// 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.

import 'dart:ui' as ui;

import 'package:flutter/cupertino.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter/services.dart';
import 'package:flutter_test/flutter_test.dart';

import '../rendering/mock_canvas.dart';

const CupertinoDynamicColor _kScrollbarColor = CupertinoDynamicColor.withBrightness(
  color: Color(0x59000000),
  darkColor: Color(0x80FFFFFF),
);

void main() {
  const Duration kScrollbarTimeToFade = Duration(milliseconds: 1200);
  const Duration kScrollbarFadeDuration = Duration(milliseconds: 250);
  const Duration kScrollbarResizeDuration = Duration(milliseconds: 100);
  const Duration kLongPressDuration = Duration(milliseconds: 100);

  testWidgets('Scrollbar never goes away until finger lift', (WidgetTester tester) async {
    await tester.pumpWidget(
      const Directionality(
        textDirection: TextDirection.ltr,
        child: MediaQuery(
          data: MediaQueryData(),
          child: CupertinoScrollbar(
            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, -10.0));
    await tester.pump();
    // Scrollbar fully showing
    await tester.pump(const Duration(milliseconds: 500));
    expect(find.byType(CupertinoScrollbar), paints..rrect(
      color: _kScrollbarColor.color,
    ));

    await tester.pump(const Duration(seconds: 3));
    await tester.pump(const Duration(seconds: 3));
    // Still there.
    expect(find.byType(CupertinoScrollbar), paints..rrect(
      color: _kScrollbarColor.color,
    ));

    await gesture.up();
    await tester.pump(kScrollbarTimeToFade);
    await tester.pump(kScrollbarFadeDuration * 0.5);

    // Opacity going down now.
    expect(find.byType(CupertinoScrollbar), paints..rrect(
      color: _kScrollbarColor.color.withAlpha(69),
    ));
  });

  testWidgets('Scrollbar dark mode', (WidgetTester tester) async {
    Brightness brightness = Brightness.light;
    late StateSetter setState;
    await tester.pumpWidget(
      Directionality(
        textDirection: TextDirection.ltr,
        child: StatefulBuilder(
          builder: (BuildContext context, StateSetter setter) {
            setState = setter;
            return MediaQuery(
              data: MediaQueryData(platformBrightness: brightness),
              child: const CupertinoScrollbar(
                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, 10.0));
    await tester.pump();
    // Scrollbar fully showing
    await tester.pumpAndSettle();
    expect(find.byType(CupertinoScrollbar), paints..rrect(
      color: _kScrollbarColor.color,
    ));

    setState(() { brightness = Brightness.dark; });
    await tester.pump();

    expect(find.byType(CupertinoScrollbar), paints..rrect(
      color: _kScrollbarColor.darkColor,
    ));
  });

  testWidgets('Scrollbar thumb can be dragged with long press', (WidgetTester tester) async {
    final ScrollController scrollController = ScrollController();
    await tester.pumpWidget(
      Directionality(
        textDirection: TextDirection.ltr,
        child: MediaQuery(
          data: const MediaQueryData(),
          child: PrimaryScrollController(
            controller: scrollController,
            child: const CupertinoScrollbar(
              child: SingleChildScrollView(child: SizedBox(width: 4000.0, height: 4000.0)),
            ),
          ),
        ),
      ),
    );

    expect(scrollController.offset, 0.0);

    // Scroll a bit.
    const double scrollAmount = 10.0;
    final TestGesture scrollGesture = await tester.startGesture(tester.getCenter(find.byType(SingleChildScrollView)));
    // Scroll down by swiping up.
    await scrollGesture.moveBy(const Offset(0.0, -scrollAmount));
    await tester.pump();
    await tester.pump(const Duration(milliseconds: 500));
    // Scrollbar thumb is fully showing and scroll offset has moved by
    // scrollAmount.
    expect(find.byType(CupertinoScrollbar), paints..rrect(
      color: _kScrollbarColor.color,
    ));
    expect(scrollController.offset, scrollAmount);
    await scrollGesture.up();
    await tester.pump();

    int hapticFeedbackCalls = 0;
    tester.binding.defaultBinaryMessenger.setMockMethodCallHandler(SystemChannels.platform, (MethodCall methodCall) async {
      if (methodCall.method == 'HapticFeedback.vibrate') {
        hapticFeedbackCalls += 1;
      }
      return null;
    });

