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

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

   JUCE is an open source framework subject to commercial or open source
   licensing.

   By downloading, installing, or using the JUCE framework, or combining the
   JUCE framework with any other source code, object code, content or any other
   copyrightable work, you agree to the terms of the JUCE End User Licence
   Agreement, and all incorporated terms including the JUCE Privacy Policy and
   the JUCE Website Terms of Service, as applicable, which will bind you. If you
   do not agree to the terms of these agreements, we will not license the JUCE
   framework to you, and you must discontinue the installation or download
   process and cease use of the JUCE framework.

   JUCE End User Licence Agreement: https://juce.com/legal/juce-8-licence/
   JUCE Privacy Policy: https://juce.com/juce-privacy-policy
   JUCE Website Terms of Service: https://juce.com/juce-website-terms-of-service/

   Or:

   You may also use this code under the terms of the AGPLv3:
   https://www.gnu.org/licenses/agpl-3.0.en.html

   THE JUCE FRAMEWORK IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL
   WARRANTIES, WHETHER EXPRESSED OR IMPLIED, INCLUDING WARRANTY OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR 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;

    struct BadgeUpdateTrait
    {
       #if JUCE_IOS_API_VERSION_CAN_BE_BUILT (16, 0)
        API_AVAILABLE (ios (16))
        static void newFn (UIApplication*)
        {
            [[UNUserNotificationCenter currentNotificationCenter] setBadgeCount: 0 withCompletionHandler: nil];
        }
       #endif

        static void oldFn (UIApplication* app)
        {
            JUCE_BEGIN_IGNORE_WARNINGS_GCC_LIKE ("-Wdeprecated-declarations")
            app.applicationIconBadgeNumber = 0;
            JUCE_END_IGNORE_WARNINGS_GCC_LIKE
        }
    };

    /*  Each successful call to beginBackgroundTask must be balanced
        by a call to endBackgroundTask.
    */
    class TaskHandle
    {
    public:
        TaskHandle() = default;

        explicit TaskHandle (UIBackgroundTaskIdentifier t)
            : task (t) {}

        ~TaskHandle()
        {
            if (task != UIBackgroundTaskInvalid)
                [[UIApplication sharedApplication] endBackgroundTask:task];
        }

        TaskHandle (TaskHandle&& other) noexcept
        {
            swap (other);
        }

        TaskHandle& operator= (TaskHandle&& other) noexcept
        {
            TaskHandle { std::move (other) }.swap (*this);
            return *this;
        }

        TaskHandle (const TaskHandle&) = delete;
        TaskHandle& operator= (const TaskHandle&) = delete;

    private:
        void swap (TaskHandle& other) noexcept
        {
            std::swap (other.task, task);
        }

        UIBackgroundTaskIdentifier task = UIBackgroundTaskInvalid;
    };

    struct SceneUtils
    {
        // This will need to become more sophisticated to enable support for multiple scenes
        static void sceneDidBecomeActive()
        {
            ifelse_17_0<BadgeUpdateTrait> ([UIApplication sharedApplication]);
            isIOSAppActive = true;
        }

        static void sceneWillResignActive()
        {
            isIOSAppActive = false;

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

        template <typename Self>
        static void sceneDidEnterBackground ([[maybe_unused]] Self* s)
        {
            if (auto* app = JUCEApplicationBase::getInstance())
            {
               #if JUCE_EXECUTE_APP_SUSPEND_ON_BACKGROUND_TASK
                s->appSuspendTask = TaskHandle { [[UIApplication sharedApplication] beginBackgroundTaskWithName:@"JUCE Suspend Task"
                                                                                              expirationHandler:^{ s->appSuspendTask = {}; }] };

                MessageManager::callAsync ([app, s]
                {
                    app->suspended();
                    s->appSuspendTask = {};
                });
               #else
                app->suspended();
               #endif
            }
        }

        static void sceneWillEnterForeground()
        {
            if (auto* app = JUCEApplicationBase::getInstance())
                app->resumed();
        }

        SceneUtils() = delete;
    };
} // namespace juce

API_AVAILABLE (ios (13.0))
@interface JuceAppSceneDelegate : NSObject<UIWindowSceneDelegate>
{
    @public
    TaskHandle appSuspendTask;
}
@end

@implementation JuceAppSceneDelegate
{
    SharedResourcePointer<WindowSceneTracker> windowSceneTracker;
}

- (void)           scene: (UIScene*) scene
    willConnectToSession: (UISceneSession*) session
                 options: (UISceneConnectionOptions*) connectionOptions
{
    if ([scene isKindOfClass: UIWindowScene.class])
        windowSceneTracker->setWindowScene (static_cast<UIWindowScene*> (scene));
    else
        jassertfalse;
}

- (void) sceneDidDisconnect: (UIScene*) scene
{
    if (scene == windowSceneTracker->getWindowScene())
        windowSceneTracker->setWindowScene (nullptr);
}

- (void) sceneDidBecomeActive: (UIScene*) scene
{
    SceneUtils::sceneDidBecomeActive();
}

- (void) sceneWillResignActive: (UIScene*) scene
{
    SceneUtils::sceneWillResignActive();
}

- (void) sceneDidEnterBackground: (UIScene*) scene
{
    SceneUtils::sceneDidEnterBackground (self);
}

- (void) sceneWillEnterForeground: (UIScene*) scene
{
    SceneUtils::sceneWillEnterForeground();
}

