BadNote/lib/screens/app_shell.dart

import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../diagnostics/badnote_log.dart';
import '../diagnostics/diagnostic_chrome.dart';
import '../diagnostics/diagnostic_export.dart';
import '../l10n/app_localizations.dart';
import '../theme/app_theme.dart';
import 'board_screen.dart';
import 'home_screen.dart';
import 'search_screen.dart';
import 'settings_screen.dart';

/// Unified product shell — single chrome for library, board, search, settings.
class AppShell extends ConsumerStatefulWidget {
  const AppShell({super.key});

  @override
  ConsumerState<AppShell> createState() => _AppShellState();
}

class _AppShellState extends ConsumerState<AppShell> {
  int _index = 0;
  final _diagKey = GlobalKey<DiagnosticChromeState>();

  @override
  void initState() {
    super.initState();
    BadNoteLog.instance.info(LogSubsystem.shell, 'shell_open');
  }

  @override
  Widget build(BuildContext context) {
    final l = AppLocalizations.of(context);
    final wide = MediaQuery.sizeOf(context).width >= 900;

    final destinations = [
      _Dest(Icons.menu_book_outlined, Icons.menu_book, l.libraryTab),
      _Dest(Icons.sticky_note_2_outlined, Icons.sticky_note_2, l.boardTab),
      _Dest(Icons.search, Icons.search, l.search),
      _Dest(Icons.tune, Icons.tune, l.settings),
    ];

    final pages = const [
      HomeScreen(embeddedInShell: true),
      BoardScreen(),
      SearchScreen(embeddedInShell: true),
      SettingsScreen(embeddedInShell: true),
    ];

    final body = DiagnosticChrome(
      key: _diagKey,
      child: pages[_index],
    );

    if (wide) {
      return Scaffold(
        body: Row(
          children: [
            NavigationRail(
              selectedIndex: _index,
              onDestinationSelected: _select,
              extended: MediaQuery.sizeOf(context).width >= 1200,
              labelType: MediaQuery.sizeOf(context).width >= 1200
                  ? NavigationRailLabelType.none
                  : NavigationRailLabelType.all,
              leading: Padding(
                padding: const EdgeInsets.only(top: 12, bottom: 24),
                child: Column(
                  children: [
                    Text(
                      'BadNote',
                      style: Theme.of(context).textTheme.titleLarge?.copyWith(
                            color: AppTokens.copper,
                            fontWeight: FontWeight.w700,
                          ),
                    ),
                    const SizedBox(height: 4),
                    Text(
                      l.shellTagline,
                      style: Theme.of(context).textTheme.labelSmall?.copyWith(
                            color: AppTokens.inkMuted,
                          ),
                    ),
                  ],
                ),
              ),
              trailing: Expanded(
                child: Align(
                  alignment: Alignment.bottomCenter,
                  child: Padding(
                    padding: const EdgeInsets.only(bottom: 16),
                    child: DiagnosticToggleButton(
                      onToggle: () => _diagKey.currentState?.toggle(),
                      onExport: () => _diagKey.currentState?.exportPack(),
                    ),
                  ),
                ),
              ),
              destinations: [
                for (final d in destinations)
                  NavigationRailDestination(
                    icon: Icon(d.icon),
                    selectedIcon: Icon(d.selectedIcon),
                    label: Text(d.label),
                  ),
              ],
            ),
            VerticalDivider(width: 1, color: AppTokens.rule.withValues(alpha: 0.8)),
            Expanded(child: body),
          ],
        ),
      );
    }

    return Scaffold(
      body: body,
      bottomNavigationBar: Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          NavigationBar(
            selectedIndex: _index,
            onDestinationSelected: _select,
            destinations: [
              for (final d in destinations)
                NavigationDestination(
                  icon: Icon(d.icon),
                  selectedIcon: Icon(d.selectedIcon),
                  label: d.label,
                ),
            ],
          ),
        ],
      ),
      floatingActionButton: FloatingActionButton.small(
        heroTag: 'diag_fab',
        tooltip: AppLocalizations.of(context).diagnosticsSection,
        onPressed: () => _diagKey.currentState?.toggle(),
        child: const Icon(Icons.bug_report_outlined),
      ),
    );
  }

  void _select(int i) {
    BadNoteLog.instance.info(LogSubsystem.shell, 'tab', fields: {'index': i});
    setState(() => _index = i);
  }
}

class _Dest {
  const _Dest(this.icon, this.selectedIcon, this.label);
  final IconData icon;
  final IconData selectedIcon;
  final String label;
}

/// Helper used by settings when not embedded — still export packs.
Future<void> exportDiagnosticPack(BuildContext context) async {
  try {
    final result = await DiagnosticExport.instance.exportPack();
    if (!context.mounted) return;
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(
        content: Text(AppLocalizations.of(context).diagExported(result.bytes)),
        duration: const Duration(seconds: 5),
      ),
    );
  } catch (e) {
    if (!context.mounted) return;
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(content: Text(AppLocalizations.of(context).diagExportFail('$e'))),
    );
  }
}