// lib/screens/search_screen.dart
import 'dart:convert';
import 'dart:ui';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import '../core/utils/error_utils.dart';

// Location packages
import 'package:geolocator/geolocator.dart';
import 'package:geocoding/geocoding.dart';

/// Data model for a location suggestion (city + optional pincode + optional coords).
class _LocationItem {
  final String city;
  final String? district;
  final String? pincode;
  final double? lat;
  final double? lng;

  const _LocationItem({required this.city, this.district, this.pincode, this.lat, this.lng});

  String get displayTitle => district != null && district!.isNotEmpty ? '$city, $district' : city;
  String get displaySubtitle => pincode ?? '';

  /// What gets returned to the caller (city name + optional district for display in pill).
  String get returnValue => displayTitle;
}

class SearchScreen extends StatefulWidget {
  const SearchScreen({Key? key}) : super(key: key);

  @override
  State<SearchScreen> createState() => _SearchScreenState();
}

class _SearchScreenState extends State<SearchScreen> {
  final TextEditingController _ctrl = TextEditingController();

  /// Popular Kerala cities shown as chips.
  static const List<String> _popularCities = [
    'Thiruvananthapuram',
    'Kochi',
    'Kozhikode',
    'Kollam',
    'Thrissur',
    'Kannur',
    'Alappuzha',
    'Palakkad',
    'Malappuram',
    'Kottayam',
  ];

  /// Searchable location database – loaded from assets/data/kerala_pincodes.json.
  List<_LocationItem> _locationDb = [];
  bool _pinsLoaded = false;

  List<_LocationItem> _searchResults = [];
  bool _showSearchResults = false;
  bool _loadingLocation = false;

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

  Future<void> _loadKeralaData() async {
    if (_pinsLoaded) return;
    try {
      final jsonStr = await rootBundle.loadString('assets/data/kerala_pincodes.json');
      final List<dynamic> list = jsonDecode(jsonStr);
      final loaded = list.map((e) => _LocationItem(
        city: e['city'] as String,
        district: e['district'] as String?,
        pincode: e['pincode'] as String?,
        lat: (e['lat'] as num?)?.toDouble(),
        lng: (e['lng'] as num?)?.toDouble(),
      )).toList();
      if (mounted) {
        setState(() {
          _locationDb = loaded;
          _pinsLoaded = true;
        });
      }
    } catch (_) {
      // fallback: keep empty list, search won't crash
    }
  }

  @override
  void dispose() {
    _ctrl.dispose();
    super.dispose();
  }

  void _onQueryChanged(String q) {
    final ql = q.trim().toLowerCase();
    setState(() {
      if (ql.isEmpty) {
        _showSearchResults = false;
        _searchResults = [];
      } else {
        _showSearchResults = true;
        _searchResults = _locationDb.where((loc) {
          return loc.city.toLowerCase().contains(ql) ||
              (loc.district?.toLowerCase().contains(ql) ?? false) ||
              (loc.pincode?.contains(ql) ?? false);
        }).toList();
      }
    });
  }

  /// Pop with a structured result so home_screen can update the display label,
  /// pincode, and GPS coordinates used for haversine filtering.
  void _selectWithPincode(String label, {String? pincode, double? lat, double? lng}) {
    final result = <String, dynamic>{
      'label': label,
      'pincode': pincode ?? 'all',
    };
    if (lat != null && lng != null) {
      result['lat'] = lat;
      result['lng'] = lng;
    }
    Navigator.of(context).pop(result);
  }

  void _selectAndClose(String location) {
    // Looks up pincode + coordinates from the database for the given city name.
    final match = _locationDb.cast<_LocationItem?>().firstWhere(
      (loc) => loc!.city.toLowerCase() == location.toLowerCase() ||
               loc.displayTitle.toLowerCase() == location.toLowerCase(),
      orElse: () => null,
    );
    _selectWithPincode(location, pincode: match?.pincode, lat: match?.lat, lng: match?.lng);
  }

