import 'dart:async';
import 'dart:typed_data';

import 'package:aves_map/aves_map.dart';
import 'package:aves_utils/aves_utils.dart';
import 'package:flutter/material.dart';
import 'package:google_maps_flutter/google_maps_flutter.dart';
import 'package:latlong2/latlong.dart' as ll;
import 'package:provider/provider.dart';

class EntryGoogleMap<T> extends StatefulWidget {
  final AvesMapController controller;
  final Listenable clusterListenable;
  final ValueNotifier<ZoomedBounds> boundsNotifier;
  final double? minZoom, maxZoom;
  final EntryMapStyle style;
  final TransitionBuilder decoratorBuilder;
  final WidgetBuilder buttonPanelBuilder;
  final MarkerClusterBuilder<T> markerClusterBuilder;
  final MarkerWidgetBuilder<T> markerWidgetBuilder;
  final MarkerImageReadyChecker<T> markerImageReadyChecker;
  final ValueNotifier<ll.LatLng?>? dotLocationNotifier;
  final ValueNotifier<double>? overlayOpacityNotifier;
  final MapOverlay? overlayEntry;
  final Set<List<ll.LatLng>>? tracks;
  final UserZoomChangeCallback? onUserZoomChange;
  final MapTapCallback? onMapTap;
  final MarkerTapCallback<T>? onMarkerTap;
  final MarkerLongPressCallback<T>? onMarkerLongPress;

  const EntryGoogleMap({
    super.key,
    required this.controller,
    required this.clusterListenable,
    required this.boundsNotifier,
    this.minZoom,
    this.maxZoom,
    required this.style,
    required this.decoratorBuilder,
    required this.buttonPanelBuilder,
    required this.markerClusterBuilder,
    required this.markerWidgetBuilder,
    required this.markerImageReadyChecker,
    required this.dotLocationNotifier,
    this.overlayOpacityNotifier,
    this.overlayEntry,
    this.tracks,
    this.onUserZoomChange,
    this.onMapTap,
    this.onMarkerTap,
    this.onMarkerLongPress,
  });

  @override
  State<StatefulWidget> createState() => _EntryGoogleMapState<T>();
}

class _EntryGoogleMapState<T> extends State<EntryGoogleMap<T>> {
  GoogleMapController? _serviceMapController;
  final List<StreamSubscription> _subscriptions = [];
  Map<MarkerKey<T>, GeoEntry<T>> _geoEntryByMarkerKey = {};
  final Map<MarkerKey<T>, Uint8List> _markerBitmaps = {};
  final StreamController<MarkerKey<T>> _markerBitmapReadyStreamController = StreamController.broadcast();
  Uint8List? _dotMarkerBitmap;
  final ValueNotifier<Size> _sizeNotifier = ValueNotifier(Size.zero);

  ValueNotifier<ZoomedBounds> get boundsNotifier => widget.boundsNotifier;

  ZoomedBounds get bounds => boundsNotifier.value;

  static const uninitializedLatLng = LatLng(0, 0);
  static const boundInitDelay = Duration(milliseconds: 100);

  @override
  void initState() {
    super.initState();
    _sizeNotifier.addListener(_onSizeChanged);
    _registerWidget(widget);
  }

  @override
  void didUpdateWidget(covariant EntryGoogleMap<T> oldWidget) {
    super.didUpdateWidget(oldWidget);
    _unregisterWidget(oldWidget);
    _registerWidget(widget);
  }

  @override
  void dispose() {
    _unregisterWidget(widget);
    _serviceMapController?.dispose();
    _sizeNotifier.dispose();
    super.dispose();
  }

  void _registerWidget(EntryGoogleMap<T> widget) {
    final avesMapController = widget.controller;
    _subscriptions.add(avesMapController.moveCommands.listen((event) => _moveTo(_toServiceLatLng(event.latLng))));
    _subscriptions.add(avesMapController.zoomCommands.listen((event) => _zoomBy(event.delta)));
    _subscriptions.add(avesMapController.rotationResetCommands.listen((_) => _resetRotation()));
    widget.clusterListenable.addListener(_updateMarkers);
  }

  void _unregisterWidget(EntryGoogleMap<T> widget) {
    widget.clusterListenable.removeListener(_updateMarkers);
    _subscriptions
      ..forEach((sub) => sub.cancel())
      ..clear();
  }