    // Long press on the scrollbar thumb and expect a vibration after it resizes.
    expect(hapticFeedbackCalls, 0);
    final TestGesture dragScrollbarGesture = await tester.startGesture(const Offset(796.0, 50.0));
    await tester.pump(kLongPressDuration);
    expect(hapticFeedbackCalls, 0);
    await tester.pump(kScrollbarResizeDuration);
    // Allow the haptic feedback some slack.
    await tester.pump(const Duration(milliseconds: 1));
    expect(hapticFeedbackCalls, 1);

    // Drag the thumb down to scroll down.
    await dragScrollbarGesture.moveBy(const Offset(0.0, scrollAmount));
    await tester.pump(const Duration(milliseconds: 100));
    await dragScrollbarGesture.up();
    await tester.pumpAndSettle();

    // The view has scrolled more than it would have by a swipe gesture of the
    // same distance.
    expect(scrollController.offset, greaterThan(scrollAmount * 2));
    // The scrollbar thumb is still fully visible.
    expect(find.byType(CupertinoScrollbar), paints..rrect(
      color: _kScrollbarColor.color,
    ));

    // Let the thumb fade out so all timers have resolved.
    await tester.pump(kScrollbarTimeToFade);
    await tester.pump(kScrollbarFadeDuration);
  });

  testWidgets('Scrollbar thumb can be dragged with long press - reverse', (WidgetTester tester) async {
    final ScrollController scrollController = ScrollController();
    await tester.pumpWidget(
      Directionality(
        textDirection: TextDirection.ltr,
        child: MediaQuery(
          data: const MediaQueryData(),
          child: PrimaryScrollController(
            controller: scrollController,
            child: const CupertinoScrollbar(
              child: SingleChildScrollView(
                reverse: true,
                child: SizedBox(width: 4000.0, height: 4000.0),
              ),
            ),
          ),
        ),
      ),
    );

    expect(scrollController.offset, 0.0);

    // Scroll a bit.
    const double scrollAmount = 10.0;
    final TestGesture scrollGesture = await tester.startGesture(tester.getCenter(find.byType(SingleChildScrollView)));
    // Scroll up by swiping down.
    await scrollGesture.moveBy(const Offset(0.0, scrollAmount));
    await tester.pump();
    await tester.pump(const Duration(milliseconds: 500));
    // Scrollbar thumb is fully showing and scroll offset has moved by
    // scrollAmount.
    expect(find.byType(CupertinoScrollbar), paints..rrect(
      color: _kScrollbarColor.color,
    ));
    expect(scrollController.offset, scrollAmount);
    await scrollGesture.up();
    await tester.pump();

    int hapticFeedbackCalls = 0;
    SystemChannels.platform.setMockMethodCallHandler((MethodCall methodCall) async {
      if (methodCall.method == 'HapticFeedback.vibrate') {
        hapticFeedbackCalls++;
      }
    });

    // Long press on the scrollbar thumb and expect a vibration after it resizes.
    expect(hapticFeedbackCalls, 0);
    final TestGesture dragScrollbarGesture = await tester.startGesture(const Offset(796.0, 550.0));
    await tester.pump(kLongPressDuration);
    expect(hapticFeedbackCalls, 0);
    await tester.pump(kScrollbarResizeDuration);
    // Allow the haptic feedback some slack.
    await tester.pump(const Duration(milliseconds: 1));
    expect(hapticFeedbackCalls, 1);

    // Drag the thumb up to scroll up.
    await dragScrollbarGesture.moveBy(const Offset(0.0, -scrollAmount));
    await tester.pump(const Duration(milliseconds: 100));
    await dragScrollbarGesture.up();
    await tester.pumpAndSettle();

    // The view has scrolled more than it would have by a swipe gesture of the
    // same distance.
    expect(scrollController.offset, greaterThan(scrollAmount * 2));
    // The scrollbar thumb is still fully visible.
    expect(find.byType(CupertinoScrollbar), paints..rrect(
      color: _kScrollbarColor.color,
    ));

    // Let the thumb fade out so all timers have resolved.
    await tester.pump(kScrollbarTimeToFade);
    await tester.pump(kScrollbarFadeDuration);
  });

  testWidgets('Scrollbar changes thickness and radius when dragged', (WidgetTester tester) async {
    const double thickness = 20;
    const double thicknessWhileDragging = 40;
    const double radius = 10;
    const double radiusWhileDragging = 20;

    const double inset = 3;
    const double scaleFactor = 2;
    final Size screenSize = tester.binding.window.physicalSize / tester.binding.window.devicePixelRatio;

    final ScrollController scrollController = ScrollController();
    await tester.pumpWidget(
      Directionality(
        textDirection: TextDirection.ltr,
        child: MediaQuery(
          data: const MediaQueryData(),
          child: PrimaryScrollController(
            controller: scrollController,
            child: CupertinoScrollbar(
              thickness: thickness,
              thicknessWhileDragging: thicknessWhileDragging,
              radius: const Radius.circular(radius),
              radiusWhileDragging: const Radius.circular(radiusWhileDragging),
              child: SingleChildScrollView(
                child: SizedBox(
                  width: screenSize.width * scaleFactor,
                  height: screenSize.height * scaleFactor,
                ),
              ),
            ),
          ),
        ),
      ),
    );

    expect(scrollController.offset, 0.0);

