// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// TODO(gspencergoog): Remove this tag once this test's state leaks/test
// dependencies have been fixed.
// https://github.com/flutter/flutter/issues/85160
// Fails with "flutter test --test-randomize-ordering-seed=20230313"
@Tags(<String>['no-shuffle'])
library;
import 'dart:ui' as ui;

import 'package:flutter/cupertino.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter/gestures.dart';
import 'package:flutter/material.dart';
import 'package:flutter/scheduler.dart';
import 'package:flutter_test/flutter_test.dart';

const Duration _kScrollbarFadeDuration = Duration(milliseconds: 300);
const Duration _kScrollbarTimeToFade = Duration(milliseconds: 600);
const Color _kAndroidThumbIdleColor = Color(0xffbcbcbc);
const Rect _kAndroidTrackDimensions = Rect.fromLTRB(796.0, 0.0, 800.0, 600.0);
const Radius _kDefaultThumbRadius = Radius.circular(8.0);
const Color _kDefaultIdleThumbColor = Color(0x1a000000);
const Offset _kTrackBorderPoint1 = Offset(796.0, 0.0);
const Offset _kTrackBorderPoint2 = Offset(796.0, 600.0);

Rect getStartingThumbRect({ required bool isAndroid }) {
  return isAndroid
    // On Android the thumb is slightly different. The thumb is only 4 pixels wide,
    // and has no margin along the side of the viewport.
    ? const Rect.fromLTRB(796.0, 0.0, 800.0, 90.0)
    // The Material Design thumb is 8 pixels wide, with a 2
    // pixel margin to the right edge of the viewport.
    : const Rect.fromLTRB(790.0, 0.0, 798.0, 90.0);
}

class TestCanvas implements Canvas {
  final List<Invocation> invocations = <Invocation>[];

  @override
  void noSuchMethod(Invocation invocation) {
    invocations.add(invocation);
  }
}

Widget _buildBoilerplate({
  TextDirection textDirection = TextDirection.ltr,
  EdgeInsets padding = EdgeInsets.zero,
  required Widget child,
}) {
  return Directionality(
    textDirection: textDirection,
    child: MediaQuery(
      data: MediaQueryData(padding: padding),
      child: ScrollConfiguration(
        behavior: const NoScrollbarBehavior(),
        child: child,
      ),
    ),
  );
}

class NoScrollbarBehavior extends MaterialScrollBehavior {
  const NoScrollbarBehavior();

  @override
  Widget buildScrollbar(BuildContext context, Widget child, ScrollableDetails details) => child;
}

void main() {
  testWidgets("Scrollbar doesn't show when tapping list", (WidgetTester tester) async {
    await tester.pumpWidget(
      _buildBoilerplate(
        child: Center(
          child: Container(
            decoration: BoxDecoration(
              border: Border.all(color: const Color(0xFFFFFF00)),
            ),
            height: 200.0,
            width: 300.0,
            child: Scrollbar(
              child: ListView(
                children: const <Widget>[
                  SizedBox(height: 40.0, child: Text('0')),
                  SizedBox(height: 40.0, child: Text('1')),
                  SizedBox(height: 40.0, child: Text('2')),
                  SizedBox(height: 40.0, child: Text('3')),
                  SizedBox(height: 40.0, child: Text('4')),
                  SizedBox(height: 40.0, child: Text('5')),
                  SizedBox(height: 40.0, child: Text('6')),
                  SizedBox(height: 40.0, child: Text('7')),
                ],
              ),
            ),
          ),
        ),
      ),
    );

    SchedulerBinding.instance.debugAssertNoTransientCallbacks('Building a list with a scrollbar triggered an animation.');
    await tester.tap(find.byType(ListView));
    SchedulerBinding.instance.debugAssertNoTransientCallbacks('Tapping a block with a scrollbar triggered an animation.');
    await tester.pump(const Duration(milliseconds: 200));
    await tester.pump(const Duration(milliseconds: 200));
    await tester.pump(const Duration(milliseconds: 200));
    await tester.pump(const Duration(milliseconds: 200));
    await tester.drag(find.byType(ListView), const Offset(0.0, -10.0));
    expect(SchedulerBinding.instance.transientCallbackCount, greaterThan(0));
    await tester.pump(const Duration(milliseconds: 200));
    await tester.pump(const Duration(milliseconds: 200));
    await tester.pump(const Duration(milliseconds: 200));
    await tester.pump(const Duration(milliseconds: 200));
  });

  testWidgets('ScrollbarPainter does not divide by zero', (WidgetTester tester) async {
    await tester.pumpWidget(
      _buildBoilerplate(child: SizedBox(
        height: 200.0,
        width: 300.0,
        child: Scrollbar(
          child: ListView(
            children: const <Widget>[
              SizedBox(height: 40.0, child: Text('0')),
            ],
          ),
        ),
      )),
    );

    final CustomPaint custom = tester.widget(find.descendant(
      of: find.byType(Scrollbar),
      matching: find.byType(CustomPaint),
    ).first);
    final ScrollbarPainter? scrollPainter = custom.foregroundPainter as ScrollbarPainter?;
    // Dragging makes the scrollbar first appear.
    await tester.drag(find.text('0'), const Offset(0.0, -10.0));
    await tester.pump(const Duration(milliseconds: 200));
    await tester.pump(const Duration(milliseconds: 200));

    final ScrollMetrics metrics = FixedScrollMetrics(
      minScrollExtent: 0.0,
      maxScrollExtent: 0.0,
      pixels: 0.0,
      viewportDimension: 100.0,
      axisDirection: AxisDirection.down,
      devicePixelRatio: tester.view.devicePixelRatio,
    );
    scrollPainter!.update(metrics, AxisDirection.down);

    final TestCanvas canvas = TestCanvas();
    scrollPainter.paint(canvas, const Size(10.0, 100.0));

    // Scrollbar is not supposed to draw anything if there isn't enough content.
    expect(canvas.invocations.isEmpty, isTrue);
  });

  testWidgets('When thumbVisibility is true, must pass a controller or find PrimaryScrollController', (WidgetTester tester) async {
    Widget viewWithScroll() {
      return _buildBoilerplate(
        child: Theme(
          data: ThemeData(),
          child: const Scrollbar(
            thumbVisibility: true,
            child: SingleChildScrollView(
              child: SizedBox(
                width: 4000.0,
                height: 4000.0,
              ),
            ),
          ),
        ),
      );
    }

    await tester.pumpWidget(viewWithScroll());
    final AssertionError exception = tester.takeException() as AssertionError;
    expect(exception, isAssertionError);
  });

  testWidgets('When thumbVisibility is true, must pass a controller that is attached to a scroll view or find PrimaryScrollController', (WidgetTester tester) async {
    final ScrollController controller = ScrollController();
    Widget viewWithScroll() {
      return _buildBoilerplate(
        child: Theme(
          data: ThemeData(),
          child: Scrollbar(
            thumbVisibility: true,
            controller: controller,
            child: const SingleChildScrollView(
              child: SizedBox(
                width: 4000.0,
                height: 4000.0,
              ),
            ),
          ),
        ),
      );
    }

    await tester.pumpWidget(viewWithScroll());
    final AssertionError exception = tester.takeException() as AssertionError;
    expect(exception, isAssertionError);

    controller.dispose();
  });

