import 'package:chain_client_sdk/chain_client_sdk.dart' as chain;

import 'hub_endpoint.dart';
import 'models.dart';
import 'repository.dart';

/// Live `EvaluationRepository` backed by a Ch∆In hub over gRPC.
///
/// Phase 0 scope: open a HubClient, run a healthy() probe, and
/// surface the connection state to the UI. The list() / byEli()
/// methods return empty data because no flow on the hub yet
/// produces Evaluation objects in the lawheatmap-specific shape —
/// that pipeline lands in Phase 0 week 1 once a chain run wraps
/// flows/durchstich-gewo-14.yaml output into the Evaluation
/// schema.
///
/// Until then [MockRepository] stays the default. Pick this
/// repository explicitly via the Hub-settings page; on first
/// healthy() failure the app falls back to MockRepository so the
/// UI keeps working.
class HubRepository implements EvaluationRepository {
  HubRepository._(this._client, this.settings, this._healthy);

  final chain.HubClient _client;
  final HubSettings settings;
  final bool _healthy;

  /// Try to connect. Returns a repository with `isHealthy=false`
  /// if the probe times out or the hub is unreachable; the
  /// caller decides whether to use it or fall back to
  /// MockRepository.
  static Future<HubRepository> connect(HubSettings settings) async {
    final endpoint = chain.HubEndpoint(
      host: settings.host,
      port: settings.port,
      secure: settings.secure,
    );
    final client = chain.HubClient(
      endpoint: endpoint,
      authToken: settings.authToken,
    );
    final ok = await client.healthy().timeout(
          const Duration(seconds: 4),
          onTimeout: () => false,
        );
    return HubRepository._(client, settings, ok);
  }

  bool get isHealthy => _healthy;

  /// Underlying SDK client — exposed so the hub-status page can
  /// list capabilities, query the audit log, and verify the
  /// event-chain without leaking gRPC types to other pages.
  chain.HubClient get client => _client;

  @override
  Future<List<Evaluation>> list() async {
    // Phase 0 placeholder. The pipeline that turns
    // flow.completed events into Evaluation objects lives in the
    // surrounding flow (flows/durchstich-gewo-14.yaml) and lands
    // in Phase 0 week 1.
    return const [];
  }

  @override
  Future<Evaluation?> byEli(String eli) async => null;

  @override
  String get mode => _healthy ? 'hub-live' : 'hub-down';

  @override
  String get hubLabel => '${settings.url}'
      '${_healthy ? '' : ' — Verbindung gestört'}';
}