    // Scroll a bit to cause the scrollbar thumb to be shown;
    // undo the scroll to put the thumb back at the top.
    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
    final TestGesture dragScrollbarGesture = await tester.startGesture(const Offset(780.0, 50.0));
    await tester.pump(kLongPressDuration);
    expect(find.byType(CupertinoScrollbar), paints..rrect(
      rrect: RRect.fromRectAndRadius(
        Rect.fromLTWH(
          screenSize.width - inset - thickness,
          inset,
          thickness,
          (screenSize.height - 2 * inset) / scaleFactor,
        ),
        const Radius.circular(radius),
      ),
    ));
    await tester.pump(kScrollbarResizeDuration ~/ 2);
    const double midpointThickness = (thickness + thicknessWhileDragging) / 2;
    const double midpointRadius = (radius + radiusWhileDragging) / 2;
    expect(find.byType(CupertinoScrollbar), paints..rrect(
      rrect: RRect.fromRectAndRadius(
        Rect.fromLTWH(
          screenSize.width - inset - midpointThickness,
          inset,
          midpointThickness,
          (screenSize.height - 2 * inset) / scaleFactor,
        ),
        const Radius.circular(midpointRadius),
      ),
    ));
    await tester.pump(kScrollbarResizeDuration ~/ 2);
    expect(find.byType(CupertinoScrollbar), paints..rrect(
      rrect: RRect.fromRectAndRadius(
        Rect.fromLTWH(
          screenSize.width - inset - thicknessWhileDragging,
          inset,
          thicknessWhileDragging,
          (screenSize.height - 2 * inset) / scaleFactor,
        ),
        const Radius.circular(radiusWhileDragging),
      ),
    ));

    // Let the thumb fade out so all timers have resolved.
    await dragScrollbarGesture.up();
    await tester.pumpAndSettle();
    await tester.pump(kScrollbarTimeToFade);
    await tester.pump(kScrollbarFadeDuration);
  });

  testWidgets('When thumbVisibility is true, must pass a controller or find PrimaryScrollController', (WidgetTester tester) async {
      Widget viewWithScroll() {
        return const Directionality(
          textDirection: TextDirection.ltr,
          child: MediaQuery(
            data: MediaQueryData(),
            child: CupertinoScrollbar(
              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 or find PrimaryScrollController that is attached to a scroll view', (WidgetTester tester) async {
      final ScrollController controller = ScrollController();
      Widget viewWithScroll() {
        return Directionality(
          textDirection: TextDirection.ltr,
          child: MediaQuery(
            data: const MediaQueryData(),
            child: CupertinoScrollbar(
              controller: controller,
              thumbVisibility: true,
              child: const SingleChildScrollView(
                child: SizedBox(
                  width: 4000.0,
                  height: 4000.0,
                ),
              ),
            ),
          ),
        );
      }

      final FlutterExceptionHandler? handler = FlutterError.onError;
      FlutterErrorDetails? error;
      FlutterError.onError = (FlutterErrorDetails details) {
        error = details;
      };

      await tester.pumpWidget(viewWithScroll());
      expect(error, isNotNull);

      FlutterError.onError = handler;
    },
  );

  testWidgets('When isAlwaysShown is true, must pass a controller or find PrimaryScrollController', (WidgetTester tester) async {
      Widget viewWithScroll() {
        return const Directionality(
          textDirection: TextDirection.ltr,
          child: MediaQuery(
            data: MediaQueryData(),
            child: CupertinoScrollbar(
              isAlwaysShown: 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 isAlwaysShown is true, must pass a controller or find PrimaryScrollController that is attached to a scroll view', (WidgetTester tester) async {
      final ScrollController controller = ScrollController();
      Widget viewWithScroll() {
        return Directionality(
          textDirection: TextDirection.ltr,
          child: MediaQuery(
            data: const MediaQueryData(),
            child: CupertinoScrollbar(
              controller: controller,
              isAlwaysShown: true,
              child: const SingleChildScrollView(
                child: SizedBox(
                  width: 4000.0,
                  height: 4000.0,
                ),
              ),
            ),
          ),
        );
      }

      final FlutterExceptionHandler? handler = FlutterError.onError;
      FlutterErrorDetails? error;
      FlutterError.onError = (FlutterErrorDetails details) {
        error = details;
      };

      await tester.pumpWidget(viewWithScroll());
      expect(error, isNotNull);