  testWidgets('On first render with thumbVisibility: true, the thumb shows', (WidgetTester tester) async {
    final ScrollController controller = ScrollController();
    Widget viewWithScroll() {
      return _buildBoilerplate(
        child: Theme(
          data: ThemeData(),
          child: Scrollbar(
            thumbVisibility: true,
            controller: controller,
            child: SingleChildScrollView(
              controller: controller,
              child: const SizedBox(
                width: 4000.0,
                height: 4000.0,
              ),
            ),
          ),
        ),
      );
    }

    await tester.pumpWidget(viewWithScroll());
    await tester.pumpAndSettle();
    expect(find.byType(Scrollbar), paints..rect());

    controller.dispose();
  });

  testWidgets('On first render with thumbVisibility: true, the thumb shows with PrimaryScrollController', (WidgetTester tester) async {
    final ScrollController controller = ScrollController();
    Widget viewWithScroll() {
      return _buildBoilerplate(
        child: Theme(
          data: ThemeData(),
          child: PrimaryScrollController(
            controller: controller,
            child: Builder(
              builder: (BuildContext context) {
                return const Scrollbar(
                  thumbVisibility: true,
                  child: SingleChildScrollView(
                    primary: true,
                    child: SizedBox(
                      width: 4000.0,
                      height: 4000.0,
                    ),
                  ),
                );
              },
            ),
          ),
        ),
      );
    }

    await tester.pumpWidget(viewWithScroll());
    await tester.pumpAndSettle();
    expect(find.byType(Scrollbar), paints..rect());

    controller.dispose();
  });

  testWidgets(
    'When thumbVisibility is true, must pass a controller or find PrimaryScrollController',
    (WidgetTester tester) async {
      Widget viewWithScroll() {
        return _buildBoilerplate(
          child: Theme(
            data: ThemeData(),
            child: const Scrollbar(
              thumbVisibility: true,
              child: SingleChildScrollView(
                child: SizedBox(
                  width: 4000.0,
                  height: 4000.0,
                ),
              ),
            ),
          ),
        );
      }

      await tester.pumpWidget(viewWithScroll());
      final AssertionError exception = tester.takeException() as AssertionError;
      expect(exception, isAssertionError);
    },
  );

  testWidgets(
    'When thumbVisibility is true, must pass a controller that is attached to a scroll view or find PrimaryScrollController',
    (WidgetTester tester) async {
      final ScrollController controller = ScrollController();
      Widget viewWithScroll() {
        return _buildBoilerplate(
          child: Theme(
            data: ThemeData(),
            child: Scrollbar(
              thumbVisibility: true,
              controller: controller,
              child: const SingleChildScrollView(
                child: SizedBox(
                  width: 4000.0,
                  height: 4000.0,
                ),
              ),
            ),
          ),
        );
      }

      await tester.pumpWidget(viewWithScroll());
      final AssertionError exception = tester.takeException() as AssertionError;
      expect(exception, isAssertionError);

      controller.dispose();
    },
  );

  testWidgets('On first render with thumbVisibility: true, the thumb shows', (WidgetTester tester) async {
    final ScrollController controller = ScrollController();
    Widget viewWithScroll() {
      return _buildBoilerplate(
        child: Theme(
          data: ThemeData(),
          child: Scrollbar(
            thumbVisibility: true,
            controller: controller,
            child: SingleChildScrollView(
              controller: controller,
              child: const SizedBox(
                width: 4000.0,
                height: 4000.0,
              ),
            ),
          ),
        ),
      );
    }

    await tester.pumpWidget(viewWithScroll());
    await tester.pumpAndSettle();
    expect(find.byType(Scrollbar), paints..rect());

    controller.dispose();
  });

  testWidgets('On first render with thumbVisibility: true, the thumb shows with PrimaryScrollController', (WidgetTester tester) async {
    final ScrollController controller = ScrollController();
    Widget viewWithScroll() {
      return _buildBoilerplate(
        child: Theme(
          data: ThemeData(),
          child: PrimaryScrollController(
            controller: controller,
            child: Builder(
              builder: (BuildContext context) {
                return const Scrollbar(
                  thumbVisibility: true,
                  child: SingleChildScrollView(
                    primary: true,
                    child: SizedBox(
                      width: 4000.0,
                      height: 4000.0,
                    ),
                  ),
                );
              },
            ),
          ),
        ),
      );
    }

    await tester.pumpWidget(viewWithScroll());
    await tester.pumpAndSettle();
    expect(find.byType(Scrollbar), paints..rect());

    controller.dispose();
  });

  testWidgets('On first render with thumbVisibility: false, the thumb is hidden', (WidgetTester tester) async {
    final ScrollController controller = ScrollController();
    Widget viewWithScroll() {
      return _buildBoilerplate(
        child: Theme(
          data: ThemeData(),
          child: Scrollbar(
            thumbVisibility: false,
            controller: controller,
            child: SingleChildScrollView(
              controller: controller,
              child: const SizedBox(
                width: 4000.0,
                height: 4000.0,
              ),
            ),
          ),
        ),
      );
    }

    await tester.pumpWidget(viewWithScroll());
    await tester.pumpAndSettle();
    expect(find.byType(Scrollbar), isNot(paints..rect()));

    controller.dispose();
  });

  testWidgets(
    'With thumbVisibility: true, fling a scroll. While it is still scrolling, set thumbVisibility: false. The thumb should not fade out until the scrolling stops.',
    (WidgetTester tester) async {
      final ScrollController controller = ScrollController();
      bool thumbVisibility = true;
      Widget viewWithScroll() {
        return _buildBoilerplate(
          child: StatefulBuilder(
            builder: (BuildContext context, StateSetter setState) {
              return Theme(
                data: ThemeData(),
                child: Scaffold(
                  floatingActionButton: FloatingActionButton(
                    child: const Icon(Icons.threed_rotation),
                    onPressed: () {
                      setState(() {
                        thumbVisibility = !thumbVisibility;
                      });
                    },
                  ),
                  body: Scrollbar(
                    thumbVisibility: thumbVisibility,
                    controller: controller,
                    child: SingleChildScrollView(
                      controller: controller,
                      child: const SizedBox(
                        width: 4000.0,
                        height: 4000.0,
                      ),
                    ),
                  ),
                ),
              );
            },
          ),
        );
      }

      await tester.pumpWidget(viewWithScroll());
      await tester.pumpAndSettle();
      await tester.fling(
        find.byType(SingleChildScrollView),
        const Offset(0.0, -10.0),
        10,
      );
      expect(find.byType(Scrollbar), paints..rect());

      await tester.tap(find.byType(FloatingActionButton));
      await tester.pumpAndSettle();
      // Scrollbar is not showing after scroll finishes
      expect(find.byType(Scrollbar), isNot(paints..rect()));

      controller.dispose();
    },
  );

  testWidgets(
    'With thumbVisibility: false, set thumbVisibility: true. The thumb should be always shown directly',
    (WidgetTester tester) async {
      final ScrollController controller = ScrollController();
      bool thumbVisibility = false;
      Widget viewWithScroll() {
        return _buildBoilerplate(
          child: StatefulBuilder(
            builder: (BuildContext context, StateSetter setState) {
              return Theme(
                data: ThemeData(),
                child: Scaffold(
                  floatingActionButton: FloatingActionButton(
                    child: const Icon(Icons.threed_rotation),
                    onPressed: () {
                      setState(() {
                        thumbVisibility = !thumbVisibility;
                      });
                    },
                  ),
                  body: Scrollbar(
                    thumbVisibility: thumbVisibility,
                    controller: controller,
                    child: SingleChildScrollView(
                      controller: controller,
                      child: const SizedBox(
                        width: 4000.0,
                        height: 4000.0,
                      ),
                    ),
                  ),
                ),
              );
            },
          ),
        );
      }