  @override
  Widget build(BuildContext context) {
    return Stack(
      children: [
        MarkerGeneratorWidget<Key>(
          markers: const [DotMarker(key: Key('dot'))],
          isReadyToRender: (key) => true,
          onRendered: (key, bitmap) => _dotMarkerBitmap = bitmap,
        ),
        MarkerGeneratorWidget<MarkerKey<T>>(
          markers: _geoEntryByMarkerKey.keys.map(widget.markerWidgetBuilder).toList(),
          isReadyToRender: widget.markerImageReadyChecker,
          onRendered: (key, bitmap) {
            _markerBitmaps[key] = bitmap;
            _markerBitmapReadyStreamController.add(key);
          },
        ),
        widget.decoratorBuilder(context, _buildMap()),
        widget.buttonPanelBuilder(context),
      ],
    );
  }

  Widget _buildMap() {
    return StreamBuilder(
      stream: _markerBitmapReadyStreamController.stream,
      builder: (context, _) {
        final mediaMarkers = <Marker>{};
        _geoEntryByMarkerKey.forEach((markerKey, geoEntry) {
          final bytes = _markerBitmaps[markerKey];
          if (bytes != null) {
            final point = LatLng(geoEntry.latitude!, geoEntry.longitude!);
            mediaMarkers.add(Marker(
              markerId: MarkerId(geoEntry.markerId!),
              consumeTapEvents: true,
              icon: BytesMapBitmap(
                bytes,
                bitmapScaling: MapBitmapScaling.none,
              ),
              position: point,
              onTap: () => widget.onMarkerTap?.call(geoEntry),
              // TODO TLAD [map] GoogleMap.onLongPress is not appropriate for mediaMarkers, so the call should be here when this is fixed: https://github.com/flutter/flutter/issues/107148
              // onLongPress: widget.onMarkerLongPress != null
              //     ? (v) {
              //         final pressLocation = _fromServiceLatLng(v);
              //         final mediaMarkers = _geoEntryByMarkerKey.values.toSet();
              //         final geoEntry = ImageMarker.markerMatch(pressLocation, bounds.zoom, mediaMarkers);
              //         if (geoEntry != null) {
              //           widget.onMarkerLongPress?.call(geoEntry, pressLocation);
              //         }
              //       }
              //     : null,
            ));
          }
        });