      FlutterError.onError = handler;
    },
  );

  testWidgets('On first render with thumbVisibility: true, the thumb shows with PrimaryScrollController', (WidgetTester tester) async {
      final ScrollController controller = ScrollController();
      Widget viewWithScroll() {
        return Directionality(
          textDirection: TextDirection.ltr,
          child: MediaQuery(
            data: const MediaQueryData(),
            child: PrimaryScrollController(
              controller: controller,
              child: Builder(
                builder: (BuildContext context) {
                  return const CupertinoScrollbar(
                    thumbVisibility: true,
                    child: SingleChildScrollView(
                      primary: true,
                      child: SizedBox(
                        width: 4000.0,
                        height: 4000.0,
                      ),
                    ),
                  );
                },
              ),
            ),
          ),
        );
      }

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

  testWidgets('On first render with thumbVisibility: true, the thumb shows', (WidgetTester tester) async {
    final ScrollController controller = ScrollController();
    Widget viewWithScroll() {
      return Directionality(
        textDirection: TextDirection.ltr,
        child: MediaQuery(
          data: const MediaQueryData(),
          child: PrimaryScrollController(
            controller: controller,
            child: CupertinoScrollbar(
              thumbVisibility: true,
              controller: controller,
              child: const SingleChildScrollView(
                child: SizedBox(
                  width: 4000.0,
                  height: 4000.0,
                ),
              ),
            ),
          ),
        ),
      );
    }

    await tester.pumpWidget(viewWithScroll());
    // The scrollbar measures its size on the first frame
    // and renders starting in the second,
    //
    // so pumpAndSettle a frame to allow it to appear.
    await tester.pumpAndSettle();
    expect(find.byType(CupertinoScrollbar), paints..rrect());
  });

  testWidgets('On first render with isAlwaysShown: true, the thumb shows with PrimaryScrollController', (WidgetTester tester) async {
      final ScrollController controller = ScrollController();
      Widget viewWithScroll() {
        return Directionality(
          textDirection: TextDirection.ltr,
          child: MediaQuery(
            data: const MediaQueryData(),
            child: PrimaryScrollController(
              controller: controller,
              child: Builder(
                builder: (BuildContext context) {
                  return const CupertinoScrollbar(
                    isAlwaysShown: true,
                    child: SingleChildScrollView(
                      primary: true,
                      child: SizedBox(
                        width: 4000.0,
                        height: 4000.0,
                      ),
                    ),
                  );
                },
              ),
            ),
          ),
        );
      }

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

  testWidgets('On first render with isAlwaysShown: true, the thumb shows', (WidgetTester tester) async {
    final ScrollController controller = ScrollController();
    Widget viewWithScroll() {
      return Directionality(
        textDirection: TextDirection.ltr,
        child: MediaQuery(
          data: const MediaQueryData(),
          child: PrimaryScrollController(
            controller: controller,
            child: CupertinoScrollbar(
              isAlwaysShown: true,
              controller: controller,
              child: const SingleChildScrollView(
                child: SizedBox(
                  width: 4000.0,
                  height: 4000.0,
                ),
              ),
            ),
          ),
        ),
      );
    }

    await tester.pumpWidget(viewWithScroll());
    // The scrollbar measures its size on the first frame
    // and renders starting in the second,
    //
    // so pumpAndSettle a frame to allow it to appear.
    await tester.pumpAndSettle();
    expect(find.byType(CupertinoScrollbar), paints..rrect());
  });

  testWidgets('On first render with isAlwaysShown: false, the thumb is hidden', (WidgetTester tester) async {
    final ScrollController controller = ScrollController();
    Widget viewWithScroll() {
      return Directionality(
        textDirection: TextDirection.ltr,
        child: MediaQuery(
          data: const MediaQueryData(),
          child: PrimaryScrollController(
            controller: controller,
            child: CupertinoScrollbar(
              controller: controller,
              child: const SingleChildScrollView(
                child: SizedBox(
                  width: 4000.0,
                  height: 4000.0,
                ),
              ),
            ),
          ),
        ),
      );
    }

