/*
 * Copyright (C) 2017 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */

#import "config.h"

#if PLATFORM(IOS) && ENABLE(FULLSCREEN_API)
#import "WKFullScreenWindowControllerIOS.h"

#import "UIKitSPI.h"
#import "WKFullScreenViewController.h"
#import "WKFullscreenStackView.h"
#import "WKWebView.h"
#import "WKWebViewInternal.h"
#import "WKWebViewPrivate.h"
#import "WebFullScreenManagerProxy.h"
#import "WebPageProxy.h"
#import <Foundation/Foundation.h>
#import <Security/SecCertificate.h>
#import <Security/SecTrust.h>
#import <UIKit/UIVisualEffectView.h>
#import <WebCore/FloatRect.h>
#import <WebCore/GeometryUtilities.h>
#import <WebCore/IntRect.h>
#import <WebCore/LocalizedStrings.h>
#import <WebCore/WebCoreNSURLExtras.h>
#import <pal/spi/cf/CFNetworkSPI.h>
#import <pal/spi/cocoa/LinkPresentationSPI.h>
#import <pal/spi/cocoa/NSStringSPI.h>
#import <pal/spi/cocoa/QuartzCoreSPI.h>
#import <wtf/SoftLinking.h>
#import <wtf/spi/cocoa/SecuritySPI.h>

using namespace WebKit;
using namespace WebCore;

SOFT_LINK_PRIVATE_FRAMEWORK_OPTIONAL(LinkPresentation)

namespace WebKit {

static void replaceViewWithView(UIView *view, UIView *otherView)
{
    [CATransaction begin];
    [CATransaction setDisableActions:YES];
    [otherView setFrame:[view frame]];
    [otherView setAutoresizingMask:[view autoresizingMask]];
    [[view superview] insertSubview:otherView aboveSubview:view];
    [view removeFromSuperview];
    [CATransaction commit];
}

enum FullScreenState : NSInteger {
    NotInFullScreen,
    WaitingToEnterFullScreen,
    EnteringFullScreen,
    InFullScreen,
    WaitingToExitFullScreen,
    ExitingFullScreen,
};

struct WKWebViewState {
    float _savedTopContentInset = 0.0;
    CGFloat _savedPageScale = 1;
    CGFloat _savedViewScale = 1.0;
    CGFloat _savedZoomScale = 1;
    UIEdgeInsets _savedEdgeInset = UIEdgeInsetsZero;
    UIEdgeInsets _savedObscuredInsets = UIEdgeInsetsZero;
    UIEdgeInsets _savedScrollIndicatorInsets = UIEdgeInsetsZero;
    CGPoint _savedContentOffset = CGPointZero;

    void applyTo(WKWebView* webView)
    {
        [webView _setPageScale:_savedPageScale withOrigin:CGPointMake(0, 0)];
        [webView _setObscuredInsets:_savedObscuredInsets];
        [[webView scrollView] setContentInset:_savedEdgeInset];
        [[webView scrollView] setContentOffset:_savedContentOffset];
        [[webView scrollView] setScrollIndicatorInsets:_savedScrollIndicatorInsets];
        [webView _page]->setTopContentInset(_savedTopContentInset);
        [webView _setViewScale:_savedViewScale];
        [[webView scrollView] setZoomScale:_savedZoomScale];
    }
    
    void store(WKWebView* webView)
    {
        _savedPageScale = [webView _pageScale];
        _savedObscuredInsets = [webView _obscuredInsets];
        _savedEdgeInset = [[webView scrollView] contentInset];
        _savedContentOffset = [[webView scrollView] contentOffset];
        _savedScrollIndicatorInsets = [[webView scrollView] scrollIndicatorInsets];
        _savedTopContentInset = [webView _page]->topContentInset();
        _savedViewScale = [webView _viewScale];
        _savedZoomScale = [[webView scrollView] zoomScale];
    }
};

} // namespace WebKit

static const NSTimeInterval kAnimationDuration = 0.2;

