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

   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
{

JUCE_BEGIN_IGNORE_WARNINGS_GCC_LIKE ("-Wundeclared-selector")
const auto menuItemInvokedSelector = @selector (menuItemInvoked:);
JUCE_END_IGNORE_WARNINGS_GCC_LIKE

//==============================================================================
struct JuceMainMenuBarHolder final : private DeletedAtShutdown
{
    JuceMainMenuBarHolder()
        : mainMenuBar ([[NSMenu alloc] initWithTitle: nsStringLiteral ("MainMenu")])
    {
        auto item = [mainMenuBar addItemWithTitle: nsStringLiteral ("Apple")
                                           action: nil
                                     keyEquivalent: nsEmptyString()];

        auto appMenu = [[NSMenu alloc] initWithTitle: nsStringLiteral ("Apple")];

        JUCE_BEGIN_IGNORE_WARNINGS_GCC_LIKE ("-Wundeclared-selector")
        [NSApp performSelector: @selector (setAppleMenu:) withObject: appMenu];
        JUCE_END_IGNORE_WARNINGS_GCC_LIKE

        [mainMenuBar setSubmenu: appMenu forItem: item];
        [appMenu release];

        [NSApp setMainMenu: mainMenuBar];
    }

    ~JuceMainMenuBarHolder()
    {
        clearSingletonInstance();

        [NSApp setMainMenu: nil];
        [mainMenuBar release];
    }

    NSMenu* mainMenuBar = nil;

    JUCE_DECLARE_SINGLETON_SINGLETHREADED_INLINE (JuceMainMenuBarHolder, true)
};

//==============================================================================
class JuceMainMenuHandler final : private MenuBarModel::Listener,
                                  private DeletedAtShutdown
{
public:
    JuceMainMenuHandler()
    {
        static JuceMenuCallbackClass cls;
        callback = [cls.createInstance() init];
        JuceMenuCallbackClass::setOwner (callback, this);
    }

    ~JuceMainMenuHandler() override
    {
        setMenu (nullptr, nullptr, String());

        jassert (instance == this);
        instance = nullptr;

        [callback release];
    }

    void setMenu (MenuBarModel* const newMenuBarModel,
                  const PopupMenu* newExtraAppleMenuItems,
                  const String& recentItemsName)
    {
        recentItemsMenuName = recentItemsName;

        if (currentModel != newMenuBarModel)
        {
            if (currentModel != nullptr)
                currentModel->removeListener (this);

            currentModel = newMenuBarModel;

            if (currentModel != nullptr)
                currentModel->addListener (this);

            menuBarItemsChanged (nullptr);
        }

        extraAppleMenuItems.reset (createCopyIfNotNull (newExtraAppleMenuItems));
    }

    void addTopLevelMenu (NSMenu* parent, const PopupMenu& child, const String& name, int menuId, int topLevelIndex)
    {
        NSMenuItem* item = [parent addItemWithTitle: juceStringToNS (name)
                                             action: nil
                                      keyEquivalent: nsEmptyString()];

        NSMenu* sub = createMenu (child, name, menuId, topLevelIndex, true);

        [parent setSubmenu: sub forItem: item];
        [sub release];
    }

    void updateTopLevelMenu (NSMenuItem* parentItem, const PopupMenu& menuToCopy, const String& name, int menuId, int topLevelIndex)
    {
        // Note: This method used to update the contents of the existing menu in-place, but that caused
        // weird side-effects which messed-up keyboard focus when switching between windows. By creating
        // a new menu and replacing the old one with it, that problem seems to be avoided..
        NSMenu* menu = [[NSMenu alloc] initWithTitle: juceStringToNS (name)];

        for (PopupMenu::MenuItemIterator iter (menuToCopy); iter.next();)
            addMenuItem (iter, menu, menuId, topLevelIndex);

        [menu update];

        removeItemRecursive ([parentItem submenu]);
        [parentItem setSubmenu: menu];

