JUCE/modules/juce_gui_basics/native/juce_Windowing_ios.mm

/*
  ==============================================================================

   This file is part of the JUCE library.
   Copyright (c) 2022 - Raw Material Software Limited

   JUCE is an open source library subject to commercial or open-source
   licensing.

   By using JUCE, you agree to the terms of both the JUCE 7 End-User License
   Agreement and JUCE Privacy Policy.

   End User License Agreement: www.juce.com/juce-7-licence
   Privacy Policy: www.juce.com/juce-privacy-policy

   Or: You may also use this code under the terms of the GPL v3 (see
   www.gnu.org/licenses).

   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.

  ==============================================================================
*/

namespace juce
{
    extern bool isIOSAppActive;

    struct AppInactivityCallback // NB: careful, this declaration is duplicated in other modules
    {
        virtual ~AppInactivityCallback() = default;
        virtual void appBecomingInactive() = 0;
    };

    // This is an internal list of callbacks (but currently used between modules)
    Array<AppInactivityCallback*> appBecomingInactiveCallbacks;
} // namespace juce

#if JUCE_PUSH_NOTIFICATIONS
@interface JuceAppStartupDelegate : NSObject <UIApplicationDelegate, UNUserNotificationCenterDelegate>
#else
@interface JuceAppStartupDelegate : NSObject <UIApplicationDelegate>
#endif
{
    UIBackgroundTaskIdentifier appSuspendTask;
}

@property (strong, nonatomic) UIWindow *window;
- (id) init;
- (void) dealloc;
- (void) applicationDidFinishLaunching: (UIApplication*) application;
- (void) applicationWillTerminate: (UIApplication*) application;
- (void) applicationDidEnterBackground: (UIApplication*) application;
- (void) applicationWillEnterForeground: (UIApplication*) application;
- (void) applicationDidBecomeActive: (UIApplication*) application;
- (void) applicationWillResignActive: (UIApplication*) application;
- (void) application: (UIApplication*) application handleEventsForBackgroundURLSession: (NSString*) identifier
   completionHandler: (void (^)(void)) completionHandler;
- (void) applicationDidReceiveMemoryWarning: (UIApplication *) application;
#if JUCE_PUSH_NOTIFICATIONS

- (void)                                 application: (UIApplication*) application
    didRegisterForRemoteNotificationsWithDeviceToken: (NSData*) deviceToken;
- (void)                                 application: (UIApplication*) application
    didFailToRegisterForRemoteNotificationsWithError: (NSError*) error;
- (void)                                 application: (UIApplication*) application
                        didReceiveRemoteNotification: (NSDictionary*) userInfo;
- (void)                                 application: (UIApplication*) application
                        didReceiveRemoteNotification: (NSDictionary*) userInfo
                              fetchCompletionHandler: (void (^)(UIBackgroundFetchResult result)) completionHandler;
- (void)                                 application: (UIApplication*) application
                          handleActionWithIdentifier: (NSString*) identifier
                               forRemoteNotification: (NSDictionary*) userInfo
                                    withResponseInfo: (NSDictionary*) responseInfo
                                   completionHandler: (void(^)()) completionHandler;

JUCE_BEGIN_IGNORE_WARNINGS_GCC_LIKE ("-Wdeprecated-declarations")

- (void)                    application: (UIApplication*) application
    didRegisterUserNotificationSettings: (UIUserNotificationSettings*) notificationSettings;
- (void)                    application: (UIApplication*) application
            didReceiveLocalNotification: (UILocalNotification*) notification;
- (void)                    application: (UIApplication*) application
             handleActionWithIdentifier: (NSString*) identifier
                   forLocalNotification: (UILocalNotification*) notification
                      completionHandler: (void(^)()) completionHandler;
- (void)                    application: (UIApplication*) application
             handleActionWithIdentifier: (NSString*) identifier
                   forLocalNotification: (UILocalNotification*) notification
                       withResponseInfo: (NSDictionary*) responseInfo
                      completionHandler: (void(^)()) completionHandler;

