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

   This file is part of the JUCE library - "Jules' Utility Class Extensions"
   Copyright 2004-11 by Raw Material Software Ltd.

  ------------------------------------------------------------------------------

   JUCE can be redistributed and/or modified under the terms of the GNU General
   Public License (Version 2), as published by the Free Software Foundation.
   A copy of the license is included in the JUCE distribution, or can be found
   online at www.gnu.org/licenses.

   JUCE is distributed in the hope that it will be useful, but WITHOUT ANY
   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
   A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

  ------------------------------------------------------------------------------

   To release a closed-source product which uses JUCE, commercial licenses are
   available: visit www.rawmaterialsoftware.com/juce for more information.

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

class JuceMainMenuHandler   : private MenuBarModel::Listener,
                              private DeletedAtShutdown
{
public:
    JuceMainMenuHandler()
        : currentModel (nullptr),
          lastUpdateTime (0)
    {
        static JuceMenuCallbackClass cls;
        callback = [cls.createInstance() init];
        JuceMenuCallbackClass::setOwner (callback, this);
    }

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

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

        [callback release];
    }

    void setMenu (MenuBarModel* const newMenuBarModel, const PopupMenu* newExtraAppleMenuItems)
    {
        if (currentModel != newMenuBarModel)
        {
            if (currentModel != nullptr)
                currentModel->removeListener (this);

            currentModel = newMenuBarModel;

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

            menuBarItemsChanged (nullptr);
        }

        extraAppleMenuItems = newExtraAppleMenuItems != nullptr ? new PopupMenu (*newExtraAppleMenuItems)
                                                                : nullptr;
    }

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

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

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

    void updateSubMenu (NSMenuItem* parentItem, const PopupMenu& menuToCopy,
                        const String& name, const int menuId, const int tag)
    {
       #if MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_5
        static bool is10_4 = (SystemStats::getOSXMinorVersionNumber() <= 4);

        if (is10_4)
        {
            [parentItem setTag: tag];
            NSMenu* menu = [parentItem submenu];

            [menu setTitle: juceStringToNS (name)];

            while ([menu numberOfItems] > 0)
                [menu removeItemAtIndex: 0];

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

            [menu setAutoenablesItems: false];
            [menu update];
            return;
        }
       #endif

        // 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, tag);

        [menu setAutoenablesItems: false];
        [menu update];
        [parentItem setTag: tag];
        [parentItem setSubmenu: menu];
        [menu release];
    }

    void menuBarItemsChanged (MenuBarModel*)
    {
        lastUpdateTime = Time::getMillisecondCounter();

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

        NSMenu* menuBar = [NSApp mainMenu];
        while ([menuBar numberOfItems] > 1 + menuNames.size())
            [menuBar removeItemAtIndex: [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)
                addSubMenu (menuBar, menu, menuNames[i], menuId, i);
            else
                updateSubMenu ([menuBar itemAtIndex: 1 + i], menu, menuNames[i], menuId, i);
        }
    }

    void menuCommandInvoked (MenuBarModel*, const ApplicationCommandTarget::InvocationInfo& info)
    {
        NSMenuItem* item = findMenuItem ([NSApp mainMenu], info);

        if (item != nil)
            flashMenuBar ([item menu]);
    }

    void updateMenus (NSMenu* menu)
    {
        if (PopupMenu::dismissAllActiveMenus())
        {
            // If we were running a juce menu, then we should let that modal loop finish before allowing
            // the OS menus to start their own modal loop - so cancel the menu that was being opened..
            if ([menu respondsToSelector: @selector (cancelTracking)])
                [menu performSelector: @selector (cancelTracking)];
        }

        if (Time::getMillisecondCounter() > lastUpdateTime + 100)
            (new AsyncMenuUpdater())->post();
    }

    void invoke (const int commandId, ApplicationCommandManager* const commandManager, const int topLevelIndex) const
    {
        if (currentModel != nullptr)
        {
            if (commandManager != nullptr)
            {
                ApplicationCommandTarget::InvocationInfo info (commandId);
                info.invocationMethod = ApplicationCommandTarget::InvocationInfo::fromMenu;

                commandManager->invoke (info, true);
            }

            (new AsyncCommandInvoker (commandId, topLevelIndex))->post();
        }
    }

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

    void addMenuItem (PopupMenu::MenuItemIterator& iter, NSMenu* menuToAddTo,
                      const int topLevelMenuId, const int topLevelIndex)
    {
        NSString* text = juceStringToNS (iter.itemName.upToFirstOccurrenceOf ("<end>", false, true));

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

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

            [item setEnabled: false];
        }
        else if (iter.subMenu != nullptr)
        {
            NSMenuItem* item = [menuToAddTo addItemWithTitle: text
                                                      action: nil
                                               keyEquivalent: nsEmptyString()];

            [item setTag: iter.itemId];
            [item setEnabled: iter.isEnabled];