- (void)         windowScene: (UIWindowScene*) windowScene
    didUpdateCoordinateSpace: (id<UICoordinateSpace>) previousCoordinateSpace
        interfaceOrientation: (UIInterfaceOrientation) previousInterfaceOrientation
             traitCollection: (UITraitCollection*) previousTraitCollection
{
    windowSceneTracker->setWindowScene (windowScene);
}
@end

#if JUCE_PUSH_NOTIFICATIONS
@interface JuceAppStartupDelegate : NSObject <UIApplicationDelegate, UNUserNotificationCenterDelegate>
#else
@interface JuceAppStartupDelegate : NSObject <UIApplicationDelegate>
#endif
{
    @public
    TaskHandle appSuspendTask;
    std::optional<ScopedJuceInitialiser_GUI> initialiser;
}

- (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;

- (UISceneConfiguration*)      application: (UIApplication*) application
    configurationForConnectingSceneSession: (UISceneSession*) connectingSceneSession
                                   options: (UISceneConnectionOptions*) options API_AVAILABLE (ios (13.0));

#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;

- (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];

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

    return self;
}

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

- (void) applicationDidFinishLaunching: (UIApplication*) application
{
    ignoreUnused (application);
    initialiser.emplace();

    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
{
    SceneUtils::sceneDidEnterBackground (self);
}

- (void) applicationWillEnterForeground: (UIApplication*) application
{
    SceneUtils::sceneWillEnterForeground();
}

- (void) applicationDidBecomeActive: (UIApplication*) application
{
    SceneUtils::sceneDidBecomeActive();
}

- (void) applicationWillResignActive: (UIApplication*) application
{
    SceneUtils::sceneWillResignActive();
}

- (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();
}

- (UISceneConfiguration*)      application: (UIApplication*) application
    configurationForConnectingSceneSession: (UISceneSession*) connectingSceneSession
                                   options: (UISceneConnectionOptions*) options
{
    auto* config = connectingSceneSession.configuration;
    config.delegateClass = JuceAppSceneDelegate.class;
    return config;
}

- (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];
    }
}

- (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];
}

//==============================================================================
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
{
    return [[[UIScreen mainScreen] traitCollection] userInterfaceStyle] == UIUserInterfaceStyleDark;
}

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 final : 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);
}

struct WindowInfo
{
    explicit WindowInfo (const UIWindow* window)
        : bounds (convertToRectInt (window.frame)),
          safeInsets (window.safeAreaInsets.top,
                      window.safeAreaInsets.left,
                      window.safeAreaInsets.bottom,
                      window.safeAreaInsets.right)
    {}

    Rectangle<int> bounds;
    BorderSize<double> safeInsets;
};

static const UIWindow* findWindow (const UIView* view)
{
    if (view == nullptr)
        return nullptr;

    if (view.window != nullptr)
        return view.window;

    return findWindow (view.superview);
}

static const UIWindow* findWindow (const Desktop& desktop)
{
    if (auto* c = desktop.getComponent (0))
        if (auto* p = static_cast<UIViewComponentPeer*> (c->getPeer()))
            if (auto* w = findWindow (p->view))
                return w;

    return {};
}

static WindowInfo getWindowInfo (const Desktop& desktop)
{
    if (! JUCEApplication::isStandaloneApp())
        if (const auto* window = findWindow (desktop))
            return WindowInfo { window };

    const auto createTemporaryWindow = []()
    {
        if (@available (iOS 13, *))
        {
            SharedResourcePointer<WindowSceneTracker> windowSceneTracker;

            if (auto* scene = windowSceneTracker->getWindowScene())
                return NSUniquePtr<UIWindow> { [[UIWindow alloc] initWithWindowScene: scene] };
        }

        return NSUniquePtr<UIWindow> { [[UIWindow alloc] init] };
    };

    auto window (createTemporaryWindow());
    return WindowInfo { window.get() };
}

static Rectangle<int> getRecommendedWindowBounds (const Desktop& desktop)
{
    return getWindowInfo (desktop).bounds;
}

static BorderSize<int> getSafeAreaInsets (const Desktop& desktop)
{
    const auto masterScale = (double) desktop.getGlobalScaleFactor();
    const auto safeInsets = getWindowInfo (desktop).safeInsets;
    return detail::WindowingHelpers::roundToInt (safeInsets.multipliedBy (1.0 / masterScale));
}

//==============================================================================
void Displays::findDisplays (const Desktop& desktop)
{
    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 final : public ObjCClass<NSObject>
        {
            DelegateClass() : ObjCClass ("JUCEOnScreenKeyboardObserver_")
            {
                addIvar<OnScreenKeyboardChangeDetectorImpl*> ("owner");

                addMethod (keyboardShownSelector, [] (id self, SEL, NSNotification* notification)
                {
                    setKeyboardScreenBounds (self, std::invoke ([&]() -> 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;
        const auto masterScale = desktop.getGlobalScaleFactor();
        d.totalArea = convertToRectInt ([s bounds]) / masterScale;
        d.userArea = getRecommendedWindowBounds (desktop) / masterScale;
        d.safeAreaInsets = getSafeAreaInsets (desktop);
        const auto scaledInsets = keyboardChangeDetector.getInsets().multipliedBy (1.0 / (double) masterScale);
        d.keyboardInsets = detail::WindowingHelpers::roundToInt (scaledInsets);
        d.isMain = true;
        d.scale = masterScale * s.scale;
        d.dpi = 160 * d.scale;

        displays.add (d);
    }
}

} // namespace juce