      await tester.pumpWidget(viewWithScroll());
      await tester.pumpAndSettle();
      expect(find.byType(Scrollbar), isNot(paints..rect()));

      await tester.tap(find.byType(FloatingActionButton));
      await tester.pumpAndSettle();
      // Scrollbar is not showing after scroll finishes
      expect(find.byType(Scrollbar), paints..rect());

      controller.dispose();
    },
  );

  testWidgets(
    'With thumbVisibility: false, fling a scroll. While it is still scrolling, set thumbVisibility: true. The thumb should not fade even after the scrolling stops',
    (WidgetTester tester) async {
      final ScrollController controller = ScrollController();
      bool thumbVisibility = false;
      Widget viewWithScroll() {
        return _buildBoilerplate(
          child: StatefulBuilder(
            builder: (BuildContext context, StateSetter setState) {
              return Theme(
                data: ThemeData(),
                child: Scaffold(
                  floatingActionButton: FloatingActionButton(
                    child: const Icon(Icons.threed_rotation),
                    onPressed: () {
                      setState(() {
                        thumbVisibility = !thumbVisibility;
                      });
                    },
                  ),
                  body: Scrollbar(
                    thumbVisibility: thumbVisibility,
                    controller: controller,
                    child: SingleChildScrollView(
                      controller: controller,
                      child: const SizedBox(
                        width: 4000.0,
                        height: 4000.0,
                      ),
                    ),
                  ),
                ),
              );
            },
          ),
        );
      }

      await tester.pumpWidget(viewWithScroll());
      await tester.pumpAndSettle();
      expect(find.byType(Scrollbar), isNot(paints..rect()));
      await tester.fling(
        find.byType(SingleChildScrollView),
        const Offset(0.0, -10.0),
        10,
      );
      expect(find.byType(Scrollbar), paints..rect());

      await tester.tap(find.byType(FloatingActionButton));
      await tester.pump();
      expect(find.byType(Scrollbar), paints..rect());

      // Wait for the timer delay to expire.
      await tester.pump(const Duration(milliseconds: 600)); // _kScrollbarTimeToFade
      await tester.pumpAndSettle();
      // Scrollbar thumb is showing after scroll finishes and timer ends.
      expect(find.byType(Scrollbar), paints..rect());

      controller.dispose();
    },
  );

  testWidgets(
    'Toggling thumbVisibility while not scrolling fades the thumb in/out. This works even when you have never scrolled at all yet',
    (WidgetTester tester) async {
      final ScrollController controller = ScrollController();
      bool thumbVisibility = true;
      Widget viewWithScroll() {
        return _buildBoilerplate(
          child: StatefulBuilder(
            builder: (BuildContext context, StateSetter setState) {
              return Theme(
                data: ThemeData(),
                child: Scaffold(
                  floatingActionButton: FloatingActionButton(
                    child: const Icon(Icons.threed_rotation),
                    onPressed: () {
                      setState(() {
                        thumbVisibility = !thumbVisibility;
                      });
                    },
                  ),
                  body: Scrollbar(
                    thumbVisibility: thumbVisibility,
                    controller: controller,
                    child: SingleChildScrollView(
                      controller: controller,
                      child: const SizedBox(
                        width: 4000.0,
                        height: 4000.0,
                      ),
                    ),
                  ),
                ),
              );
            },
          ),
        );
      }

      await tester.pumpWidget(viewWithScroll());
      await tester.pumpAndSettle();
      final Finder materialScrollbar = find.byType(Scrollbar);
      expect(materialScrollbar, paints..rect());

      await tester.tap(find.byType(FloatingActionButton));
      await tester.pumpAndSettle();
      expect(materialScrollbar, isNot(paints..rect()));

      controller.dispose();
    },
  );

  testWidgets('Scrollbar respects thickness and radius', (WidgetTester tester) async {
    final ScrollController controller = ScrollController();
    Widget viewWithScroll({Radius? radius}) {
      return _buildBoilerplate(
        child: Theme(
          data: ThemeData(),
          child: Scrollbar(
            controller: controller,
            thickness: 20,
            radius: radius,
            child: SingleChildScrollView(
              controller: controller,
              child: const SizedBox(
                width: 1600.0,
                height: 1200.0,
              ),
            ),
          ),
        ),
      );
    }

    // Scroll a bit to cause the scrollbar thumb to be shown;
    // undo the scroll to put the thumb back at the top.
    await tester.pumpWidget(viewWithScroll());
    const double scrollAmount = 10.0;
    final TestGesture scrollGesture = await tester.startGesture(tester.getCenter(find.byType(SingleChildScrollView)));
    await scrollGesture.moveBy(const Offset(0.0, -scrollAmount));
    await tester.pump();
    await tester.pump(const Duration(milliseconds: 500));
    await scrollGesture.moveBy(const Offset(0.0, scrollAmount));
    await tester.pump();
    await scrollGesture.up();
    await tester.pump();

    // Long press on the scrollbar thumb and expect it to grow
    expect(
      find.byType(Scrollbar),
      paints
        ..rect(
          rect: const Rect.fromLTRB(780.0, 0.0, 800.0, 600.0),
          color: Colors.transparent,
        )
        ..line(
          p1: const Offset(780.0, 0.0),
          p2: const Offset(780.0, 600.0),
          strokeWidth: 1.0,
          color: Colors.transparent,
        )
        ..rect(
          rect: const Rect.fromLTRB(780.0, 0.0, 800.0, 300.0),
          color: _kAndroidThumbIdleColor,
        ),
    );
    await tester.pumpWidget(viewWithScroll(radius: const Radius.circular(10)));
    expect(find.byType(Scrollbar), paints..rrect(
      rrect: RRect.fromRectAndRadius(const Rect.fromLTRB(780, 0.0, 800.0, 300.0), const Radius.circular(10)),
    ));

    await tester.pumpAndSettle();

    controller.dispose();
  });

  testWidgets('Tapping the track area pages the Scroll View', (WidgetTester tester) async {
    final ScrollController scrollController = ScrollController();
    await tester.pumpWidget(
      Directionality(
        textDirection: TextDirection.ltr,
        child: MediaQuery(
          data: const MediaQueryData(),
          child: Scrollbar(
            interactive: true,
            thumbVisibility: true,
            controller: scrollController,
            child: SingleChildScrollView(
              controller: scrollController,
              child: const SizedBox(width: 1000.0, height: 1000.0),
            ),
          ),
        ),
      ),
    );

    await tester.pumpAndSettle();
    expect(scrollController.offset, 0.0);
    expect(
      find.byType(Scrollbar),
      paints
        ..rect(
          rect: _kAndroidTrackDimensions,
          color: Colors.transparent,
        )
        ..line(
          p1: _kTrackBorderPoint1,
          p2: _kTrackBorderPoint2,
          strokeWidth: 1.0,
          color: Colors.transparent,
        )
        ..rect(
          rect: const Rect.fromLTRB(796.0, 0.0, 800.0, 360.0),
          color: _kAndroidThumbIdleColor,
        ),
    );

