// Copyright 2017 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_test/flutter_test.dart';

void main() {
  testWidgets('test iOS page transition (LTR)', (WidgetTester tester) async {
    await tester.pumpWidget(
      CupertinoApp(
        onGenerateRoute: (RouteSettings settings) {
          return CupertinoPageRoute<void>(
            settings: settings,
            builder: (BuildContext context) {
              final String pageNumber = settings.name == '/' ? '1' : '2';
              return Center(child: Text('Page $pageNumber'));
            }
          );
        },
      ),
    );

    final Offset widget1InitialTopLeft = tester.getTopLeft(find.text('Page 1'));

    tester.state<NavigatorState>(find.byType(Navigator)).pushNamed('/next');

    await tester.pump();
    await tester.pump(const Duration(milliseconds: 150));

    Offset widget1TransientTopLeft = tester.getTopLeft(find.text('Page 1'));
    Offset widget2TopLeft = tester.getTopLeft(find.text('Page 2'));

    // Page 1 is moving to the left.
    expect(widget1TransientTopLeft.dx, lessThan(widget1InitialTopLeft.dx));
    // Page 1 isn't moving vertically.
    expect(widget1TransientTopLeft.dy, equals(widget1InitialTopLeft.dy));
    // iOS transition is horizontal only.
    expect(widget1InitialTopLeft.dy, equals(widget2TopLeft.dy));
    // Page 2 is coming in from the right.
    expect(widget2TopLeft.dx, greaterThan(widget1InitialTopLeft.dx));

    await tester.pumpAndSettle();

    // Page 2 covers page 1.
    expect(find.text('Page 1'), findsNothing);
    expect(find.text('Page 2'), isOnstage);

    tester.state<NavigatorState>(find.byType(Navigator)).pop();
    await tester.pump();
    await tester.pump(const Duration(milliseconds: 100));

    widget1TransientTopLeft = tester.getTopLeft(find.text('Page 1'));
    widget2TopLeft = tester.getTopLeft(find.text('Page 2'));

    // Page 1 is coming back from the left.
    expect(widget1TransientTopLeft.dx, lessThan(widget1InitialTopLeft.dx));
    // Page 1 isn't moving vertically.
    expect(widget1TransientTopLeft.dy, equals(widget1InitialTopLeft.dy));
    // iOS transition is horizontal only.
    expect(widget1InitialTopLeft.dy, equals(widget2TopLeft.dy));
    // Page 2 is leaving towards the right.
    expect(widget2TopLeft.dx, greaterThan(widget1InitialTopLeft.dx));

    await tester.pumpAndSettle();

    expect(find.text('Page 1'), isOnstage);
    expect(find.text('Page 2'), findsNothing);

    widget1TransientTopLeft = tester.getTopLeft(find.text('Page 1'));

    // Page 1 is back where it started.
    expect(widget1InitialTopLeft, equals(widget1TransientTopLeft));
  });

  testWidgets('test iOS page transition (RTL)', (WidgetTester tester) async {
    await tester.pumpWidget(
      CupertinoApp(
        localizationsDelegates: const <LocalizationsDelegate<dynamic>>[
          RtlOverrideWidgetsDelegate(),
        ],
        onGenerateRoute: (RouteSettings settings) {
          return CupertinoPageRoute<void>(
            settings: settings,
            builder: (BuildContext context) {
              final String pageNumber = settings.name == '/' ? '1' : '2';
              return Center(child: Text('Page $pageNumber'));
            }
          );
        },
      ),
    );
    await tester.pump(); // to load the localization, since it doesn't use a synchronous future

    final Offset widget1InitialTopLeft = tester.getTopLeft(find.text('Page 1'));

    tester.state<NavigatorState>(find.byType(Navigator)).pushNamed('/next');

    await tester.pump();
    await tester.pump(const Duration(milliseconds: 150));

    Offset widget1TransientTopLeft = tester.getTopLeft(find.text('Page 1'));
    Offset widget2TopLeft = tester.getTopLeft(find.text('Page 2'));

    // Page 1 is moving to the right.
    expect(widget1TransientTopLeft.dx, greaterThan(widget1InitialTopLeft.dx));
    // Page 1 isn't moving vertically.
    expect(widget1TransientTopLeft.dy, equals(widget1InitialTopLeft.dy));
    // iOS transition is horizontal only.
    expect(widget1InitialTopLeft.dy, equals(widget2TopLeft.dy));
    // Page 2 is coming in from the left.
    expect(widget2TopLeft.dx, lessThan(widget1InitialTopLeft.dx));

    await tester.pumpAndSettle();

