// Backend API endpoints:
//   POST /auth/login              body: {"username":"...","secret":"..."}
//                                 → {"access_token":"...","token_type":"bearer"}
//   GET  /groups/me               header: Authorization: Bearer TOKEN
//                                 → [{"id":"uuid","name":"...","description":"...","is_active":true}]
//
// LiveKit token از طریق WebSocket دریافت می‌شود:
//   WS   /ws/groups/{id}?token={jwt}

import 'dart:convert';
import 'package:http/http.dart' as http;
import '../config/app_config.dart';
import '../models/channel.dart';
import 'auth_service.dart';

// ── Fake data (only used when AppConfig.debug == true) ────────────────────
const _fakeChannels = [
  {'id': '1', 'name': 'تیم آلفا'},
  {'id': '2', 'name': 'پشتیبانی میدانی'},
  {'id': '3', 'name': 'فرماندهی'},
  {'id': '4', 'name': 'گروه لجستیک'},
  {'id': '5', 'name': 'واحد امنیت'},
];
// ─────────────────────────────────────────────────────────────────────────

class ApiService {
  final AuthService _auth;

  ApiService(this._auth);

  Future<Map<String, String>> _headers() async {
    final token = await _auth.getToken();
    return {
      'Content-Type': 'application/json',
      if (token != null) 'Authorization': 'Bearer $token',
    };
  }

  // استخراج user_id از JWT token (بدون نیاز به کتابخانه)
  String? _extractUserIdFromJwt(String token) {
    try {
      final parts = token.split('.');
      if (parts.length < 2) return null;
      // base64url decode payload
      var payload = parts[1];
      // اضافه کردن padding اگه لازمه
      while (payload.length % 4 != 0) {
        payload += '=';
      }
      final decoded = utf8.decode(base64Url.decode(payload));
      final map = jsonDecode(decoded) as Map<String, dynamic>;
      return map['sub']?.toString();
    } catch (_) {
      return null;
    }
  }

  Future<bool> login(String username, String secret) async {
    if (AppConfig.debug) {
      await Future.delayed(const Duration(milliseconds: 600));
      await _auth.saveAuth(token: 'debug_jwt', userId: 'debug_user');
      return true;
    }

    try {
      final res = await http
          .post(
            Uri.parse('${AppConfig.baseUrl}/auth/login'),
            headers: {'Content-Type': 'application/json'},
            body: jsonEncode({'username': username, 'secret': secret}),
          )
          .timeout(const Duration(seconds: 10));

      if (res.statusCode == 200) {
        final data = jsonDecode(res.body) as Map<String, dynamic>;
        final accessToken = data['access_token'] as String?;
        if (accessToken == null) return false;
        final userId = _extractUserIdFromJwt(accessToken);
        await _auth.saveAuth(token: accessToken, userId: userId);
        return true;
      }
      return false;
    } catch (_) {
      return false;
    }
  }

  Future<List<Channel>> getChannels() async {
    if (AppConfig.debug) {
      await Future.delayed(const Duration(milliseconds: 500));
      return _fakeChannels
          .map((e) => Channel.fromJson(e as Map<String, dynamic>))
          .toList();
    }

    try {
      final res = await http
          .get(
            Uri.parse('${AppConfig.baseUrl}/users/me/groups'),
            headers: await _headers(),
          )
          .timeout(const Duration(seconds: 10));

      if (res.statusCode == 200) {
        final list = jsonDecode(res.body) as List;
        return list
            .map((e) => Channel.fromJson(e as Map<String, dynamic>))
            .toList();
      }
      return [];
    } catch (_) {
      return [];
    }
  }
}