            NSMenu* sub = createMenu (*iter.subMenu, iter.itemName, topLevelMenuId, topLevelIndex);
            [sub setDelegate: nil];
            [menuToAddTo setSubmenu: sub forItem: item];
            [sub release];
        }
        else
        {
            NSMenuItem* item = [menuToAddTo addItemWithTitle: text
                                                      action: @selector (menuItemInvoked:)
                                               keyEquivalent: nsEmptyString()];

            [item setTag: iter.itemId];
            [item setEnabled: iter.isEnabled];
            [item setState: iter.isTicked ? NSOnState : NSOffState];
            [item setTarget: (id) callback];

            NSMutableArray* info = [NSMutableArray arrayWithObject: [NSNumber numberWithUnsignedLongLong: (pointer_sized_int) (void*) iter.commandManager]];
            [info addObject: [NSNumber numberWithInt: topLevelIndex]];
            [item setRepresentedObject: info];

            if (iter.commandManager != nullptr)
            {
                const Array <KeyPress> keyPresses (iter.commandManager->getKeyMappings()
                                                   ->getKeyPressesAssignedToCommand (iter.itemId));

                if (keyPresses.size() > 0)
                {
                    const KeyPress& kp = keyPresses.getReference(0);

                    if (kp.getKeyCode() != KeyPress::backspaceKey   // (adding these is annoying because it flashes the menu bar
                         && kp.getKeyCode() != 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())];
                    }
                }
            }
        }
    }

    static JuceMainMenuHandler* instance;

    MenuBarModel* currentModel;
    ScopedPointer<PopupMenu> extraAppleMenuItems;
    uint32 lastUpdateTime;
    NSObject* callback;

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

        [m setAutoenablesItems: false];

       #if defined (MAC_OS_X_VERSION_10_6) && MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_6
        [m setDelegate: (id<NSMenuDelegate>) callback];
       #else
        [m setDelegate: callback];
       #endif

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

        [m update];
        return m;
    }

    static NSMenuItem* findMenuItem (NSMenu* const menu, const ApplicationCommandTarget::InvocationInfo& info)
    {
        for (NSInteger i = [menu numberOfItems]; --i >= 0;)
        {
            NSMenuItem* m = [menu itemAtIndex: i];
            if ([m tag] == info.commandID)
                return m;

            if ([m submenu] != nil)
            {
                NSMenuItem* found = findMenuItem ([m submenu], info);
                if (found != nil)
                    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: nil
                                               keyEquivalent: f35String];
        [item setTarget: nil];
        [menu insertItem: item atIndex: [menu numberOfItems]];
        [item release];

        if ([menu indexOfItem: item] >= 0)
        {
            NSEvent* f35Event = [NSEvent keyEventWithType: NSKeyDown
                                                 location: NSZeroPoint
                                            modifierFlags: NSCommandKeyMask
                                                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 |= NSShiftKeyMask;
        if (mods.isCtrlDown())     m |= NSControlKeyMask;
        if (mods.isAltDown())      m |= NSAlternateKeyMask;
        if (mods.isCommandDown())  m |= NSCommandKeyMask;
        return m;
    }

    class AsyncMenuUpdater  : public CallbackMessage
    {
    public:
        AsyncMenuUpdater() {}

        void messageCallback()
        {
            if (instance != nullptr)
                instance->menuBarItemsChanged (nullptr);
        }

    private:
        JUCE_DECLARE_NON_COPYABLE (AsyncMenuUpdater);
    };

    class AsyncCommandInvoker  : public CallbackMessage
    {
    public:
        AsyncCommandInvoker (const int commandId_, const int topLevelIndex_)
            : commandId (commandId_), topLevelIndex (topLevelIndex_)
        {}

        void messageCallback()
        {
            if (instance != nullptr)
                instance->invokeDirectly (commandId, topLevelIndex);
        }

    private:
        const int commandId, topLevelIndex;

        JUCE_DECLARE_NON_COPYABLE (AsyncCommandInvoker);
    };

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

            addMethod (@selector (menuItemInvoked:),  menuItemInvoked, "v@:@");
            addMethod (@selector (menuNeedsUpdate:),  menuNeedsUpdate, "v@:@");

           #if defined (MAC_OS_X_VERSION_10_6) && MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_6
            addProtocol (@protocol (NSMenuDelegate));
           #endif

            registerClass();
        }

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

    private:
        static void menuItemInvoked (id self, SEL, id menu)
        {
            JuceMainMenuHandler* const owner = getIvar<JuceMainMenuHandler*> (self, "owner");

