mainAxisSize: MainAxisSize.min, children: [Text(label, style: const TextStyle(color: Colors.white54, fontSize: 10, fontWeight: FontWeight.w900, letterSpacing: 1.5)), const SizedBox(height: 6), Row(crossAxisAlignment: CrossAxisAlignment.baseline, textBaseline: TextBaseline.alphabetic, children: [Text(value, style: const TextStyle(color: Colors.white, fontSize: 26, fontWeight: FontWeight.w900)), const SizedBox(width: 3), Text(unit, style: const TextStyle(color: Colors.white54, fontSize: 10, fontWeight: FontWeight.bold))])]);
  }
}