import 'dart:convert';
import 'dart:math';

import 'package:absen/config/config.dart';
import 'package:absen/models/attendance_area.dart';
import 'package:absen/widgets/google_map_web_view.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:geolocator/geolocator.dart';
import 'package:google_maps_flutter/google_maps_flutter.dart';
import 'package:http/http.dart' as http;

import 'checkin_photo_screen.dart';

class CheckinScreen extends StatefulWidget {
  final String token;
  const CheckinScreen({Key? key, required this.token}) : super(key: key);

  @override
  State<CheckinScreen> createState() => _CheckinScreenState();
}

class _CheckinScreenState extends State<CheckinScreen> {
  Position? _position;
  bool _isLoading = false;
  GoogleMapController? _mapController;
  List<AttendanceArea> _areas = [];

  LatLng? get _latLng =>
      _position != null
          ? LatLng(_position!.latitude, _position!.longitude)
          : null;

  @override
  void initState() {
    super.initState();
    _getLocation();
    _fetchAttendanceAreas();
  }

  Future<void> _getLocation() async {
    try {
      bool serviceEnabled = await Geolocator.isLocationServiceEnabled();
      if (!serviceEnabled) {
        await Geolocator.openLocationSettings();
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(content: Text('Aktifkan layanan lokasi!')),
        );
        return;
      }
      LocationPermission permission = await Geolocator.checkPermission();
      if (permission == LocationPermission.denied) {
        permission = await Geolocator.requestPermission();
        if (permission == LocationPermission.denied) {
          ScaffoldMessenger.of(
            context,
          ).showSnackBar(const SnackBar(content: Text('Izin lokasi ditolak!')));
          return;
        }
      }
      if (permission == LocationPermission.deniedForever) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(content: Text('Izin lokasi permanen ditolak!')),
        );
        return;
      }
      Position? pos;
      try {
        pos = await Geolocator.getCurrentPosition(
          desiredAccuracy: LocationAccuracy.best,
          timeLimit: const Duration(seconds: 10),
        );
      } catch (_) {
        pos = await Geolocator.getLastKnownPosition();
      }

      if (pos == null || (pos.latitude == 0.0 && pos.longitude == 0.0)) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(content: Text('Lokasi belum akurat, coba lagi.')),
        );
        return;
      }

      setState(() => _position = pos);

      if (!kIsWeb &&
          _mapController != null &&
          _latLng != null &&
          _areas.isNotEmpty) {
        _moveCameraToBounds();
      }
    } catch (e) {
      ScaffoldMessenger.of(
        context,
      ).showSnackBar(SnackBar(content: Text('Gagal mengambil lokasi: $e')));
    }
  }

  Future<void> _fetchAttendanceAreas() async {
    final uri = Uri.parse('${AppConfig.baseUrl}/api/employee/attendance/areas');
    final token = widget.token;
    try {
      final resp = await http.get(
        uri,
        headers: {'Authorization': 'Bearer $token'},
      );
      if (resp.statusCode == 200) {
        final List<dynamic> data = jsonDecode(resp.body);
        final List<AttendanceArea> fetched =
            data.map((e) {
              return AttendanceArea(
                lat: (e['center_lat'] as num).toDouble(),
                lng: (e['center_lng'] as num).toDouble(),
                radius: (e['radius'] as num).toDouble(),
              );
            }).toList();
        setState(() {
          _areas = fetched;
        });
        if (_mapController != null && _position != null) {
          _moveCameraToBounds();
        }
      }
    } catch (_) {}
  }

  void _moveCameraToBounds() {
    if (_mapController == null || _position == null) return;
    final List<LatLng> points = [
      LatLng(_position!.latitude, _position!.longitude),
      ..._areas.map((a) => LatLng(a.lat, a.lng)),
    ];
    double south = points.first.latitude, north = points.first.latitude;
    double west = points.first.longitude, east = points.first.longitude;
    for (var p in points) {
      south = min(south, p.latitude);
      north = max(north, p.latitude);
      west = min(west, p.longitude);
      east = max(east, p.longitude);
    }
    final bounds = LatLngBounds(
      southwest: LatLng(south, west),
      northeast: LatLng(north, east),
    );
    Future.delayed(const Duration(milliseconds: 300), () {
      _mapController?.animateCamera(CameraUpdate.newLatLngBounds(bounds, 60));
    });
  }