    // Tap on the track area below the thumb.
    await tester.tapAt(const Offset(796.0, 550.0));
    await tester.pumpAndSettle();

    expect(scrollController.offset, 400.0);
    expect(
      find.byType(Scrollbar),
      paints
        ..rect(
          rect: _kAndroidTrackDimensions,
          color: Colors.transparent,
        )
        ..line(
          p1: _kTrackBorderPoint1,
          p2: _kTrackBorderPoint2,
          strokeWidth: 1.0,
          color: Colors.transparent,
        )
        ..rect(
          rect: const Rect.fromLTRB(796.0, 240.0, 800.0, 600.0),
          color: _kAndroidThumbIdleColor,
        ),
    );

    // Tap on the track area above the thumb.
    await tester.tapAt(const Offset(796.0, 50.0));
    await tester.pumpAndSettle();

    expect(scrollController.offset, 0.0);
    expect(
      find.byType(Scrollbar),
      paints
        ..rect(
          rect: _kAndroidTrackDimensions,
          color: Colors.transparent,
        )
        ..line(
          p1: _kTrackBorderPoint1,
          p2: _kTrackBorderPoint2,
          strokeWidth: 1.0,
          color: Colors.transparent,
        )
        ..rect(
          rect: const Rect.fromLTRB(796.0, 0.0, 800.0, 360.0),
          color: _kAndroidThumbIdleColor,
        ),
    );

    scrollController.dispose();
  });

  testWidgets('Scrollbar never goes away until finger lift', (WidgetTester tester) async {
    await tester.pumpWidget(
      const MaterialApp(
        home: Scrollbar(
          child: SingleChildScrollView(
            child: SizedBox(width: 4000.0, height: 4000.0),
          ),
        ),
      ),
    );
    final TestGesture gesture = await tester.startGesture(tester.getCenter(find.byType(SingleChildScrollView)));
    await gesture.moveBy(const Offset(0.0, -20.0));
    await tester.pump();
    // Scrollbar fully showing
    await tester.pump(const Duration(milliseconds: 500));
    expect(
      find.byType(Scrollbar),
      paints
        ..rect(
          rect: _kAndroidTrackDimensions,
          color: Colors.transparent,
        )
        ..line(
          p1: _kTrackBorderPoint1,
          p2: _kTrackBorderPoint2,
          strokeWidth: 1.0,
          color: Colors.transparent,
        )
        ..rect(
          rect: const Rect.fromLTRB(796.0, 3.0, 800.0, 93.0),
          color: _kAndroidThumbIdleColor,
        ),
    );

    await tester.pump(const Duration(seconds: 3));
    await tester.pump(const Duration(seconds: 3));
    // Still there.
    expect(
      find.byType(Scrollbar),
      paints
        ..rect(
          rect: _kAndroidTrackDimensions,
          color: Colors.transparent,
        )
        ..line(
          p1: _kTrackBorderPoint1,
          p2: _kTrackBorderPoint2,
          strokeWidth: 1.0,
          color: Colors.transparent,
        )
        ..rect(
          rect: const Rect.fromLTRB(796.0, 3.0, 800.0, 93.0),
          color: _kAndroidThumbIdleColor,
        ),
    );

    await gesture.up();
    await tester.pump(_kScrollbarTimeToFade);
    await tester.pump(_kScrollbarFadeDuration * 0.5);

    // Opacity going down now.
    expect(
      find.byType(Scrollbar),
      paints
        ..rect(
          rect: _kAndroidTrackDimensions,
          color: Colors.transparent,
        )
        ..line(
          p1: _kTrackBorderPoint1,
          p2: _kTrackBorderPoint2,
          strokeWidth: 1.0,
          color: Colors.transparent,
        )
        ..rect(
          rect: const Rect.fromLTRB(796.0, 3.0, 800.0, 93.0),
          color: const Color(0xc6bcbcbc),
        ),
    );
  });

  testWidgets('Scrollbar thumb can be dragged', (WidgetTester tester) async {
    final ScrollController scrollController = ScrollController();
    await tester.pumpWidget(
      MaterialApp(
        theme: ThemeData(useMaterial3: false),
        home: PrimaryScrollController(
          controller: scrollController,
          child: Scrollbar(
            interactive: true,
            thumbVisibility: true,
            controller: scrollController,
            child: const SingleChildScrollView(
              child: SizedBox(width: 4000.0, height: 4000.0),
            ),
          ),
        ),
      ),
    );
    await tester.pumpAndSettle();
    expect(scrollController.offset, 0.0);
    expect(
      find.byType(Scrollbar),
      paints
        ..rect(
          rect: _kAndroidTrackDimensions,
          color: Colors.transparent,
        )
        ..line(
          p1: _kTrackBorderPoint1,
          p2: _kTrackBorderPoint2,
          strokeWidth: 1.0,
          color: Colors.transparent,
        )
        ..rect(
          rect: getStartingThumbRect(isAndroid: true),
          color: _kAndroidThumbIdleColor,
        ),
    );

    // Drag the thumb down to scroll down.
    const double scrollAmount = 10.0;
    final TestGesture dragScrollbarGesture = await tester.startGesture(const Offset(797.0, 45.0));
    await tester.pumpAndSettle();

    expect(
      find.byType(Scrollbar),
      paints
        ..rect(
          rect: _kAndroidTrackDimensions,
          color: Colors.transparent,
        )
        ..line(
          p1: _kTrackBorderPoint1,
          p2: _kTrackBorderPoint2,
          strokeWidth: 1.0,
          color: Colors.transparent,
        )
        ..rect(
          rect: getStartingThumbRect(isAndroid: true),
          // Drag color
          color: const Color(0x99000000),
        ),
    );

    await dragScrollbarGesture.moveBy(const Offset(0.0, scrollAmount));
    await tester.pumpAndSettle();
    await dragScrollbarGesture.up();
    await tester.pumpAndSettle();

    // The view has scrolled more than it would have by a swipe pointer of the
    // same distance.
    expect(scrollController.offset, greaterThan(scrollAmount * 2));
    expect(
      find.byType(Scrollbar),
      paints
        ..rect(
          rect: _kAndroidTrackDimensions,
          color: Colors.transparent,
        )
        ..line(
          p1: _kTrackBorderPoint1,
          p2: _kTrackBorderPoint2,
          strokeWidth: 1.0,
          color: Colors.transparent,
        )
        ..rect(
          rect: const Rect.fromLTRB(796.0, 10.0, 800.0, 100.0),
          color: _kAndroidThumbIdleColor,
        ),
    );

    scrollController.dispose();
  });

  testWidgets('Scrollbar thumb color completes a hover animation', (WidgetTester tester) async {
    await tester.pumpWidget(
      MaterialApp(
        theme: ThemeData(
          useMaterial3: false,
          scrollbarTheme: ScrollbarThemeData(thumbVisibility: MaterialStateProperty.all(true)),
        ),
        home: const SingleChildScrollView(
          child: SizedBox(width: 4000.0, height: 4000.0),
        ),
      ),
    );
    await tester.pumpAndSettle();
    expect(
      find.byType(Scrollbar),
      paints..rrect(
        rrect: RRect.fromRectAndRadius(
          getStartingThumbRect(isAndroid: false),
          _kDefaultThumbRadius,
        ),
        color: _kDefaultIdleThumbColor,
      ),
    );

