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

   This file is part of the JUCE library.
   Copyright (c) 2017 - ROLI Ltd.

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

   The code included in this file is provided under the terms of the ISC license
   http://www.isc.org/downloads/software-support-policy/isc-license. Permission
   To use, copy, modify, and/or distribute this software for any purpose with or
   without fee is hereby granted provided that the above copyright notice and
   this permission notice appear in all copies.

   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
{

using AppFocusChangeCallback = void (*)();
AppFocusChangeCallback appFocusChangeCallback = nullptr;

using CheckEventBlockedByModalComps = bool (*)(NSEvent*);
CheckEventBlockedByModalComps isEventBlockedByModalComps = nullptr;

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

//==============================================================================
struct AppDelegate
{
public:
    AppDelegate()
    {
        static AppDelegateClass cls;
        delegate = [cls.createInstance() init];

        NSNotificationCenter* center = [NSNotificationCenter defaultCenter];

        [center addObserver: delegate selector: @selector (mainMenuTrackingBegan:)
                       name: NSMenuDidBeginTrackingNotification object: nil];
        [center addObserver: delegate selector: @selector (mainMenuTrackingEnded:)
                       name: NSMenuDidEndTrackingNotification object: nil];

        if (JUCEApplicationBase::isStandaloneApp())
        {
            [NSApp setDelegate: delegate];

            [[NSDistributedNotificationCenter defaultCenter] addObserver: delegate
                                                                selector: @selector (broadcastMessageCallback:)
                                                                    name: getBroadcastEventName()
                                                                  object: nil
                                                      suspensionBehavior: NSNotificationSuspensionBehaviorDeliverImmediately];
        }
        else
        {
            [center addObserver: delegate selector: @selector (applicationDidResignActive:)
                           name: NSApplicationDidResignActiveNotification object: NSApp];

            [center addObserver: delegate selector: @selector (applicationDidBecomeActive:)
                           name: NSApplicationDidBecomeActiveNotification object: NSApp];

            [center addObserver: delegate selector: @selector (applicationWillUnhide:)
                           name: NSApplicationWillUnhideNotification object: NSApp];
        }
    }

    ~AppDelegate()
    {
        [[NSRunLoop currentRunLoop] cancelPerformSelectorsWithTarget: delegate];
        [[NSNotificationCenter defaultCenter] removeObserver: delegate];

        if (JUCEApplicationBase::isStandaloneApp())
        {
            [NSApp setDelegate: nil];

            [[NSDistributedNotificationCenter defaultCenter] removeObserver: delegate
                                                                       name: getBroadcastEventName()
                                                                     object: nil];
        }

        [delegate release];
    }

    static NSString* getBroadcastEventName()
    {
        return juceStringToNS ("juce_" + String::toHexString (File::getSpecialLocation (File::currentExecutableFile).hashCode64()));
    }

    MessageQueue messageQueue;
    id delegate;

private:
    //==============================================================================
    struct AppDelegateClass   : public ObjCClass<NSObject>
    {
        AppDelegateClass()  : ObjCClass<NSObject> ("JUCEAppDelegate_")
        {
            addMethod (@selector (applicationWillFinishLaunching:), applicationWillFinishLaunching, "v@:@");
            addMethod (@selector (getUrl:withReplyEvent:),          getUrl_withReplyEvent,          "v@:@@");
            addMethod (@selector (applicationShouldTerminate:),     applicationShouldTerminate,     "I@:@");
            addMethod (@selector (applicationWillTerminate:),       applicationWillTerminate,       "v@:@");
            addMethod (@selector (application:openFile:),           application_openFile,           "c@:@@");
            addMethod (@selector (application:openFiles:),          application_openFiles,          "v@:@@");
            addMethod (@selector (applicationDidBecomeActive:),     applicationDidBecomeActive,     "v@:@");
            addMethod (@selector (applicationDidResignActive:),     applicationDidResignActive,     "v@:@");
            addMethod (@selector (applicationWillUnhide:),          applicationWillUnhide,          "v@:@");
            addMethod (@selector (broadcastMessageCallback:),       broadcastMessageCallback,       "v@:@");
            addMethod (@selector (mainMenuTrackingBegan:),          mainMenuTrackingBegan,          "v@:@");
            addMethod (@selector (mainMenuTrackingEnded:),          mainMenuTrackingEnded,          "v@:@");
            addMethod (@selector (dummyMethod),                     dummyMethod,                    "v@:");