        final interactive = context.select<MapThemeData, bool>((v) => v.interactive);
        final overlayEntry = widget.overlayEntry;
        final tracks = widget.tracks;
        final trackColor = Theme.of(context).colorScheme.primary;
        return NullableValueListenableBuilder<ll.LatLng?>(
          valueListenable: widget.dotLocationNotifier,
          builder: (context, dotLocation, child) {
            return NullableValueListenableBuilder<double>(
              valueListenable: widget.overlayOpacityNotifier,
              builder: (context, value, child) {
                final double overlayOpacity = value ?? 1.0;
                return LayoutBuilder(
                  builder: (context, constraints) {
                    _sizeNotifier.value = constraints.biggest;
                    return _GoogleMap(
                      dotLocationNotifier: widget.dotLocationNotifier ?? ValueNotifier(null),
                      initialCameraPosition: CameraPosition(
                        bearing: -bounds.rotation,
                        target: _toServiceLatLng(bounds.projectedCenter),
                        zoom: bounds.zoom,
                      ),
                      onMapCreated: (controller) async {
                        _serviceMapController = controller;
                        final zoom = await controller.getZoomLevel();
                        // the visible region is sometimes incorrect when queried right after creation,
                        await Future.delayed(boundInitDelay);
                        await _updateVisibleRegion(zoom: zoom, rotation: bounds.rotation);
                        // `onCameraIdle` is not always automatically triggered following map creation
                        _onIdle();
                      },
                      mapType: _toMapType(widget.style),
                      minMaxZoomPreference: MinMaxZoomPreference(widget.minZoom, widget.maxZoom),
                      interactive: interactive,
                      markers: {
                        ...mediaMarkers,
                        if (dotLocation != null && _dotMarkerBitmap != null)
                          Marker(
                            markerId: const MarkerId('dot'),
                            anchor: const Offset(.5, .5),
                            consumeTapEvents: true,
                            icon: BytesMapBitmap(
                              _dotMarkerBitmap!,
                              bitmapScaling: MapBitmapScaling.none,
                            ),
                            position: _toServiceLatLng(dotLocation),
                            zIndexInt: 1,
                          )
                      },
                      polylines: {
                        if (tracks != null)
                          for (final track in tracks)
                            Polyline(
                              polylineId: PolylineId(track.hashCode.toString()),
                              points: track.map(_toServiceLatLng).toList(),
                              width: MapThemeData.trackWidth,
                              color: trackColor,
                            ),
                      },
                      // TODO TLAD [geotiff] may use ground overlay instead when this is fixed: https://github.com/flutter/flutter/issues/26479
                      tileOverlays: {
                        if (overlayEntry != null && overlayEntry.canOverlay)
                          TileOverlay(
                            tileOverlayId: TileOverlayId(overlayEntry.id),
                            tileProvider: GmsGeoTiffTileProvider(overlayEntry),
                            transparency: 1 - overlayOpacity,
                          ),
                      },
                      onCameraMove: (position) => _updateVisibleRegion(zoom: position.zoom, rotation: -position.bearing),
                      onCameraIdle: _onIdle,
                      onTap: (v) => widget.onMapTap?.call(_fromServiceLatLng(v)),
                    );
                  },
                );
              },
            );
          },
        );
      },
    );
  }

  // sometimes the map does not properly update after changing the widget size,
  // so we monitor the size and force refreshing after an arbitrary small delay
  Future<void> _onSizeChanged() async {
    await Future.delayed(boundInitDelay);
    _onIdle();
  }

  void _onIdle() {
    if (!mounted) return;
    widget.controller.notifyIdle(bounds);
    _updateMarkers();
  }

  void _updateMarkers() {
    setState(() => _geoEntryByMarkerKey = widget.markerClusterBuilder());
  }

  Future<void> _updateVisibleRegion({required double zoom, required double rotation}) async {
    if (!mounted) return;

    final bounds = await _serviceMapController?.getVisibleRegion();
    if (bounds != null && (bounds.northeast != uninitializedLatLng || bounds.southwest != uninitializedLatLng)) {
      final sw = bounds.southwest;
      final ne = bounds.northeast;
      boundsNotifier.value = ZoomedBounds(
        sw: _fromServiceLatLng(sw),
        ne: _fromServiceLatLng(ne),
        zoom: zoom,
        rotation: rotation,
      );
    }
  }

  Future<void> _resetRotation() async {
    final controller = _serviceMapController;
    if (controller == null) return;

    await controller.animateCamera(CameraUpdate.newCameraPosition(CameraPosition(
      target: _toServiceLatLng(bounds.projectedCenter),
      zoom: bounds.zoom,
    )));
  }

  Future<void> _zoomBy(double amount) async {
    final controller = _serviceMapController;
    if (controller == null) return;

    widget.onUserZoomChange?.call(await controller.getZoomLevel() + amount);
    await controller.animateCamera(CameraUpdate.zoomBy(amount));
  }

  Future<void> _moveTo(LatLng point) async {
    final controller = _serviceMapController;
    if (controller == null) return;

    await controller.animateCamera(CameraUpdate.newLatLng(point));
  }

  // `LatLng` used by `google_maps_flutter` is not the one from `latlong2` package
  LatLng _toServiceLatLng(ll.LatLng location) => LatLng(location.latitude, location.longitude);

  ll.LatLng _fromServiceLatLng(LatLng location) => ll.LatLng(location.latitude, location.longitude);