        [menu release];
    }

    void updateTopLevelMenu (NSMenu* menu)
    {
        NSMenu* superMenu = [menu supermenu];
        auto menuNames = currentModel->getMenuBarNames();
        auto indexOfMenu = (int) [superMenu indexOfItemWithSubmenu: menu] - 1;

        if (indexOfMenu >= 0)
        {
            removeItemRecursive (menu);

            auto updatedPopup = currentModel->getMenuForIndex (indexOfMenu, menuNames[indexOfMenu]);

            for (PopupMenu::MenuItemIterator iter (updatedPopup); iter.next();)
                addMenuItem (iter, menu, 1, indexOfMenu);

            [menu update];
        }
    }

    void menuBarItemsChanged (MenuBarModel*) override
    {
        if (isOpen)
        {
            defferedUpdateRequested = true;
            return;
        }

        lastUpdateTime = Time::getMillisecondCounter();

        StringArray menuNames;
        if (currentModel != nullptr)
            menuNames = currentModel->getMenuBarNames();

        auto* menuBar = getMainMenuBar();

        while ([menuBar numberOfItems] > 1 + menuNames.size())
            removeItemRecursive (menuBar, static_cast<int> ([menuBar numberOfItems] - 1));

        int menuId = 1;

        for (int i = 0; i < menuNames.size(); ++i)
        {
            const PopupMenu menu (currentModel->getMenuForIndex (i, menuNames[i]));

            if (i >= [menuBar numberOfItems] - 1)
                addTopLevelMenu (menuBar, menu, menuNames[i], menuId, i);
            else
                updateTopLevelMenu ([menuBar itemAtIndex: 1 + i], menu, menuNames[i], menuId, i);
        }
    }

    void menuCommandInvoked (MenuBarModel*, const ApplicationCommandTarget::InvocationInfo& info) override
    {
        if ((info.commandFlags & ApplicationCommandInfo::dontTriggerVisualFeedback) == 0
              && info.invocationMethod != ApplicationCommandTarget::InvocationInfo::fromKeyPress)
            if (auto* item = findMenuItemWithCommandID (getMainMenuBar(), info.commandID))
                flashMenuBar ([item menu]);
    }

    void invoke (const PopupMenu::Item& item, int topLevelIndex) const
    {
        if (currentModel != nullptr)
        {
            if (item.action != nullptr)
            {
                MessageManager::callAsync (item.action);
                return;
            }

            if (item.customCallback != nullptr)
                if (! item.customCallback->menuItemTriggered())
                    return;

            if (item.commandManager != nullptr)
            {
                ApplicationCommandTarget::InvocationInfo info (item.itemID);
                info.invocationMethod = ApplicationCommandTarget::InvocationInfo::fromMenu;

                item.commandManager->invoke (info, true);
            }

            MessageManager::callAsync ([=]
            {
                if (instance != nullptr)
                    instance->invokeDirectly (item.itemID, topLevelIndex);
            });
        }
    }

    void invokeDirectly (int commandId, int topLevelIndex)
    {
        if (currentModel != nullptr)
            currentModel->menuItemSelected (commandId, topLevelIndex);
    }

    void addMenuItem (PopupMenu::MenuItemIterator& iter, NSMenu* menuToAddTo,
                      const int topLevelMenuId, const int topLevelIndex)
    {
        const PopupMenu::Item& i = iter.getItem();
        NSString* text = juceStringToNS (i.text);

        if (text == nil)
            text = nsEmptyString();

        if (i.isSeparator)
        {
            [menuToAddTo addItem: [NSMenuItem separatorItem]];
        }
        else if (i.isSectionHeader)
        {
            NSMenuItem* item = [menuToAddTo addItemWithTitle: text
                                                      action: nil
                                               keyEquivalent: nsEmptyString()];

            [item setEnabled: false];
        }
        else if (i.subMenu != nullptr)
        {
            if (recentItemsMenuName.isNotEmpty() && i.text == recentItemsMenuName)
            {
                if (recent == nullptr)
                    recent = std::make_unique<RecentFilesMenuItem>();

                if (recent->recentItem != nil)
                {
                    if (NSMenu* parent = [recent->recentItem menu])
                        [parent removeItem: recent->recentItem];

