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

import '../../../../core/constants/auth_constants.dart';
import '../../../../core/theme/app_theme.dart';

const _kRelleno = LatLng(20.5111, -100.9037);

const _kRouteColors = [
  Colors.blue,
  Colors.green,
  Colors.orange,
  Colors.red,
  Colors.purple,
  Colors.teal,
];

class _RouteData {
  const _RouteData({
    required this.routeId,
    required this.currentPositionId,
    required this.status,
    required this.positions,
  });

  final String routeId;
  final int currentPositionId;
  final String status;
  final List<LatLng> positions;
}

class AdminDashboardScreen extends StatefulWidget {
  const AdminDashboardScreen({super.key});

  @override
  State<AdminDashboardScreen> createState() => _AdminDashboardScreenState();
}

class _AdminDashboardScreenState extends State<AdminDashboardScreen> {
  List<_RouteData> _routes = [];
  bool _isLoading = true;
  String? _error;

  @override
  void initState() {
    super.initState();
    _loadRoutes();
  }

  Future<void> _loadRoutes() async {
    setState(() {
      _isLoading = true;
      _error = null;
    });

    try {
      const storage = FlutterSecureStorage();
      final token = await storage.read(key: authTokenStorageKey) ?? '';

      final dio = Dio(
        BaseOptions(
          baseUrl: const String.fromEnvironment(
            'API_BASE_URL',
            defaultValue: 'http://10.0.2.2:8000',
          ),
          headers: {
            'Authorization': 'Bearer $token',
            'Content-Type': 'application/json',
          },
        ),
      );

      final routesRes = await dio.get<List<dynamic>>('/routes');
      final routeList = routesRes.data ?? [];

      final List<_RouteData> loaded = [];

      for (final r in routeList) {
        final routeId = (r['route_id'] ?? r['id'] ?? '').toString();
        if (routeId.isEmpty) continue;

        List<LatLng> positions = [];
        try {
          final posRes = await dio.get<List<dynamic>>('/routes/$routeId/positions');
          positions = (posRes.data ?? [])
              .map<LatLng>((p) => LatLng(
                    (p['lat'] as num).toDouble(),
                    (p['lng'] as num).toDouble(),
                  ))
              .toList();
        } catch (_) {}

        loaded.add(_RouteData(
          routeId: routeId,
          currentPositionId: (r['current_position_id'] as int?) ?? 1,
          status: (r['status'] ?? 'pendiente').toString(),
          positions: positions,
        ));
      }

      if (mounted) {
        setState(() {
          _routes = loaded;
          _isLoading = false;
        });
      }
    } catch (e) {
      if (mounted) {
        setState(() {
          _error = e.toString();
          _isLoading = false;
        });
      }
    }
  }

  Marker _buildTruckMarker(_RouteData route, Color color) {
    final posIdx = (route.currentPositionId - 1).clamp(0, route.positions.length - 1);
    return Marker(
      point: route.positions[posIdx],
      width: 48,
      height: 48,
      child: Tooltip(
        message: '${route.routeId} · pos ${route.currentPositionId} · ${route.status}',
        child: Container(
          decoration: BoxDecoration(
            color: color,
            shape: BoxShape.circle,
            border: Border.all(color: Colors.white, width: 2),
          ),
          child: const Icon(Icons.local_shipping, color: Colors.white, size: 22),
        ),
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    final routesWithPos = _routes.where((r) => r.positions.isNotEmpty).toList();