  MapType _toMapType(EntryMapStyle style) {
    switch (style) {
      case EntryMapStyle.googleNormal:
        return MapType.normal;
      case EntryMapStyle.googleHybrid:
        return MapType.hybrid;
      case EntryMapStyle.googleTerrain:
        return MapType.terrain;
      default:
        return MapType.none;
    }
  }
}

class GmsGeoTiffTileProvider extends TileProvider {
  MapOverlay overlayEntry;

  GmsGeoTiffTileProvider(this.overlayEntry);

  @override
  Future<Tile> getTile(int x, int y, int? zoom) async {
    final tile = await overlayEntry.getTile(x, y, zoom);
    if (tile != null) {
      return Tile(tile.width, tile.height, tile.data);
    }
    return TileProvider.noTile;
  }
}

class _GoogleMap extends StatefulWidget {
  final ValueNotifier<ll.LatLng?>? dotLocationNotifier;
  final CameraPosition initialCameraPosition;
  final MapCreatedCallback? onMapCreated;
  final MapType mapType;
  final MinMaxZoomPreference minMaxZoomPreference;
  final bool interactive;
  final Set<Marker> markers;
  final Set<Polyline> polylines;
  final Set<TileOverlay> tileOverlays;
  final CameraPositionCallback? onCameraMove;
  final VoidCallback? onCameraIdle;
  final ArgumentCallback<LatLng>? onTap;

  const _GoogleMap({
    required this.dotLocationNotifier,
    required this.initialCameraPosition,
    required this.onMapCreated,
    required this.mapType,
    required this.minMaxZoomPreference,
    required this.interactive,
    required this.markers,
    required this.polylines,
    required this.tileOverlays,
    required this.onCameraMove,
    required this.onCameraIdle,
    required this.onTap,
  });

  @override
  State<_GoogleMap> createState() => _GoogleMapState();
}

class _GoogleMapState extends State<_GoogleMap> {
  @override
  void initState() {
    super.initState();
    _registerWidget(widget);
  }

  @override
  void didUpdateWidget(covariant _GoogleMap oldWidget) {
    super.didUpdateWidget(oldWidget);
    _unregisterWidget(oldWidget);
    _registerWidget(widget);
  }

  @override
  void dispose() {
    _unregisterWidget(widget);
    super.dispose();
  }

  void _registerWidget(_GoogleMap widget) {
    widget.dotLocationNotifier?.addListener(_onDotLocationChanged);
  }

  void _unregisterWidget(_GoogleMap widget) {
    widget.dotLocationNotifier?.removeListener(_onDotLocationChanged);
  }

  // TODO TLAD [map] remove when this is fixed: https://github.com/flutter/flutter/issues/103686
  Future<void> _onDotLocationChanged() async {
    // workaround for dot location marker not always reflecting the current location,
    // despite `ValueListenableBuilder` on `widget.dotLocationNotifier`
    await Future.delayed(const Duration(milliseconds: 100));
    if (mounted) {
      setState(() {});
    }
  }

  @override
  Widget build(BuildContext context) {
    return GoogleMap(
      initialCameraPosition: widget.initialCameraPosition,
      onMapCreated: widget.onMapCreated,
      // compass disabled to use provider agnostic controls
      compassEnabled: false,
      mapToolbarEnabled: false,
      mapType: widget.mapType,
      minMaxZoomPreference: widget.minMaxZoomPreference,
      rotateGesturesEnabled: true,
      scrollGesturesEnabled: widget.interactive,
      // zoom controls disabled to use provider agnostic controls
      zoomControlsEnabled: false,
      zoomGesturesEnabled: widget.interactive,
      // lite mode disabled because it lacks camera animation
      liteModeEnabled: false,
      // tilt disabled to match leaflet
      tiltGesturesEnabled: false,
      myLocationEnabled: false,
      myLocationButtonEnabled: false,
      markers: widget.markers,
      polylines: widget.polylines,
      tileOverlays: widget.tileOverlays,
      onCameraMove: widget.onCameraMove,
      onCameraIdle: widget.onCameraIdle,
      onTap: widget.onTap,
    );
  }
}