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

  testWidgets('With isAlwaysShown: true, fling a scroll. While it is still scrolling, set isAlwaysShown: false. The thumb should not fade out until the scrolling stops.', (WidgetTester tester) async {
      final ScrollController controller = ScrollController();
      bool isAlwaysShown = true;
      Widget viewWithScroll() {
        return StatefulBuilder(
          builder: (BuildContext context, StateSetter setState) {
            return Directionality(
              textDirection: TextDirection.ltr,
              child: MediaQuery(
                data: const MediaQueryData(),
                child: Stack(
                  children: <Widget>[
                    CupertinoScrollbar(
                      isAlwaysShown: isAlwaysShown,
                      controller: controller,
                      child: SingleChildScrollView(
                        controller: controller,
                        child: const SizedBox(
                          width: 4000.0,
                          height: 4000.0,
                        ),
                      ),
                    ),
                    Positioned(
                      bottom: 10,
                      child: CupertinoButton(
                        onPressed: () {
                          setState(() {
                            isAlwaysShown = !isAlwaysShown;
                          });
                        },
                        child: const Text('change isAlwaysShown'),
                      ),
                    ),
                  ],
                ),
              ),
            );
          },
        );
      }

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

      await tester.tap(find.byType(CupertinoButton));
      await tester.pumpAndSettle();
      expect(find.byType(CupertinoScrollbar), isNot(paints..rrect()));
    },
  );

  testWidgets(
    'With isAlwaysShown: false, set isAlwaysShown: true. The thumb should be always shown directly',
    (WidgetTester tester) async {
      final ScrollController controller = ScrollController();
      bool isAlwaysShown = false;
      Widget viewWithScroll() {
        return StatefulBuilder(
          builder: (BuildContext context, StateSetter setState) {
            return Directionality(
              textDirection: TextDirection.ltr,
              child: MediaQuery(
                data: const MediaQueryData(),
                child: Stack(
                  children: <Widget>[
                    CupertinoScrollbar(
                      isAlwaysShown: isAlwaysShown,
                      controller: controller,
                      child: SingleChildScrollView(
                        controller: controller,
                        child: const SizedBox(
                          width: 4000.0,
                          height: 4000.0,
                        ),
                      ),
                    ),
                    Positioned(
                      bottom: 10,
                      child: CupertinoButton(
                        onPressed: () {
                          setState(() {
                            isAlwaysShown = !isAlwaysShown;
                          });
                        },
                        child: const Text('change isAlwaysShown'),
                      ),
                    ),
                  ],
                ),
              ),
            );
          },
        );
      }

      await tester.pumpWidget(viewWithScroll());
      await tester.pumpAndSettle();
      expect(find.byType(CupertinoScrollbar), isNot(paints..rrect()));

      await tester.tap(find.byType(CupertinoButton));
      await tester.pumpAndSettle();
      expect(find.byType(CupertinoScrollbar), paints..rrect());
    },
  );

  testWidgets(
    'With isAlwaysShown: false, fling a scroll. While it is still scrolling, set isAlwaysShown: true. '
    'The thumb should not fade even after the scrolling stops',
    (WidgetTester tester) async {
      final ScrollController controller = ScrollController();
      bool isAlwaysShown = false;
      Widget viewWithScroll() {
        return StatefulBuilder(
          builder: (BuildContext context, StateSetter setState) {
            return Directionality(
              textDirection: TextDirection.ltr,
              child: MediaQuery(
                data: const MediaQueryData(),
                child: Stack(
                  children: <Widget>[
                    CupertinoScrollbar(
                      isAlwaysShown: isAlwaysShown,
                      controller: controller,
                      child: SingleChildScrollView(
                        controller: controller,
                        child: const SizedBox(
                          width: 4000.0,
                          height: 4000.0,
                        ),
                      ),
                    ),
                    Positioned(
                      bottom: 10,
                      child: CupertinoButton(
                        onPressed: () {
                          setState(() {
                            isAlwaysShown = !isAlwaysShown;
                          });
                        },
                        child: const Text('change isAlwaysShown'),
                      ),
                    ),
                  ],
                ),
              ),
            );
          },
        );
      }

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

      await tester.tap(find.byType(CupertinoButton));
      await tester.pump();
      expect(find.byType(CupertinoScrollbar), paints..rrect());

