import 'dart:async';
import 'dart:convert';
import 'package:flutter_secure_storage/flutter_secure_storage.dart';
import 'package:http/http.dart' as http;

class TokenStorage {
  final _storage = const FlutterSecureStorage();
  final String baseUrl;
  TokenStorage(this.baseUrl);

  Future<void> save(String access, String refresh) async {
    await _storage.write(key: 'access', value: access);
    await _storage.write(key: 'refresh', value: refresh);
  }

  Future<String?> get access async => await _storage.read(key: 'access');
  Future<String?> get refresh async => await _storage.read(key: 'refresh');
  Future<void> clear() async {
    await _storage.deleteAll();
  }

  /// Einfache Auto‑Refresh Logik
  Future<String?> getValidAccessToken() async {
    final token = await access;
// (Optional) hier exp prüfen. Für Kürze direkt refresh call beim 401 außerhalb.
    return token;
  }

  Future<void> refreshAccess() async {
    final r = await refresh;
    if (r == null) return;
    final res = await http.post(Uri.parse('$baseUrl/auth/refresh'),
        headers: {'Content-Type': 'application/json'},
        body: jsonEncode({'refresh_token': r}));
    if (res.statusCode == 200) {
      final m = jsonDecode(res.body) as Map<String, dynamic>;
      await _storage.write(key: 'access', value: m['access_token'] as String);
    } else {
      await clear();
    }
  }

  Future<bool> hasValidAccessToken() async {
    final a = await access;
    if (a == null || a.isEmpty) return false;
    try {
      final parts = a.split('.');
      if (parts.length != 3) return false;
      final payload = jsonDecode(
              utf8.decode(base64Url.decode(base64Url.normalize(parts[1]))))
          as Map<String, dynamic>;
      final exp = (payload['exp'] as num?)?.toInt();
      if (exp == null) return true;
      final now = DateTime.now().millisecondsSinceEpoch ~/ 1000;
      return now < exp - 15;
    } catch (_) {
      return false;
    }
  }
}