                    [menuToAddTo addItem: recent->recentItem];
                    return;
                }
            }

            NSMenuItem* item = [menuToAddTo addItemWithTitle: text
                                                      action: nil
                                               keyEquivalent: nsEmptyString()];

            [item setTag: i.itemID];
            [item setEnabled: i.isEnabled];

            NSMenu* sub = createMenu (*i.subMenu, i.text, topLevelMenuId, topLevelIndex, false);
            [menuToAddTo setSubmenu: sub forItem: item];
            [sub release];
        }
        else
        {
            auto item = [[NSMenuItem alloc] initWithTitle: text
                                                   action: menuItemInvokedSelector
                                            keyEquivalent: nsEmptyString()];

            [item setTag: topLevelIndex];
            [item setEnabled: i.isEnabled];
            [item setState: i.isTicked ? NSControlStateValueOn : NSControlStateValueOff];
            [item setTarget: (id) callback];

            auto* juceItem = new PopupMenu::Item (i);
            juceItem->customComponent = nullptr;

            [item setRepresentedObject: [createNSObjectFromJuceClass (juceItem) autorelease]];

            if (i.commandManager != nullptr)
            {
                for (auto& kp : i.commandManager->getKeyMappings()->getKeyPressesAssignedToCommand (i.itemID))
                {
                    if (kp != KeyPress::backspaceKey   // (adding these is annoying because it flashes the menu bar
                         && kp != KeyPress::deleteKey) // every time you press the key while editing text)
                    {
                        juce_wchar key = kp.getTextCharacter();

                        if (key == 0)
                            key = (juce_wchar) kp.getKeyCode();

                        [item setKeyEquivalent: juceStringToNS (String::charToString (key).toLowerCase())];
                        [item setKeyEquivalentModifierMask: juceModsToNSMods (kp.getModifiers())];
                    }

                    break;
                }
            }

            [menuToAddTo addItem: item];
            [item release];
        }
    }

    NSMenu* createMenu (const PopupMenu menu,
                        const String& menuName,
                        const int topLevelMenuId,
                        const int topLevelIndex,
                        const bool addDelegate)
    {
        NSMenu* m = [[NSMenu alloc] initWithTitle: juceStringToNS (menuName)];

        if (addDelegate)
            [m setDelegate: (id<NSMenuDelegate>) callback];

        for (PopupMenu::MenuItemIterator iter (menu); iter.next();)
            addMenuItem (iter, m, topLevelMenuId, topLevelIndex);

        [m update];
        return m;
    }

    static JuceMainMenuHandler* instance;

    MenuBarModel* currentModel = nullptr;
    std::unique_ptr<PopupMenu> extraAppleMenuItems;
    uint32 lastUpdateTime = 0;
    NSObject* callback = nil;
    String recentItemsMenuName;
    bool isOpen = false, defferedUpdateRequested = false;

private:
    struct RecentFilesMenuItem
    {
        RecentFilesMenuItem() : recentItem (nil)
        {
            if (NSNib* menuNib = [[[NSNib alloc] initWithNibNamed: @"RecentFilesMenuTemplate" bundle: nil] autorelease])
            {
                NSArray* array = nil;

                [menuNib instantiateWithOwner: NSApp
                              topLevelObjects: &array];

                for (id object in array)
                {
                    if ([object isKindOfClass: [NSMenu class]])
                    {
                        if (NSArray* items = [object itemArray])
                        {
                            if (NSMenuItem* item = findRecentFilesItem (items))
                            {
                                recentItem = [item retain];
                                break;
                            }
                        }
                    }
                }
            }
        }

        ~RecentFilesMenuItem()
        {
            [recentItem release];
        }

        static NSMenuItem* findRecentFilesItem (NSArray* const items)
        {
            for (id object in items)
                if (NSArray* subMenuItems = [[object submenu] itemArray])
                    for (id subObject in subMenuItems)
                        if ([subObject isKindOfClass: [NSMenuItem class]])
                            return subObject;
            return nil;
        }

