// Copyright 2016 The Chromium 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 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter/rendering.dart';
import 'package:flutter/scheduler.dart';
import 'package:flutter_test/flutter_test.dart';

import '../widgets/semantics_tester.dart';

void main() {

  Future<Null> _dragSlider(WidgetTester tester, Key sliderKey) {
    final Offset topLeft = tester.getTopLeft(find.byKey(sliderKey));
    const double unit = CupertinoThumbPainter.radius;
    const double delta = 3.0 * unit;
    return tester.dragFrom(topLeft + const Offset(unit, unit), const Offset(delta, 0.0));
  }

  testWidgets('Slider does not move when tapped (LTR)', (WidgetTester tester) async {
    final Key sliderKey = new UniqueKey();
    double value = 0.0;

    await tester.pumpWidget(new Directionality(
      textDirection: TextDirection.ltr,
      child: new StatefulBuilder(
        builder: (BuildContext context, StateSetter setState) {
          return new Material(
            child: new Center(
              child: new CupertinoSlider(
                key: sliderKey,
                value: value,
                onChanged: (double newValue) {
                  setState(() {
                    value = newValue;
                  });
                },
              ),
            ),
          );
        },
      ),
    ));

    expect(value, equals(0.0));
    await tester.tap(find.byKey(sliderKey));
    expect(value, equals(0.0));
    await tester.pump(); // No animation should start.
    // Check the transientCallbackCount before tearing down the widget to ensure
    // that no animation is running.
    expect(SchedulerBinding.instance.transientCallbackCount, equals(0));
  });

  testWidgets('Slider does not move when tapped (RTL)', (WidgetTester tester) async {
    final Key sliderKey = new UniqueKey();
    double value = 0.0;

    await tester.pumpWidget(new Directionality(
      textDirection: TextDirection.rtl,
      child: new StatefulBuilder(
        builder: (BuildContext context, StateSetter setState) {
          return new Material(
            child: new Center(
              child: new CupertinoSlider(
                key: sliderKey,
                value: value,
                onChanged: (double newValue) {
                  setState(() {
                    value = newValue;
                  });
                },
              ),
            ),
          );
        },
      ),
    ));

    expect(value, equals(0.0));
    await tester.tap(find.byKey(sliderKey));
    expect(value, equals(0.0));
    await tester.pump(); // No animation should start.
    // Check the transientCallbackCount before tearing down the widget to ensure
    // that no animation is running.
    expect(SchedulerBinding.instance.transientCallbackCount, equals(0));
  });

  testWidgets('Slider calls onChangeStart once when interaction begins', (WidgetTester tester) async {
    final Key sliderKey = new UniqueKey();
    double value = 0.0;
    int numberOfTimesOnChangeStartIsCalled = 0;

    await tester.pumpWidget(new Directionality(
      textDirection: TextDirection.ltr,
      child: new StatefulBuilder(
        builder: (BuildContext context, StateSetter setState) {
          return new Material(
            child: new Center(
              child: new CupertinoSlider(
                key: sliderKey,
                value: value,
                onChanged: (double newValue) {
                  setState(() {
                    value = newValue;
                  });
                },
                onChangeStart: (double value) {
                  numberOfTimesOnChangeStartIsCalled++;
                }
              ),
            ),
          );
        },
      ),
    ));

    await _dragSlider(tester, sliderKey);
    
    expect(numberOfTimesOnChangeStartIsCalled, equals(1));

    await tester.pump(); // No animation should start.
    // Check the transientCallbackCount before tearing down the widget to ensure
    // that no animation is running.
    expect(SchedulerBinding.instance.transientCallbackCount, equals(0));
  });

  testWidgets('Slider calls onChangeEnd once after interaction has ended', (WidgetTester tester) async {
    final Key sliderKey = new UniqueKey();
    double value = 0.0;
    int numberOfTimesOnChangeEndIsCalled = 0;

    await tester.pumpWidget(new Directionality(
      textDirection: TextDirection.ltr,
      child: new StatefulBuilder(
        builder: (BuildContext context, StateSetter setState) {
          return new Material(
            child: new Center(
              child: new CupertinoSlider(
                key: sliderKey,
                value: value,
                onChanged: (double newValue) {
                  setState(() {
                    value = newValue;
                  });
                },
                onChangeEnd: (double value) {
                  numberOfTimesOnChangeEndIsCalled++;
                }
              ),
            ),
          );
        },
      ),
    ));
    
    await _dragSlider(tester, sliderKey);
    
    expect(numberOfTimesOnChangeEndIsCalled, equals(1));