JUCE_END_IGNORE_WARNINGS_GCC_LIKE

- (void) userNotificationCenter: (UNUserNotificationCenter*) center
        willPresentNotification: (UNNotification*) notification
          withCompletionHandler: (void (^)(UNNotificationPresentationOptions options)) completionHandler;
- (void) userNotificationCenter: (UNUserNotificationCenter*) center
 didReceiveNotificationResponse: (UNNotificationResponse*) response
          withCompletionHandler: (void(^)())completionHandler;

#endif

@end

@implementation JuceAppStartupDelegate

    NSObject* _pushNotificationsDelegate;

- (id) init
{
    self = [super init];
    appSuspendTask = UIBackgroundTaskInvalid;

   #if JUCE_PUSH_NOTIFICATIONS
    [UNUserNotificationCenter currentNotificationCenter].delegate = self;
   #endif

    return self;
}

- (void) dealloc
{
    [super dealloc];
}

- (void) applicationDidFinishLaunching: (UIApplication*) application
{
    ignoreUnused (application);
    initialiseJuce_GUI();

    if (auto* app = JUCEApplicationBase::createInstance())
    {
        if (! app->initialiseApp())
            exit (app->shutdownApp());
    }
    else
    {
        jassertfalse; // you must supply an application object for an iOS app!
    }
}

- (void) applicationWillTerminate: (UIApplication*) application
{
    ignoreUnused (application);
    JUCEApplicationBase::appWillTerminateByForce();
}

- (void) applicationDidEnterBackground: (UIApplication*) application
{
    if (auto* app = JUCEApplicationBase::getInstance())
    {
       #if JUCE_EXECUTE_APP_SUSPEND_ON_BACKGROUND_TASK
        appSuspendTask = [application beginBackgroundTaskWithName:@"JUCE Suspend Task" expirationHandler:^{
            if (appSuspendTask != UIBackgroundTaskInvalid)
            {
                [application endBackgroundTask:appSuspendTask];
                appSuspendTask = UIBackgroundTaskInvalid;
            }
        }];

        MessageManager::callAsync ([app] { app->suspended(); });
       #else
        ignoreUnused (application);
        app->suspended();
       #endif
    }
}

- (void) applicationWillEnterForeground: (UIApplication*) application
{
    ignoreUnused (application);

    if (auto* app = JUCEApplicationBase::getInstance())
        app->resumed();
}

- (void) applicationDidBecomeActive: (UIApplication*) application
{
    application.applicationIconBadgeNumber = 0;

    isIOSAppActive = true;
}

- (void) applicationWillResignActive: (UIApplication*) application
{
    ignoreUnused (application);
    isIOSAppActive = false;

    for (int i = appBecomingInactiveCallbacks.size(); --i >= 0;)
        appBecomingInactiveCallbacks.getReference(i)->appBecomingInactive();
}

- (void) application: (UIApplication*) application handleEventsForBackgroundURLSession: (NSString*)identifier
   completionHandler: (void (^)(void))completionHandler
{
    ignoreUnused (application);
    URL::DownloadTask::juce_iosURLSessionNotify (nsStringToJuce (identifier));
    completionHandler();
}

- (void) applicationDidReceiveMemoryWarning: (UIApplication*) application
{
    ignoreUnused (application);

    if (auto* app = JUCEApplicationBase::getInstance())
        app->memoryWarningReceived();
}

- (void) setPushNotificationsDelegateToUse: (NSObject*) delegate
{
    _pushNotificationsDelegate = delegate;
}

#if JUCE_PUSH_NOTIFICATIONS

- (void)                                 application: (UIApplication*) application
    didRegisterForRemoteNotificationsWithDeviceToken: (NSData*) deviceToken
{
    ignoreUnused (application);