        NSMenuItem* recentItem;

        JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (RecentFilesMenuItem)
    };

    std::unique_ptr<RecentFilesMenuItem> recent;

    //==============================================================================
    static NSMenuItem* findMenuItemWithCommandID (NSMenu* const menu, int commandID)
    {
        for (NSInteger i = [menu numberOfItems]; --i >= 0;)
        {
            NSMenuItem* m = [menu itemAtIndex: i];
            if (auto* menuItem = getJuceClassFromNSObject<PopupMenu::Item> ([m representedObject]))
                if (menuItem->itemID == commandID)
                    return m;

            if (NSMenu* sub = [m submenu])
                if (NSMenuItem* found = findMenuItemWithCommandID (sub, commandID))
                    return found;
        }

        return nil;
    }

    static void flashMenuBar (NSMenu* menu)
    {
        if ([[menu title] isEqualToString: nsStringLiteral ("Apple")])
            return;

        [menu retain];

        const unichar f35Key = NSF35FunctionKey;
        NSString* f35String = [NSString stringWithCharacters: &f35Key length: 1];

        NSMenuItem* item = [[NSMenuItem alloc] initWithTitle: nsStringLiteral ("x")
                                                      action: menuItemInvokedSelector
                                               keyEquivalent: f35String];

        // When the f35Event is invoked, the item's enablement is checked and a
        // NSBeep is triggered if the item appears to be disabled.
        // This ValidatorClass exists solely to return YES from validateMenuItem.
        struct ValidatorClass final : public ObjCClass<NSObject>
        {
            ValidatorClass()  : ObjCClass ("JUCEMenuValidator_")
            {
                addMethod (menuItemInvokedSelector,       [] (id, SEL, NSMenuItem*) {});
                addMethod (@selector (validateMenuItem:), [] (id, SEL, NSMenuItem*) { return YES; });
                addProtocol (@protocol (NSMenuItemValidation));

                registerClass();
            }
        };

        static ValidatorClass validatorClass;
        static auto* vcInstance = validatorClass.createInstance();

        [item setTarget: vcInstance];
        [menu insertItem: item atIndex: [menu numberOfItems]];
        [item release];

        if ([menu indexOfItem: item] >= 0)
        {
            NSEvent* f35Event = [NSEvent keyEventWithType: NSEventTypeKeyDown
                                                 location: NSZeroPoint
                                            modifierFlags: NSEventModifierFlagCommand
                                                timestamp: 0
                                             windowNumber: 0
                                                  context: [NSGraphicsContext currentContext]
                                               characters: f35String
                              charactersIgnoringModifiers: f35String
                                                isARepeat: NO
                                                  keyCode: 0];

            [menu performKeyEquivalent: f35Event];

            if ([menu indexOfItem: item] >= 0)
                [menu removeItem: item]; // (this throws if the item isn't actually in the menu)
        }

        [menu release];
    }

    static unsigned int juceModsToNSMods (const ModifierKeys mods)
    {
        unsigned int m = 0;
        if (mods.isShiftDown())    m |= NSEventModifierFlagShift;
        if (mods.isCtrlDown())     m |= NSEventModifierFlagControl;
        if (mods.isAltDown())      m |= NSEventModifierFlagOption;
        if (mods.isCommandDown())  m |= NSEventModifierFlagCommand;
        return m;
    }

    // Apple Bug: For some reason [NSMenu removeAllItems] seems to leak its objects
    // on shutdown, so we need this method to release the items one-by-one manually
    static void removeItemRecursive (NSMenu* parentMenu, int menuItemIndex)
    {
        if (isPositiveAndBelow (menuItemIndex, (int) [parentMenu numberOfItems]))
        {
            if (auto menuItem = [parentMenu itemAtIndex:menuItemIndex])
            {
                if (auto submenu = [menuItem submenu])
                    removeItemRecursive (submenu);