    await tester.pump(); // No animation should start.
    // Check the transientCallbackCount before tearing down the widget to ensure
    // that no animation is running.
    expect(SchedulerBinding.instance.transientCallbackCount, equals(0));
  });

  testWidgets('Slider moves when dragged (LTR)', (WidgetTester tester) async {
    final Key sliderKey = new UniqueKey();
    double value = 0.0;
    double startValue;
    double endValue;

    await tester.pumpWidget(new Directionality(
      textDirection: TextDirection.ltr,
      child: new StatefulBuilder(
        builder: (BuildContext context, StateSetter setState) {
          return new Material(
            child: new Center(
              child: new CupertinoSlider(
                key: sliderKey,
                value: value,
                onChanged: (double newValue) {
                  setState(() {
                    value = newValue;
                  });
                },
                onChangeStart: (double value) {
                  startValue = value;
                },
                onChangeEnd: (double value) {
                  endValue = value;
                }
              ),
            ),
          );
        },
      ),
    ));

    expect(value, equals(0.0));
    
    final Offset topLeft = tester.getTopLeft(find.byKey(sliderKey));
    const double unit = CupertinoThumbPainter.radius;
    const double delta = 3.0 * unit;
    await tester.dragFrom(topLeft + const Offset(unit, unit), const Offset(delta, 0.0));

    final Size size = tester.getSize(find.byKey(sliderKey));
    final double finalValue = delta / (size.width - 2.0 * (8.0 + CupertinoThumbPainter.radius));
    expect(startValue, equals(0.0));
    expect(value, equals(finalValue));
    expect(endValue, equals(finalValue));
    
    await tester.pump(); // No animation should start.
    // Check the transientCallbackCount before tearing down the widget to ensure
    // that no animation is running.
    expect(SchedulerBinding.instance.transientCallbackCount, equals(0));
  });

  testWidgets('Slider moves when dragged (RTL)', (WidgetTester tester) async {
    final Key sliderKey = new UniqueKey();
    double value = 0.0;
    double startValue;
    double endValue;
    
    await tester.pumpWidget(new Directionality(
      textDirection: TextDirection.rtl,
      child: new StatefulBuilder(
        builder: (BuildContext context, StateSetter setState) {
          return new Material(
            child: new Center(
              child: new CupertinoSlider(
                key: sliderKey,
                value: value,
                onChanged: (double newValue) {
                  setState(() {
                    value = newValue;
                  });
                },
                onChangeStart: (double value) {
                  setState(() {
                    startValue = value;
                  });
                },
                onChangeEnd: (double value) {
                  setState(() {
                    endValue = value;
                  });
                }
              ),
            ),
          );
        },
      ),
    ));

    expect(value, equals(0.0));
    
    final Offset bottomRight = tester.getBottomRight(find.byKey(sliderKey));
    const double unit = CupertinoThumbPainter.radius;
    const double delta = 3.0 * unit;
    await tester.dragFrom(bottomRight - const Offset(unit, unit), const Offset(-delta, 0.0));
    
    final Size size = tester.getSize(find.byKey(sliderKey));
    final double finalValue = delta / (size.width - 2.0 * (8.0 + CupertinoThumbPainter.radius));
    expect(startValue, equals(0.0));
    expect(value, equals(finalValue));
    expect(endValue, equals(finalValue));
    
    await tester.pump(); // No animation should start.
    // Check the transientCallbackCount before tearing down the widget to ensure
    // that no animation is running.
    expect(SchedulerBinding.instance.transientCallbackCount, equals(0));
  });

  testWidgets('Slider Semantics', (WidgetTester tester) async {
    final SemanticsTester semantics = new SemanticsTester(tester);

    await tester.pumpWidget(new Directionality(
      textDirection: TextDirection.ltr,
      child: new CupertinoSlider(
        value: 0.5,
        onChanged: (double v) {},
      ),
    ));

    expect(semantics, hasSemantics(
      new TestSemantics.root(
        children: <TestSemantics>[
          new TestSemantics.rootChild(
            id: 1,
            actions: SemanticsAction.decrease.index | SemanticsAction.increase.index,
          ),
        ]
      ),
      ignoreRect: true,
      ignoreTransform: true,
    ));

    // Disable slider
    await tester.pumpWidget(const Directionality(
      textDirection: TextDirection.ltr,
      child: const CupertinoSlider(
        value: 0.5,
        onChanged: null,
      ),
    ));

    expect(semantics, hasSemantics(
      new TestSemantics.root(),
      ignoreRect: true,
      ignoreTransform: true,
    ));

    semantics.dispose();
  });
}