// Copyright (c) 2010 Spotify AB
#import "SPMediaKeyTap.h"
#import "SPInvocationGrabbing/NSObject+SPInvocationGrabbing.h" // https://gist.github.com/511181, in submodule

@interface SPMediaKeyTap ()
-(BOOL)shouldInterceptMediaKeyEvents;
-(void)setShouldInterceptMediaKeyEvents:(BOOL)newSetting;
-(void)startWatchingAppSwitching;
-(void)stopWatchingAppSwitching;
-(void)eventTapThread;
@end
static SPMediaKeyTap *singleton = nil;

static pascal OSStatus appSwitched (EventHandlerCallRef nextHandler, EventRef evt, void* userData);
static pascal OSStatus appTerminated (EventHandlerCallRef nextHandler, EventRef evt, void* userData);
static CGEventRef tapEventCallback(CGEventTapProxy proxy, CGEventType type, CGEventRef event, void *refcon);

// Inspired by http://gist.github.com/546311

@implementation SPMediaKeyTap

#pragma mark -
#pragma mark Setup and teardown
-(id)initWithDelegate:(id)delegate;
{
_delegate = delegate;
[self startWatchingAppSwitching];
singleton = self;
_mediaKeyAppList = [NSMutableArray new];
return self;
}
-(void)dealloc;
{
[self stopWatchingMediaKeys];
[self stopWatchingAppSwitching];
[_mediaKeyAppList release];
[super dealloc];
}

-(void)startWatchingAppSwitching;
{
// Listen to "app switched" event, so that we don't intercept media keys if we
// weren't the last "media key listening" app to be active
EventTypeSpec eventType = { kEventClassApplication, kEventAppFrontSwitched };
OSStatus err = InstallApplicationEventHandler(NewEventHandlerUPP(appSwitched), 1, &eventType, self, &_app_switching_ref);
assert(err == noErr);

eventType.eventKind = kEventAppTerminated;
err = InstallApplicationEventHandler(NewEventHandlerUPP(appTerminated), 1, &eventType, self, &_app_terminating_ref);
assert(err == noErr);
}
-(void)stopWatchingAppSwitching;
{
if(!_app_switching_ref) return;
RemoveEventHandler(_app_switching_ref);
_app_switching_ref = NULL;
}

-(void)startWatchingMediaKeys;{
[self setShouldInterceptMediaKeyEvents:YES];

// Add an event tap to intercept the system defined media key events
_eventPort = CGEventTapCreate(kCGSessionEventTap,
kCGHeadInsertEventTap,
kCGEventTapOptionDefault,
CGEventMaskBit(NX_SYSDEFINED),
tapEventCallback,
self);
assert(_eventPort != NULL);

_eventPortSource = CFMachPortCreateRunLoopSource(kCFAllocatorSystemDefault, _eventPort, 0);
assert(_eventPortSource != NULL);

// Let's do this in a separate thread so that a slow app doesn't lag the event tap
[NSThread detachNewThreadSelector:@selector(eventTapThread) toTarget:self withObject:nil];
}
-(void)stopWatchingMediaKeys;
{
// TODO<nevyn>: Shut down thread, remove event tap port and source
}

#pragma mark -
#pragma mark Accessors

+(BOOL)usesGlobalMediaKeyTap
{
#ifdef _DEBUG
// breaking in gdb with a key tap inserted sometimes locks up all mouse and keyboard input forever, forcing reboot
return NO;
#else
// XXX(nevyn): MediaKey event tap doesn't work on 10.4, feel free to figure out why if you have the energy.
return floor(NSAppKitVersionNumber) >= 949/*NSAppKitVersionNumber10_5*/;
#endif
}

+ (NSArray*)defaultMediaKeyUserBundleIdentifiers;
{
return [NSArray arrayWithObjects:
[[NSBundle mainBundle] bundleIdentifier], // your app
@"com.spotify.client",
@"com.apple.iTunes",
@"com.apple.QuickTimePlayerX",
@"com.apple.quicktimeplayer",
@"com.apple.iWork.Keynote",
@"com.apple.iPhoto",
@"org.videolan.vlc",
@"com.apple.Aperture",
@"com.plexsquared.Plex",
@"com.soundcloud.desktop",
@"com.macromedia.fireworks", // the tap messes up their mouse input
nil
];
}

-(BOOL)shouldInterceptMediaKeyEvents;
{
BOOL shouldIntercept = NO;
@synchronized(self) {
shouldIntercept = _shouldInterceptMediaKeyEvents;
}
return shouldIntercept;
}