    // Page 2 covers page 1.
    expect(find.text('Page 1'), findsNothing);
    expect(find.text('Page 2'), isOnstage);

    tester.state<NavigatorState>(find.byType(Navigator)).pop();
    await tester.pump();
    await tester.pump(const Duration(milliseconds: 100));

    widget1TransientTopLeft = tester.getTopLeft(find.text('Page 1'));
    widget2TopLeft = tester.getTopLeft(find.text('Page 2'));

    // Page 1 is coming back from the right.
    expect(widget1TransientTopLeft.dx, greaterThan(widget1InitialTopLeft.dx));
    // Page 1 isn't moving vertically.
    expect(widget1TransientTopLeft.dy, equals(widget1InitialTopLeft.dy));
    // iOS transition is horizontal only.
    expect(widget1InitialTopLeft.dy, equals(widget2TopLeft.dy));
    // Page 2 is leaving towards the left.
    expect(widget2TopLeft.dx, lessThan(widget1InitialTopLeft.dx));

    await tester.pumpAndSettle();

    expect(find.text('Page 1'), isOnstage);
    expect(find.text('Page 2'), findsNothing);

    widget1TransientTopLeft = tester.getTopLeft(find.text('Page 1'));

    // Page 1 is back where it started.
    expect(widget1InitialTopLeft, equals(widget1TransientTopLeft));
  });

  testWidgets('test iOS fullscreen dialog transition', (WidgetTester tester) async {
    await tester.pumpWidget(
      const CupertinoApp(
        home: Center(child: Text('Page 1')),
      ),
    );

    final Offset widget1InitialTopLeft = tester.getTopLeft(find.text('Page 1'));

    tester.state<NavigatorState>(find.byType(Navigator)).push(CupertinoPageRoute<void>(
      builder: (BuildContext context) {
        return const Center(child: Text('Page 2'));
      },
      fullscreenDialog: true,
    ));

    await tester.pump();
    await tester.pump(const Duration(milliseconds: 100));

    Offset widget1TransientTopLeft = tester.getTopLeft(find.text('Page 1'));
    Offset widget2TopLeft = tester.getTopLeft(find.text('Page 2'));

    // Page 1 doesn't move.
    expect(widget1TransientTopLeft, equals(widget1InitialTopLeft));
    // Fullscreen dialogs transitions vertically only.
    expect(widget1InitialTopLeft.dx, equals(widget2TopLeft.dx));
    // Page 2 is coming in from the bottom.
    expect(widget2TopLeft.dy, greaterThan(widget1InitialTopLeft.dy));

    await tester.pumpAndSettle();

    // Page 2 covers page 1.
    expect(find.text('Page 1'), findsNothing);
    expect(find.text('Page 2'), isOnstage);

    tester.state<NavigatorState>(find.byType(Navigator)).pop();
    await tester.pump();
    await tester.pump(const Duration(milliseconds: 100));

    widget1TransientTopLeft = tester.getTopLeft(find.text('Page 1'));
    widget2TopLeft = tester.getTopLeft(find.text('Page 2'));

    // Page 1 doesn't move.
    expect(widget1TransientTopLeft, equals(widget1InitialTopLeft));
    // Fullscreen dialogs transitions vertically only.
    expect(widget1InitialTopLeft.dx, equals(widget2TopLeft.dx));
    // Page 2 is leaving towards the bottom.
    expect(widget2TopLeft.dy, greaterThan(widget1InitialTopLeft.dy));

    await tester.pumpAndSettle();

    expect(find.text('Page 1'), isOnstage);
    expect(find.text('Page 2'), findsNothing);

    widget1TransientTopLeft = tester.getTopLeft(find.text('Page 1'));

    // Page 1 is back where it started.
    expect(widget1InitialTopLeft, equals(widget1TransientTopLeft));
  });

  testWidgets('test only edge swipes work (LTR)', (WidgetTester tester) async {
    await tester.pumpWidget(
      CupertinoApp(
        onGenerateRoute: (RouteSettings settings) {
          return CupertinoPageRoute<void>(
            settings: settings,
            builder: (BuildContext context) {
              final String pageNumber = settings.name == '/' ? '1' : '2';
              return Center(child: Text('Page $pageNumber'));
            }
          );
        },
      ),
    );

    tester.state<NavigatorState>(find.byType(Navigator)).pushNamed('/next');

    await tester.pump();
    await tester.pump(const Duration(milliseconds: 400));

