kent_logistics_app/lib/services/token_interceptor.dart

import 'dart:async';
import 'package:dio/dio.dart';
import 'package:flutter/material.dart';
import 'package:shared_preferences/shared_preferences.dart';
import '../config/api_config.dart';
import '../providers/auth_provider.dart';

class TokenInterceptor extends Interceptor {
  final AuthProvider authProvider;
  final BuildContext context;
  final Dio dio;

  Completer<bool>? _refreshCompleter;

  TokenInterceptor(this.authProvider, this.context, this.dio);

  // 🔐 Attach token to every request
  @override
  void onRequest(
      RequestOptions options, RequestInterceptorHandler handler) async {
    final prefs = await SharedPreferences.getInstance();
    final token = prefs.getString('token');

    if (token != null && token.isNotEmpty) {
      options.headers['Authorization'] = 'Bearer $token';
      debugPrint('🔐🔐🔐🔐🔐🔐 [REQUEST] Token attached → ${options.uri}');
    } else {
      debugPrint('⚠️⚠️⚠️⚠️⚠️⚠️ [REQUEST] No token found → ${options.uri}');
    }

    handler.next(options);
  }

  // 🔄 Handle 401 & refresh token
  @override
  void onError(DioException err, ErrorInterceptorHandler handler) async {
    debugPrint(
        '❌❌❌❌❌ [ERROR] ${err.response?.statusCode} on ${err.requestOptions.uri}');

    if (err.response?.statusCode == 401) {
      debugPrint('🔄🔄🔄🔄🔄🔄🔄 [AUTH] 401 detected, attempting refresh…');

      // If refresh already running, wait
      if (_refreshCompleter != null) {
        debugPrint('⏳⏳⏳⏳⏳⏳⏳⏳⏳ [REFRESH] Waiting for ongoing refresh to complete…');

        final success = await _refreshCompleter!.future;

        if (success) {
          debugPrint('✅✅✅✅✅✅✅✅ [REFRESH] Token refreshed, retrying request');

          final prefs = await SharedPreferences.getInstance();
          err.requestOptions.headers['Authorization'] =
          'Bearer ${prefs.getString('token')}';

          final response = await dio.fetch(err.requestOptions);
          return handler.resolve(response);
        } else {
          debugPrint('❌❌❌❌❌❌ [REFRESH] Refresh failed while waiting');
        }
      }

      _refreshCompleter = Completer<bool>();

      debugPrint('🚀🚀🚀🚀🚀🚀🚀🚀 [REFRESH] Starting new refresh request');

      final refreshed = await _refreshToken();

      _refreshCompleter!.complete(refreshed);
      _refreshCompleter = null;

      if (refreshed) {
        debugPrint('✅✅✅✅✅✅✅✅✅ [REFRESH] Refresh successful, retrying original request');

        final prefs = await SharedPreferences.getInstance();
        err.requestOptions.headers['Authorization'] =
        'Bearer ${prefs.getString('token')}';

        final response = await dio.fetch(err.requestOptions);
        return handler.resolve(response);
      }

      debugPrint('🚪🚪🚪🚪🚪🚪 [AUTH] Refresh failed → logging out user');
      await authProvider.logout(context);
      //await authProvider.forceLogout(context);

    }

    handler.next(err);
  }

  // 🔁 Call refresh API using SEPARATE Dio
  Future<bool> _refreshToken() async {
    try {
      final prefs = await SharedPreferences.getInstance();
      final oldToken = prefs.getString('token');

      if (oldToken == null) {
        debugPrint('❌❌❌❌❌❌❌ [REFRESH] No old token found');
        return false;
      }

      debugPrint('📤📤📤📤📤 [REFRESH] Calling /auth/refresh');

      final refreshDio = Dio(
        BaseOptions(
          baseUrl: ApiConfig.baseUrl,
          headers: {
            'Authorization': 'Bearer $oldToken',
            'Accept': 'application/json',
          },
        ),
      );

      final res = await refreshDio.post('/auth/refresh');

      if (res.data['success'] == true && res.data['token'] != null) {
        await prefs.setString('token', res.data['token']);
        debugPrint('💾💾💾💾💾💾💾 [REFRESH] New token saved to SharedPreferences');
        return true;
      }

      debugPrint('❌❌❌❌❌❌ [REFRESH] API responded but refresh not allowed');
      return false;
    } catch (e) {
      debugPrint('🔥🔥🔥🔥🔥🔥 [REFRESH] Exception occurred: $e');
      return false;
    }
  }
}