           #if JUCE_PUSH_NOTIFICATIONS
            //==============================================================================
            addIvar<NSObject<NSApplicationDelegate, NSUserNotificationCenterDelegate>*> ("pushNotificationsDelegate");

            addMethod (@selector (applicationDidFinishLaunching:),                                applicationDidFinishLaunching,          "v@:@");
            addMethod (@selector (setPushNotificationsDelegate:),                                 setPushNotificationsDelegate,           "v@:@");
            addMethod (@selector (application:didRegisterForRemoteNotificationsWithDeviceToken:), registeredForRemoteNotifications,       "v@:@@");
            addMethod (@selector (application:didFailToRegisterForRemoteNotificationsWithError:), failedToRegisterForRemoteNotifications, "v@:@@");
            addMethod (@selector (application:didReceiveRemoteNotification:),                     didReceiveRemoteNotification,           "v@:@@");
           #endif

            registerClass();
        }

    private:
        static void applicationWillFinishLaunching (id self, SEL, NSNotification*)
        {
            [[NSAppleEventManager sharedAppleEventManager] setEventHandler: self
                                                               andSelector: @selector (getUrl:withReplyEvent:)
                                                             forEventClass: kInternetEventClass
                                                                andEventID: kAEGetURL];
        }

       #if JUCE_PUSH_NOTIFICATIONS
        static void applicationDidFinishLaunching (id self, SEL, NSNotification* notification)
        {
            if (notification.userInfo != nil)
            {
                NSUserNotification* userNotification = [notification.userInfo objectForKey: nsStringLiteral ("NSApplicationLaunchUserNotificationKey")];

                if (userNotification != nil && userNotification.userInfo != nil)
                    didReceiveRemoteNotification (self, nil, [NSApplication sharedApplication], userNotification.userInfo);
            }
        }
       #endif

        static NSApplicationTerminateReply applicationShouldTerminate (id /*self*/, SEL, NSApplication*)
        {
            if (auto* app = JUCEApplicationBase::getInstance())
            {
                app->systemRequestedQuit();

                if (! MessageManager::getInstance()->hasStopMessageBeenSent())
                    return NSTerminateCancel;
            }

            return NSTerminateNow;
        }

        static void applicationWillTerminate (id /*self*/, SEL, NSNotification*)
        {
            JUCEApplicationBase::appWillTerminateByForce();
        }

        static BOOL application_openFile (id /*self*/, SEL, NSApplication*, NSString* filename)
        {
            if (auto* app = JUCEApplicationBase::getInstance())
            {
                app->anotherInstanceStarted (quotedIfContainsSpaces (filename));
                return YES;
            }

            return NO;
        }

        static void application_openFiles (id /*self*/, SEL, NSApplication*, NSArray* filenames)
        {
            if (auto* app = JUCEApplicationBase::getInstance())
            {
                StringArray files;

                for (NSString* f in filenames)
                    files.add (quotedIfContainsSpaces (f));

                if (files.size() > 0)
                    app->anotherInstanceStarted (files.joinIntoString (" "));
            }
        }

        static void applicationDidBecomeActive (id /*self*/, SEL, NSNotification*)  { focusChanged(); }
        static void applicationDidResignActive (id /*self*/, SEL, NSNotification*)  { focusChanged(); }
        static void applicationWillUnhide      (id /*self*/, SEL, NSNotification*)  { focusChanged(); }

        static void broadcastMessageCallback (id /*self*/, SEL, NSNotification* n)
        {
            NSDictionary* dict = (NSDictionary*) [n userInfo];
            auto messageString = nsStringToJuce ((NSString*) [dict valueForKey: nsStringLiteral ("message")]);
            MessageManager::getInstance()->deliverBroadcastMessage (messageString);
        }

        static void mainMenuTrackingBegan (id /*self*/, SEL, NSNotification*)
        {
            if (menuTrackingChangedCallback != nullptr)
                (*menuTrackingChangedCallback) (true);
        }

        static void mainMenuTrackingEnded (id /*self*/, SEL, NSNotification*)
        {
            if (menuTrackingChangedCallback != nullptr)
                (*menuTrackingChangedCallback) (false);
        }

