import 'dart:async';
// ignore: avoid_web_libraries_in_flutter
import 'dart:js' as js;
import 'package:flutter/foundation.dart';
import 'package:prosapp_web_app/services/api_service.dart';

// Result of a reverse geocode via the Maps JS SDK Geocoder
class GeocodeResult {
  final String formattedAddress;
  final List<Map<String, dynamic>> addressComponents;
  const GeocodeResult({required this.formattedAddress, required this.addressComponents});
}

class MapsService {
  static bool _loaded = false;
  static Completer<bool>? _completer;

  static Future<bool> load() async {
    if (_loaded) return true;
    if (_completer != null) return _completer!.future;

    _completer = Completer<bool>();

    try {
      final data = await ApiService.instance.get('/settings/maps-key');
      final apiKey = data['api_key'] as String? ?? '';

      if (apiKey.isEmpty) {
        debugPrint('MapsService: API key no configurada');
        _completer!.complete(false);
        return false;
      }

      if (kIsWeb) {
        _injectScript(apiKey);
      }

      _loaded = true;
      _completer!.complete(true);
      return true;
    } catch (e) {
      debugPrint('MapsService: error cargando key — $e');
      _completer!.complete(false);
      return false;
    }
  }

  // Uses the already-loaded Maps JS SDK Geocoder — no separate Geocoding API enablement needed.
  static Future<GeocodeResult?> reverseGeocode(double lat, double lng) async {
    final completer = Completer<GeocodeResult?>();
    final id = '_gc${DateTime.now().millisecondsSinceEpoch}';

    try {
      js.context['${id}_ok'] = js.allowInterop((String address, String compsJson) {
        try { js.context.deleteProperty('${id}_ok'); } catch (_) {}
        try {
          final rawList = js.context.callMethod('eval', ['JSON.parse(\'${compsJson.replaceAll("'", "\\'")}\')']);
          final comps = <Map<String, dynamic>>[];
          // rawList is a JS array; iterate by index
          final len = (rawList['length'] as num?)?.toInt() ?? 0;
          for (var i = 0; i < len; i++) {
            final item = rawList[i] as js.JsObject;
            final types = <String>[];
            final tLen = (item['types']['length'] as num?)?.toInt() ?? 0;
            for (var t = 0; t < tLen; t++) types.add(item['types'][t].toString());
            comps.add({'long_name': item['long_name'].toString(), 'types': types});
          }
          completer.complete(GeocodeResult(formattedAddress: address, addressComponents: comps));
        } catch (_) {
          completer.complete(GeocodeResult(formattedAddress: address, addressComponents: []));
        }
      });

      js.context['${id}_err'] = js.allowInterop(() {
        try { js.context.deleteProperty('${id}_err'); } catch (_) {}
        completer.complete(null);
      });

      js.context.callMethod('eval', ['''
        (function(){
          try {
            var g = new google.maps.Geocoder();
            g.geocode({location:{lat:$lat,lng:$lng},language:'es'}, function(r,s){
              if(s==='OK'&&r&&r.length>0){
                var compsStr = JSON.stringify(r[0].address_components.map(function(c){
                  return {long_name:c.long_name,types:c.types};
                }));
                window['${id}_ok'](r[0].formatted_address, compsStr);
              } else { window['${id}_err'](); }
            });
          } catch(e){ window['${id}_err'](); }
        })();
      ''']);
    } catch (e) {
      completer.complete(null);
    }

    return completer.future.timeout(const Duration(seconds: 10), onTimeout: () => null);
  }

  static void _injectScript(String apiKey) {
    // Verifica si ya está cargado
    final existing = js.context.callMethod('eval', [
      'typeof google !== "undefined" && typeof google.maps !== "undefined"'
    ]);
    if (existing == true) {
      _loaded = true;
      return;
    }

    js.context.callMethod('eval', ['''
      (function() {
        var s = document.createElement('script');
        s.src = 'https://maps.googleapis.com/maps/api/js?key=$apiKey';
        s.async = true;
        document.head.appendChild(s);
      })();
    ''']);
  }
}