      // 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(CupertinoScrollbar), paints..rrect());
    },
  );

  testWidgets(
    'Toggling isAlwaysShown 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 isAlwaysShown = true;
      Widget viewWithScroll() {
        return StatefulBuilder(
          builder: (BuildContext context, StateSetter setState) {
            return Directionality(
              textDirection: TextDirection.ltr,
              child: MediaQuery(
                data: const MediaQueryData(),
                child: Stack(
                  children: <Widget>[
                    CupertinoScrollbar(
                      isAlwaysShown: isAlwaysShown,
                      controller: controller,
                      child: SingleChildScrollView(
                        controller: controller,
                        child: const SizedBox(
                          width: 4000.0,
                          height: 4000.0,
                        ),
                      ),
                    ),
                    Positioned(
                      bottom: 10,
                      child: CupertinoButton(
                        onPressed: () {
                          setState(() {
                            isAlwaysShown = !isAlwaysShown;
                          });
                        },
                        child: const Text('change isAlwaysShown'),
                      ),
                    ),
                  ],
                ),
              ),
            );
          },
        );
      }

      await tester.pumpWidget(viewWithScroll());
      await tester.pumpAndSettle();
      expect(find.byType(CupertinoScrollbar), paints..rrect());

      await tester.tap(find.byType(CupertinoButton));
      await tester.pumpAndSettle();
      expect(find.byType(CupertinoScrollbar), isNot(paints..rrect()));
    },
  );

  testWidgets('Scrollbar thumb can be dragged with long press - horizontal axis', (WidgetTester tester) async {
    final ScrollController scrollController = ScrollController();
    await tester.pumpWidget(
      Directionality(
        textDirection: TextDirection.ltr,
        child: MediaQuery(
          data: const MediaQueryData(),
          child: CupertinoScrollbar(
            controller: scrollController,
            child: SingleChildScrollView(
              controller: scrollController,
              scrollDirection: Axis.horizontal,
              child: const SizedBox(width: 4000.0, height: 4000.0),
            ),
          ),
        ),
      ),
    );

    expect(scrollController.offset, 0.0);

    // Scroll a bit.
    const double scrollAmount = 10.0;
    final TestGesture scrollGesture = await tester.startGesture(tester.getCenter(find.byType(SingleChildScrollView)));
    // Scroll right by swiping left.
    await scrollGesture.moveBy(const Offset(-scrollAmount, 0.0));
    await tester.pump();
    await tester.pump(const Duration(milliseconds: 500));
    // Scrollbar thumb is fully showing and scroll offset has moved by
    // scrollAmount.
    expect(find.byType(CupertinoScrollbar), paints..rrect(
      color: _kScrollbarColor.color,
    ));
    expect(scrollController.offset, scrollAmount);
    await scrollGesture.up();
    await tester.pump();

    int hapticFeedbackCalls = 0;
    tester.binding.defaultBinaryMessenger.setMockMethodCallHandler(SystemChannels.platform, (MethodCall methodCall) async {
      if (methodCall.method == 'HapticFeedback.vibrate') {
        hapticFeedbackCalls += 1;
      }
      return null;
    });

    // Long press on the scrollbar thumb and expect a vibration after it resizes.
    expect(hapticFeedbackCalls, 0);
    final TestGesture dragScrollbarGesture = await tester.startGesture(const Offset(50.0, 596.0));
    await tester.pump(kLongPressDuration);
    expect(hapticFeedbackCalls, 0);
    await tester.pump(kScrollbarResizeDuration);
    // Allow the haptic feedback some slack.
    await tester.pump(const Duration(milliseconds: 1));
    expect(hapticFeedbackCalls, 1);

    // Drag the thumb down to scroll back to the left.
    await dragScrollbarGesture.moveBy(const Offset(scrollAmount, 0.0));
    await tester.pump(const Duration(milliseconds: 100));
    await dragScrollbarGesture.up();
    await tester.pumpAndSettle();

    // The view has scrolled more than it would have by a swipe gesture of the
    // same distance.
    expect(scrollController.offset, greaterThan(scrollAmount * 2));
    // The scrollbar thumb is still fully visible.
    expect(find.byType(CupertinoScrollbar), paints..rrect(
      color: _kScrollbarColor.color,
    ));

    // Let the thumb fade out so all timers have resolved.
    await tester.pump(kScrollbarTimeToFade);
    await tester.pump(kScrollbarFadeDuration);
  });

  testWidgets('Scrollbar thumb can be dragged with long press - horizontal axis, reverse', (WidgetTester tester) async {
    final ScrollController scrollController = ScrollController();
    await tester.pumpWidget(
      Directionality(
        textDirection: TextDirection.ltr,
        child: MediaQuery(
          data: const MediaQueryData(),
          child: CupertinoScrollbar(
            controller: scrollController,
            child: SingleChildScrollView(
              reverse: true,
              controller: scrollController,
              scrollDirection: Axis.horizontal,
              child: const SizedBox(width: 4000.0, height: 4000.0),
            ),
          ),
        ),
      ),
    );

    expect(scrollController.offset, 0.0);