#pragma mark -

@interface WKFullscreenAnimationController : NSObject <UIViewControllerAnimatedTransitioning, UIViewControllerInteractiveTransitioning>
@property (retain, nonatomic) UIViewController* viewController;
@property (nonatomic) CGRect initialFrame;
@property (nonatomic) CGRect finalFrame;
@property (nonatomic, getter=isAnimatingIn) BOOL animatingIn;
@end

@implementation WKFullscreenAnimationController {
    CGRect _initialMaskViewBounds;
    CGRect _finalMaskViewBounds;
    CGAffineTransform _initialAnimatingViewTransform;
    CGAffineTransform _finalAnimatingViewTransform;
    CGPoint _initialMaskViewCenter;
    CGPoint _finalMaskViewCenter;
    RetainPtr<UIView> _maskView;
    RetainPtr<UIView> _animatingView;
    RetainPtr<id<UIViewControllerContextTransitioning>> _context;
    CGFloat _initialBackgroundAlpha;
    CGFloat _finalBackgroundAlpha;
}

- (void)_createViewsForTransitionContext:(id<UIViewControllerContextTransitioning>)transitionContext
{
    _maskView = adoptNS([[UIView alloc] init]);
    [_maskView setBackgroundColor:[UIColor blackColor]];
    [_maskView setBounds:_initialMaskViewBounds];
    [_maskView setCenter:_initialMaskViewCenter];
    [_animatingView setMaskView:_maskView.get()];
    [_animatingView setTransform:_initialAnimatingViewTransform];

    UIView *containerView = [transitionContext containerView];
    [containerView addSubview:_animatingView.get()];
}

- (NSTimeInterval)transitionDuration:(id<UIViewControllerContextTransitioning>)transitionContext
{
    return kAnimationDuration;
}

- (void)configureInitialAndFinalStatesForTransition:(id<UIViewControllerContextTransitioning>)transitionContext
{
    _context = transitionContext;
    UIView *fromView = [transitionContext viewForKey:UITransitionContextFromViewKey];
    UIView *toView = [transitionContext viewForKey:UITransitionContextToViewKey];

    CGRect inlineFrame = _animatingIn ? _initialFrame : _finalFrame;
    CGRect fullscreenFrame = _animatingIn ? _finalFrame : _initialFrame;
    _animatingView = _animatingIn ? toView : fromView;

    CGRect boundsRect = largestRectWithAspectRatioInsideRect(FloatRect(inlineFrame).size().aspectRatio(), fullscreenFrame);
    boundsRect.origin = CGPointZero;

    _initialMaskViewBounds = _animatingIn ? boundsRect : [_animatingView bounds];
    _initialMaskViewCenter = CGPointMake(CGRectGetMidX([_animatingView bounds]), CGRectGetMidY([_animatingView bounds]));
    _finalMaskViewBounds = _animatingIn ? [_animatingView bounds] : boundsRect;
    _finalMaskViewCenter = CGPointMake(CGRectGetMidX([_animatingView bounds]), CGRectGetMidY([_animatingView bounds]));

    FloatRect scaleRect = smallestRectWithAspectRatioAroundRect(FloatRect(fullscreenFrame).size().aspectRatio(), inlineFrame);
    CGAffineTransform scaleTransform = CGAffineTransformMakeScale(scaleRect.width() / fullscreenFrame.size.width, scaleRect.height() / fullscreenFrame.size.height);
    CGAffineTransform translateTransform = CGAffineTransformMakeTranslation(CGRectGetMidX(inlineFrame) - CGRectGetMidX(fullscreenFrame), CGRectGetMidY(inlineFrame) - CGRectGetMidY(fullscreenFrame));

    CGAffineTransform finalTransform = CGAffineTransformConcat(scaleTransform, translateTransform);
    _initialAnimatingViewTransform = _animatingIn ? finalTransform : CGAffineTransformIdentity;
    _finalAnimatingViewTransform = _animatingIn ? CGAffineTransformIdentity : finalTransform;

    _initialBackgroundAlpha = _animatingIn ? 0 : 1;
    _finalBackgroundAlpha = _animatingIn ? 1 : 0;
}

- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext
{
    [self configureInitialAndFinalStatesForTransition:transitionContext];
    [self _createViewsForTransitionContext:transitionContext];