    final TestGesture gesture = await tester.createGesture(kind: ui.PointerDeviceKind.mouse);
    await gesture.addPointer();
    await gesture.moveTo(const Offset(794.0, 5.0));
    await tester.pumpAndSettle();

    expect(
      find.byType(Scrollbar),
      paints..rrect(
        rrect: RRect.fromRectAndRadius(
          getStartingThumbRect(isAndroid: false),
          _kDefaultThumbRadius,
        ),
        // Hover color
        color: const Color(0x80000000),
      ),
    );
  },
    variant: const TargetPlatformVariant(<TargetPlatform>{
      TargetPlatform.linux,
      TargetPlatform.macOS,
      TargetPlatform.windows,
    }),
  );

  testWidgets('Hover animation is not triggered by tap gestures', (WidgetTester tester) async {
    await tester.pumpWidget(
      MaterialApp(
        theme: ThemeData(
          useMaterial3: false,
          scrollbarTheme: ScrollbarThemeData(
            thumbVisibility: MaterialStateProperty.all(true),
            trackVisibility: MaterialStateProperty.resolveWith((Set<MaterialState> states) {
              if (states.contains(MaterialState.hovered)) {
                return true;
              }
              return false;
            })
          ),
        ),
        home: const SingleChildScrollView(
          child: SizedBox(width: 4000.0, height: 4000.0),
        ),
      ),
    );
    await tester.pumpAndSettle();
    expect(
      find.byType(Scrollbar),
      paints..rrect(
        rrect: RRect.fromRectAndRadius(
          getStartingThumbRect(isAndroid: false),
          _kDefaultThumbRadius,
        ),
        color: _kDefaultIdleThumbColor,
      ),
    );
    await tester.tapAt(const Offset(794.0, 5.0));
    await tester.pumpAndSettle();

    // Tapping triggers a hover enter event. In this case, the Scrollbar should
    // be unchanged since it ignores hover events that aren't from a mouse.
    expect(
      find.byType(Scrollbar),
      paints..rrect(
        rrect: RRect.fromRectAndRadius(
          getStartingThumbRect(isAndroid: false),
          _kDefaultThumbRadius,
        ),
        color: _kDefaultIdleThumbColor,
      ),
    );

    // Now trigger hover with a mouse.
    final TestGesture gesture = await tester.createGesture(kind: ui.PointerDeviceKind.mouse);
    await gesture.addPointer();
    await gesture.moveTo(const Offset(794.0, 5.0));
    await tester.pump();

    expect(
      find.byType(Scrollbar),
      paints
        ..rect(
          rect: const Rect.fromLTRB(784.0, 0.0, 800.0, 600.0),
          color: const Color(0x08000000),
        )
        ..line(
          p1: const Offset(784.0, 0.0),
          p2: const Offset(784.0, 600.0),
          strokeWidth: 1.0,
          color: _kDefaultIdleThumbColor,
        )
        ..rrect(
          rrect: RRect.fromRectAndRadius(
            // Scrollbar thumb is larger
            const Rect.fromLTRB(786.0, 0.0, 798.0, 90.0),
            _kDefaultThumbRadius,
          ),
          // Hover color
          color: const Color(0x80000000),
        ),
    );
  },
    variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.linux }),
  );

  testWidgets('ScrollbarThemeData.thickness replaces hoverThickness', (WidgetTester tester) async {
    await tester.pumpWidget(
      MaterialApp(
        theme: ThemeData(
          useMaterial3: false,
          scrollbarTheme: ScrollbarThemeData(
            thumbVisibility: MaterialStateProperty.resolveWith((Set<MaterialState> states) => true),
            trackVisibility: MaterialStateProperty.resolveWith((Set<MaterialState> states) {
              return states.contains(MaterialState.hovered);
            }),
            thickness: MaterialStateProperty.resolveWith((Set<MaterialState> states) {
              if (states.contains(MaterialState.hovered)) {
                return 40.0;
              }
              // Default thickness
              return 8.0;
            }),
          ),
        ),
        home: const SingleChildScrollView(
          child: SizedBox(width: 4000.0, height: 4000.0),
        ),
      ),
    );
    await tester.pumpAndSettle();
    expect(
      find.byType(Scrollbar),
      paints..rrect(
        rrect: RRect.fromRectAndRadius(
          getStartingThumbRect(isAndroid: false),
          _kDefaultThumbRadius,
        ),
        color: _kDefaultIdleThumbColor,
      ),
    );

    final TestGesture gesture = await tester.createGesture(kind: ui.PointerDeviceKind.mouse);
    await gesture.addPointer();
    await gesture.moveTo(const Offset(794.0, 5.0));
    await tester.pump();

    expect(
      find.byType(Scrollbar),
      paints
        ..rect(
          rect: const Rect.fromLTRB(756.0, 0.0, 800.0, 600.0),
          color: const Color(0x08000000),
        )
        ..line(
          p1: const Offset(756.0, 0.0),
          p2: const Offset(756.0, 600.0),
          strokeWidth: 1.0,
          color: _kDefaultIdleThumbColor,
        )
        ..rrect(
          rrect: RRect.fromRectAndRadius(
            // Scrollbar thumb is larger
            const Rect.fromLTRB(758.0, 0.0, 798.0, 90.0),
            _kDefaultThumbRadius,
          ),
          // Hover color
          color: const Color(0x80000000),
        ),
    );
  },
    variant: const TargetPlatformVariant(<TargetPlatform>{
      TargetPlatform.linux,
      TargetPlatform.macOS,
      TargetPlatform.windows,
    }),
  );

  testWidgets('ScrollbarThemeData.trackVisibility', (WidgetTester tester) async {
    await tester.pumpWidget(
      MaterialApp(
        theme: ThemeData(
          useMaterial3: false,
          scrollbarTheme: ScrollbarThemeData(
            thumbVisibility: MaterialStateProperty.all(true),
            trackVisibility: MaterialStateProperty.resolveWith((Set<MaterialState> states) {
              if (states.contains(MaterialState.hovered)) {
                return true;
              }
              return false;
            }),
          ),
        ),
        home: const SingleChildScrollView(
          child: SizedBox(width: 4000.0, height: 4000.0),
        ),
      ),
    );
    await tester.pumpAndSettle();
    expect(
      find.byType(Scrollbar),
      paints..rrect(
        rrect: RRect.fromRectAndRadius(
          getStartingThumbRect(isAndroid: false),
          _kDefaultThumbRadius,
        ),
        color: _kDefaultIdleThumbColor,
      ),
    );

    final TestGesture gesture = await tester.createGesture(kind: ui.PointerDeviceKind.mouse);
    await gesture.addPointer();
    await gesture.moveTo(const Offset(794.0, 5.0));
    await tester.pump();

    expect(
      find.byType(Scrollbar),
      paints
        ..rect(
          rect: const Rect.fromLTRB(784.0, 0.0, 800.0, 600.0),
          color: const Color(0x08000000),
        )
        ..line(
          p1: const Offset(784.0, 0.0),
          p2: const Offset(784.0, 600.0),
          strokeWidth: 1.0,
          color: _kDefaultIdleThumbColor,
        )
        ..rrect(
          rrect: RRect.fromRectAndRadius(
            // Scrollbar thumb is larger
            const Rect.fromLTRB(786.0, 0.0, 798.0, 90.0),
            _kDefaultThumbRadius,
          ),
          // Hover color
          color: const Color(0x80000000),
        ),
    );
  },
    variant: const TargetPlatformVariant(<TargetPlatform>{
      TargetPlatform.linux,
      TargetPlatform.macOS,
      TargetPlatform.windows,
    }),
  );