    // Scroll a bit.
    const double scrollAmount = 10.0;
    final TestGesture scrollGesture = await tester.startGesture(tester.getCenter(find.byType(SingleChildScrollView)));
    // Scroll right by swiping right.
    await scrollGesture.moveBy(const Offset(scrollAmount, 0.0));
    await tester.pump();
    await tester.pump(const Duration(milliseconds: 500));
    // Scrollbar thumb is fully showing and scroll offset has moved by
    // scrollAmount.
    expect(find.byType(CupertinoScrollbar), paints..rrect(
      color: _kScrollbarColor.color,
    ));
    expect(scrollController.offset, scrollAmount);
    await scrollGesture.up();
    await tester.pump();

    int hapticFeedbackCalls = 0;
    SystemChannels.platform.setMockMethodCallHandler((MethodCall methodCall) async {
      if (methodCall.method == 'HapticFeedback.vibrate') {
        hapticFeedbackCalls++;
      }
    });

    // Long press on the scrollbar thumb and expect a vibration after it resizes.
    expect(hapticFeedbackCalls, 0);
    final TestGesture dragScrollbarGesture = await tester.startGesture(const Offset(750.0, 596.0));
    await tester.pump(kLongPressDuration);
    expect(hapticFeedbackCalls, 0);
    await tester.pump(kScrollbarResizeDuration);
    // Allow the haptic feedback some slack.
    await tester.pump(const Duration(milliseconds: 1));
    expect(hapticFeedbackCalls, 1);

    // Drag the thumb to scroll back to the right.
    await dragScrollbarGesture.moveBy(const Offset(-scrollAmount, 0.0));
    await tester.pump(const Duration(milliseconds: 100));
    await dragScrollbarGesture.up();
    await tester.pumpAndSettle();

    // The view has scrolled more than it would have by a swipe gesture of the
    // same distance.
    expect(scrollController.offset, greaterThan(scrollAmount * 2));
    // The scrollbar thumb is still fully visible.
    expect(find.byType(CupertinoScrollbar), paints..rrect(
      color: _kScrollbarColor.color,
    ));

    // Let the thumb fade out so all timers have resolved.
    await tester.pump(kScrollbarTimeToFade);
    await tester.pump(kScrollbarFadeDuration);
  });

  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: CupertinoScrollbar(
            isAlwaysShown: 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(CupertinoScrollbar),
      paints..rrect(
        color: _kScrollbarColor.color,
        rrect: RRect.fromLTRBR(794.0, 3.0, 797.0, 359.4, const Radius.circular(1.5)),
      ),
    );

    // 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(CupertinoScrollbar),
      paints..rrect(
        color: _kScrollbarColor.color,
        rrect: RRect.fromRectAndRadius(
          const Rect.fromLTRB(794.0, 240.6, 797.0, 597.0),
          const Radius.circular(1.5),
        ),
      ),
    );

    // 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(CupertinoScrollbar),
      paints..rrect(
        color: _kScrollbarColor.color,
        rrect: RRect.fromLTRBR(794.0, 3.0, 797.0, 359.4, const Radius.circular(1.5)),
      ),
    );
  });

  testWidgets('Throw if interactive with the bar when no position attached', (WidgetTester tester) async {
    final ScrollController scrollController = ScrollController();

    await tester.pumpWidget(
      Directionality(
        textDirection: TextDirection.ltr,
        child: MediaQuery(
          data: const MediaQueryData(),
          child: CupertinoScrollbar(
            controller: scrollController,
            thumbVisibility: true,
            child: SingleChildScrollView(
              controller: scrollController,
              child: const SizedBox(
                height: 1000.0,
                width: 1000.0,
              ),
            ),
          ),
        ),
      ),
    );

    await tester.pumpAndSettle();

    final ScrollPosition position = scrollController.position;
    scrollController.detach(position);

    final FlutterExceptionHandler? handler = FlutterError.onError;
    FlutterErrorDetails? error;
    FlutterError.onError = (FlutterErrorDetails details) {
      error = details;
    };

    // long press the thumb
    await tester.startGesture(const Offset(796.0, 50.0));
    await tester.pump(kLongPressDuration);

    expect(error, isNotNull);

    scrollController.attach(position);
    FlutterError.onError = handler;
  });

  testWidgets('Interactive scrollbars should have a valid scroll controller', (WidgetTester tester) async {
    final ScrollController primaryScrollController = ScrollController();
    final ScrollController scrollController = ScrollController();

    await tester.pumpWidget(
      Directionality(
        textDirection: TextDirection.ltr,
        child: MediaQuery(
          data: const MediaQueryData(),
          child: PrimaryScrollController(
            controller: primaryScrollController,
              child: CupertinoScrollbar(
                child: SingleChildScrollView(
                controller: scrollController,
                child: const SizedBox(
                  height: 1000.0,
                  width: 1000.0,
                ),
              ),
            ),
          ),
        ),
      ),
    );

    await tester.pumpAndSettle();