    UIWindow *window = [transitionContext containerView].window;
    window.backgroundColor = [UIColor colorWithWhite:0 alpha:_initialBackgroundAlpha];

    [UIView animateWithDuration:kAnimationDuration delay:0 options:UIViewAnimationOptionCurveEaseInOut animations:^{
        [self updateWithProgress:1];
    } completion:^(BOOL finished) {
        [self animationEnded:![transitionContext transitionWasCancelled]];
        [transitionContext completeTransition:![transitionContext transitionWasCancelled]];
    }];
}

- (void)animationEnded:(BOOL)transitionCompleted
{
    if (([self isAnimatingIn] && !transitionCompleted) || (![self isAnimatingIn] && transitionCompleted))
        [_animatingView removeFromSuperview];

    [_animatingView setMaskView:nil];
    _maskView = nil;
    _animatingView = nil;
}

- (void)startInteractiveTransition:(id <UIViewControllerContextTransitioning>)transitionContext
{
    [self configureInitialAndFinalStatesForTransition:transitionContext];
    [self _createViewsForTransitionContext:transitionContext];
}

- (void)updateWithProgress:(CGFloat)progress
{
    CGAffineTransform progressTransform = _initialAnimatingViewTransform;
    progressTransform.a += progress * (_finalAnimatingViewTransform.a - _initialAnimatingViewTransform.a);
    progressTransform.b += progress * (_finalAnimatingViewTransform.b - _initialAnimatingViewTransform.b);
    progressTransform.c += progress * (_finalAnimatingViewTransform.c - _initialAnimatingViewTransform.c);
    progressTransform.d += progress * (_finalAnimatingViewTransform.d - _initialAnimatingViewTransform.d);
    progressTransform.tx += progress * (_finalAnimatingViewTransform.tx - _initialAnimatingViewTransform.tx);
    progressTransform.ty += progress * (_finalAnimatingViewTransform.ty - _initialAnimatingViewTransform.ty);
    [_animatingView setTransform:progressTransform];

    CGRect progressBounds = _initialMaskViewBounds;
    progressBounds.origin.x += progress * (_finalMaskViewBounds.origin.x - _initialMaskViewBounds.origin.x);
    progressBounds.origin.y += progress * (_finalMaskViewBounds.origin.y - _initialMaskViewBounds.origin.y);
    progressBounds.size.width += progress * (_finalMaskViewBounds.size.width - _initialMaskViewBounds.size.width);
    progressBounds.size.height += progress * (_finalMaskViewBounds.size.height - _initialMaskViewBounds.size.height);
    [_maskView setBounds:progressBounds];

    CGPoint progressCenter = _initialMaskViewCenter;
    progressCenter.x += progress * (_finalMaskViewCenter.x - _finalMaskViewCenter.x);
    progressCenter.y += progress * (_finalMaskViewCenter.y - _finalMaskViewCenter.y);
    [_maskView setCenter:progressCenter];

    UIWindow *window = [_animatingView window];
    window.backgroundColor = [UIColor colorWithWhite:0 alpha:_initialBackgroundAlpha + progress * (_finalBackgroundAlpha - _initialBackgroundAlpha)];
}

- (void)updateWithProgress:(CGFloat)progress translation:(CGSize)translation anchor:(CGPoint)anchor
{
    CGAffineTransform progressTransform = _initialAnimatingViewTransform;
    progressTransform.a += progress * (_finalAnimatingViewTransform.a - _initialAnimatingViewTransform.a);
    progressTransform.b += progress * (_finalAnimatingViewTransform.b - _initialAnimatingViewTransform.b);
    progressTransform.c += progress * (_finalAnimatingViewTransform.c - _initialAnimatingViewTransform.c);
    progressTransform.d += progress * (_finalAnimatingViewTransform.d - _initialAnimatingViewTransform.d);
    progressTransform.tx += _initialAnimatingViewTransform.tx + translation.width;
    progressTransform.ty += _initialAnimatingViewTransform.ty + translation.height;
    [_animatingView setTransform:progressTransform];

