import 'dart:convert';
import 'dart:io';

List<List<double>> decodePolyline(String encoded) {
  List<List<double>> poly = [];
  int index = 0, len = encoded.length;
  int lat = 0, lng = 0;

  while (index < len) {
    int b, shift = 0, result = 0;
    do {
      if (index >= len) break;
      b = encoded.codeUnitAt(index++) - 63;
      result |= (b & 0x1f) << shift;
      shift += 5;
    } while (b >= 0x20);
    int dlat = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
    lat += dlat;

    shift = 0;
    result = 0;
    do {
      if (index >= len) break;
      b = encoded.codeUnitAt(index++) - 63;
      result |= (b & 0x1f) << shift;
      shift += 5;
    } while (b >= 0x20);
    int dlng = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
    lng += dlng;

    poly.add([lat / 1e5, lng / 1e5]);
  }
  return poly;
}

void main() async {
  final origin = "401 route du camping, 69850 Saint Martin en haut";
  final destination = "Salle des fêtes, Orliénas";

  final requestBody = jsonEncode({
    "data": {
      "origin": origin,
      "destination": destination,
      "vehicleTollCategory": 2
    }
  });

  // Since we don't have the auth token, let's bypass auth if possible, or just call Google Maps directly!
  // Wait, I can't call Google Maps directly without API_MAPS key.
  // I will read .env file.
  final envFile = File('functions/.env');
  final lines = await envFile.readAsLines();
  String apiKey = '';
  for (var line in lines) {
    if (line.startsWith('API_MAPS=')) {
      apiKey = line.split('=')[1].replaceAll('"', '');
    }
  }

  if (apiKey.isEmpty) {
    print("API_MAPS not found");
    return;
  }

  final url = 'https://routes.googleapis.com/directions/v2:computeRoutes';
  final client = HttpClient();
  final request = await client.postUrl(Uri.parse(url));
  request.headers.set('Content-Type', 'application/json');
  request.headers.set('X-Goog-Api-Key', apiKey);
  request.headers.set('X-Goog-FieldMask', 'routes.distanceMeters,routes.duration,routes.polyline.encodedPolyline');
  
  final payload = jsonEncode({
    "travelMode": "DRIVE",
    "routingPreference": "TRAFFIC_AWARE",
    "origin": { "address": origin },
    "destination": { "address": destination }
  });
  
  request.write(payload);
  final response = await request.close();
  final responseBody = await response.transform(utf8.decoder).join();
  
  try {
    final json = jsonDecode(responseBody);
    final routes = json['routes'] as List;
    final polyStr = routes[0]['polyline']['encodedPolyline'];
    print("POLYLINE_START");
    print(polyStr);
    print("POLYLINE_END");
  } catch (e) {
    print("Error: $e\n$responseBody");
  }
}