        static void dummyMethod (id /*self*/, SEL) {}   // (used as a way of running a dummy thread)

        static void focusChanged()
        {
            if (appFocusChangeCallback != nullptr)
                (*appFocusChangeCallback)();
        }

        static void getUrl_withReplyEvent (id /*self*/, SEL, NSAppleEventDescriptor* event, NSAppleEventDescriptor*)
        {
            if (auto* app = JUCEApplicationBase::getInstance())
                app->anotherInstanceStarted (quotedIfContainsSpaces ([[event paramDescriptorForKeyword: keyDirectObject] stringValue]));
        }

        static String quotedIfContainsSpaces (NSString* file)
        {
            String s (nsStringToJuce (file));
            if (s.containsChar (' '))
                s = s.quoted ('"');

            return s;
        }

       #if JUCE_PUSH_NOTIFICATIONS
        //==============================================================================
        static void setPushNotificationsDelegate (id self, SEL, NSObject<NSApplicationDelegate, NSUserNotificationCenterDelegate>* delegate)
        {
            object_setInstanceVariable (self, "pushNotificationsDelegate", delegate);
        }

        static NSObject<NSApplicationDelegate, NSUserNotificationCenterDelegate>* getPushNotificationsDelegate (id self)
        {
            return getIvar<NSObject<NSApplicationDelegate, NSUserNotificationCenterDelegate>*> (self, "pushNotificationsDelegate");
        }

        static void registeredForRemoteNotifications (id self, SEL, NSApplication* application, NSData* deviceToken)
        {
            auto* delegate = getPushNotificationsDelegate (self);

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

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

                [invocation invoke];
            }
        }

        static void failedToRegisterForRemoteNotifications (id self, SEL, NSApplication* application, NSError* error)
        {
            auto* delegate = getPushNotificationsDelegate (self);

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

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

                [invocation invoke];
            }
        }

        static void didReceiveRemoteNotification (id self, SEL, NSApplication* application, NSDictionary* userInfo)
        {
            auto* delegate = getPushNotificationsDelegate (self);

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

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

                [invocation invoke];
            }
        }
       #endif
    };
};

//==============================================================================
void MessageManager::runDispatchLoop()
{
    if (quitMessagePosted.get() == 0) // check that the quit message wasn't already posted..
    {
        JUCE_AUTORELEASEPOOL
        {
            // must only be called by the message thread!
            jassert (isThisTheMessageThread());

          #if JUCE_PROJUCER_LIVE_BUILD
            runDispatchLoopUntil (std::numeric_limits<int>::max());
          #else
           #if JUCE_CATCH_UNHANDLED_EXCEPTIONS
            @try
            {
                [NSApp run];
            }
            @catch (NSException* e)
            {
                // An AppKit exception will kill the app, but at least this provides a chance to log it.,
                std::runtime_error ex (std::string ("NSException: ") + [[e name] UTF8String] + ", Reason:" + [[e reason] UTF8String]);
                JUCEApplicationBase::sendUnhandledException (&ex, __FILE__, __LINE__);
            }
            @finally
            {
            }
           #else
            [NSApp run];
           #endif
          #endif
        }
    }
}

static void shutdownNSApp()
{
    [NSApp stop: nil];
    [NSEvent startPeriodicEventsAfterDelay: 0  withPeriod: 0.1];
}

void MessageManager::stopDispatchLoop()
{
   #if JUCE_PROJUCER_LIVE_BUILD
    quitMessagePosted = true;
   #else

    if (isThisTheMessageThread())
    {
        quitMessagePosted = true;
        shutdownNSApp();
    }
    else
    {
        struct QuitCallback  : public CallbackMessage
        {
            QuitCallback() {}
            void messageCallback() override    { MessageManager::getInstance()->stopDispatchLoop(); }
        };

        (new QuitCallback())->post();
    }
   #endif
}

#if JUCE_MODAL_LOOPS_PERMITTED
bool MessageManager::runDispatchLoopUntil (int millisecondsToRunFor)
{
    jassert (millisecondsToRunFor >= 0);
    jassert (isThisTheMessageThread()); // must only be called by the message thread

    uint32 endTime = Time::getMillisecondCounter() + (uint32) millisecondsToRunFor;

    while (quitMessagePosted.get() == 0)
    {
        JUCE_AUTORELEASEPOOL
        {
            CFRunLoopRunInMode (kCFRunLoopDefaultMode, 0.001, true);