    UIWindow *window = [_animatingView window];
    window.backgroundColor = [UIColor colorWithWhite:0 alpha:_initialBackgroundAlpha + progress * (_finalBackgroundAlpha - _initialBackgroundAlpha)];
}

- (void)end:(BOOL)cancelled {
    if (cancelled) {
        [UIView animateWithDuration:kAnimationDuration animations:^{
            [self updateWithProgress:0];
        } completion:^(BOOL finished) {
            [_context cancelInteractiveTransition];
            [_context completeTransition:NO];
        }];
    } else {
        [UIView animateWithDuration:kAnimationDuration animations:^{
            [self updateWithProgress:1];
        } completion:^(BOOL finished) {
            [_context finishInteractiveTransition];
            [_context completeTransition:YES];
        }];
    }
}

@end

#pragma mark -

@interface WKFullScreenInteractiveTransition : NSObject<UIViewControllerInteractiveTransitioning>
- (id)initWithAnimator:(WKFullscreenAnimationController *)animator anchor:(CGPoint)point;
@end

@implementation WKFullScreenInteractiveTransition {
    RetainPtr<WKFullscreenAnimationController> _animator;
    RetainPtr<id<UIViewControllerContextTransitioning>> _context;
    CGPoint _anchor;
}

- (id)initWithAnimator:(WKFullscreenAnimationController *)animator anchor:(CGPoint)point
{
    if (!(self = [super init]))
        return nil;

    _animator = animator;
    _anchor = point;
    return self;
}

- (BOOL)wantsInteractiveStart
{
    return YES;
}

- (void)startInteractiveTransition:(id <UIViewControllerContextTransitioning>)transitionContext
{
    _context = transitionContext;
    [_animator startInteractiveTransition:transitionContext];
}

- (void)updateInteractiveTransition:(CGFloat)progress withTranslation:(CGSize)translation
{
    [_animator updateWithProgress:progress translation:translation anchor:_anchor];
    [_context updateInteractiveTransition:progress];
}

- (void)cancelInteractiveTransition
{
    [_animator end:YES];
}

- (void)finishInteractiveTransition
{
    [_animator end:NO];
}
@end

#pragma mark -

@interface WKFullScreenWindowController () <UIGestureRecognizerDelegate>
@end

@implementation WKFullScreenWindowController {
    WKWebView *_webView; // Cannot be retained, see <rdar://problem/14884666>.
    RetainPtr<UIView> _webViewPlaceholder;

    FullScreenState _fullScreenState;
    WKWebViewState _viewState;

    RetainPtr<UIWindow> _window;
    RetainPtr<UIViewController> _rootViewController;

    RefPtr<WebKit::VoidCallback> _repaintCallback;
    RetainPtr<UIViewController> _viewControllerForPresentation;
    RetainPtr<WKFullScreenViewController> _fullscreenViewController;
    RetainPtr<UISwipeGestureRecognizer> _startDismissGestureRecognizer;
    RetainPtr<UIPanGestureRecognizer> _interactiveDismissGestureRecognizer;
    RetainPtr<WKFullScreenInteractiveTransition> _interactiveDismissTransitionCoordinator;

    CGRect _initialFrame;
    CGRect _finalFrame;

    RetainPtr<NSString> _EVOrganizationName;
    BOOL _EVOrganizationNameIsValid;
    BOOL _inInteractiveDismiss;

    RetainPtr<id> _notificationListener;
}

#pragma mark -
#pragma mark Initialization
- (id)initWithWebView:(WKWebView *)webView
{
    if (!(self = [super init]))
        return nil;

    _webView = webView;

    return self;
}

- (void)dealloc
{
    [NSObject cancelPreviousPerformRequestsWithTarget:self];
    [[NSNotificationCenter defaultCenter] removeObserver:self];

    [super dealloc];
}

#pragma mark -
#pragma mark Accessors

- (BOOL)isFullScreen
{
    return _fullScreenState == WaitingToEnterFullScreen
        || _fullScreenState == EnteringFullScreen
        || _fullScreenState == InFullScreen;
}

- (UIView *)webViewPlaceholder
{
    return _webViewPlaceholder.get();
}

#pragma mark -
#pragma mark External Interface

- (void)enterFullScreen
{
    if ([self isFullScreen])
        return;