  Future<void> _validateLocation() async {
    if (_position == null) return;
    setState(() => _isLoading = true);
    final uri = Uri.parse(
      '${AppConfig.baseUrl}/api/employee/attendance/check-location',
    );
    try {
      final response = await http.post(
        uri,
        headers: {
          'Authorization': 'Bearer ${widget.token}',
          'Content-Type': 'application/json',
        },
        body: jsonEncode({
          'latitude': _position!.latitude,
          'longitude': _position!.longitude,
          'type': 'in',
        }),
      );
      setState(() => _isLoading = false);
      final data = jsonDecode(response.body);
      if (response.statusCode == 200 && data['valid'] == true) {
        Navigator.push(
          context,
          MaterialPageRoute(
            builder:
                (_) => CheckinPhotoScreen(
                  token: widget.token,
                  position: _position!,
                ),
          ),
        );
      } else {
        final msg = data['message'] ?? 'Lokasi tidak valid';
        ScaffoldMessenger.of(
          context,
        ).showSnackBar(SnackBar(content: Text(msg)));
      }
    } catch (e) {
      setState(() => _isLoading = false);
      ScaffoldMessenger.of(
        context,
      ).showSnackBar(SnackBar(content: Text('Gagal validasi lokasi: $e')));
    }
  }

  @override
  Widget build(BuildContext context) {
    final buttonStyle = ElevatedButton.styleFrom(
      minimumSize: const Size.fromHeight(48),
      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(8)),
    );

    return Scaffold(
      appBar: AppBar(
        title: const Text('Check-in: Validasi Lokasi'),
        centerTitle: true,
      ),
      body: SafeArea(
        child: Padding(
          padding: const EdgeInsets.symmetric(horizontal: 16.0),
          child: Column(
            children: [
              const SizedBox(height: 16),
              const Text(
                'Pastikan GPS aktif dan Anda berada dalam area yang diperbolehkan. '
                'Tekan tombol di bawah untuk cek lokasi.',
                textAlign: TextAlign.center,
                style: TextStyle(fontSize: 16),
              ),
              const SizedBox(height: 16),
              Expanded(
                child: Card(
                  shape: RoundedRectangleBorder(
                    borderRadius: BorderRadius.circular(12),
                  ),
                  clipBehavior: Clip.hardEdge,
                  elevation: 4,
                  child: _buildMapWidget(),
                ),
              ),
              const SizedBox(height: 16),
              SizedBox(
                width: double.infinity,
                child: ElevatedButton(
                  style: buttonStyle,
                  onPressed:
                      (_position != null && !_isLoading)
                          ? _validateLocation
                          : null,
                  child:
                      _isLoading
                          ? const SizedBox(
                            width: 24,
                            height: 24,
                            child: CircularProgressIndicator(
                              color: Colors.white,
                              strokeWidth: 2,
                            ),
                          )
                          : const Text('Cek Lokasi & Lanjut'),
                ),
              ),
              const SizedBox(height: 16),
            ],
          ),
        ),
      ),
    );
  }

  Widget _buildMapWidget() {
    if (kIsWeb) {
      if (_position == null) {
        return const Center(child: Text('Lokasi belum diambil'));
      }
      return GoogleMapWebView(
        latitude: _position!.latitude,
        longitude: _position!.longitude,
        areas: _areas,
      );
    }
    if (_latLng == null) {
      return const Center(child: Text('Lokasi belum diambil'));
    }
    return SizedBox(
      height: 300,
      child: GoogleMap(
        initialCameraPosition: CameraPosition(
          target:
              _areas.isNotEmpty
                  ? LatLng(_areas[0].lat, _areas[0].lng)
                  : _latLng!,
          zoom: 17,
        ),
        markers: {
          Marker(
            markerId: const MarkerId('me'),
            position: _latLng!,
            infoWindow: const InfoWindow(title: 'Lokasi Anda'),
          ),
          ..._areas.asMap().entries.map(
            (entry) => Marker(
              markerId: MarkerId('area_${entry.key}'),
              position: LatLng(entry.value.lat, entry.value.lng),
              infoWindow: InfoWindow(title: 'Area Absen ${entry.key + 1}'),
              icon: BitmapDescriptor.defaultMarkerWithHue(
                BitmapDescriptor.hueAzure,
              ),
            ),
          ),
        },
        circles:
            _areas
                .asMap()
                .entries
                .map(
                  (entry) => Circle(
                    circleId: CircleId('absen_area_${entry.key}'),
                    center: LatLng(entry.value.lat, entry.value.lng),
                    radius: entry.value.radius,
                    fillColor: Colors.blue.withOpacity(0.2),
                    strokeColor: Colors.blue,
                    strokeWidth: 2,
                  ),
                )
                .toSet(),
        onMapCreated: (controller) {
          _mapController = controller;
          if (_position != null && _areas.isNotEmpty) {
            _moveCameraToBounds();
          }
        },
        myLocationEnabled: true,
      ),
    );
  }
}