  testWidgets('Scrollbar trackVisibility on hovered', (WidgetTester tester) async {
    await tester.pumpWidget(
      MaterialApp(
        theme: ThemeData(
          useMaterial3: false,
          scrollbarTheme: ScrollbarThemeData(
            thumbVisibility: MaterialStateProperty.all(true),
            trackVisibility: MaterialStateProperty.resolveWith((Set<MaterialState> states) {
              if (states.contains(MaterialState.hovered)) {
                return true;
              }
              return false;
            }),
          ),
        ),
        home: const SingleChildScrollView(
          child: SizedBox(width: 4000.0, height: 4000.0),
        ),
      ),
    );
    await tester.pumpAndSettle();
    expect(
      find.byType(Scrollbar),
      paints..rrect(
        rrect: RRect.fromRectAndRadius(
          getStartingThumbRect(isAndroid: false),
          _kDefaultThumbRadius,
        ),
        color: _kDefaultIdleThumbColor,
      ),
    );

    final TestGesture gesture = await tester.createGesture(kind: ui.PointerDeviceKind.mouse);
    await gesture.addPointer();
    await gesture.moveTo(const Offset(794.0, 5.0));
    await tester.pump();

    expect(
      find.byType(Scrollbar),
      paints
        ..rect(
          rect: const Rect.fromLTRB(784.0, 0.0, 800.0, 600.0),
          color: const Color(0x08000000),
        )
        ..line(
          p1: const Offset(784.0, 0.0),
          p2: const Offset(784.0, 600.0),
          strokeWidth: 1.0,
          color: _kDefaultIdleThumbColor,
        )
        ..rrect(
          rrect: RRect.fromRectAndRadius(
            // Scrollbar thumb is larger
            const Rect.fromLTRB(786.0, 0.0, 798.0, 90.0),
            _kDefaultThumbRadius,
          ),
          // Hover color
          color: const Color(0x80000000),
      ),
    );
  },
    variant: const TargetPlatformVariant(<TargetPlatform>{
      TargetPlatform.linux,
      TargetPlatform.macOS,
      TargetPlatform.windows,
    }),
  );

  testWidgets('Adaptive scrollbar', (WidgetTester tester) async {
    Widget viewWithScroll(TargetPlatform platform) {
      return _buildBoilerplate(
        child: Theme(
          data: ThemeData(
            platform: platform,
          ),
          child: const Scrollbar(
            child: SingleChildScrollView(
              child: SizedBox(width: 4000.0, height: 4000.0),
            ),
          ),
        ),
      );
    }

    await tester.pumpWidget(viewWithScroll(TargetPlatform.android));
    await tester.drag(find.byType(SingleChildScrollView), const Offset(0.0, -10.0));
    await tester.pump();
    // Scrollbar fully showing
    await tester.pump(const Duration(milliseconds: 500));
    expect(find.byType(Scrollbar), paints..rect());

    await tester.pumpWidget(viewWithScroll(TargetPlatform.iOS));
    final TestGesture gesture = await tester.startGesture(
      tester.getCenter(find.byType(SingleChildScrollView)),
    );
    await gesture.moveBy(const Offset(0.0, -10.0));
    await tester.drag(find.byType(SingleChildScrollView), const Offset(0.0, -10.0));
    await tester.pump();
    await tester.pump(const Duration(milliseconds: 200));
    expect(find.byType(Scrollbar), paints..rrect());
    expect(find.byType(CupertinoScrollbar), paints..rrect());
    await gesture.up();
    await tester.pumpAndSettle();
  });

  testWidgets('Scrollbar passes controller to CupertinoScrollbar', (WidgetTester tester) async {
    final ScrollController controller = ScrollController();
    Widget viewWithScroll(TargetPlatform? platform) {
      return _buildBoilerplate(
        child: Theme(
          data: ThemeData(
            platform: platform,
          ),
          child: Scrollbar(
            controller: controller,
            child: SingleChildScrollView(
              controller: controller,
              child: const SizedBox(width: 4000.0, height: 4000.0),
            ),
          ),
        ),
      );
    }

    await tester.pumpWidget(viewWithScroll(debugDefaultTargetPlatformOverride));
    final TestGesture gesture = await tester.startGesture(
      tester.getCenter(find.byType(SingleChildScrollView)),
    );
    await gesture.moveBy(const Offset(0.0, -10.0));
    await tester.drag(find.byType(SingleChildScrollView), const Offset(0.0, -10.0));
    await tester.pump();
    await tester.pump(const Duration(milliseconds: 200));
    expect(find.byType(CupertinoScrollbar), paints..rrect());
    final CupertinoScrollbar scrollbar = tester.widget<CupertinoScrollbar>(find.byType(CupertinoScrollbar));
    expect(scrollbar.controller, isNotNull);

    controller.dispose();
  }, variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.iOS }));

  testWidgets("Scrollbar doesn't show when scroll the inner scrollable widget", (WidgetTester tester) async {
    final GlobalKey key1 = GlobalKey();
    final GlobalKey key2 = GlobalKey();
    final GlobalKey outerKey = GlobalKey();
    final GlobalKey innerKey = GlobalKey();
    await tester.pumpWidget(
      Directionality(
        textDirection: TextDirection.ltr,
        child: MediaQuery(
          data: const MediaQueryData(),
          child: ScrollConfiguration(
            behavior: const NoScrollbarBehavior(),
            child: Scrollbar(
              key: key2,
              child: SingleChildScrollView(
                key: outerKey,
                child: SizedBox(
                  height: 1000.0,
                  width: double.infinity,
                  child: Column(
                    children: <Widget>[
                      Scrollbar(
                        key: key1,
                        child: SizedBox(
                          height: 300.0,
                          width: double.infinity,
                          child: SingleChildScrollView(
                            key: innerKey,
                            child: const SizedBox(
                              key: Key('Inner scrollable'),
                              height: 1000.0,
                              width: double.infinity,
                            ),
                          ),
                        ),
                      ),
                    ],
                  ),
                ),
              ),
            ),
          ),
        ),
      ),
    );

    // Drag the inner scrollable widget.
    await tester.drag(find.byKey(innerKey), const Offset(0.0, -25.0));
    await tester.pump();
    // Scrollbar fully showing.
    await tester.pump(const Duration(milliseconds: 500));

    expect(
      tester.renderObject(find.byKey(key2)),
      paintsExactlyCountTimes(#drawRect, 2), // Each bar will call [drawRect] twice.
    );

    expect(
      tester.renderObject(find.byKey(key1)),
      paintsExactlyCountTimes(#drawRect, 2),
    );
  }, variant: TargetPlatformVariant.all());

  testWidgets('Scrollbar dragging can be disabled', (WidgetTester tester) async {
    final ScrollController scrollController = ScrollController();
    await tester.pumpWidget(
      MaterialApp(
        theme: ThemeData(useMaterial3: false),
        home: PrimaryScrollController(
          controller: scrollController,
          child: Scrollbar(
            interactive: false,
            thumbVisibility: true,
            controller: scrollController,
            child: const SingleChildScrollView(
              child: SizedBox(width: 4000.0, height: 4000.0),
            ),
          ),
        ),
      ),
    );
    await tester.pumpAndSettle();
    expect(scrollController.offset, 0.0);
    expect(
      find.byType(Scrollbar),
      paints
        ..rect(
          rect: const Rect.fromLTRB(788.0, 0.0, 800.0, 600.0),
          color: Colors.transparent,
        )
        ..line(
          p1: const Offset(788.0, 0.0),
          p2: const Offset(788.0, 600.0),
          strokeWidth: 1.0,
          color: Colors.transparent,
        )
        ..rrect(
          rrect: RRect.fromRectAndRadius(
            getStartingThumbRect(isAndroid: false),
            _kDefaultThumbRadius,
          ),
          color: _kDefaultIdleThumbColor,
        ),
    );