    return Scaffold(
      appBar: AppBar(
        title: const Text('Panel de Control - Flotilla'),
        backgroundColor: AppTheme.primaryDark,
        foregroundColor: Colors.white,
        elevation: 0,
        actions: [
          IconButton(
            icon: const Icon(Icons.refresh),
            onPressed: _loadRoutes,
            tooltip: 'Actualizar',
          ),
        ],
      ),
      body: Column(
        children: [
          Container(
            width: double.infinity,
            color: AppTheme.amberLight,
            padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 12),
            child: const Row(
              children: [
                Icon(Icons.security, color: AppTheme.amber, size: 20),
                SizedBox(width: 10),
                Expanded(
                  child: Text(
                    'Privilegio Admin: Vista global de coordenadas. No compartir pantalla.',
                    style: TextStyle(
                      fontSize: 12,
                      fontWeight: FontWeight.w600,
                      color: AppTheme.amber,
                    ),
                  ),
                ),
              ],
            ),
          ),
          Expanded(
            child: Stack(
              children: [
                FlutterMap(
                  options: const MapOptions(
                    initialCenter: _kRelleno,
                    initialZoom: 12.5,
                    interactionOptions: InteractionOptions(
                      flags: InteractiveFlag.all,
                    ),
                  ),
                  children: [
                    TileLayer(
                      urlTemplate:
                          'https://tile.openstreetmap.org/{z}/{x}/{y}.png',
                      userAgentPackageName: 'com.onlineshack.recolecta',
                    ),
                    if (routesWithPos.isNotEmpty) ...[
                      PolylineLayer(
                        polylines: [
                          for (int i = 0; i < routesWithPos.length; i++)
                            if (routesWithPos[i].positions.length > 1)
                              Polyline(
                                points: routesWithPos[i].positions,
                                color: _kRouteColors[i % _kRouteColors.length]
                                    .withValues(alpha: 0.7),
                                strokeWidth: 3.5,
                              ),
                        ],
                      ),
                      MarkerLayer(
                        markers: [
                          for (int i = 0; i < routesWithPos.length; i++)
                            _buildTruckMarker(
                              routesWithPos[i],
                              _kRouteColors[i % _kRouteColors.length],
                            ),
                        ],
                      ),
                    ],
                  ],
                ),
                if (_isLoading)
                  const Center(child: CircularProgressIndicator()),
                if (_error != null && !_isLoading)
                  Positioned(
                    bottom: 16,
                    left: 16,
                    right: 16,
                    child: Container(
                      padding: const EdgeInsets.all(12),
                      decoration: BoxDecoration(
                        color: AppTheme.danger.withValues(alpha: 0.9),
                        borderRadius: BorderRadius.circular(8),
                      ),
                      child: Text(
                        'Sin conexión al backend: $_error',
                        style: const TextStyle(
                          color: Colors.white,
                          fontSize: 12,
                        ),
                      ),
                    ),
                  ),
                if (routesWithPos.isNotEmpty)
                  Positioned(
                    top: 12,
                    right: 12,
                    child: _RouteLegend(routes: routesWithPos),
                  ),
              ],
            ),
          ),
        ],
      ),
    );
  }
}

class _RouteLegend extends StatelessWidget {
  const _RouteLegend({required this.routes});

  final List<_RouteData> routes;

  @override
  Widget build(BuildContext context) {
    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 10, vertical: 8),
      decoration: BoxDecoration(
        color: Colors.white.withValues(alpha: 0.93),
        borderRadius: BorderRadius.circular(8),
        boxShadow: const [BoxShadow(color: Colors.black12, blurRadius: 4)],
      ),
      child: Column(
        mainAxisSize: MainAxisSize.min,
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          for (int i = 0; i < routes.length; i++)
            Padding(
              padding: const EdgeInsets.symmetric(vertical: 2),
              child: Row(
                mainAxisSize: MainAxisSize.min,
                children: [
                  Container(
                    width: 10,
                    height: 10,
                    decoration: BoxDecoration(
                      color: _kRouteColors[i % _kRouteColors.length],
                      shape: BoxShape.circle,
                    ),
                  ),
                  const SizedBox(width: 6),
                  Text(
                    '${routes[i].routeId}  ·  pos ${routes[i].currentPositionId}',
                    style: const TextStyle(
                      fontSize: 10,
                      color: AppTheme.textPrimary,
                    ),
                  ),
                ],
              ),
            ),
        ],
      ),
    );
  }
}