            NSMenuItem* item = (NSMenuItem*) menu;

            if ([[item representedObject] isKindOfClass: [NSArray class]])
            {
                // If the menu is being triggered by a keypress, the OS will have picked it up before we had a chance to offer it to
                // our own components, which may have wanted to intercept it. So, rather than dispatching directly, we'll feed it back
                // into the focused component and let it trigger the menu item indirectly.
                NSEvent* e = [NSApp currentEvent];
                if ([e type] == NSKeyDown || [e type] == NSKeyUp)
                {
                    if (juce::Component::getCurrentlyFocusedComponent() != nullptr)
                    {
                        juce::NSViewComponentPeer* peer = dynamic_cast <juce::NSViewComponentPeer*> (juce::Component::getCurrentlyFocusedComponent()->getPeer());

                        if (peer != nullptr)
                        {
                            if ([e type] == NSKeyDown)
                                peer->redirectKeyDown (e);
                            else
                                peer->redirectKeyUp (e);

                            return;
                        }
                    }
                }

                NSArray* info = (NSArray*) [item representedObject];

                owner->invoke ((int) [item tag],
                               (ApplicationCommandManager*) (pointer_sized_int)
                                    [((NSNumber*) [info objectAtIndex: 0]) unsignedLongLongValue],
                               (int) [((NSNumber*) [info objectAtIndex: 1]) intValue]);
            }
        }

        static void menuNeedsUpdate (id self, SEL, NSMenu* menu)
        {
            if (instance != nullptr)
                instance->updateMenus (menu);
        }
    };
};

JuceMainMenuHandler* JuceMainMenuHandler::instance = nullptr;

//==============================================================================
namespace MainMenuHelpers
{
    static NSMenu* 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]];
        }

        NSMenuItem* item;

        // Services...
        item = [[NSMenuItem alloc] initWithTitle: NSLocalizedString (nsStringLiteral ("Services"), nil)
                                          action: nil  keyEquivalent: nsEmptyString()];
        [menu addItem: item];
        [item release];
        NSMenu* servicesMenu = [[NSMenu alloc] initWithTitle: nsStringLiteral ("Services")];
        [menu setSubmenu: servicesMenu forItem: item];
        [NSApp setServicesMenu: servicesMenu];
        [servicesMenu release];
        [menu addItem: [NSMenuItem separatorItem]];

        // Hide + Show stuff...
        item = [[NSMenuItem alloc] initWithTitle: juceStringToNS ("Hide " + appName)
                                          action: @selector (hide:)  keyEquivalent: nsStringLiteral ("h")];
        [item setTarget: NSApp];
        [menu addItem: item];
        [item release];

        item = [[NSMenuItem alloc] initWithTitle: NSLocalizedString (nsStringLiteral ("Hide Others"), nil)
                                          action: @selector (hideOtherApplications:)  keyEquivalent: nsStringLiteral ("h")];
        [item setKeyEquivalentModifierMask: NSCommandKeyMask | NSAlternateKeyMask];
        [item setTarget: NSApp];
        [menu addItem: item];
        [item release];

        item = [[NSMenuItem alloc] initWithTitle: NSLocalizedString (nsStringLiteral ("Show All"), nil)
                                          action: @selector (unhideAllApplications:)  keyEquivalent: nsEmptyString()];
        [item setTarget: NSApp];
        [menu addItem: item];
        [item release];

        [menu addItem: [NSMenuItem separatorItem]];

        // Quit item....
        item = [[NSMenuItem alloc] initWithTitle: juceStringToNS ("Quit " + appName)
                                          action: @selector (terminate:)  keyEquivalent: nsStringLiteral ("q")];

        [item setTarget: NSApp];
        [menu addItem: item];
        [item release];

        return menu;
    }

    // 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 (JUCEApplication::isStandaloneApp());

        if (JUCEApplication::getInstance() != nullptr)
        {
            JUCE_AUTORELEASEPOOL

            NSMenu* mainMenu = [[NSMenu alloc] initWithTitle: nsStringLiteral ("MainMenu")];
            NSMenuItem* item = [mainMenu addItemWithTitle: nsStringLiteral ("Apple") action: nil keyEquivalent: nsEmptyString()];

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

            [NSApp performSelector: @selector (setAppleMenu:) withObject: appMenu];
            [mainMenu setSubmenu: appMenu forItem: item];

            [NSApp setMainMenu: mainMenu];
            MainMenuHelpers::createStandardAppMenu (appMenu, JUCEApplication::getInstance()->getApplicationName(), extraItems);

            [appMenu release];
            [mainMenu release];
        }
    }
}

void MenuBarModel::setMacMainMenu (MenuBarModel* newMenuBarModel,
                                   const PopupMenu* extraAppleMenuItems)
{
    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);
        }
    }

    MainMenuHelpers::rebuildMainMenu (extraAppleMenuItems);

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

MenuBarModel* MenuBarModel::getMacMainMenu()
{
    return JuceMainMenuHandler::instance != nullptr
             ? JuceMainMenuHandler::instance->currentModel : nullptr;
}

const PopupMenu* MenuBarModel::getMacExtraAppleItemsMenu()
{
    return JuceMainMenuHandler::instance != nullptr
             ? JuceMainMenuHandler::instance->extraAppleMenuItems.get() : nullptr;
}

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