import 'dart:convert';

import 'package:shared_preferences/shared_preferences.dart';

import 'connection.dart';

const _connectionsKey = 'connections';
const _activeConnectionIdKey = 'active_connection_id';

/// Reads/writes the saved connection list and active-connection id to
/// [SharedPreferences] as a plain JSON-encoded array. Not a secret store —
/// the API has no auth, so there's nothing sensitive in a saved base URL.
class ConnectionStorage {
  const ConnectionStorage(this._prefs);

  final SharedPreferences _prefs;

  List<Connection> readConnections() {
    final raw = _prefs.getString(_connectionsKey);
    if (raw == null || raw.isEmpty) return const [];
    final decoded = jsonDecode(raw) as List<dynamic>;
    return decoded
        .map((e) => Connection.fromJson(e as Map<String, dynamic>))
        .toList(growable: false);
  }

  Future<void> writeConnections(List<Connection> connections) async {
    final encoded = jsonEncode(connections.map((c) => c.toJson()).toList());
    await _prefs.setString(_connectionsKey, encoded);
  }

  String? readActiveConnectionId() => _prefs.getString(_activeConnectionIdKey);

  Future<void> writeActiveConnectionId(String? id) async {
    if (id == null) {
      await _prefs.remove(_activeConnectionIdKey);
    } else {
      await _prefs.setString(_activeConnectionIdKey, id);
    }
  }
}