                JUCE_BEGIN_IGNORE_WARNINGS_GCC_LIKE ("-Wnullable-to-nonnull-conversion")
                [parentMenu removeItem: menuItem];
                JUCE_END_IGNORE_WARNINGS_GCC_LIKE
            }
        }
        else
            jassertfalse;
    }

    static void removeItemRecursive (NSMenu* menu)
    {
        if (menu != nullptr)
        {
            auto n = static_cast<int> ([menu numberOfItems]);

            for (auto i = n; --i >= 0;)
                removeItemRecursive (menu, i);
        }
    }

    static NSMenu* getMainMenuBar()
    {
        return JuceMainMenuBarHolder::getInstance()->mainMenuBar;
    }

    //==============================================================================
    struct JuceMenuCallbackClass final : public ObjCClass<NSObject>
    {
        JuceMenuCallbackClass()  : ObjCClass ("JUCEMainMenu_")
        {
            addIvar<JuceMainMenuHandler*> ("owner");

            addMethod (menuItemInvokedSelector, [] (id self, SEL, NSMenuItem* item)
            {
                if (auto* juceItem = getPopupMenuItem (item))
                    getOwner (self)->invoke (*juceItem, static_cast<int> ([item tag]));
            });

            addMethod (@selector (menuNeedsUpdate:), [] (id self, SEL, NSMenu* menu)
            {
                getOwner (self)->updateTopLevelMenu (menu);
            });

            addMethod (@selector (validateMenuItem:), [] (id, SEL, NSMenuItem* item) -> BOOL
            {
                if (auto* juceItem = getPopupMenuItem (item))
                    return juceItem->isEnabled;

                return YES;
            });

            addProtocol (@protocol (NSMenuDelegate));
            addProtocol (@protocol (NSMenuItemValidation));

            registerClass();
        }

        static void setOwner (id self, JuceMainMenuHandler* owner)
        {
            object_setInstanceVariable (self, "owner", owner);
        }

    private:
        static PopupMenu::Item* getPopupMenuItem (NSMenuItem* item)
        {
            return getJuceClassFromNSObject<PopupMenu::Item> ([item representedObject]);
        }

        static JuceMainMenuHandler* getOwner (id self)
        {
            return getIvar<JuceMainMenuHandler*> (self, "owner");
        }
    };
};

JuceMainMenuHandler* JuceMainMenuHandler::instance = nullptr;

//==============================================================================
class TemporaryMainMenuWithStandardCommands
{
public:
    explicit TemporaryMainMenuWithStandardCommands (FilePreviewComponent* filePreviewComponent)
        : oldMenu (MenuBarModel::getMacMainMenu()), dummyModalComponent (filePreviewComponent)
    {
        if (auto* appleMenu = MenuBarModel::getMacExtraAppleItemsMenu())
            oldAppleMenu = std::make_unique<PopupMenu> (*appleMenu);

        if (auto* handler = JuceMainMenuHandler::instance)
            oldRecentItems = handler->recentItemsMenuName;

        MenuBarModel::setMacMainMenu (nullptr);

        if (auto* mainMenu = JuceMainMenuBarHolder::getInstance()->mainMenuBar)
        {
            NSMenu* menu = [[NSMenu alloc] initWithTitle: nsStringLiteral ("Edit")];
            NSMenuItem* item;

            item = [[NSMenuItem alloc] initWithTitle: NSLocalizedString (nsStringLiteral ("Cut"), nil)
                                              action: @selector (cut:)  keyEquivalent: nsStringLiteral ("x")];
            [menu addItem: item];
            [item release];

            item = [[NSMenuItem alloc] initWithTitle: NSLocalizedString (nsStringLiteral ("Copy"), nil)
                                              action: @selector (copy:)  keyEquivalent: nsStringLiteral ("c")];
            [menu addItem: item];
            [item release];

            item = [[NSMenuItem alloc] initWithTitle: NSLocalizedString (nsStringLiteral ("Paste"), nil)
                                              action: @selector (paste:)  keyEquivalent: nsStringLiteral ("v")];
            [menu addItem: item];
            [item release];

            editMenuIndex = [mainMenu numberOfItems];

            item = [mainMenu addItemWithTitle: NSLocalizedString (nsStringLiteral ("Edit"), nil)
                                       action: nil  keyEquivalent: nsEmptyString()];
            [mainMenu setSubmenu: menu forItem: item];
            [menu release];
        }

