import '../map/map_provider_interface.dart';
import 'route_models.dart';

/// Result of a place/location search query.
class PlaceSearchResult {
  final String name;
  final String address;
  final double latitude;
  final double longitude;
  final String? placeId;

  const PlaceSearchResult({
    required this.name,
    this.address = '',
    required this.latitude,
    required this.longitude,
    this.placeId,
  });

  AppLatLng get latLng => AppLatLng(latitude, longitude);
}

/// Result of calculating a route along ordered stops.
class RouteCalculationResult {
  final double straightLineDistanceMeters;
  final double? estimatedDistanceMeters;
  final int? estimatedDurationSeconds;
  final List<AppLatLng> geometry;
  final bool isStraightLine;
  final String providerName;

  const RouteCalculationResult({
    required this.straightLineDistanceMeters,
    this.estimatedDistanceMeters,
    this.estimatedDurationSeconds,
    required this.geometry,
    required this.isStraightLine,
    required this.providerName,
  });

  /// Alias for geometry points.
  List<AppLatLng> get points => geometry;

  /// Total straight-line distance in meters.
  double get totalDistanceMeters => straightLineDistanceMeters;

  /// Alias for isStraightLine.
  bool get isHonestStraightLine => isStraightLine;

  /// Total distance in miles.
  double get distanceMiles {
    final meters = estimatedDistanceMeters ?? straightLineDistanceMeters;
    return meters * 0.000621371;
  }

  /// Truthful distance description.
  String get distanceLabel {
    if (estimatedDistanceMeters != null) {
      return '${distanceMiles.toStringAsFixed(1)} mi (Road Est.)';
    }
    return '${distanceMiles.toStringAsFixed(1)} mi (Straight-line)';
  }
}

/// Abstract provider interface for calculating routes and searching places.
abstract class RouteProvider {
  String get name;

  /// Calculates route geometry and metrics between ordered stops.
  Future<RouteCalculationResult> calculateRoute(List<RouteStop> stops);

  /// Searches for places by textual query.
  Future<List<PlaceSearchResult>> searchPlaces(
    String query, {
    AppLatLng? nearLocation,
  });
}

/// Default geodesic straight-line preview implementation.
///
/// Truthfully connects stops with direct segments and calculates geodesic
/// distance without fabricating road paths or speculative turn ETAs.
class StraightLineRouteProvider implements RouteProvider {
  const StraightLineRouteProvider();

  @override
  String get name => 'Straight-line Preview';

  @override
  Future<RouteCalculationResult> calculateRoute(List<RouteStop> stops) async {
    final ordered = List<RouteStop>.from(stops);
    ordered.sort((a, b) => a.order.compareTo(b.order));

    final distanceMeters = MotorSignalRoute.calculateTotalDistanceMeters(ordered);
    final points = ordered.map((s) => s.latLng).toList();

    return RouteCalculationResult(
      straightLineDistanceMeters: distanceMeters,
      estimatedDistanceMeters: null,
      estimatedDurationSeconds: null,
      geometry: points,
      isStraightLine: true,
      providerName: name,
    );
  }

  @override
  Future<List<PlaceSearchResult>> searchPlaces(
    String query, {
    AppLatLng? nearLocation,
  }) async {
    final clean = query.trim();
    if (clean.isEmpty) return const [];

    // Support direct coordinate input (e.g. "34.5378, -83.9849")
    final parts = clean.split(RegExp(r'[,\s]+'));
    if (parts.length == 2) {
      final lat = double.tryParse(parts[0]);
      final lng = double.tryParse(parts[1]);
      if (lat != null && lng != null && lat >= -90 && lat <= 90 && lng >= -180 && lng <= 180) {
        return [
          PlaceSearchResult(
            name: 'Coordinate Pin',
            address: '${lat.toStringAsFixed(5)}, ${lng.toStringAsFixed(5)}',
            latitude: lat,
            longitude: lng,
          ),
        ];
      }
    }

    // Default fallback: return query name centered at reference location if provided
    if (nearLocation != null) {
      return [
        PlaceSearchResult(
          name: clean,
          address: 'Near Current Map Location',
          latitude: nearLocation.latitude,
          longitude: nearLocation.longitude,
        ),
      ];
    }

    return const [];
  }
}