import 'dart:convert';
import 'dart:math' as math;
import 'package:flutter/foundation.dart';
import 'package:http/http.dart' as http;
import 'road_alert_models.dart';
import 'road_alert_provider_interface.dart';

/// Client provider for Georgia 511 official traffic feeds via MotorSignal FastAPI backend.
class Georgia511RoadAlertProvider implements RoadAlertProvider {
  final http.Client _client;
  final String backendBaseUrl;
  final Future<String?> Function()? getAuthToken;

  Georgia511RoadAlertProvider({
    http.Client? client,
    String? backendBaseUrl,
    this.getAuthToken,
  })  : _client = client ?? http.Client(),
        backendBaseUrl = backendBaseUrl ?? _resolveDefaultBaseUrl();

  static String _resolveDefaultBaseUrl() {
    const apiUrl = String.fromEnvironment('MOTORSIGNAL_API_URL');
    if (apiUrl.isNotEmpty) return apiUrl;
    const apiBaseUrl = String.fromEnvironment('MOTORSIGNAL_API_BASE_URL');
    if (apiBaseUrl.isNotEmpty) return apiBaseUrl;
    return 'https://api.motorsignal.app';
  }

  @override
  String get id => 'ga511_official';

  @override
  String get name => 'Georgia 511 (Experimental)';

  @override
  Set<RoadAlertCategory> get supportedCategories => const {
        RoadAlertCategory.accident,
        RoadAlertCategory.roadClosure,
        RoadAlertCategory.construction,
        RoadAlertCategory.hazard,
      };

  Future<Map<String, String>> _buildHeaders({String? apiKey}) async {
    final headers = <String, String>{
      'Accept': 'application/json',
    };
    if (getAuthToken != null) {
      try {
        final token = await getAuthToken!();
        if (token != null && token.isNotEmpty) {
          headers['Authorization'] = 'Bearer $token';
          return headers;
        }
      } catch (e) {
        if (kDebugMode) {
          debugPrint('[Georgia511RoadAlertProvider] Error resolving auth token: $e');
        }
      }
    }
    if (apiKey != null && apiKey.isNotEmpty) {
      headers['Authorization'] = 'Bearer $apiKey';
    }
    return headers;
  }

  @override
  Future<RoadAlertProviderStatus> testConnection(String apiKey) async {
    try {
      final headers = await _buildHeaders(apiKey: apiKey);
      final uri = Uri.parse('$backendBaseUrl/api/v1/alerts/ops/health');
      final res = await _client.get(uri, headers: headers).timeout(const Duration(seconds: 4));
      if (res.statusCode == 200) {
        return RoadAlertProviderStatus.connected;
      } else if (res.statusCode == 401 || res.statusCode == 403) {
        return RoadAlertProviderStatus.authError;
      }
      return RoadAlertProviderStatus.networkError;
    } catch (e) {
      return RoadAlertProviderStatus.networkError;
    }
  }

  @override
  Future<List<RoadAlert>> getAlerts({
    required double latitude,
    required double longitude,
    required double radiusMeters,
    String? apiKey,
  }) async {
    const metersPerDegreeLat = 111320.0;
    final latDelta = radiusMeters / metersPerDegreeLat;
    final metersPerDegreeLng = metersPerDegreeLat * math.cos(latitude * math.pi / 180.0).abs();
    final lngDelta = metersPerDegreeLng > 0 ? radiusMeters / metersPerDegreeLng : latDelta;

    final minLat = (latitude - latDelta).clamp(-90.0, 90.0);
    final maxLat = (latitude + latDelta).clamp(-90.0, 90.0);
    final minLng = (longitude - lngDelta).clamp(-180.0, 180.0);
    final maxLng = (longitude + lngDelta).clamp(-180.0, 180.0);

    final queryParams = {
      'min_lat': minLat.toStringAsFixed(4),
      'min_lng': minLng.toStringAsFixed(4),
      'max_lat': maxLat.toStringAsFixed(4),
      'max_lng': maxLng.toStringAsFixed(4),
    };

    final uri = Uri.parse('$backendBaseUrl/api/v1/alerts/ga511').replace(
      queryParameters: queryParams,
    );

    try {
      final headers = await _buildHeaders(apiKey: apiKey);
      final response = await _client.get(uri, headers: headers).timeout(const Duration(seconds: 5));
      if (response.statusCode != 200) {
        return [];
      }

      final data = json.decode(response.body);
      final rawAlerts = data['alerts'] as List<dynamic>? ?? [];
      final List<RoadAlert> alerts = [];

      for (final raw in rawAlerts) {
        if (raw is! Map<String, dynamic>) continue;
        final id = raw['id']?.toString() ?? '';
        final catStr = raw['category']?.toString() ?? 'hazard';
        final category = RoadAlertCategory.values.firstWhere(
          (c) => c.name.toLowerCase() == catStr.toLowerCase(),
          orElse: () => RoadAlertCategory.hazard,
        );

        final lat = (raw['latitude'] as num?)?.toDouble() ?? 0.0;
        final lng = (raw['longitude'] as num?)?.toDouble() ?? 0.0;
        if (lat < -90.0 || lat > 90.0 || lng < -180.0 || lng > 180.0) continue;

        final reportedAtStr = raw['reported_at_utc']?.toString();
        final reportedAt = reportedAtStr != null
            ? (DateTime.tryParse(reportedAtStr) ?? DateTime.now())
            : DateTime.now();

        final expiresAtStr = raw['expires_at_utc']?.toString();
        final expiresAt = expiresAtStr != null ? DateTime.tryParse(expiresAtStr) : null;

        final dLat = (lat - latitude) * 111320.0;
        final dLng = (lng - longitude) * 111320.0 * math.cos(latitude * math.pi / 180.0);
        final distance = math.sqrt(dLat * dLat + dLng * dLng);

        alerts.add(
          RoadAlert(
            id: id,
            providerId: this.id,
            category: category,
            subtype: raw['subtype']?.toString(),
            latitude: lat,
            longitude: lng,
            roadName: raw['road_name']?.toString(),
            description: raw['description']?.toString() ?? 'GDOT 511 Incident',
            reportedAt: reportedAt,
            expiresAt: expiresAt,
            lastUpdated: DateTime.now(),
            confidence: (raw['confidence'] as num?)?.toDouble() ?? 0.95,
            severity: category == RoadAlertCategory.accident || category == RoadAlertCategory.roadClosure
                ? RoadAlertSeverity.high
                : RoadAlertSeverity.medium,
            source: raw['source']?.toString() ?? 'Georgia 511 (Experimental)',
            sourceType: RoadAlertSourceType.providerReported,
            status: RoadAlertStatus.active,
            distanceFromUser: distance,
            confirmations: 1,
            dismissals: 0,
          ),
        );
      }

      return alerts;
    } catch (e) {
      if (kDebugMode) {
        debugPrint('[Georgia511RoadAlertProvider] Failed to fetch alerts: $e');
      }
      return [];
    }
  }
}