        // use a dummy modal component so that apps can tell that something is currently modal.
        dummyModalComponent.enterModalState (false);
    }

    ~TemporaryMainMenuWithStandardCommands()
    {
        if (auto* mainMenu = JuceMainMenuBarHolder::getInstance()->mainMenuBar)
            [mainMenu removeItemAtIndex:editMenuIndex];

        MenuBarModel::setMacMainMenu (oldMenu, oldAppleMenu.get(), oldRecentItems);
    }

    static bool checkModalEvent (FilePreviewComponent* preview, const Component* targetComponent)
    {
        if (targetComponent == nullptr)
            return false;

        return (targetComponent == preview
               || targetComponent->findParentComponentOfClass<FilePreviewComponent>() != nullptr);
    }

private:
    MenuBarModel* const oldMenu = nullptr;
    std::unique_ptr<PopupMenu> oldAppleMenu;
    String oldRecentItems;
    NSInteger editMenuIndex;

    // The OS view already plays an alert when clicking outside
    // the modal comp, so this override avoids adding extra
    // inappropriate noises when the cancel button is pressed.
    // This override is also important because it stops the base class
    // calling ModalComponentManager::bringToFront, which can get
    // recursive when file dialogs are involved
    struct SilentDummyModalComp final : public Component
    {
        explicit SilentDummyModalComp (FilePreviewComponent* p)
            : preview (p) {}

        void inputAttemptWhenModal() override {}

        bool canModalEventBeSentToComponent (const Component* targetComponent) override
        {
            return checkModalEvent (preview, targetComponent);
        }

        FilePreviewComponent* preview = nullptr;
    };

    SilentDummyModalComp dummyModalComponent;
};

//==============================================================================
namespace MainMenuHelpers
{
    static NSString* translateMenuName (const String& name)
    {
        return NSLocalizedString (juceStringToNS (TRANS (name)), nil);
    }

    static NSMenuItem* createMenuItem (NSMenu* menu, const String& name, SEL sel, NSString* key)
    {
        NSMenuItem* item = [[[NSMenuItem alloc] initWithTitle: translateMenuName (name)
                                                       action: sel
                                                keyEquivalent: key] autorelease];
        [item setTarget: NSApp];
        [menu addItem: item];
        return item;
    }

    static void createStandardAppMenu (NSMenu* menu, const String& appName, const PopupMenu* extraItems)
    {
        if (extraItems != nullptr && JuceMainMenuHandler::instance != nullptr && extraItems->getNumItems() > 0)
        {
            for (PopupMenu::MenuItemIterator iter (*extraItems); iter.next();)
                JuceMainMenuHandler::instance->addMenuItem (iter, menu, 0, -1);

            [menu addItem: [NSMenuItem separatorItem]];
        }

        // Services...
        NSMenuItem* services = [[[NSMenuItem alloc] initWithTitle: translateMenuName ("Services")
                                                           action: nil  keyEquivalent: nsEmptyString()] autorelease];
        [menu addItem: services];

        NSMenu* servicesMenu = [[[NSMenu alloc] initWithTitle: translateMenuName ("Services")] autorelease];
        [menu setSubmenu: servicesMenu forItem: services];
        [NSApp setServicesMenu: servicesMenu];
        [menu addItem: [NSMenuItem separatorItem]];

        createMenuItem (menu, TRANS ("Hide") + String (" ") + appName, @selector (hide:), nsStringLiteral ("h"));

        [createMenuItem (menu, TRANS ("Hide Others"), @selector (hideOtherApplications:), nsStringLiteral ("h"))
            setKeyEquivalentModifierMask: NSEventModifierFlagCommand | NSEventModifierFlagOption];

        createMenuItem (menu, TRANS ("Show All"), @selector (unhideAllApplications:), nsEmptyString());