    [self _invalidateEVOrganizationName];

    _fullScreenState = WaitingToEnterFullScreen;

    _window = adoptNS([[UIWindow alloc] init]);
    [_window setBackgroundColor:[UIColor clearColor]];
    [_window setWindowLevel:UIWindowLevelNormal - 1];
    [_window setHidden:NO];

    _rootViewController = [[UIViewController alloc] init];
    _rootViewController.get().view = [[[UIView alloc] initWithFrame:_window.get().bounds] autorelease];
    _rootViewController.get().view.backgroundColor = [UIColor clearColor];
    _rootViewController.get().view.autoresizingMask = (UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight);
    [_rootViewController setModalPresentationStyle:UIModalPresentationCustom];
    [_rootViewController setTransitioningDelegate:self];

    _window.get().rootViewController = _rootViewController.get();

    _fullscreenViewController = adoptNS([[WKFullScreenViewController alloc] initWithWebView:_webView]);
    [_fullscreenViewController setModalPresentationStyle:UIModalPresentationCustom];
    [_fullscreenViewController setTransitioningDelegate:self];
    [_fullscreenViewController setModalPresentationCapturesStatusBarAppearance:YES];
    [_fullscreenViewController setTarget:self];
    [_fullscreenViewController setAction:@selector(requestExitFullScreen)];
    _fullscreenViewController.get().view.frame = _rootViewController.get().view.bounds;
    [self _updateLocationInfo];

    _startDismissGestureRecognizer = adoptNS([[UISwipeGestureRecognizer alloc]  initWithTarget:self action:@selector(_startToDismissFullscreenChanged:)]);
    [_startDismissGestureRecognizer setDelegate:self];
    [_startDismissGestureRecognizer setCancelsTouchesInView:YES];
    [_startDismissGestureRecognizer setNumberOfTouchesRequired:1];
    [_startDismissGestureRecognizer setDirection:UISwipeGestureRecognizerDirectionDown];
    [_fullscreenViewController.get().view addGestureRecognizer:_startDismissGestureRecognizer.get()];

    _interactiveDismissGestureRecognizer = adoptNS([[UIPanGestureRecognizer alloc]  initWithTarget:self action:@selector(_interactiveDismissChanged:)]);
    [_interactiveDismissGestureRecognizer setDelegate:self];
    [_interactiveDismissGestureRecognizer setCancelsTouchesInView:NO];
    [_fullscreenViewController.get().view addGestureRecognizer:_interactiveDismissGestureRecognizer.get()];

    [self _manager]->saveScrollPosition();

    [_webView _page]->setSuppressVisibilityUpdates(true);

    _viewState.store(_webView);

    _webViewPlaceholder = adoptNS([[UIView alloc] init]);
    [[_webViewPlaceholder layer] setName:@"Fullscreen Placeholder View"];

    WKSnapshotConfiguration* config = nil;
    [_webView takeSnapshotWithConfiguration:config completionHandler:^(UIImage * snapshotImage, NSError * error) {
        if (![_webView _page])
            return;

        [CATransaction begin];
        [CATransaction setDisableActions:YES];
        
        [[_webViewPlaceholder layer] setContents:(id)[snapshotImage CGImage]];
        replaceViewWithView(_webView, _webViewPlaceholder.get());

        WKWebViewState().applyTo(_webView);
        
        [_webView setAutoresizingMask:(UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight)];
        [_webView setFrame:[_window bounds]];
        [_webView _overrideLayoutParametersWithMinimumLayoutSize:[_window bounds].size maximumUnobscuredSizeOverride:[_window bounds].size];
        [_window insertSubview:_webView atIndex:0];
        [_webView setNeedsLayout];
        [_webView layoutIfNeeded];
        
        [self _manager]->setAnimatingFullScreen(true);

        _repaintCallback = VoidCallback::create([protectedSelf = retainPtr(self), self](WebKit::CallbackBase::Error) {
            _repaintCallback = nullptr;
            if (auto* manager = [protectedSelf _manager]) {
                manager->willEnterFullScreen();
                return;
            }