    SEL selector = @selector (application:didRegisterForRemoteNotificationsWithDeviceToken:);

    if (_pushNotificationsDelegate != nil && [_pushNotificationsDelegate respondsToSelector: selector])
    {
        NSInvocation* invocation = [NSInvocation invocationWithMethodSignature: [_pushNotificationsDelegate methodSignatureForSelector: selector]];
        [invocation setSelector: selector];
        [invocation setTarget: _pushNotificationsDelegate];
        [invocation setArgument: &application atIndex:2];
        [invocation setArgument: &deviceToken atIndex:3];

        [invocation invoke];
    }
}

- (void)                                 application: (UIApplication*) application
    didFailToRegisterForRemoteNotificationsWithError: (NSError*) error
{
    ignoreUnused (application);

    SEL selector = @selector (application:didFailToRegisterForRemoteNotificationsWithError:);

    if (_pushNotificationsDelegate != nil && [_pushNotificationsDelegate respondsToSelector: selector])
    {
        NSInvocation* invocation = [NSInvocation invocationWithMethodSignature: [_pushNotificationsDelegate methodSignatureForSelector: selector]];
        [invocation setSelector: selector];
        [invocation setTarget: _pushNotificationsDelegate];
        [invocation setArgument: &application atIndex:2];
        [invocation setArgument: &error       atIndex:3];

        [invocation invoke];
    }
}

- (void)             application: (UIApplication*) application
    didReceiveRemoteNotification: (NSDictionary*) userInfo
{
    ignoreUnused (application);

    SEL selector = @selector (application:didReceiveRemoteNotification:);

    if (_pushNotificationsDelegate != nil && [_pushNotificationsDelegate respondsToSelector: selector])
    {
        NSInvocation* invocation = [NSInvocation invocationWithMethodSignature: [_pushNotificationsDelegate methodSignatureForSelector: selector]];
        [invocation setSelector: selector];
        [invocation setTarget: _pushNotificationsDelegate];
        [invocation setArgument: &application atIndex:2];
        [invocation setArgument: &userInfo    atIndex:3];

        [invocation invoke];
    }
}

- (void)             application: (UIApplication*) application
    didReceiveRemoteNotification: (NSDictionary*) userInfo
          fetchCompletionHandler: (void (^)(UIBackgroundFetchResult result)) completionHandler
{
    ignoreUnused (application);

    SEL selector = @selector (application:didReceiveRemoteNotification:fetchCompletionHandler:);

    if (_pushNotificationsDelegate != nil && [_pushNotificationsDelegate respondsToSelector: selector])
    {
        NSInvocation* invocation = [NSInvocation invocationWithMethodSignature: [_pushNotificationsDelegate methodSignatureForSelector: selector]];
        [invocation setSelector: selector];
        [invocation setTarget: _pushNotificationsDelegate];
        [invocation setArgument: &application       atIndex:2];
        [invocation setArgument: &userInfo          atIndex:3];
        [invocation setArgument: &completionHandler atIndex:4];

        [invocation invoke];
    }
}

- (void)           application: (UIApplication*) application
    handleActionWithIdentifier: (NSString*) identifier
         forRemoteNotification: (NSDictionary*) userInfo
              withResponseInfo: (NSDictionary*) responseInfo
             completionHandler: (void(^)()) completionHandler
{
    ignoreUnused (application);

    SEL selector = @selector (application:handleActionWithIdentifier:forRemoteNotification:withResponseInfo:completionHandler:);

    if (_pushNotificationsDelegate != nil && [_pushNotificationsDelegate respondsToSelector: selector])
    {
        NSInvocation* invocation = [NSInvocation invocationWithMethodSignature: [_pushNotificationsDelegate methodSignatureForSelector: selector]];
        [invocation setSelector: selector];
        [invocation setTarget: _pushNotificationsDelegate];
        [invocation setArgument: &application       atIndex:2];
        [invocation setArgument: &identifier        atIndex:3];
        [invocation setArgument: &userInfo          atIndex:4];
        [invocation setArgument: &responseInfo      atIndex:5];
        [invocation setArgument: &completionHandler atIndex:6];