    // Page 2 covers page 1.
    expect(find.text('Page 1'), findsNothing);
    expect(find.text('Page 2'), isOnstage);

    // Drag from the middle to the right.
    TestGesture gesture = await tester.startGesture(const Offset(200.0, 200.0));
    await gesture.moveBy(const Offset(300.0, 0.0));
    await tester.pump();

    // Nothing should happen.
    expect(find.text('Page 1'), findsNothing);
    expect(find.text('Page 2'), isOnstage);

    // Drag from the right to the left.
    gesture = await tester.startGesture(const Offset(795.0, 200.0));
    await gesture.moveBy(const Offset(-300.0, 0.0));
    await tester.pump();

    // Nothing should happen.
    expect(find.text('Page 1'), findsNothing);
    expect(find.text('Page 2'), isOnstage);

    // Drag from the right to the further right.
    gesture = await tester.startGesture(const Offset(795.0, 200.0));
    await gesture.moveBy(const Offset(300.0, 0.0));
    await tester.pump();

    // Nothing should happen.
    expect(find.text('Page 1'), findsNothing);
    expect(find.text('Page 2'), isOnstage);

    // Now drag from the left edge.
    gesture = await tester.startGesture(const Offset(5.0, 200.0));
    await gesture.moveBy(const Offset(300.0, 0.0));
    await tester.pump();

    // Page 1 is now visible.
    expect(find.text('Page 1'), isOnstage);
    expect(find.text('Page 2'), isOnstage);
  });

  testWidgets('test only edge swipes work (RTL)', (WidgetTester tester) async {
    await tester.pumpWidget(
      CupertinoApp(
        localizationsDelegates: const <LocalizationsDelegate<dynamic>>[
          RtlOverrideWidgetsDelegate(),
        ],
        onGenerateRoute: (RouteSettings settings) {
          return CupertinoPageRoute<void>(
            settings: settings,
            builder: (BuildContext context) {
              final String pageNumber = settings.name == '/' ? '1' : '2';
              return Center(child: Text('Page $pageNumber'));
            }
          );
        },
      ),
    );
    await tester.pump(); // to load the localization, since it doesn't use a synchronous future

    tester.state<NavigatorState>(find.byType(Navigator)).pushNamed('/next');

    await tester.pump();
    await tester.pump(const Duration(milliseconds: 400));

    // Page 2 covers page 1.
    expect(find.text('Page 1'), findsNothing);
    expect(find.text('Page 2'), isOnstage);

    // Drag from the middle to the left.
    TestGesture gesture = await tester.startGesture(const Offset(200.0, 200.0));
    await gesture.moveBy(const Offset(-300.0, 0.0));
    await tester.pump();

    // Nothing should happen.
    expect(find.text('Page 1'), findsNothing);
    expect(find.text('Page 2'), isOnstage);

    // Drag from the left to the right.
    gesture = await tester.startGesture(const Offset(5.0, 200.0));
    await gesture.moveBy(const Offset(300.0, 0.0));
    await tester.pump();

    // Nothing should happen.
    expect(find.text('Page 1'), findsNothing);
    expect(find.text('Page 2'), isOnstage);

    // Drag from the left to the further left.
    gesture = await tester.startGesture(const Offset(5.0, 200.0));
    await gesture.moveBy(const Offset(-300.0, 0.0));
    await tester.pump();

    // Nothing should happen.
    expect(find.text('Page 1'), findsNothing);
    expect(find.text('Page 2'), isOnstage);

    // Now drag from the right edge.
    gesture = await tester.startGesture(const Offset(795.0, 200.0));
    await gesture.moveBy(const Offset(-300.0, 0.0));
    await tester.pump();

    // Page 1 is now visible.
    expect(find.text('Page 1'), isOnstage);
    expect(find.text('Page 2'), isOnstage);
  });
}

class RtlOverrideWidgetsDelegate extends LocalizationsDelegate<WidgetsLocalizations> {
  const RtlOverrideWidgetsDelegate();
  @override
  bool isSupported(Locale locale) => true;
  @override
  Future<WidgetsLocalizations> load(Locale locale) async => const RtlOverrideWidgetsLocalization();
  @override
  bool shouldReload(LocalizationsDelegate<WidgetsLocalizations> oldDelegate) => false;
}

class RtlOverrideWidgetsLocalization implements WidgetsLocalizations {
  const RtlOverrideWidgetsLocalization();
  @override
  TextDirection get textDirection => TextDirection.rtl;
}