07 - ApiService

class ApiService {
  final StorageService _storage;

  ApiService({required StorageService storage}) : _storage = storage;
}

Map<String, String> get _headers {
  final headers = <String, String>{
    'Content-Type': 'application/json',
    'Accept': 'application/json',
  };

  final token = _storage.token;
  if (token != null) headers['Authorization'] = 'Bearer $token';

  final leadId = _storage.leadId;
  if (leadId != null) headers['X-Lead-Id'] = leadId;

  final sessionId = _storage.sessionId;
  if (sessionId != null) headers['X-Session-Id'] = sessionId;

  return headers;
}

Future<ApiResponse<T>> _post<T>(
  String url,
  Map<String, dynamic> body, {
  required T Function(Map<String, dynamic>) fromJson,
}) async {
  // Auto-inject leadId if missing from body
  body['leadId'] ??= _storage.leadId;

  try {
    final response = await http.post(
      Uri.parse(url),
      headers: _headers,
      body: jsonEncode(body),
    ).timeout(ApiConfig.apiTimeout);

    await _storage.updateActivity();   // reset session timer

    final json = jsonDecode(response.body) as Map<String, dynamic>;
    if (response.statusCode == 200 && json['success'] == true) {
      return ApiResponse.ok(
        fromJson(json['data'] as Map<String, dynamic>),
        json['message'] as String?,
      );
    }
    return ApiResponse.fail(
      json['message'] as String? ?? 'Unknown error',
      json['errorCode'] as String?,
    );
  } on SocketException {
    return ApiResponse.fail('No internet connection');
  } on TimeoutException {
    return ApiResponse.fail('Request timed out');
  } catch (e) {
    debugPrint('API error: $e');
    return ApiResponse.fail('Something went wrong');
  }
}

static String stageConfig(int stage) => '$_base/config/stage/$stage';

class StageConfig {
  final int stageNumber;
  final String displayName;
  final int progressPercent;

  StageConfig({required this.stageNumber, required this.displayName, required this.progressPercent});

  factory StageConfig.fromJson(Map<String, dynamic> json) => StageConfig(
    stageNumber: json['stageNumber'] as int,
    displayName: json['displayName'] as String,
    progressPercent: json['progressPercent'] as int,
  );
}

// Under the appropriate stage section
Future<ApiResponse<StageConfig>> getStageConfig(int stage) async {
  return _get<StageConfig>(
    ApiConfig.stageConfig(stage),
    fromJson: StageConfig.fromJson,
  );
}

final result = await api.getStageConfig(6);
if (result.success) {
  debugPrint('Stage 6: ${result.data!.displayName}');
}

class StorageService {
  // Singleton
  static Future<StorageService> getInstance();

  // Session identifiers
  String? get leadId;
  String? get sessionId;
  String? get token;
  int get currentStage;

  // Setters (all async, persist immediately)
  Future<void> setLeadId(String id);
  Future<void> setSessionId(String id);
  Future<void> setToken(String t);
  Future<void> setCurrentStage(int stage);

  // Derived
  bool get hasActiveLead => leadId != null;

  // Activity tracking (for session timer)
  Future<void> updateActivity();
  DateTime? get lastActivity;

  // Clear all (used on journey exit)
  Future<void> clearAll();
}