  Future<void> _useCurrentLocation() async {
    setState(() => _loadingLocation = true);

    try {
      LocationPermission permission = await Geolocator.checkPermission();
      if (permission == LocationPermission.denied) {
        permission = await Geolocator.requestPermission();
      }

      if (permission == LocationPermission.deniedForever || permission == LocationPermission.denied) {
        if (mounted) {
          ScaffoldMessenger.of(context).showSnackBar(const SnackBar(content: Text('Location permission denied')));
          Navigator.of(context).pop(<String, dynamic>{'label': 'Current Location', 'pincode': 'all'});
        }
        return;
      }

      final pos = await Geolocator.getCurrentPosition(desiredAccuracy: LocationAccuracy.best);

      String label = 'Current Location';
      try {
        final placemarks = await placemarkFromCoordinates(pos.latitude, pos.longitude);
        if (placemarks.isNotEmpty) {
          final p = placemarks.first;
          final parts = <String>[];
          if ((p.subLocality ?? '').isNotEmpty) parts.add(p.subLocality!);
          if ((p.locality ?? '').isNotEmpty) parts.add(p.locality!);
          if ((p.subAdministrativeArea ?? '').isNotEmpty) parts.add(p.subAdministrativeArea!);
          if (parts.isNotEmpty) label = parts.join(', ');
        }
      } catch (_) {}

      if (mounted) {
        // Return lat/lng so home_screen can use haversine filtering
        Navigator.of(context).pop(<String, dynamic>{
          'label': label,
          'pincode': 'all',
          'lat': pos.latitude,
          'lng': pos.longitude,
        });
      }
      return;
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text(userFriendlyError(e))));
        Navigator.of(context).pop(<String, dynamic>{'label': 'Current Location', 'pincode': 'all'});
      }
    } finally {
      if (mounted) setState(() => _loadingLocation = false);
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.transparent,
      body: GestureDetector(
        onTap: () => Navigator.of(context).pop(),
        behavior: HitTestBehavior.opaque,
        child: Stack(
          children: [
            RepaintBoundary(
              child: BackdropFilter(
                filter: ImageFilter.blur(sigmaX: 8.0, sigmaY: 8.0),
                child: Container(color: Colors.black.withOpacity(0.16)),
              ),
            ),
            Align(
              alignment: Alignment.bottomCenter,
              child: GestureDetector(
                onTap: () {}, // prevent taps on sheet from closing
                child: _buildSheet(context),
              ),
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildSheet(BuildContext context) {
    return Container(
      constraints: BoxConstraints(maxHeight: MediaQuery.of(context).size.height * 0.78, minHeight: 240),
      decoration: const BoxDecoration(
        color: Colors.white,
        borderRadius: BorderRadius.vertical(top: Radius.circular(24)),
        boxShadow: [BoxShadow(color: Colors.black26, blurRadius: 12)],
      ),
      child: SafeArea(
        top: false,
        child: SingleChildScrollView(
          padding: const EdgeInsets.fromLTRB(20, 18, 20, 28),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              // Header row
              Row(
                mainAxisAlignment: MainAxisAlignment.spaceBetween,
                children: [
                  const Text('Set Your Location', style: TextStyle(fontSize: 22, fontWeight: FontWeight.bold, color: Color(0xFF1A1A2E))),
                  InkWell(
                    onTap: () => Navigator.of(context).pop(),
                    borderRadius: BorderRadius.circular(12),
                    child: Container(
                      width: 40,
                      height: 40,
                      decoration: BoxDecoration(color: const Color(0xFF1A1A2E), borderRadius: BorderRadius.circular(10)),
                      child: const Icon(Icons.close, color: Colors.white, size: 20),
                    ),
                  ),
                ],
              ),
              const SizedBox(height: 16),

              // Search field
              Container(
                padding: const EdgeInsets.symmetric(horizontal: 14),
                decoration: BoxDecoration(
                  color: Colors.grey[100],
                  borderRadius: BorderRadius.circular(14),
                  border: _ctrl.text.isNotEmpty ? Border.all(color: const Color(0xFF2563EB).withOpacity(0.5), width: 1.5) : null,
                ),
                child: Row(
                  children: [
                    Icon(Icons.search, color: Colors.grey[500]),
                    const SizedBox(width: 10),
                    Expanded(
                      child: TextField(
                        controller: _ctrl,
                        decoration: const InputDecoration(
                          hintText: 'Search city, area or locality',
                          hintStyle: TextStyle(color: Color(0xFF9CA3AF)),
                          border: InputBorder.none,
                          contentPadding: EdgeInsets.symmetric(vertical: 14),
                        ),
                        textInputAction: TextInputAction.search,
                        onChanged: _onQueryChanged,
                        onSubmitted: (v) {
                          final q = v.trim();
                          if (q.isEmpty) return;
                          if (_searchResults.isNotEmpty) {
                            _selectAndClose(_searchResults.first.returnValue);
                          } else {
                            _selectAndClose(q);
                          }
                        },
                      ),
                    ),
                    if (_ctrl.text.isNotEmpty)
                      IconButton(
                        icon: const Icon(Icons.clear, size: 20),
                        onPressed: () {
                          _ctrl.clear();
                          _onQueryChanged('');
                        },
                      ),
                  ],
                ),
              ),
              const SizedBox(height: 16),

