import 'package:flutter/material.dart';
import 'package:flutter_map/flutter_map.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';
import 'package:path_provider/path_provider.dart';
import 'package:vector_map_tiles/vector_map_tiles.dart';
import '../../../../core/api/api_client.dart';
import '../../providers/map_provider.dart';
import '../../providers/map_style_provider.dart';
import '../widgets/map_controls.dart';
import '../widgets/place_card.dart';

class MapScreen extends ConsumerStatefulWidget {
  const MapScreen({super.key});

  @override
  ConsumerState<MapScreen> createState() => _MapScreenState();
}

class _MapScreenState extends ConsumerState<MapScreen> {
  late final MapController _mapController;

  @override
  void initState() {
    super.initState();
    _mapController = MapController();
    WidgetsBinding.instance.addPostFrameCallback((_) {
      ref.read(mapProvider.notifier).locateUser();
    });
  }

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

  @override
  Widget build(BuildContext context) {
    final mapState = ref.watch(mapProvider);
    final apiClient = ref.watch(apiClientProvider);
    final styleAsync = ref.watch(mapStyleProvider(apiClient.baseUrl));

    // Move the map only for programmatic state changes (locateUser,
    // zoomIn/zoomOut).  Gesture-driven pans no longer call updateCamera(),
    // so this listener only fires for intentional moves and won't interfere
    // with the TileLayer's in-flight tile loads.
    ref.listen<MapState>(mapProvider, (previous, next) {
      if (previous?.center != next.center || previous?.zoom != next.zoom) {
        _mapController.move(next.center, next.zoom);
      }
    });

    return Scaffold(
      body: Stack(
        children: [
          FlutterMap(
            mapController: _mapController,
            options: MapOptions(
              backgroundColor: Colors.transparent,
              initialCenter: mapState.center,
              initialZoom: mapState.zoom,
              minZoom: 0,
              maxZoom: 18,
              onPositionChanged: (position, hasGesture) {
                // Intentionally not syncing gesture-driven position changes
                // back to the provider.  Doing so caused ref.listen to call
                // _mapController.move() on every pan/zoom frame, which made
                // flutter_map's TileLayer cancel in-flight tile loads —
                // producing a partially-rendered (diagonal) map and crashes
                // when zooming out during tile loading.
              },
              onTap: (tapPosition, point) {
                ref.read(mapProvider.notifier).clearSelectedPlace();
              },
            ),
            children: [
              styleAsync.when(
                data: (style) => VectorTileLayer(
                  tileProviders: style.providers,
                  theme: style.theme,
                  concurrency: 4,
                  memoryTileCacheMaxSize: 20 * 1024 * 1024,   // 20 MB raw tiles
                  memoryTileDataCacheMaxSize: 50,              // 50 parsed tiles
                  fileCacheMaximumSizeInBytes: 50 * 1024 * 1024, // 50 MB on disk
                  cacheFolder: () => getApplicationCacheDirectory(),
                ),
                loading: () => const SizedBox.shrink(),
                error: (e, _) => const SizedBox.shrink(),
              ),
              if (mapState.currentLocation != null)
                MarkerLayer(
                  markers: [
                    Marker(
                      point: mapState.currentLocation!,
                      width: 24,
                      height: 24,
                      child: Container(
                        decoration: BoxDecoration(
                          color: Theme.of(context).colorScheme.primary,
                          shape: BoxShape.circle,
                          border: Border.all(color: Colors.white, width: 3),
                          boxShadow: [
                            BoxShadow(
                              color: Colors.black.withValues(alpha: 0.3),
                              blurRadius: 4,
                              offset: const Offset(0, 2),
                            ),
                          ],
                        ),
                      ),
                    ),
                  ],
                ),
            ],
          ),
          // Search bar at the top
          Positioned(
            top: MediaQuery.of(context).padding.top + 8,
            left: 12,
            right: 12,
            child: GestureDetector(
              onTap: () => context.push('/search'),
              child: Card(
                child: Padding(
                  padding:
                      const EdgeInsets.symmetric(horizontal: 16, vertical: 12),
                  child: Row(
                    children: [
                      Icon(Icons.search,
                          color: Theme.of(context).colorScheme.onSurfaceVariant),
                      const SizedBox(width: 12),
                      Expanded(
                        child: Text(
                          'Search places...',
                          style:
                              Theme.of(context).textTheme.bodyLarge?.copyWith(
                                    color: Theme.of(context)
                                        .colorScheme
                                        .onSurfaceVariant,
                                  ),
                        ),
                      ),
                      IconButton(
                        icon: const Icon(Icons.settings),
                        onPressed: () => context.push('/settings'),
                        padding: EdgeInsets.zero,
                        constraints: const BoxConstraints(),
                      ),
                    ],
                  ),
                ),
              ),
            ),
          ),
          // Map controls
          const MapControls(),
          // Place card bottom sheet
          const PlaceCard(),
          // Offline button
          Positioned(
            left: 16,
            bottom: 120,
            child: FloatingActionButton.small(
              heroTag: 'offline',
              onPressed: () => context.push('/offline'),
              child: const Icon(Icons.download),
            ),
          ),
        ],
      ),
    );
  }
}