    // Try to drag the thumb down.
    const double scrollAmount = 10.0;
    final TestGesture dragScrollbarThumbGesture = await tester.startGesture(const Offset(797.0, 45.0));
    await tester.pumpAndSettle();
    await dragScrollbarThumbGesture.moveBy(const Offset(0.0, scrollAmount));
    await tester.pumpAndSettle();
    await dragScrollbarThumbGesture.up();
    await tester.pumpAndSettle();
    // Dragging on the thumb does not change the offset.
    expect(scrollController.offset, 0.0);

    // Drag in the track area to validate pass through to scrollable.
    final TestGesture dragPassThroughTrack = await tester.startGesture(const Offset(797.0, 250.0));
    await dragPassThroughTrack.moveBy(const Offset(0.0, -scrollAmount));
    await tester.pumpAndSettle();
    await dragPassThroughTrack.up();
    await tester.pumpAndSettle();
    // The scroll view received the drag.
    expect(scrollController.offset, scrollAmount);

    // Tap on the track to validate the scroll view will not page.
    await tester.tapAt(const Offset(797.0, 200.0));
    await tester.pumpAndSettle();
    // The offset should not have changed.
    expect(scrollController.offset, scrollAmount);

    scrollController.dispose();
  }, variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.fuchsia }));

  testWidgets('Scrollbar dragging is disabled by default on Android', (WidgetTester tester) async {
    int tapCount = 0;
    final ScrollController scrollController = ScrollController();
    await tester.pumpWidget(
      MaterialApp(
        home: PrimaryScrollController(
          controller: scrollController,
          child: Scrollbar(
            thumbVisibility: true,
            controller: scrollController,
            child: SingleChildScrollView(
              dragStartBehavior: DragStartBehavior.down,
              child: GestureDetector(
                behavior: HitTestBehavior.opaque,
                onTap: () {
                  tapCount += 1;
                },
                child: const SizedBox(
                  width: 4000.0,
                  height: 4000.0,
                ),
              ),
            ),
          ),
        ),
      ),
    );
    await tester.pumpAndSettle();
    expect(scrollController.offset, 0.0);
    expect(
      find.byType(Scrollbar),
      paints
        ..rect(
          rect: _kAndroidTrackDimensions,
          color: Colors.transparent,
        )
        ..line(
          p1: _kTrackBorderPoint1,
          p2: _kTrackBorderPoint2,
          strokeWidth: 1.0,
          color: Colors.transparent,
        )
        ..rect(
          rect: getStartingThumbRect(isAndroid: true),
          color: _kAndroidThumbIdleColor,
        ),
    );

    // Try to drag the thumb down.
    const double scrollAmount = 50.0;
    await tester.dragFrom(
      const Offset(797.0, 45.0),
      const Offset(0.0, scrollAmount),
      touchSlopY: 0.0,
    );
    await tester.pumpAndSettle();
    // Dragging on the thumb does not change the offset.
    expect(scrollController.offset, 0.0);
    expect(tapCount, 0);

    // Try to drag up in the thumb area to validate pass through to scrollable.
    await tester.dragFrom(
      const Offset(797.0, 45.0),
      const Offset(0.0, -scrollAmount),
    );
    await tester.pumpAndSettle();
    // The scroll view received the drag.
    expect(scrollController.offset, scrollAmount);
    expect(tapCount, 0);

    // Drag in the track area to validate pass through to scrollable.
    await tester.dragFrom(
      const Offset(797.0, 45.0),
      const Offset(0.0, -scrollAmount),
      touchSlopY: 0.0,
    );
    await tester.pumpAndSettle();
    // The scroll view received the drag.
    expect(scrollController.offset, scrollAmount * 2);
    expect(tapCount, 0);

    // Tap on the thumb to validate the scroll view receives a click.
    await tester.tapAt(const Offset(797.0, 45.0));
    await tester.pumpAndSettle();
    expect(tapCount, 1);

    // Tap on the track to validate the scroll view will not page and receives a click.
    await tester.tapAt(const Offset(797.0, 400.0));
    await tester.pumpAndSettle();
    // The offset should not have changed.
    expect(scrollController.offset, scrollAmount * 2);
    expect(tapCount, 2);

    scrollController.dispose();
  });

  testWidgets('Simultaneous dragging and pointer scrolling does not cause a crash', (WidgetTester tester) async {
    // Regression test for https://github.com/flutter/flutter/issues/70105
    final ScrollController scrollController = ScrollController();
    await tester.pumpWidget(
      MaterialApp(
        theme: ThemeData(useMaterial3: false),
        home: PrimaryScrollController(
          controller: scrollController,
          child: Scrollbar(
            interactive: true,
            thumbVisibility: true,
            controller: scrollController,
            child: const SingleChildScrollView(
              child: SizedBox(width: 4000.0, height: 4000.0),
            ),
          ),
        ),
      ),
    );
    await tester.pumpAndSettle();
    expect(scrollController.offset, 0.0);
    expect(
      find.byType(Scrollbar),
      paints
        ..rect(
          rect: _kAndroidTrackDimensions,
          color: Colors.transparent,
        )
        ..line(
          p1: _kTrackBorderPoint1,
          p2: _kTrackBorderPoint2,
          strokeWidth: 1.0,
          color: Colors.transparent,
        )
        ..rect(
          rect: getStartingThumbRect(isAndroid: true),
          color: _kAndroidThumbIdleColor,
        ),
    );

    // Drag the thumb down to scroll down.
    const double scrollAmount = 10.0;
    final TestGesture dragScrollbarGesture = await tester.startGesture(const Offset(797.0, 45.0));
    await tester.pumpAndSettle();

    expect(
      find.byType(Scrollbar),
      paints
        ..rect(
          rect: _kAndroidTrackDimensions,
          color: Colors.transparent,
        )
        ..line(
          p1: _kTrackBorderPoint1,
          p2: _kTrackBorderPoint2,
          strokeWidth: 1.0,
          color: Colors.transparent,
        )
        ..rect(
          rect: getStartingThumbRect(isAndroid: true),
          // Drag color
          color: const Color(0x99000000),
        ),
    );

    await dragScrollbarGesture.moveBy(const Offset(0.0, scrollAmount));
    await tester.pumpAndSettle();
    expect(scrollController.offset, greaterThan(10.0));
    final double previousOffset = scrollController.offset;
    expect(
      find.byType(Scrollbar),
      paints
        ..rect(
          rect: const Rect.fromLTRB(796.0, 0.0, 800.0, 600.0),
          color: Colors.transparent,
        )
        ..line(
          p1: const Offset(796.0, 0.0),
          p2: const Offset(796.0, 600.0),
          strokeWidth: 1.0,
          color: Colors.transparent,
        )
        ..rect(
          rect: const Rect.fromLTRB(796.0, 10.0, 800.0, 100.0),
          color: const Color(0x99000000),
        ),
    );

