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

/// Home's app bar carries the rider's identity **and the ON/OFF duty toggle**,
/// and it used to be the first sliver inside the page's `CustomScrollView` — so
/// it scrolled away the moment he looked at his second stop, taking the duty
/// control with it.
///
/// The fix is structural: the bar becomes the first child of a `Column` and the
/// scrollable takes the rest via `Expanded`. `_HomePageState` cannot be built in
/// a test (Get, SharedPreferences, Geolocator, live fetches), so — as in
/// `card_stripe_layout_test.dart` — these pin the *idiom* rather than the widget.
void main() {
  const barKey = ValueKey('appbar');
  const contentKey = ValueKey('tall-content');

  // The default test viewport is 800×600 and the bar is 96 tall, so this point
  // is always inside the scroll area below it. Gestures are aimed here rather
  // than at the content's centre: the content is 2000pt tall, so its centre is
  // off-screen and a drag there hit-tests against nothing.
  const inScrollArea = Offset(400, 350);

  /// The shape Home now uses.
  Widget pinned({Future<void> Function()? onRefresh}) {
    final scroller = CustomScrollView(
      physics: const AlwaysScrollableScrollPhysics(),
      slivers: [
        SliverToBoxAdapter(
          child: Container(key: contentKey, height: 2000, color: Colors.grey),
        ),
      ],
    );

    return MaterialApp(
      home: Scaffold(
        body: Stack(
          children: [
            Column(
              children: [
                Container(key: barKey, height: 96, color: Colors.white),
                Expanded(
                  child: onRefresh == null
                      ? scroller
                      : RefreshIndicator(onRefresh: onRefresh, child: scroller),
                ),
              ],
            ),
          ],
        ),
      ),
    );
  }

  /// The shape it used to use — bar as a sliver.
  Widget scrolling() {
    return MaterialApp(
      home: Scaffold(
        body: CustomScrollView(
          physics: const AlwaysScrollableScrollPhysics(),
          slivers: [
            SliverToBoxAdapter(
              child: Container(key: barKey, height: 96, color: Colors.white),
            ),
            SliverToBoxAdapter(
              child: Container(key: contentKey, height: 2000, color: Colors.grey),
            ),
          ],
        ),
      ),
    );
  }

  testWidgets('as a sliver, the bar scrolls off the top', (tester) async {
    await tester.pumpWidget(scrolling());
    expect(find.byKey(barKey), findsOneWidget);

    await tester.dragFrom(inScrollArea, const Offset(0, -300));
    await tester.pumpAndSettle();

    // Not merely pushed off-screen — a sliver that leaves the viewport and its
    // cache extent is unmounted outright, so the duty toggle stopped existing
    // rather than just moving. This is the behaviour being fixed.
    expect(find.byKey(barKey), findsNothing,
        reason: 'this is the behaviour that hid the duty toggle');
  });

  testWidgets('as a Column child, the bar does not move', (tester) async {
    await tester.pumpWidget(pinned());
    final before = tester.getRect(find.byKey(barKey));
    final contentBefore = tester.getRect(find.byKey(contentKey)).top;

    await tester.dragFrom(inScrollArea, const Offset(0, -300));
    await tester.pumpAndSettle();

    expect(tester.getRect(find.byKey(barKey)), before,
        reason: 'the app bar is fixed');
    // And the page really did scroll underneath it.
    expect(tester.getRect(find.byKey(contentKey)).top,
        lessThan(contentBefore - 200));
  });

  testWidgets('the bar stays put through a long scroll and back',
      (tester) async {
    await tester.pumpWidget(pinned());
    final rect = tester.getRect(find.byKey(barKey));

    for (final dy in [-600.0, -600.0, 400.0, -900.0, 1200.0]) {
      await tester.dragFrom(inScrollArea, Offset(0, dy));
      await tester.pumpAndSettle();
      expect(tester.getRect(find.byKey(barKey)), rect);
    }
  });

  testWidgets('pull to refresh still fires below the fixed bar',
      (tester) async {
    var fired = 0;
    await tester.pumpWidget(pinned(onRefresh: () async {
      fired++;
      await Future<void>.delayed(const Duration(milliseconds: 50));
    }));
    final rect = tester.getRect(find.byKey(barKey));

    await tester.flingFrom(inScrollArea, const Offset(0, 320), 1200);
    await tester.pump();
    await tester.pump(const Duration(seconds: 1));

    expect(fired, 1, reason: 'the gesture still reaches the scroll view');
    // The spinner must not drag the bar down with it, which is what the old
    // unbounded-overscroll page did to the whole header.
    expect(tester.getRect(find.byKey(barKey)), rect);
    await tester.pumpAndSettle();
  });

  testWidgets('the refresh spinner comes down below the bar, not behind it',
      (tester) async {
    await tester.pumpWidget(pinned(onRefresh: () async {
      await Future<void>.delayed(const Duration(milliseconds: 400));
    }));

    await tester.flingFrom(inScrollArea, const Offset(0, 320), 1200);
    await tester.pump();
    await tester.pump(const Duration(milliseconds: 200));

    final spinner = find.byType(RefreshProgressIndicator);
    expect(spinner, findsOneWidget);
    // `edgeOffset` is no longer needed precisely because the scroll viewport now
    // starts under the bar — so the indicator is already in clear space.
    expect(tester.getRect(spinner).top,
        greaterThanOrEqualTo(tester.getRect(find.byKey(barKey)).bottom - 0.01));
    await tester.pumpAndSettle();
  });
}