              // Use current location
              Material(
                color: const Color(0xFF2563EB),
                borderRadius: BorderRadius.circular(14),
                child: InkWell(
                  onTap: _loadingLocation ? null : () => _useCurrentLocation(),
                  borderRadius: BorderRadius.circular(14),
                  child: Padding(
                    padding: const EdgeInsets.symmetric(vertical: 16, horizontal: 16),
                    child: Row(
                      children: [
                        const Icon(Icons.my_location, color: Colors.white, size: 22),
                        const SizedBox(width: 12),
                        Expanded(
                          child: Text(
                            _loadingLocation ? 'Detecting location...' : 'Use Current Location',
                            style: const TextStyle(color: Colors.white, fontWeight: FontWeight.w600, fontSize: 15),
                          ),
                        ),
                        if (_loadingLocation)
                          const SizedBox(width: 20, height: 20, child: CircularProgressIndicator(color: Colors.white, strokeWidth: 2))
                        else
                          const Icon(Icons.chevron_right, color: Colors.white),
                      ],
                    ),
                  ),
                ),
              ),
              const SizedBox(height: 20),

              // Search results or Popular Cities
              if (_showSearchResults) ...[
                if (_searchResults.isEmpty)
                  Padding(
                    padding: const EdgeInsets.symmetric(vertical: 24),
                    child: Center(child: Text('No results found', style: TextStyle(color: Colors.grey[500]))),
                  )
                else
                  ConstrainedBox(
                    constraints: const BoxConstraints(maxHeight: 320),
                    child: ListView.separated(
                    shrinkWrap: false,
                    physics: const ClampingScrollPhysics(),
                    itemCount: _searchResults.length,
                    separatorBuilder: (_, __) => Divider(color: Colors.grey[200], height: 1),
                    itemBuilder: (ctx, idx) {
                      final loc = _searchResults[idx];
                      return ListTile(
                        contentPadding: const EdgeInsets.symmetric(horizontal: 4, vertical: 4),
                        leading: Icon(Icons.location_on_outlined, color: Colors.grey[400], size: 24),
                        title: Text(
                          loc.displayTitle,
                          style: const TextStyle(fontWeight: FontWeight.w600, fontSize: 15, color: Color(0xFF1A1A2E)),
                        ),
                        subtitle: loc.pincode != null && loc.pincode!.isNotEmpty
                            ? Text(loc.pincode!, style: TextStyle(color: Colors.grey[500], fontSize: 13))
                            : null,
                        onTap: () => _selectWithPincode(loc.displayTitle, pincode: loc.pincode, lat: loc.lat, lng: loc.lng),
                      );
                    },
                  ),
                  ),
              ] else ...[
                const Text('Popular Cities', style: TextStyle(fontWeight: FontWeight.bold, fontSize: 16, color: Color(0xFF1A1A2E))),
                const SizedBox(height: 12),
                Wrap(
                  spacing: 10,
                  runSpacing: 10,
                  children: [
                    for (final city in _popularCities)
                      InkWell(
                        onTap: () => _selectAndClose(city),
                        borderRadius: BorderRadius.circular(12),
                        child: Container(
                          padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 12),
                          decoration: BoxDecoration(color: const Color(0xFFF3F4F6), borderRadius: BorderRadius.circular(12)),
                          child: Text(
                            city.length > 16 ? '${city.substring(0, 14)}...' : city,
                            style: const TextStyle(color: Color(0xFF374151), fontWeight: FontWeight.w500, fontSize: 14),
                          ),
                        ),
                      ),
                  ],
                ),
              ],

              const SizedBox(height: 8),
            ],
          ),
        ),
      ),
    );
  }
}