// Locks the sidebar invariant: destination icons sit at the same Y
// whether the rail is collapsed or expanded. The header rows above the
// destinations list have FIXED pixel heights (see _SidebarState), so
// expanding the rail (a width-only change) must not shift any
// destination vertically. This was a recurring regression source; this
// test pins it.
//
// Expansion is driven via StudioApp(startSidebarExpanded: true), NOT a
// hover gesture — hover mid-transition trips RenderFlex overflow in
// widget tests (see widget_test.dart). With the flag the rail's
// animation controller starts at value 1.0 (fully expanded), so no
// animation needs to settle.

import 'package:flutter/widgets.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:chain_studio/data/hub.dart';
import 'package:chain_studio/main.dart';

const _destinations = <String>[
  'welcome',
  'store',
  'doctor',
  'flows',
  'audit',
  'approvals',
  'federation',
];

Map<String, double> _destinationYs(WidgetTester tester) {
  final ys = <String, double>{};
  for (final id in _destinations) {
    final finder = find.byKey(ValueKey('sidebar-item-$id'));
    expect(finder, findsOneWidget, reason: 'destination "$id" must render');
    ys[id] = tester.getTopLeft(finder).dy;
  }
  return ys;
}

void main() {
  testWidgets(
    'sidebar destination Y positions are stable across rail expansion',
    (tester) async {
      // Collapsed (default).
      await tester.pumpWidget(
        const StudioApp(
          initialThemeMode: ThemeModeValue.system,
          initialLocale: Locale('en'),
        ),
      );
      // pump (not pumpAndSettle): the app has long-lived timers/animations
      // that never "settle"; one frame is enough to lay the sidebar out.
      await tester.pump(const Duration(milliseconds: 100));
      final collapsed = _destinationYs(tester);

      // Expanded: controller starts at 1.0 via the flag, hover disabled.
      await tester.pumpWidget(
        const StudioApp(
          initialThemeMode: ThemeModeValue.system,
          initialLocale: Locale('en'),
          startSidebarExpanded: true,
        ),
      );
      await tester.pump(const Duration(milliseconds: 100));
      final expanded = _destinationYs(tester);

      for (final id in _destinations) {
        expect(
          expanded[id],
          closeTo(collapsed[id]!, 0.5),
          reason: 'destination "$id" Y shifted on expansion '
              '(${collapsed[id]} -> ${expanded[id]}) — the rows above the '
              'destinations list must keep fixed heights',
        );
      }
    },
  );
}