        [invocation invoke];
    }
}

JUCE_BEGIN_IGNORE_WARNINGS_GCC_LIKE ("-Wdeprecated-declarations")

- (void)                    application: (UIApplication*) application
    didRegisterUserNotificationSettings: (UIUserNotificationSettings*) notificationSettings
{
    ignoreUnused (application);

    SEL selector = @selector (application:didRegisterUserNotificationSettings:);

    if (_pushNotificationsDelegate != nil && [_pushNotificationsDelegate respondsToSelector:selector])
    {
        NSInvocation* invocation = [NSInvocation invocationWithMethodSignature: [_pushNotificationsDelegate methodSignatureForSelector: selector]];
        [invocation setSelector: selector];
        [invocation setTarget: _pushNotificationsDelegate];
        [invocation setArgument: &application atIndex: 2];
        [invocation setArgument: &notificationSettings atIndex: 3];

        [invocation invoke];
    }
}

- (void)            application: (UIApplication*) application
    didReceiveLocalNotification: (UILocalNotification*) notification
{
    ignoreUnused (application);

    SEL selector = @selector (application:didReceiveLocalNotification:);

    if (_pushNotificationsDelegate != nil && [_pushNotificationsDelegate respondsToSelector: selector])
    {
        NSInvocation* invocation = [NSInvocation invocationWithMethodSignature: [_pushNotificationsDelegate methodSignatureForSelector: selector]];
        [invocation setSelector: selector];
        [invocation setTarget: _pushNotificationsDelegate];
        [invocation setArgument: &application  atIndex: 2];
        [invocation setArgument: &notification atIndex: 3];

        [invocation invoke];
    }
}

- (void)           application: (UIApplication*) application
    handleActionWithIdentifier: (NSString*) identifier
          forLocalNotification: (UILocalNotification*) notification
             completionHandler: (void(^)()) completionHandler
{
    ignoreUnused (application);

    SEL selector = @selector (application:handleActionWithIdentifier:forLocalNotification:completionHandler:);

    if (_pushNotificationsDelegate != nil && [_pushNotificationsDelegate respondsToSelector: selector])
    {
        NSInvocation* invocation = [NSInvocation invocationWithMethodSignature: [_pushNotificationsDelegate methodSignatureForSelector: selector]];
        [invocation setSelector: selector];
        [invocation setTarget: _pushNotificationsDelegate];
        [invocation setArgument: &application       atIndex:2];
        [invocation setArgument: &identifier        atIndex:3];
        [invocation setArgument: &notification      atIndex:4];
        [invocation setArgument: &completionHandler atIndex:5];

        [invocation invoke];
    }
}

- (void)           application: (UIApplication*) application
    handleActionWithIdentifier: (NSString*) identifier
          forLocalNotification: (UILocalNotification*) notification
              withResponseInfo: (NSDictionary*) responseInfo
             completionHandler: (void(^)()) completionHandler
{
    ignoreUnused (application);

    SEL selector = @selector (application:handleActionWithIdentifier:forLocalNotification:withResponseInfo:completionHandler:);

    if (_pushNotificationsDelegate != nil && [_pushNotificationsDelegate respondsToSelector: selector])
    {
        NSInvocation* invocation = [NSInvocation invocationWithMethodSignature: [_pushNotificationsDelegate methodSignatureForSelector: selector]];
        [invocation setSelector: selector];
        [invocation setTarget: _pushNotificationsDelegate];
        [invocation setArgument: &application       atIndex:2];
        [invocation setArgument: &identifier        atIndex:3];
        [invocation setArgument: &notification      atIndex:4];
        [invocation setArgument: &responseInfo      atIndex:5];
        [invocation setArgument: &completionHandler atIndex:6];