            ASSERT_NOT_REACHED();
            [self _exitFullscreenImmediately];
        });
        [_webView _page]->forceRepaint(_repaintCallback.copyRef());

        [CATransaction commit];
    }];
}

- (void)beganEnterFullScreenWithInitialFrame:(CGRect)initialFrame finalFrame:(CGRect)finalFrame
{
    if (_fullScreenState != WaitingToEnterFullScreen)
        return;
    _fullScreenState = EnteringFullScreen;

    _initialFrame = initialFrame;
    _finalFrame = finalFrame;

    [CATransaction begin];
    [CATransaction setDisableActions:YES];

    [_webView removeFromSuperview];

    [_window setWindowLevel:UIWindowLevelNormal];
    [_window makeKeyAndVisible];
    [_fullscreenViewController setPrefersStatusBarHidden:NO];
    [_fullscreenViewController showUI];

    [CATransaction commit];

    [_rootViewController presentViewController:_fullscreenViewController.get() animated:YES completion:^{
        _fullScreenState = InFullScreen;

        auto* page = [_webView _page];
        auto* manager = self._manager;
        if (page && manager) {
            manager->didEnterFullScreen();
            manager->setAnimatingFullScreen(false);
            page->setSuppressVisibilityUpdates(false);
            return;
        }

        ASSERT_NOT_REACHED();
        [self _exitFullscreenImmediately];
    }];
}

- (void)requestExitFullScreen
{
    if (auto* manager = self._manager) {
        manager->requestExitFullScreen();
        return;
    }

    ASSERT_NOT_REACHED();
    [self _exitFullscreenImmediately];
}

- (void)exitFullScreen
{
    if (!self.isFullScreen)
        return;
    _fullScreenState = WaitingToExitFullScreen;

    if (auto* manager = self._manager) {
        manager->setAnimatingFullScreen(true);
        manager->willExitFullScreen();
        return;
    }

    ASSERT_NOT_REACHED();
    [self _exitFullscreenImmediately];
}

- (void)beganExitFullScreenWithInitialFrame:(CGRect)initialFrame finalFrame:(CGRect)finalFrame
{
    if (_fullScreenState != WaitingToExitFullScreen)
        return;
    _fullScreenState = ExitingFullScreen;

    _initialFrame = initialFrame;
    _finalFrame = finalFrame;
    
    [_webView _page]->setSuppressVisibilityUpdates(true);

    [_fullscreenViewController setPrefersStatusBarHidden:NO];

    if (_interactiveDismissTransitionCoordinator) {
        [_interactiveDismissTransitionCoordinator finishInteractiveTransition];
        _interactiveDismissTransitionCoordinator = nil;
        return;
    }

    [_fullscreenViewController dismissViewControllerAnimated:YES completion:^{
        if (![_webView _page])
            return;

        [self _completedExitFullScreen];
    }];
}

- (void)_completedExitFullScreen
{
    if (_fullScreenState != ExitingFullScreen)
        return;
    _fullScreenState = NotInFullScreen;

    [CATransaction begin];
    [CATransaction setDisableActions:YES];

    [[_webViewPlaceholder superview] insertSubview:_webView belowSubview:_webViewPlaceholder.get()];
    [_webView setFrame:[_webViewPlaceholder frame]];
    [_webView setAutoresizingMask:[_webViewPlaceholder autoresizingMask]];

    [[_webView window] makeKeyAndVisible];

    _viewState.applyTo(_webView);

    [_webView setNeedsLayout];
    [_webView layoutIfNeeded];

    [CATransaction commit];

    [_window setHidden:YES];
    _window = nil;

    if (auto* manager = self._manager) {
        manager->setAnimatingFullScreen(false);
        manager->didExitFullScreen();
    }

    if (_repaintCallback) {
        _repaintCallback->invalidate(WebKit::CallbackBase::Error::OwnerWasInvalidated);
        ASSERT(!_repaintCallback);
    }

    _repaintCallback = VoidCallback::create([protectedSelf = retainPtr(self), self](WebKit::CallbackBase::Error) {
        _repaintCallback = nullptr;
        [_webViewPlaceholder removeFromSuperview];

        if (![_webView _page])
            return;