    // Execute a pointer scroll while dragging (drag gesture has not come up yet)
    final TestPointer pointer = TestPointer(1, ui.PointerDeviceKind.mouse);
    pointer.hover(const Offset(798.0, 15.0));
    await tester.sendEventToBinding(pointer.scroll(const Offset(0.0, 20.0)));
    await tester.pumpAndSettle();

    if (!kIsWeb) {
      // Scrolling while holding the drag on the scrollbar and still hovered over
      // the scrollbar should not have changed the scroll offset.
      expect(pointer.location, const Offset(798.0, 15.0));
      expect(scrollController.offset, previousOffset);
      expect(
        find.byType(Scrollbar),
        paints
          ..rect(
            rect: const Rect.fromLTRB(796.0, 0.0, 800.0, 600.0),
            color: Colors.transparent,
          )
          ..line(
            p1: const Offset(796.0, 0.0),
            p2: const Offset(796.0, 600.0),
            strokeWidth: 1.0,
            color: Colors.transparent,
          )
          ..rect(
            rect: const Rect.fromLTRB(796.0, 10.0, 800.0, 100.0),
            color: const Color(0x99000000),
          ),
      );
    } else {
      expect(pointer.location, const Offset(798.0, 15.0));
      expect(scrollController.offset, previousOffset + 20.0);
    }

    // Drag is still being held, move pointer to be hovering over another area
    // of the scrollable (not over the scrollbar) and execute another pointer scroll
    pointer.hover(tester.getCenter(find.byType(SingleChildScrollView)));
    await tester.sendEventToBinding(pointer.scroll(const Offset(0.0, -90.0)));
    await tester.pumpAndSettle();
    // Scrolling while holding the drag on the scrollbar changed the offset
    expect(pointer.location, const Offset(400.0, 300.0));
    expect(scrollController.offset, 0.0);
    expect(
      find.byType(Scrollbar),
      paints
        ..rect(
          rect: const Rect.fromLTRB(796.0, 0.0, 800.0, 600.0),
          color: Colors.transparent,
        )
        ..line(
          p1: const Offset(796.0, 0.0),
          p2: const Offset(796.0, 600.0),
          strokeWidth: 1.0,
          color: Colors.transparent,
        )
        ..rect(
          rect: const Rect.fromLTRB(796.0, 0.0, 800.0, 90.0),
          color: const Color(0x99000000),
        ),
    );

    await dragScrollbarGesture.up();
    await tester.pumpAndSettle();
    expect(scrollController.offset, 0.0);
    expect(
      find.byType(Scrollbar),
      paints
        ..rect(
          rect: const Rect.fromLTRB(796.0, 0.0, 800.0, 600.0),
          color: Colors.transparent,
        )
        ..line(
          p1: const Offset(796.0, 0.0),
          p2: const Offset(796.0, 600.0),
          strokeWidth: 1.0,
          color: Colors.transparent,
        )
        ..rect(
          rect: const Rect.fromLTRB(796.0, 0.0, 800.0, 90.0),
          color: const Color(0xffbcbcbc),
        ),
    );

    scrollController.dispose();
  });

  testWidgets('Scrollbar.thumbVisibility triggers assertion when multiple ScrollPositions are attached.', (WidgetTester tester) async {
    Widget getTabContent({ ScrollController? scrollController }) {
      return Scrollbar(
        thumbVisibility: true,
        controller: scrollController,
        child: ListView.builder(
          controller: scrollController,
          itemCount: 200,
          itemBuilder: (BuildContext context, int index) => const Text('Test'),
        ),
      );
    }

    Widget buildApp({
      required String id,
      ScrollController? scrollController,
    }) {
      return MaterialApp(
        key: ValueKey<String>(id),
        home: DefaultTabController(
          length: 2,
          child: Scaffold(
            body: TabBarView(
              children: <Widget>[
                getTabContent(scrollController: scrollController),
                getTabContent(scrollController: scrollController),
              ],
            ),
          ),
        ),
      );
    }

    // Asserts when using the PrimaryScrollController.
    await tester.pumpWidget(buildApp(id: 'PrimaryScrollController'));

    // Swipe to the second tab, resulting in two attached ScrollPositions during
    // the transition.
    await tester.drag(find.text('Test').first, const Offset(-100.0, 0.0));
    await tester.pump();

    FlutterError error = tester.takeException() as FlutterError;
    expect(
      error.message,
      '''
The PrimaryScrollController is attached to more than one ScrollPosition.
The Scrollbar requires a single ScrollPosition in order to be painted.
When Scrollbar.thumbVisibility is true, the associated ScrollController must only have one ScrollPosition attached.
If a ScrollController has not been provided, the PrimaryScrollController is used by default on mobile platforms for ScrollViews with an Axis.vertical scroll direction.
More than one ScrollView may have tried to use the PrimaryScrollController of the current context. ScrollView.primary can override this behavior.''',
    );

    // Asserts when using the ScrollController provided by the user.
    final ScrollController scrollController = ScrollController();
    await tester.pumpWidget(
      buildApp(
        id: 'Provided ScrollController',
        scrollController: scrollController,
      ),
    );

    // Swipe to the second tab, resulting in two attached ScrollPositions during
    // the transition.
    await tester.drag(find.text('Test').first, const Offset(-100.0, 0.0));
    await tester.pump();
    error = tester.takeException() as FlutterError;
    expect(
      error.message,
      '''
The provided ScrollController is attached to more than one ScrollPosition.
The Scrollbar requires a single ScrollPosition in order to be painted.
When Scrollbar.thumbVisibility is true, the associated ScrollController must only have one ScrollPosition attached.
The provided ScrollController cannot be shared by multiple ScrollView widgets.''',
    );

    scrollController.dispose();
  });

  testWidgets('Scrollbar scrollOrientation works correctly', (WidgetTester tester) async {
    final ScrollController scrollController = ScrollController();

    Widget buildScrollWithOrientation(ScrollbarOrientation orientation) {
      return _buildBoilerplate(
        child: Theme(
          data: ThemeData(
            platform: TargetPlatform.android,
          ),
          child: PrimaryScrollController(
            controller: scrollController,
            child: Scrollbar(
              interactive: true,
              thumbVisibility: true,
              scrollbarOrientation: orientation,
              controller: scrollController,
              child: const SingleChildScrollView(
                child: SizedBox(width: 4000.0, height: 4000.0)
              ),
            ),
          ),
        )
      );
    }

    await tester.pumpWidget(buildScrollWithOrientation(ScrollbarOrientation.left));
    await tester.pumpAndSettle();

    expect(
      find.byType(Scrollbar),
      paints
        ..rect(
          rect: const Rect.fromLTRB(0.0, 0.0, 4.0, 600.0),
          color: Colors.transparent,
        )
        ..line(
          p1: const Offset(4.0, 0.0),
          p2: const Offset(4.0, 600.0),
          strokeWidth: 1.0,
          color: Colors.transparent,
        )
        ..rect(
          rect: const Rect.fromLTRB(0.0, 0.0, 4.0, 90.0),
          color: _kAndroidThumbIdleColor,
        ),
    );

    scrollController.dispose();
  });
}
