import 'package:flutter/material.dart';
import 'package:flutter_map/flutter_map.dart';
import 'package:flutter_map_animations/flutter_map_animations.dart';
import 'package:latlong2/latlong.dart';

import '../../models/osm_node.dart';
import '../../models/suspected_location.dart';
import '../../app_state.dart';
import '../../state/session_state.dart';
import '../../dev_config.dart';
import '../camera_icon.dart';
import '../provisional_pin.dart';
import 'node_markers.dart';
import 'suspected_location_markers.dart';

/// Enumeration for different pin types in navigation
enum PinType { start, end }

/// Simple location pin widget for route visualization
class LocationPin extends StatelessWidget {
  final PinType type;
  
  const LocationPin({super.key, required this.type});
  
  @override
  Widget build(BuildContext context) {
    return Container(
      width: 32.0,
      height: 32.0,
      decoration: BoxDecoration(
        color: type == PinType.start ? Colors.green : Colors.red,
        shape: BoxShape.circle,
        border: Border.all(color: Colors.white, width: 2),
      ),
      child: Icon(
        type == PinType.start ? Icons.play_arrow : Icons.stop,
        color: Colors.white,
        size: 16,
      ),
    );
  }
}

/// Builds all marker layers for the map including surveillance nodes, suspected locations,
/// session markers, navigation pins, and route visualization.
class MarkerLayerBuilder {
  
  /// Build complete marker layers for the map
  static Widget buildMarkerLayers({
    required List<OsmNode> nodesToRender,
    required AnimatedMapController mapController,
    required AppState appState,
    required AddNodeSession? session,
    required EditNodeSession? editSession,
    required int? selectedNodeId,
    required LatLng? userLocation,
    required double currentZoom,
    required LatLngBounds? mapBounds,
    required Function(OsmNode)? onNodeTap,
    required Function(SuspectedLocation)? onSuspectedLocationTap,
  }) {
    return LayoutBuilder(
      builder: (context, constraints) {
        
        // Determine if we should dim node markers (when suspected location is selected)
        final shouldDimNodes = appState.selectedSuspectedLocation != null;
        
        final markers = NodeMarkersBuilder.buildNodeMarkers(
          nodes: nodesToRender,
          mapController: mapController.mapController,
          userLocation: userLocation,
          selectedNodeId: selectedNodeId,
          onNodeTap: onNodeTap,
          shouldDim: shouldDimNodes,
        );

        // Build suspected location markers (respect same zoom and count limits as nodes)
        final suspectedLocationMarkers = <Marker>[];
        if (appState.suspectedLocationsEnabled && mapBounds != null && 
            currentZoom >= (appState.uploadMode == UploadMode.sandbox ? kOsmApiMinZoomLevel : kNodeMinZoomLevel)) {
          final suspectedLocations = appState.getSuspectedLocationsInBounds(
            north: mapBounds.north,
            south: mapBounds.south,
            east: mapBounds.east,
            west: mapBounds.west,
          );
          
          // Apply same node count limit as surveillance nodes
          final maxNodes = appState.maxNodes;
          final limitedSuspectedLocations = suspectedLocations.take(maxNodes).toList();
          
          // Filter out suspected locations that are too close to real nodes
          final filteredSuspectedLocations = _filterSuspectedLocationsByProximity(
            suspectedLocations: limitedSuspectedLocations,
            realNodes: nodesToRender,
            minDistance: appState.suspectedLocationMinDistance,
          );
          
          suspectedLocationMarkers.addAll(
            SuspectedLocationMarkersBuilder.buildSuspectedLocationMarkers(
              locations: filteredSuspectedLocations,
              mapController: mapController.mapController,
              selectedLocationId: appState.selectedSuspectedLocation?.ticketNo,
              onLocationTap: onSuspectedLocationTap,
            ),
          );
        }

        // Build center marker for add/edit sessions
        final centerMarkers = _buildSessionMarkers(
          mapController: mapController,
          session: session,
          editSession: editSession,
        );

        // Build provisional pin for navigation/search mode
        final navigationMarkers = _buildNavigationMarkers(appState);

        // Build start/end pins for route visualization
        final routeMarkers = _buildRouteMarkers(appState);

        return MarkerLayer(
          markers: [
            ...suspectedLocationMarkers, 
            ...markers, 
            ...centerMarkers,
            ...navigationMarkers,
            ...routeMarkers,
          ]
        );
      },
    );
  }

  /// Build center markers for add/edit sessions
  static List<Marker> _buildSessionMarkers({
    required AnimatedMapController mapController,
    required AddNodeSession? session,
    required EditNodeSession? editSession,
  }) {
    final centerMarkers = <Marker>[];
    if (session != null || editSession != null) {
      try {
        final center = mapController.mapController.camera.center;
        centerMarkers.add(
          Marker(
            point: center,
            width: kNodeIconDiameter,
            height: kNodeIconDiameter,
            child: CameraIcon(
              type: editSession != null ? CameraIconType.editing : CameraIconType.mock,
            ),
          ),
        );
      } catch (_) {
        // Controller not ready yet
      }
    }
    return centerMarkers;
  }

  /// Build provisional pin for navigation/search mode
  static List<Marker> _buildNavigationMarkers(AppState appState) {
    final markers = <Marker>[];
    if (appState.showProvisionalPin && appState.provisionalPinLocation != null) {
      markers.add(
        Marker(
          point: appState.provisionalPinLocation!,
          width: 32.0,
          height: 32.0,
          child: const ProvisionalPin(),
        ),
      );
    }
    return markers;
  }

  /// Build start/end pins for route visualization
  static List<Marker> _buildRouteMarkers(AppState appState) {
    final markers = <Marker>[];
    if (appState.showingOverview || appState.isInRouteMode || appState.isSettingSecondPoint) {
      if (appState.routeStart != null) {
        markers.add(
          Marker(
            point: appState.routeStart!,
            width: 32.0,
            height: 32.0,
            child: const LocationPin(type: PinType.start),
          ),
        );
      }
      if (appState.routeEnd != null) {
        markers.add(
          Marker(
            point: appState.routeEnd!,
            width: 32.0,
            height: 32.0,
            child: const LocationPin(type: PinType.end),
          ),
        );
      }
    }
    return markers;
  }

  /// Filter suspected locations that are too close to real nodes
  static List<SuspectedLocation> _filterSuspectedLocationsByProximity({
    required List<SuspectedLocation> suspectedLocations,
    required List<OsmNode> realNodes,
    required int minDistance, // in meters
  }) {
    if (minDistance <= 0) return suspectedLocations;
    
    const distance = Distance();
    final filteredLocations = <SuspectedLocation>[];
    
    for (final suspected in suspectedLocations) {
      bool tooClose = false;
      
      for (final realNode in realNodes) {
        final distanceMeters = distance.as(
          LengthUnit.Meter,
          suspected.centroid,
          realNode.coord,
        );
        
        if (distanceMeters < minDistance) {
          tooClose = true;
          break;
        }
      }
      
      if (!tooClose) {
        filteredLocations.add(suspected);
      }
    }
    
    return filteredLocations;
  }
}