    AssertionError? exception = tester.takeException() as AssertionError?;
    // The scrollbar is not visible and cannot be interacted with, so no assertion.
    expect(exception, isNull);
    // Scroll to trigger the scrollbar to come into view.
    final TestGesture gesture = await tester.startGesture(tester.getCenter(find.byType(SingleChildScrollView)));
    await gesture.moveBy(const Offset(0.0, -20.0));
    exception = tester.takeException() as AssertionError;
    expect(exception, isAssertionError);
    expect(
      exception.message,
      contains("The Scrollbar's ScrollController has no ScrollPosition attached."),
    );
  });

  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(
      CupertinoApp(
        home: PrimaryScrollController(
          controller: scrollController,
          child: CupertinoScrollbar(
            isAlwaysShown: true,
            controller: scrollController,
            child: const SingleChildScrollView(
              child: SizedBox(width: 4000.0, height: 4000.0),
            ),
          ),
        ),
      ),
    );
    const double scrollAmount = 10.0;

    await tester.pumpAndSettle();
    expect(
        find.byType(CupertinoScrollbar),
        paints..rrect(
          rrect: RRect.fromRectAndRadius(
            const Rect.fromLTRB(794.0, 3.0, 797.0, 92.1),
            const Radius.circular(1.5),
          ),
          color: _kScrollbarColor.color,
        ),
    );
    final TestGesture dragScrollbarGesture = await tester.startGesture(const Offset(796.0, 50.0));
    await tester.pump(kLongPressDuration);
    await tester.pump(kScrollbarResizeDuration);

    // Drag the thumb down to scroll down.
    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(CupertinoScrollbar),
      paints..rrect(
        rrect: RRect.fromRectAndRadius(
          const Rect.fromLTRB(789.0, 13.0, 797.0, 102.1),
          const Radius.circular(4.0),
        ),
        color: _kScrollbarColor.color,
      ),
    );

    // 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(793.0, 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(793.0, 15.0));
      expect(scrollController.offset, previousOffset);
      expect(
        find.byType(CupertinoScrollbar),
        paints..rrect(
          rrect: RRect.fromRectAndRadius(
            const Rect.fromLTRB(789.0, 13.0, 797.0, 102.1),
            const Radius.circular(4.0),
          ),
          color: _kScrollbarColor.color,
        ),
      );
    } else {
      expect(pointer.location, const Offset(793.0, 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(CupertinoScrollbar),
      paints..rrect(
        rrect: RRect.fromRectAndRadius(
          const Rect.fromLTRB(789.0, 3.0, 797.0, 92.1),
          const Radius.circular(4.0),
        ),
        color: _kScrollbarColor.color,
      ),
    );

    await dragScrollbarGesture.up();
    await tester.pumpAndSettle();
    expect(scrollController.offset, 0.0);
    expect(
      find.byType(CupertinoScrollbar),
      paints..rrect(
        rrect: RRect.fromRectAndRadius(
          const Rect.fromLTRB(794.0, 3.0, 797.0, 92.1),
          const Radius.circular(1.5),
        ),
        color: _kScrollbarColor.color,
      ),
    );
  });

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

    await tester.pumpWidget(
      CupertinoApp(
        home: PrimaryScrollController(
          controller: scrollController,
          child: CupertinoScrollbar(
            isAlwaysShown: true,
            controller: scrollController,
            scrollbarOrientation: ScrollbarOrientation.left,
            child: const SingleChildScrollView(
              child: SizedBox(width: 4000.0, height: 4000.0),
            ),
          ),
        ),
      ),
    );

    await tester.pumpAndSettle();

    expect(
      find.byType(CupertinoScrollbar),
      paints
        ..rect(
          rect: const Rect.fromLTRB(0.0, 0.0, 9.0, 600.0),
        )
        ..line(
          p1: const Offset(9.0, 0.0),
          p2: const Offset(9.0, 600.0),
          strokeWidth: 1.0,
        )
        ..rrect(
          rrect: RRect.fromRectAndRadius(const Rect.fromLTRB(3.0, 3.0, 6.0, 92.1), const Radius.circular(1.5)),
          color: _kScrollbarColor.color,
        ),
    );
  });
}
