import 'package:dio/dio.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:shared_preferences/shared_preferences.dart';
import '../../config/app_config.dart';
import 'api_exception.dart';

class ApiClient {
  late final Dio _dio;

  ApiClient() {
    _dio = Dio(
      BaseOptions(
        baseUrl: AppConfig.apiBaseUrl,
        connectTimeout: const Duration(seconds: 10),
        // Upload triggers a synchronous OCR pass server-side that can take up to
        // 210s worst case (see v1/documents/upload/route.ts's AbortSignal.timeout).
        // Keep a safety margin above that so a legitimately slow-but-successful
        // parse isn't killed client-side as a false "connection timeout".
        receiveTimeout: const Duration(seconds: 240),
        headers: {
          'Content-Type': 'application/json',
          'Accept': 'application/json',
        },
      ),
    );

    _setupInterceptors();
  }

  void _setupInterceptors() {
    // Request interceptor to append JWT token
    _dio.interceptors.add(InterceptorsWrapper(
      onRequest: (options, handler) async {
        final prefs = await SharedPreferences.getInstance();
        final token = prefs.getString('auth_token');
        if (token != null) {
          options.headers['Authorization'] = 'Bearer $token';
        }
        return handler.next(options);
      },
    ));

    // Logging interceptor for debugging
    _dio.interceptors.add(LogInterceptor(
      requestBody: true,
      responseBody: true,
    ));

    // Standardized Error Interceptor: wraps every failure into an ApiException
    // (attached as DioException.error) so call sites read one consistent shape
    // instead of reverse-engineering DioException.toString().
    _dio.interceptors.add(InterceptorsWrapper(
      onError: (DioException e, handler) {
        final apiException = ApiException.fromDioException(e);
        final customError = DioException(
          requestOptions: e.requestOptions,
          response: e.response,
          type: e.type,
          error: apiException,
        );
        return handler.next(customError);
      },
    ));

    // Dummy Response Interceptor for Development
    // TODO: Remove this interceptor before production release
    // _dio.interceptors.add(DummyResponseInterceptor());
  }

  Dio get client => _dio;
}

// Single shared instance so every screen/notifier reuses the same Dio HTTP client
// (connection keep-alive) instead of paying a fresh TCP/TLS handshake per call site.
final apiClientProvider = Provider<ApiClient>((ref) => ApiClient());