        [_webView _page]->setSuppressVisibilityUpdates(false);
    });

    if (auto* page = [_webView _page])
        page->forceRepaint(_repaintCallback.copyRef());
    else
        _repaintCallback->performCallback();

    [_fullscreenViewController setPrefersStatusBarHidden:YES];
}

- (void)close
{
    [self _exitFullscreenImmediately];
    _webView = nil;
}

- (void)webViewDidRemoveFromSuperviewWhileInFullscreen
{
    if (_fullScreenState == InFullScreen && _webView.window != _window.get())
        [self _exitFullscreenImmediately];
}

- (void)videoControlsManagerDidChange
{
    if (_fullscreenViewController)
        [_fullscreenViewController videoControlsManagerDidChange];
}

#pragma mark -
#pragma mark UIGestureRecognizerDelegate

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
    return YES;
}

#pragma mark -
#pragma mark UIViewControllerTransitioningDelegate

- (id<UIViewControllerAnimatedTransitioning>)animationControllerForPresentedController:(UIViewController *)presented presentingController:(UIViewController *)presenting sourceController:(UIViewController *)source
{
    RetainPtr<WKFullscreenAnimationController> animationController = adoptNS([[WKFullscreenAnimationController alloc] init]);
    [animationController setViewController:presented];
    [animationController setInitialFrame:_initialFrame];
    [animationController setFinalFrame:_finalFrame];
    [animationController setAnimatingIn:YES];
    return animationController.autorelease();
}

- (id<UIViewControllerAnimatedTransitioning>)animationControllerForDismissedController:(UIViewController *)dismissed
{
    CGRect initialFrame = _initialFrame;
    CGRect finalFrame = _finalFrame;

    // Because we're not calling "requestExitFullscreen()" at the beginning of an interactive animation,
    // the _initialFrame and _finalFrame values are left over from when we entered fullscreen.
    if (_inInteractiveDismiss)
        std::swap(initialFrame, finalFrame);

    RetainPtr<WKFullscreenAnimationController> animationController = adoptNS([[WKFullscreenAnimationController alloc] init]);
    [animationController setViewController:dismissed];
    [animationController setInitialFrame:initialFrame];
    [animationController setFinalFrame:finalFrame];
    [animationController setAnimatingIn:NO];
    return animationController.autorelease();
}

- (id<UIViewControllerInteractiveTransitioning>)interactionControllerForDismissal:(id<UIViewControllerAnimatedTransitioning>)animator
{
    if (!_inInteractiveDismiss)
        return nil;

    if (![animator isKindOfClass:[WKFullscreenAnimationController class]])
        return nil;

    if (!_interactiveDismissTransitionCoordinator)
        _interactiveDismissTransitionCoordinator = adoptNS([[WKFullScreenInteractiveTransition alloc] initWithAnimator:(WKFullscreenAnimationController *)animator anchor:CGPointZero]);

    return _interactiveDismissTransitionCoordinator.get();
}

#pragma mark -
#pragma mark Internal Interface

- (void)_exitFullscreenImmediately
{
    if (![self isFullScreen])
        return;

    auto* manager = self._manager;
    if (manager)
        manager->requestExitFullScreen();
    [self exitFullScreen];
    _fullScreenState = ExitingFullScreen;
    [self _completedExitFullScreen];
    replaceViewWithView(_webViewPlaceholder.get(), _webView);
    if (auto* page = [_webView _page])
        page->setSuppressVisibilityUpdates(false);
    if (manager) {
        manager->didExitFullScreen();
        manager->setAnimatingFullScreen(false);
    }
    _webViewPlaceholder = nil;
}

- (void)_invalidateEVOrganizationName
{
    _EVOrganizationName = nil;
    _EVOrganizationNameIsValid = NO;
}

- (BOOL)_isSecure
{
    return _webView.hasOnlySecureContent;
}

- (SecTrustRef)_serverTrust
{
    return _webView.serverTrust;
}

- (NSString *)_EVOrganizationName
{
    if (!self._isSecure)
        return nil;

    if (_EVOrganizationNameIsValid)
        return _EVOrganizationName.get();

