// Workspace — the active project selection shared across pages.
//
// One switcher in the AppBar drives two things at once (see
// docs/architecture/projects.md in the platform repo, § Studio):
// the page filter (audit, approvals) AND the label new runs are
// stamped with. "All projects" stays reachable — the selection is
// a filter, not a jail. Sealed areas are NOT listed here; they are
// their own hub instance and arrive with the stage-3 connection
// switch.

import 'package:flutter/foundation.dart';
import 'package:shared_preferences/shared_preferences.dart';

import 'hub.dart';

class Workspace extends ChangeNotifier {
  Workspace._();
  static final Workspace instance = Workspace._();

  static const _prefsKey = 'workspace.active';

  /// Registry projects (`general` first, as ordered by the hub).
  List<ProjectRef> _projects = const [];
  List<ProjectRef> get projects => _projects;

  /// Active project slug; empty = all projects (no filter).
  String _activeSlug = '';
  String get activeSlug => _activeSlug;
  bool get isAll => _activeSlug.isEmpty;

  /// The active project's registry entry, or null for "all".
  ProjectRef? get active {
    if (_activeSlug.isEmpty) return null;
    for (final p in _projects) {
      if (p.slug == _activeSlug) return p;
    }
    return null;
  }

  bool _loaded = false;

  /// Restore the persisted selection and pull the registry once.
  /// Safe to call repeatedly; only the first call restores.
  Future<void> ensureLoaded() async {
    if (!_loaded) {
      _loaded = true;
      try {
        final prefs = await SharedPreferences.getInstance();
        _activeSlug = prefs.getString(_prefsKey) ?? '';
      } catch (_) {
        // No persisted selection — start on "all projects".
      }
    }
    await refresh();
  }

  /// Re-pull the registry from the hub. Soft-fails (keeps the
  /// last list) so a hub restart doesn't blank the switcher; an
  /// active slug that vanished from the registry stays selected —
  /// its historical rows remain filterable, which is the honest
  /// behaviour for an audit surface.
  Future<void> refresh() async {
    try {
      final fresh = await HubService.instance.listProjects();
      if (!listEquals(fresh, _projects)) {
        _projects = fresh;
        notifyListeners();
      }
    } catch (_) {
      // Hub unreachable — the pages already surface that state.
    }
  }

  /// Test hook: seed registry + selection without a hub and mark
  /// the persisted state as restored so [ensureLoaded] won't
  /// overwrite the seed.
  @visibleForTesting
  void debugSeed({
    required List<ProjectRef> projects,
    required String active,
  }) {
    _projects = projects;
    _activeSlug = active;
    _loaded = true;
    notifyListeners();
  }

  /// Switch the active workspace ('' = all projects) and persist.
  Future<void> setActive(String slug) async {
    if (slug == _activeSlug) return;
    _activeSlug = slug;
    notifyListeners();
    try {
      final prefs = await SharedPreferences.getInstance();
      await prefs.setString(_prefsKey, slug);
    } catch (_) {
      // Persistence is best-effort; the in-memory switch stands.
    }
  }
}