        [invocation invoke];
    }
}

JUCE_END_IGNORE_WARNINGS_GCC_LIKE

- (void) userNotificationCenter: (UNUserNotificationCenter*) center
        willPresentNotification: (UNNotification*) notification
          withCompletionHandler: (void (^)(UNNotificationPresentationOptions options)) completionHandler
{
    ignoreUnused (center);

    SEL selector = @selector (userNotificationCenter:willPresentNotification:withCompletionHandler:);

    if (_pushNotificationsDelegate != nil && [_pushNotificationsDelegate respondsToSelector: selector])
    {
        NSInvocation* invocation = [NSInvocation invocationWithMethodSignature: [_pushNotificationsDelegate methodSignatureForSelector: selector]];
        [invocation setSelector: selector];
        [invocation setTarget: _pushNotificationsDelegate];
        [invocation setArgument: &center            atIndex:2];
        [invocation setArgument: &notification      atIndex:3];
        [invocation setArgument: &completionHandler atIndex:4];

        [invocation invoke];
    }
}

- (void) userNotificationCenter: (UNUserNotificationCenter*) center
 didReceiveNotificationResponse: (UNNotificationResponse*) response
          withCompletionHandler: (void(^)()) completionHandler
{
    ignoreUnused (center);

    SEL selector = @selector (userNotificationCenter:didReceiveNotificationResponse:withCompletionHandler:);

    if (_pushNotificationsDelegate != nil && [_pushNotificationsDelegate respondsToSelector: selector])
    {
        NSInvocation* invocation = [NSInvocation invocationWithMethodSignature: [_pushNotificationsDelegate methodSignatureForSelector: selector]];
        [invocation setSelector: selector];
        [invocation setTarget: _pushNotificationsDelegate];
        [invocation setArgument: &center            atIndex:2];
        [invocation setArgument: &response          atIndex:3];
        [invocation setArgument: &completionHandler atIndex:4];

        [invocation invoke];
    }
}
#endif

@end

namespace juce
{

int juce_iOSMain (int argc, const char* argv[], void* customDelegatePtr);
int juce_iOSMain (int argc, const char* argv[], void* customDelegatePtr)
{
    Class delegateClass = (customDelegatePtr != nullptr ? reinterpret_cast<Class> (customDelegatePtr) : [JuceAppStartupDelegate class]);

    return UIApplicationMain (argc, const_cast<char**> (argv), nil, NSStringFromClass (delegateClass));
}

//==============================================================================
void LookAndFeel::playAlertSound()
{
    // TODO
}

//==============================================================================
bool DragAndDropContainer::performExternalDragDropOfFiles (const StringArray&, bool, Component*, std::function<void()>)
{
    jassertfalse;    // no such thing on iOS!
    return false;
}

bool DragAndDropContainer::performExternalDragDropOfText (const String&, Component*, std::function<void()>)
{
    jassertfalse;    // no such thing on iOS!
    return false;
}

//==============================================================================
void Desktop::setScreenSaverEnabled (const bool isEnabled)
{
    if (! SystemStats::isRunningInAppExtensionSandbox())
        [[UIApplication sharedApplication] setIdleTimerDisabled: ! isEnabled];
}

bool Desktop::isScreenSaverEnabled()
{
    if (SystemStats::isRunningInAppExtensionSandbox())
        return true;

    return ! [[UIApplication sharedApplication] isIdleTimerDisabled];
}

//==============================================================================
bool detail::WindowingHelpers::areThereAnyAlwaysOnTopWindows()
{
    return false;
}

//==============================================================================
Image detail::WindowingHelpers::createIconForFile (const File&)
{
    return {};
}

//==============================================================================
void SystemClipboard::copyTextToClipboard (const String& text)
{
    [[UIPasteboard generalPasteboard] setValue: juceStringToNS (text)
                             forPasteboardType: @"public.text"];
}

String SystemClipboard::getTextFromClipboard()
{
    return nsStringToJuce ([[UIPasteboard generalPasteboard] string]);
}

