import 'package:flutter/material.dart';
import 'package:flutter_map/flutter_map.dart';
import 'package:latlong2/latlong.dart';
import 'package:em2rp/models/route_result_model.dart';

/// Affiche 1 ou 2 itinéraires sur une carte OpenStreetMap.
/// Route TOLL = bleu, Route TOLL_FREE = vert.
class RouteMapWidget extends StatelessWidget {
  final List<RouteResult> routes;
  final RouteResult? selectedRoute;

  const RouteMapWidget({
    super.key,
    required this.routes,
    this.selectedRoute,
  });

  /// Décode une polyline Google encodée en liste de LatLng.
  List<LatLng> _decode(String encoded) {
    if (encoded.isEmpty) return [];
    try {
      final result = <LatLng>[];
      int index = 0, lat = 0, lng = 0;
      final len = encoded.length;

      while (index < len) {
        int shift = 0, result0 = 0;
        int b;
        do {
          b = encoded.codeUnitAt(index++) - 63;
          result0 |= (b & 0x1f) << shift;
          shift += 5;
        } while (b >= 0x20);
        final dlat = (result0 & 1) != 0 ? ~(result0 >> 1) : (result0 >> 1);
        lat += dlat;

        shift = 0;
        result0 = 0;
        do {
          b = encoded.codeUnitAt(index++) - 63;
          result0 |= (b & 0x1f) << shift;
          shift += 5;
        } while (b >= 0x20);
        final dlng = (result0 & 1) != 0 ? ~(result0 >> 1) : (result0 >> 1);
        lng += dlng;

        result.add(LatLng(lat / 1e5, lng / 1e5));
      }
      return result;
    } catch (e) {
      return [];
    }
  }

  LatLngBounds? _computeBounds(List<List<LatLng>> allPoints) {
    double? minLat, maxLat, minLng, maxLng;
    for (final pts in allPoints) {
      for (final p in pts) {
        minLat = minLat == null ? p.latitude : p.latitude < minLat ? p.latitude : minLat;
        maxLat = maxLat == null ? p.latitude : p.latitude > maxLat ? p.latitude : maxLat;
        minLng = minLng == null ? p.longitude : p.longitude < minLng ? p.longitude : minLng;
        maxLng = maxLng == null ? p.longitude : p.longitude > maxLng ? p.longitude : maxLng;
      }
    }
    if (minLat == null) return null;
    return LatLngBounds(
      LatLng(minLat - 0.02, minLng! - 0.02),
      LatLng(maxLat! + 0.02, maxLng! + 0.02),
    );
  }

  @override
  Widget build(BuildContext context) {
    final allPolylines = <Polyline>[];
    final allPointGroups = <List<LatLng>>[];

    for (final route in routes) {
      final pts = _decode(route.encodedPolyline);
      if (pts.isEmpty) continue;
      allPointGroups.add(pts);

      final isSelected =
          selectedRoute == null || selectedRoute!.routeType == route.routeType;
      final isToll = route.routeType == 'TOLL';

      allPolylines.add(Polyline(
        points: pts,
        strokeWidth: isSelected ? 5.0 : 3.0,
        color: isToll
            ? (isSelected
                ? const Color(0xFF1565C0)
                : const Color(0xFF1565C0).withValues(alpha: 0.4))
            : (isSelected
                ? const Color(0xFF2E7D32)
                : const Color(0xFF2E7D32).withValues(alpha: 0.4)),
      ));
    }

    final bounds = _computeBounds(allPointGroups);
    final mapController = MapController();

    // Marqueurs de départ / arrivée
    final markers = <Marker>[];
    for (final group in allPointGroups) {
      if (group.isEmpty) continue;
      // Départ
      markers.add(Marker(
        point: group.first,
        width: 32,
        height: 32,
        child: const Icon(Icons.circle, color: Colors.green, size: 20),
      ));
      // Arrivée
      markers.add(Marker(
        point: group.last,
        width: 32,
        height: 32,
        child: const Icon(Icons.location_pin, color: Colors.red, size: 32),
      ));
    }

    return FlutterMap(
      mapController: mapController,
      options: MapOptions(
        initialCameraFit: bounds != null
            ? CameraFit.bounds(
                bounds: bounds,
                padding: const EdgeInsets.all(32),
              )
            : const CameraFit.coordinates(
                coordinates: [LatLng(46.2276, 2.2137)], padding: EdgeInsets.all(32)),
        interactionOptions: const InteractionOptions(
          flags: InteractiveFlag.all,
        ),
      ),
      children: [
        TileLayer(
          urlTemplate: 'https://tile.openstreetmap.org/{z}/{x}/{y}.png',
          userAgentPackageName: 'com.em2events.em2rp',
        ),
        PolylineLayer(polylines: allPolylines),
        MarkerLayer(markers: markers),
      ],
    );
  }
}