    ASSERT(!_EVOrganizationName.get());
    _EVOrganizationNameIsValid = YES;

    SecTrustRef trust = [self _serverTrust];
    if (!trust)
        return nil;

    NSDictionary *infoDictionary = [(__bridge NSDictionary *)SecTrustCopyInfo(trust) autorelease];
    // If SecTrustCopyInfo returned NULL then it's likely that the SecTrustRef has not been evaluated
    // and the only way to get the information we need is to call SecTrustEvaluate ourselves.
    if (!infoDictionary) {
        SecTrustResultType result = kSecTrustResultProceed;
        OSStatus err = SecTrustEvaluate(trust, &result);
        if (err == noErr)
            infoDictionary = [(__bridge NSDictionary *)SecTrustCopyInfo(trust) autorelease];
        if (!infoDictionary)
            return nil;
    }

    // Make sure that the EV certificate is valid against our certificate chain.
    id hasEV = [infoDictionary objectForKey:(__bridge NSString *)kSecTrustInfoExtendedValidationKey];
    if (![hasEV isKindOfClass:[NSValue class]] || ![hasEV boolValue])
        return nil;

    // Make sure that we could contact revocation server and it is still valid.
    id isNotRevoked = [infoDictionary objectForKey:(__bridge NSString *)kSecTrustInfoRevocationKey];
    if (![isNotRevoked isKindOfClass:[NSValue class]] || ![isNotRevoked boolValue])
        return nil;

    _EVOrganizationName = [infoDictionary objectForKey:(__bridge NSString *)kSecTrustInfoCompanyNameKey];
    return _EVOrganizationName.get();
}

- (void)_updateLocationInfo
{
    NSURL* url = _webView._committedURL;

    NSString *EVOrganizationName = [self _EVOrganizationName];
    BOOL showsEVOrganizationName = [EVOrganizationName length] > 0;

    NSString *domain = nil;

    if (LinkPresentationLibrary())
        domain = [url _lp_simplifiedDisplayString];
    else
        domain = userVisibleString(url);

    NSString *text = nil;
    if ([[url scheme] caseInsensitiveCompare:@"data"] == NSOrderedSame)
        text = @"data:";
    else if (showsEVOrganizationName)
        text = EVOrganizationName;
    else
        text = domain;

    [_fullscreenViewController setLocation:text];
}

- (WebFullScreenManagerProxy*)_manager
{
    if (![_webView _page])
        return nullptr;
    return [_webView _page]->fullScreenManager();
}

- (void)_startToDismissFullscreenChanged:(id)sender
{
    _inInteractiveDismiss = true;
    [_fullscreenViewController dismissViewControllerAnimated:YES completion:^{
        if (![_webView _page])
            return;

        [self _completedExitFullScreen];
        [_fullscreenViewController setPrefersStatusBarHidden:YES];
    }];
}

- (void)_interactiveDismissChanged:(id)sender
{
    if (!_inInteractiveDismiss)
        return;

    CGPoint translation = [_interactiveDismissGestureRecognizer translationInView:_fullscreenViewController.get().view];
    CGPoint velocity = [_interactiveDismissGestureRecognizer velocityInView:_fullscreenViewController.get().view];
    CGFloat progress = translation.y / (_fullscreenViewController.get().view.bounds.size.height / 2);
    progress = std::min(1., std::max(0., progress));

    if (_interactiveDismissGestureRecognizer.get().state == UIGestureRecognizerStateEnded) {
        _inInteractiveDismiss = false;

        if (progress > 0.25 || (progress > 0 && velocity.y > 5))
            [self requestExitFullScreen];
        else {
            [_interactiveDismissTransitionCoordinator cancelInteractiveTransition];
            _interactiveDismissTransitionCoordinator = nil;
        }
        return;
    }

    [_interactiveDismissTransitionCoordinator updateInteractiveTransition:progress withTranslation:CGSizeMake(translation.x, translation.y)];
}

@end

#endif // PLATFORM(IOS) && ENABLE(FULLSCREEN_API)