//==============================================================================
bool detail::MouseInputSourceList::addSource()
{
    addSource (sources.size(), MouseInputSource::InputSourceType::touch);
    return true;
}

bool detail::MouseInputSourceList::canUseTouch() const
{
    return true;
}

bool Desktop::canUseSemiTransparentWindows() noexcept
{
    return true;
}

bool Desktop::isDarkModeActive() const
{
    if (@available (iOS 12.0, *))
        return [[[UIScreen mainScreen] traitCollection] userInterfaceStyle] == UIUserInterfaceStyleDark;

    return false;
}

JUCE_BEGIN_IGNORE_WARNINGS_GCC_LIKE ("-Wundeclared-selector")
static const auto darkModeSelector = @selector (darkModeChanged:);
JUCE_END_IGNORE_WARNINGS_GCC_LIKE

class Desktop::NativeDarkModeChangeDetectorImpl
{
public:
    NativeDarkModeChangeDetectorImpl()
    {
        static DelegateClass delegateClass;
        delegate.reset ([delegateClass.createInstance() init]);
        observer.emplace (delegate.get(), darkModeSelector, UIViewComponentPeer::getDarkModeNotificationName(), nil);
    }

private:
    struct DelegateClass  : public ObjCClass<NSObject>
    {
        DelegateClass()  : ObjCClass<NSObject> ("JUCEDelegate_")
        {
            addMethod (darkModeSelector, [] (id, SEL, NSNotification*) { Desktop::getInstance().darkModeChanged(); });
            registerClass();
        }
    };

    NSUniquePtr<NSObject> delegate;
    Optional<ScopedNotificationCenterObserver> observer;

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (NativeDarkModeChangeDetectorImpl)
};

std::unique_ptr<Desktop::NativeDarkModeChangeDetectorImpl> Desktop::createNativeDarkModeChangeDetectorImpl()
{
    return std::make_unique<NativeDarkModeChangeDetectorImpl>();
}

//==============================================================================
Point<float> MouseInputSource::getCurrentRawMousePosition()
{
    return juce_lastMousePos;
}

void MouseInputSource::setRawMousePosition (Point<float>)
{
}

double Desktop::getDefaultMasterScale()
{
    return 1.0;
}

Desktop::DisplayOrientation Desktop::getCurrentOrientation() const
{
    UIInterfaceOrientation orientation = SystemStats::isRunningInAppExtensionSandbox() ? UIInterfaceOrientationPortrait
                                                                                       : getWindowOrientation();

    return Orientations::convertToJuce (orientation);
}

template <typename Value>
static BorderSize<Value> operator/ (BorderSize<Value> border, Value scale)
{
    return { border.getTop()    / scale,
             border.getLeft()   / scale,
             border.getBottom() / scale,
             border.getRight()  / scale };
}

template <typename Value>
static BorderSize<int> roundToInt (BorderSize<Value> border)
{
    return { roundToInt (border.getTop()),
             roundToInt (border.getLeft()),
             roundToInt (border.getBottom()),
             roundToInt (border.getRight()) };
}

// The most straightforward way of retrieving the screen area available to an iOS app
// seems to be to create a new window (which will take up all available space) and to
// query its frame.
struct TemporaryWindow
{
    UIWindow* window = [[UIWindow alloc] init];
    ~TemporaryWindow() noexcept { [window release]; }
};

static Rectangle<int> getRecommendedWindowBounds()
{
    return convertToRectInt (TemporaryWindow().window.frame);
}

static BorderSize<int> getSafeAreaInsets (float masterScale)
{
    if (@available (iOS 11.0, *))
    {
        UIEdgeInsets safeInsets = TemporaryWindow().window.safeAreaInsets;
        return roundToInt (BorderSize<double> { safeInsets.top,
                                                safeInsets.left,
                                                safeInsets.bottom,
                                                safeInsets.right } / (double) masterScale);
    }