            NSEvent* e = [NSApp nextEventMatchingMask: NSEventMaskAny
                                            untilDate: [NSDate dateWithTimeIntervalSinceNow: 0.001]
                                               inMode: NSDefaultRunLoopMode
                                              dequeue: YES];

            if (e != nil && (isEventBlockedByModalComps == nullptr || ! (*isEventBlockedByModalComps) (e)))
                [NSApp sendEvent: e];

            if (Time::getMillisecondCounter() >= endTime)
                break;
        }
    }

    return quitMessagePosted.get() == 0;
}
#endif

//==============================================================================
void initialiseNSApplication();
void initialiseNSApplication()
{
    JUCE_AUTORELEASEPOOL
    {
        [NSApplication sharedApplication];
    }
}

static AppDelegate* appDelegate = nullptr;

void MessageManager::doPlatformSpecificInitialisation()
{
    if (appDelegate == nil)
        appDelegate = new AppDelegate();
}

void MessageManager::doPlatformSpecificShutdown()
{
    delete appDelegate;
    appDelegate = nullptr;
}

bool MessageManager::postMessageToSystemQueue (MessageBase* message)
{
    jassert (appDelegate != nil);
    appDelegate->messageQueue.post (message);
    return true;
}

void MessageManager::broadcastMessage (const String& message)
{
    NSDictionary* info = [NSDictionary dictionaryWithObject: juceStringToNS (message)
                                                     forKey: nsStringLiteral ("message")];

    [[NSDistributedNotificationCenter defaultCenter] postNotificationName: AppDelegate::getBroadcastEventName()
                                                                   object: nil
                                                                 userInfo: info];
}

// Special function used by some plugin classes to re-post carbon events
void __attribute__ ((visibility("default"))) repostCurrentNSEvent();
void __attribute__ ((visibility("default"))) repostCurrentNSEvent()
{
    struct EventReposter  : public CallbackMessage
    {
        EventReposter() : e ([[NSApp currentEvent] retain])  {}
        ~EventReposter()  { [e release]; }

        void messageCallback() override
        {
            [NSApp postEvent: e atStart: YES];
        }

        NSEvent* e;
    };

    (new EventReposter())->post();
}


//==============================================================================
#if JUCE_MAC
struct MountedVolumeListChangeDetector::Pimpl
{
    Pimpl (MountedVolumeListChangeDetector& d)  : owner (d)
    {
        static ObserverClass cls;
        delegate = [cls.createInstance() init];
        ObserverClass::setOwner (delegate, this);

        NSNotificationCenter* nc = [[NSWorkspace sharedWorkspace] notificationCenter];

        [nc addObserver: delegate selector: @selector (changed:) name: NSWorkspaceDidMountNotification   object: nil];
        [nc addObserver: delegate selector: @selector (changed:) name: NSWorkspaceDidUnmountNotification object: nil];
    }

    ~Pimpl()
    {
        [[[NSWorkspace sharedWorkspace] notificationCenter] removeObserver: delegate];
        [delegate release];
    }

private:
    MountedVolumeListChangeDetector& owner;
    id delegate;

    struct ObserverClass   : public ObjCClass<NSObject>
    {
        ObserverClass()  : ObjCClass<NSObject> ("JUCEDriveObserver_")
        {
            addIvar<Pimpl*> ("owner");
            addMethod (@selector (changed:), changed, "v@:@");
            addProtocol (@protocol (NSTextInput));
            registerClass();
        }

        static Pimpl* getOwner (id self)                { return getIvar<Pimpl*> (self, "owner"); }
        static void setOwner (id self, Pimpl* owner)    { object_setInstanceVariable (self, "owner", owner); }

        static void changed (id self, SEL, NSNotification*)
        {
            getOwner (self)->owner.mountedVolumeListChanged();
        }
    };
};

MountedVolumeListChangeDetector::MountedVolumeListChangeDetector()  { pimpl.reset (new Pimpl (*this)); }
MountedVolumeListChangeDetector::~MountedVolumeListChangeDetector() {}
#endif

} // namespace juce
