chain-studio/lib/widgets/chain_workspace_switcher.dart

// ChainWorkspaceSwitcher — the AppBar workspace (project) control.
//
// One control, two mechanics (docs/architecture/projects.md,
// § Studio): for open/protected projects the choice sets the page
// filter AND the label new runs are stamped with. "All projects"
// stays reachable — a filter, not a jail. Sealed areas never
// appear here (own hub instance; stage-3 connection switch).
//
// The project colour is a marking dot only — Studio's blue stays
// the app accent (registered design deviation).

import 'package:flutter/material.dart';

import '../data/hub.dart';
import '../data/workspace.dart';
import '../l10n/app_localizations.dart';
import '../theme/tokens.dart';

class ChainWorkspaceSwitcher extends StatelessWidget {
  const ChainWorkspaceSwitcher({super.key});

  @override
  Widget build(BuildContext context) {
    return ListenableBuilder(
      listenable: Workspace.instance,
      builder: (context, _) {
        final l = AppLocalizations.of(context)!;
        final theme = Theme.of(context);
        final ws = Workspace.instance;
        final active = ws.active;
        final label = ws.isAll
            ? l.workspaceAll
            : (active?.name ?? ws.activeSlug);

        return Tooltip(
          message: l.workspaceSwitcherTooltip,
          child: PopupMenuButton<String>(
            onOpened: ws.refresh,
            onSelected: ws.setActive,
            itemBuilder: (context) => [
              PopupMenuItem(
                value: '',
                child: Row(
                  children: [
                    Icon(
                      Icons.grid_view_outlined,
                      size: 16,
                      color: theme.colorScheme.onSurfaceVariant,
                    ),
                    const SizedBox(width: ChainSpace.sm),
                    Text(l.workspaceAll),
                  ],
                ),
              ),
              if (ws.projects.isNotEmpty) const PopupMenuDivider(),
              for (final p in ws.projects)
                PopupMenuItem(
                  value: p.slug,
                  child: Row(
                    children: [
                      _ProjectDot(project: p),
                      const SizedBox(width: ChainSpace.sm),
                      Flexible(
                        child: Text(p.name, overflow: TextOverflow.ellipsis),
                      ),
                      if (p.isProtected) ...[
                        const SizedBox(width: ChainSpace.sm),
                        Tooltip(
                          message: l.workspaceProtectedHint,
                          child: Icon(
                            Icons.shield_outlined,
                            size: 14,
                            color: theme.colorScheme.onSurfaceVariant,
                          ),
                        ),
                      ],
                    ],
                  ),
                ),
            ],
            child: Container(
              padding: const EdgeInsets.symmetric(
                horizontal: ChainSpace.md,
                vertical: 5,
              ),
              decoration: BoxDecoration(
                color: theme.colorScheme.surfaceContainerHighest,
                borderRadius: BorderRadius.circular(ChainRadius.sm),
              ),
              child: Row(
                mainAxisSize: MainAxisSize.min,
                children: [
                  if (active != null) ...[
                    _ProjectDot(project: active),
                    const SizedBox(width: 6),
                  ] else ...[
                    Icon(
                      Icons.grid_view_outlined,
                      size: 14,
                      color: theme.colorScheme.onSurfaceVariant,
                    ),
                    const SizedBox(width: 6),
                  ],
                  ConstrainedBox(
                    constraints: const BoxConstraints(maxWidth: 160),
                    child: Text(
                      label,
                      overflow: TextOverflow.ellipsis,
                      style: theme.textTheme.labelMedium,
                    ),
                  ),
                  if (active?.isProtected ?? false) ...[
                    const SizedBox(width: 4),
                    Icon(
                      Icons.shield_outlined,
                      size: 13,
                      color: theme.colorScheme.onSurfaceVariant,
                    ),
                  ],
                  const SizedBox(width: 2),
                  Icon(
                    Icons.arrow_drop_down,
                    size: 18,
                    color: theme.colorScheme.onSurfaceVariant,
                  ),
                ],
              ),
            ),
          ),
        );
      },
    );
  }
}

/// The project's registry colour as a small marking dot. Falls
/// back to the theme's outline colour when the project has none.
class _ProjectDot extends StatelessWidget {
  final ProjectRef project;

  const _ProjectDot({required this.project});

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    return Container(
      width: 10,
      height: 10,
      decoration: BoxDecoration(
        color: _parseHex(project.color) ?? theme.colorScheme.outline,
        shape: BoxShape.circle,
      ),
    );
  }

  static Color? _parseHex(String hex) {
    final h = hex.replaceFirst('#', '');
    if (h.length != 6) return null;
    final v = int.tryParse(h, radix: 16);
    if (v == null) return null;
    return Color(0xFF000000 | v);
  }
}