    JUCE_BEGIN_IGNORE_WARNINGS_GCC_LIKE ("-Wdeprecated-declarations")
    auto statusBarSize = [UIApplication sharedApplication].statusBarFrame.size;
    JUCE_END_IGNORE_WARNINGS_GCC_LIKE

    auto statusBarHeight = jmin (statusBarSize.width, statusBarSize.height);

    return { roundToInt (statusBarHeight / masterScale), 0, 0, 0 };
}

//==============================================================================
void Displays::findDisplays (float masterScale)
{
    JUCE_BEGIN_IGNORE_WARNINGS_GCC_LIKE ("-Wundeclared-selector")
    static const auto keyboardShownSelector  = @selector (juceKeyboardShown:);
    static const auto keyboardHiddenSelector = @selector (juceKeyboardHidden:);
    JUCE_END_IGNORE_WARNINGS_GCC_LIKE

    class OnScreenKeyboardChangeDetectorImpl
    {
    public:
        OnScreenKeyboardChangeDetectorImpl()
        {
            static DelegateClass delegateClass;
            delegate.reset ([delegateClass.createInstance() init]);
            object_setInstanceVariable (delegate.get(), "owner", this);
            observers.emplace_back (delegate.get(), keyboardShownSelector,  UIKeyboardDidShowNotification, nil);
            observers.emplace_back (delegate.get(), keyboardHiddenSelector, UIKeyboardDidHideNotification, nil);
        }

        auto getInsets() const { return insets; }

    private:
        struct DelegateClass : public ObjCClass<NSObject>
        {
            DelegateClass() : ObjCClass<NSObject> ("JUCEOnScreenKeyboardObserver_")
            {
                addIvar<OnScreenKeyboardChangeDetectorImpl*> ("owner");

                addMethod (keyboardShownSelector, [] (id self, SEL, NSNotification* notification)
                {
                    setKeyboardScreenBounds (self, [&]() -> BorderSize<double>
                    {
                        auto* info = [notification userInfo];

                        if (info == nullptr)
                            return {};

                        auto* value = static_cast<NSValue*> ([info objectForKey: UIKeyboardFrameEndUserInfoKey]);

                        if (value == nullptr)
                            return {};

                        auto* display = Desktop::getInstance().getDisplays().getPrimaryDisplay();

                        if (display == nullptr)
                            return {};

                        const auto rect = convertToRectInt ([value CGRectValue]);

                        BorderSize<double> result;

                        if (rect.getY() == display->totalArea.getY())
                            result.setTop (rect.getHeight());

                        if (rect.getBottom() == display->totalArea.getBottom())
                            result.setBottom (rect.getHeight());

                        return result;
                    }());
                });

                addMethod (keyboardHiddenSelector, [] (id self, SEL, NSNotification*)
                {
                    setKeyboardScreenBounds (self, {});
                });

                registerClass();
            }

        private:
            static void setKeyboardScreenBounds (id self, BorderSize<double> insets)
            {
                if (std::exchange (getIvar<OnScreenKeyboardChangeDetectorImpl*> (self, "owner")->insets, insets) != insets)
                    Desktop::getInstance().displays->refresh();
            }
        };

        BorderSize<double> insets;
        NSUniquePtr<NSObject> delegate;
        std::vector<ScopedNotificationCenterObserver> observers;

        JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (OnScreenKeyboardChangeDetectorImpl)
    };

    JUCE_AUTORELEASEPOOL
    {
        static OnScreenKeyboardChangeDetectorImpl keyboardChangeDetector;

        UIScreen* s = [UIScreen mainScreen];

        Display d;
        d.totalArea = convertToRectInt ([s bounds]) / masterScale;
        d.userArea = getRecommendedWindowBounds() / masterScale;
        d.safeAreaInsets = getSafeAreaInsets (masterScale);
        d.keyboardInsets = roundToInt (keyboardChangeDetector.getInsets() / (double) masterScale);
        d.isMain = true;
        d.scale = masterScale * s.scale;
        d.dpi = 160 * d.scale;

        displays.add (d);
    }
}

} // namespace juce