import 'package:flutter/material.dart';
import 'package:google_maps_flutter/google_maps_flutter.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'package:geocoding/geocoding.dart';
import 'package:geolocator/geolocator.dart';

import 'package:anyway/core/constants.dart';
import 'package:anyway/presentation/pages/new_trip_preferences.dart';

class TripLocationSelectionPage extends StatefulWidget {
  const TripLocationSelectionPage({
    super.key,
    this.autoNavigateToPreferences = true,
  });

  final bool autoNavigateToPreferences;

  @override
  State<TripLocationSelectionPage> createState() =>
      _TripLocationSelectionPageState();
}

class _TripLocationSelectionPageState extends State<TripLocationSelectionPage> {
  final CameraPosition _initialCameraPosition = const CameraPosition(
    // TODO - maybe Paris is not the best default?
    target: LatLng(48.8566, 2.3522),
    zoom: 11.0,
  );

  GoogleMapController? _mapController;
  LatLng? _selectedLocation;
  bool _useLocation = true;
  bool _loadingPreferences = true;
  bool _isSearchingAddress = false;
  final TextEditingController _searchController = TextEditingController();

  static const Map<String, List<double>> _debugLocations = {
    'paris': [48.8575, 2.3514],
    'london': [51.5074, -0.1278],
    'new york': [40.7128, -74.006],
    'tokyo': [35.6895, 139.6917],
  };

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

  @override
  void dispose() {
    _searchController.dispose();
    super.dispose();
  }

  Future<void> _loadLocationPreference() async {
    final prefs = await SharedPreferences.getInstance();
    final useLocation = prefs.getBool('useLocation') ?? true;
    if (!mounted) return;
    setState(() {
      _useLocation = useLocation;
      _loadingPreferences = false;
    });
  }

  void _onLongPress(LatLng location) {
    setState(() {
      _selectedLocation = location;
    });
    _mapController?.animateCamera(CameraUpdate.newLatLng(location));
  }

  void _setSelectedLocationFromCoords(double lat, double lng) {
    final latLng = LatLng(lat, lng);
    setState(() {
      _selectedLocation = latLng;
    });
    _mapController?.animateCamera(CameraUpdate.newLatLng(latLng));
  }

  Future<void> _useCurrentLocation() async {
    try {
      var permission = await Geolocator.checkPermission();
      if (permission == LocationPermission.denied) {
        permission = await Geolocator.requestPermission();
      }

      if (permission == LocationPermission.denied) {
        if (!mounted) return;
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(content: Text('Location permission denied.')),
        );
        return;
      }

      if (permission == LocationPermission.deniedForever) {
        if (!mounted) return;
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(
            content: Text('Location permission permanently denied.'),
          ),
        );
        return;
      }

      final position = await Geolocator.getCurrentPosition();
      if (!mounted) return;
      _setSelectedLocationFromCoords(position.latitude, position.longitude);
    } catch (e) {
      if (!mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('Unable to get current location: $e')),
      );
    }
  }

  Future<void> _searchForLocation(String rawQuery) async {
    final query = rawQuery.trim();
    if (query.isEmpty) {
      return;
    }

    setState(() => _isSearchingAddress = true);
    try {
      List<Location> locations = [];
      if (GeocodingPlatform.instance != null) {
        locations = await locationFromAddress(query);
      }

      Location? selected;
      if (locations.isNotEmpty) {
        selected = locations.first;
      } else {
        final fallback = _debugLocations[query.toLowerCase()];
        if (fallback != null) {
          selected = Location(
            latitude: fallback[0],
            longitude: fallback[1],
            timestamp: DateTime.now(),
          );
        }
      }

      if (selected == null) {
        if (!mounted) return;
        ScaffoldMessenger.of(
          context,
        ).showSnackBar(SnackBar(content: Text('No results for "$query".')));
        return;
      }

      if (!mounted) return;
      _setSelectedLocationFromCoords(selected.latitude, selected.longitude);
    } catch (e) {
      if (!mounted) return;
      ScaffoldMessenger.of(
        context,
      ).showSnackBar(SnackBar(content: Text('Search failed: $e')));
    } finally {
      if (mounted) {
        setState(() => _isSearchingAddress = false);
      }
    }
  }

  Set<Marker> get _markers => _selectedLocation == null
      ? <Marker>{}
      : {
          Marker(
            markerId: const MarkerId('new-trip-start'),
            position: _selectedLocation!,
            infoWindow: const InfoWindow(title: 'Trip start'),
          ),
        };

  void _confirmLocation() {
    if (_selectedLocation == null) return;
    final startLocation = <double>[
      _selectedLocation!.latitude,
      _selectedLocation!.longitude,
    ];

    if (!widget.autoNavigateToPreferences) {
      Navigator.of(context).pop(startLocation);
      return;
    }

    Navigator.of(context).push(
      MaterialPageRoute(
        builder: (_) => NewTripPreferencesPage(startLocation: startLocation),
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    if (_loadingPreferences) {
      return Scaffold(
        appBar: AppBar(title: const Text('Choose Start Location')),
        body: const Center(child: CircularProgressIndicator()),
      );
    }

    return Scaffold(
      appBar: AppBar(title: const Text('Choose Start Location')),
      body: Stack(
        children: [
          GoogleMap(
            onMapCreated: (controller) => _mapController = controller,
            initialCameraPosition: _initialCameraPosition,
            onLongPress: _onLongPress,
            markers: _markers,
            cloudMapId: MAP_ID,
            mapToolbarEnabled: false,
            zoomControlsEnabled: false,
            myLocationButtonEnabled: false,
            myLocationEnabled: _useLocation,
          ),
          Positioned(
            top: 16,
            left: 16,
            right: 16,
            child: Column(
              children: [
                SearchBar(
                  controller: _searchController,
                  hintText: 'Enter a city or long-press on the map',
                  leading: const Icon(Icons.search),
                  onSubmitted: _searchForLocation,
                  trailing: [
                    IconButton(
                      icon: _isSearchingAddress
                          ? const SizedBox(
                              width: 16,
                              height: 16,
                              child: CircularProgressIndicator(strokeWidth: 2),
                            )
                          : const Icon(Icons.send),
                      onPressed: _isSearchingAddress
                          ? null
                          : () => _searchForLocation(_searchController.text),
                    ),
                  ],
                ),
                const SizedBox(height: 8),
                if (_useLocation)
                  Align(
                    alignment: Alignment.centerLeft,
                    child: TextButton.icon(
                      icon: const Icon(Icons.my_location),
                      label: const Text('Use current location'),
                      onPressed: _useCurrentLocation,
                    ),
                  ),
                Align(
                  alignment: Alignment.centerLeft,
                  child: Padding(
                    padding: const EdgeInsets.only(top: 8.0),
                    child: Text(
                      _selectedLocation == null
                          ? 'Long-press anywhere to drop the starting point.'
                          : 'Selected: ${_selectedLocation!.latitude.toStringAsFixed(4)}, ${_selectedLocation!.longitude.toStringAsFixed(4)}',
                      style: Theme.of(context).textTheme.bodyMedium,
                    ),
                  ),
                ),
              ],
            ),
          ),
        ],
      ),
      floatingActionButton: _selectedLocation == null
          ? null
          : FloatingActionButton.extended(
              onPressed: _confirmLocation,
              icon: widget.autoNavigateToPreferences
                  ? const Icon(Icons.tune)
                  : const Icon(Icons.check),
              label: Text(
                widget.autoNavigateToPreferences
                    ? 'Select Preferences'
                    : 'Use this location',
              ),
            ),
    );
  }
}