        [menu addItem: [NSMenuItem separatorItem]];

        createMenuItem (menu, TRANS ("Quit") + String (" ") + appName, @selector (terminate:), nsStringLiteral ("q"));
    }

    // Since our app has no NIB, this initialises a standard app menu...
    static void rebuildMainMenu (const PopupMenu* extraItems)
    {
        // this can't be used in a plugin!
        jassert (JUCEApplicationBase::isStandaloneApp());

        if (auto* app = JUCEApplicationBase::getInstance())
        {
            if (auto* mainMenu = JuceMainMenuBarHolder::getInstance()->mainMenuBar)
            {
                if ([mainMenu numberOfItems] > 0)
                {
                    if (auto appMenu = [[mainMenu itemAtIndex: 0] submenu])
                    {
                        [appMenu removeAllItems];
                        MainMenuHelpers::createStandardAppMenu (appMenu, app->getApplicationName(), extraItems);
                    }
                }
            }
        }
    }
}

void MenuBarModel::setMacMainMenu (MenuBarModel* newMenuBarModel,
                                   const PopupMenu* extraAppleMenuItems,
                                   const String& recentItemsMenuName)
{
    if (getMacMainMenu() != newMenuBarModel)
    {
        JUCE_AUTORELEASEPOOL
        {
            if (newMenuBarModel == nullptr)
            {
                delete JuceMainMenuHandler::instance;
                jassert (JuceMainMenuHandler::instance == nullptr); // should be zeroed in the destructor
                jassert (extraAppleMenuItems == nullptr); // you can't specify some extra items without also supplying a model

                extraAppleMenuItems = nullptr;
            }
            else
            {
                if (JuceMainMenuHandler::instance == nullptr)
                    JuceMainMenuHandler::instance = new JuceMainMenuHandler();

                JuceMainMenuHandler::instance->setMenu (newMenuBarModel, extraAppleMenuItems, recentItemsMenuName);
            }
        }
    }

    MainMenuHelpers::rebuildMainMenu (extraAppleMenuItems);

    if (newMenuBarModel != nullptr)
        newMenuBarModel->menuItemsChanged();
}

MenuBarModel* MenuBarModel::getMacMainMenu()
{
    if (auto* mm = JuceMainMenuHandler::instance)
        return mm->currentModel;

    return nullptr;
}

const PopupMenu* MenuBarModel::getMacExtraAppleItemsMenu()
{
    if (auto* mm = JuceMainMenuHandler::instance)
        return mm->extraAppleMenuItems.get();

    return nullptr;
}

using MenuTrackingChangedCallback = void (*)(bool);
extern MenuTrackingChangedCallback menuTrackingChangedCallback;

static void mainMenuTrackingChanged (bool isTracking)
{
    PopupMenu::dismissAllActiveMenus();

    if (auto* menuHandler = JuceMainMenuHandler::instance)
    {
        menuHandler->isOpen = isTracking;

        if (auto* model = menuHandler->currentModel)
            model->handleMenuBarActivate (isTracking);

        if (menuHandler->defferedUpdateRequested && ! isTracking)
        {
            menuHandler->defferedUpdateRequested = false;
            menuHandler->menuBarItemsChanged (menuHandler->currentModel);
        }
    }
}

static void initialiseMacMainMenu()
{
    menuTrackingChangedCallback = mainMenuTrackingChanged;

    if (JuceMainMenuHandler::instance == nullptr)
        MainMenuHelpers::rebuildMainMenu (nullptr);
}

// (used from other modules that need to create an NSMenu)
NSMenu* createNSMenu (const PopupMenu&, const String&, int, int, bool);
NSMenu* createNSMenu (const PopupMenu& menu, const String& name, int topLevelMenuId, int topLevelIndex, bool addDelegate)
{
    initialiseMacMainMenu();

    if (auto* mm = JuceMainMenuHandler::instance)
        return mm->createMenu (menu, name, topLevelMenuId, topLevelIndex, addDelegate);

    jassertfalse; // calling this before making sure the OSX main menu stuff was initialised?
    return nil;
}

} // namespace juce
