import 'package:halkyon_learn_flutter/src/feature/assistant/data/assistant_gateway.dart';
import 'package:halkyon_learn_flutter/src/feature/assistant/model/connected_assistant.dart';

/// An instance offering the connector at [url] (none when null), with
/// [initially] connected; [unreachable] makes every call fail as offline.
class FakeAssistantGateway({
  /// Where the connector is; none when null.
  final String? url = 'https://learn.example.org/mcp',

  /// The assistants connected at first.
  final List<ConnectedAssistant> initially = const [],
}) implements AssistantGateway {
  /// Whether the instance can't be reached, failing every call while set.
  bool unreachable = false;

  /// The assistants connected.
  late final List<ConnectedAssistant> connected = [...initially];

  /// The codes given out, the last one valid.
  final codes = <String>[];

  void _reach() {
    if (unreachable) {
      throw Exception('offline');
    }
  }

  @override
  Future<String?> connectorUrl() async {
    _reach();
    return url;
  }

  @override
  Future<ConnectCode> connectCode() async {
    _reach();
    final code = 'K7QX-M2P${codes.length}';
    codes.add(code);
    return (code: code, expiresAt: DateTime.utc(2026, 10, 10, 12, 10));
  }

  @override
  Future<List<ConnectedAssistant>> connections() async {
    _reach();
    return [...connected];
  }

  @override
  Future<void> disconnect(int id) async {
    _reach();
    connected.removeWhere((assistant) => assistant.id == id);
  }
}