-(void)pauseTapOnTapThread:(BOOL)yeahno;
{
CGEventTapEnable(self->_eventPort, yeahno);
}
-(void)setShouldInterceptMediaKeyEvents:(BOOL)newSetting;
{
BOOL oldSetting;
@synchronized(self) {
oldSetting = _shouldInterceptMediaKeyEvents;
_shouldInterceptMediaKeyEvents = newSetting;
}
if(_tapThreadRL && oldSetting != newSetting) {
id grab = [self grab];
[grab pauseTapOnTapThread:newSetting];
NSTimer *timer = [NSTimer timerWithTimeInterval:0 invocation:[grab invocation] repeats:NO];
CFRunLoopAddTimer(_tapThreadRL, (CFRunLoopTimerRef)timer, kCFRunLoopCommonModes);
}
}

#pragma mark
#pragma mark -
#pragma mark Event tap callbacks

// Note: method called on background thread

static CGEventRef tapEventCallback2(CGEventTapProxy proxy, CGEventType type, CGEventRef event, void *refcon)
{
SPMediaKeyTap *self = refcon;

if(type == kCGEventTapDisabledByTimeout) {
NSLog(@"Media key event tap was disabled by timeout");
CGEventTapEnable(self->_eventPort, TRUE);
return event;
} else if(type == kCGEventTapDisabledByUserInput) {
// Was disabled manually by -[pauseTapOnTapThread]
return event;
}
NSEvent *nsEvent = nil;
@try {
nsEvent = [NSEvent eventWithCGEvent:event];
}
@catch (NSException * e) {
NSLog(@"Strange CGEventType: %d: %@", type, e);
assert(0);
return event;
}

if (type != NX_SYSDEFINED || [nsEvent subtype] != SPSystemDefinedEventMediaKeys)
return event;

int keyCode = (([nsEvent data1] & 0xFFFF0000) >> 16);
if (keyCode != NX_KEYTYPE_PLAY && keyCode != NX_KEYTYPE_FAST && keyCode != NX_KEYTYPE_REWIND)
return event;

if (![self shouldInterceptMediaKeyEvents])
return event;

[nsEvent retain]; // matched in handleAndReleaseMediaKeyEvent:
[self performSelectorOnMainThread:@selector(handleAndReleaseMediaKeyEvent:) withObject:nsEvent waitUntilDone:NO];

return NULL;
}

static CGEventRef tapEventCallback(CGEventTapProxy proxy, CGEventType type, CGEventRef event, void *refcon)
{
NSAutoreleasePool *pool = [NSAutoreleasePool new];
CGEventRef ret = tapEventCallback2(proxy, type, event, refcon);
[pool drain];
return ret;
}

// event will have been retained in the other thread
-(void)handleAndReleaseMediaKeyEvent:(NSEvent *)event {
[event autorelease];

[_delegate mediaKeyTap:self receivedMediaKeyEvent:event];
}

-(void)eventTapThread;
{
_tapThreadRL = CFRunLoopGetCurrent();
CFRunLoopAddSource(_tapThreadRL, _eventPortSource, kCFRunLoopCommonModes);
CFRunLoopRun();
}

#pragma mark Task switching callbacks

NSString *kMediaKeyUsingBundleIdentifiersDefaultsKey = @"SPApplicationsNeedingMediaKeys";

-(void)mediaKeyAppListChanged;
{
if([_mediaKeyAppList count] == 0) return;

/*NSLog(@"--");
int i = 0;
for (NSValue *psnv in _mediaKeyAppList) {
ProcessSerialNumber psn; [psnv getValue:&psn];
NSDictionary *processInfo = [(id)ProcessInformationCopyDictionary(
&psn,
kProcessDictionaryIncludeAllInformationMask
) autorelease];
NSString *bundleIdentifier = [processInfo objectForKey:(id)kCFBundleIdentifierKey];
NSLog(@"%d: %@", i++, bundleIdentifier);
}*/

ProcessSerialNumber mySerial, topSerial;
GetCurrentProcess(&mySerial);
[[_mediaKeyAppList objectAtIndex:0] getValue:&topSerial];

Boolean same;
OSErr err = SameProcess(&mySerial, &topSerial, &same);
[self setShouldInterceptMediaKeyEvents:(err == noErr && same)];

}
-(void)appIsNowFrontmost:(ProcessSerialNumber)psn;
{
NSValue *psnv = [NSValue valueWithBytes:&psn objCType:@encode(ProcessSerialNumber)];

NSDictionary *processInfo = [(id)ProcessInformationCopyDictionary(
&psn,
kProcessDictionaryIncludeAllInformationMask
) autorelease];
NSString *bundleIdentifier = [processInfo objectForKey:(id)kCFBundleIdentifierKey];

NSArray *whitelistIdentifiers = [[NSUserDefaults standardUserDefaults] arrayForKey:kMediaKeyUsingBundleIdentifiersDefaultsKey];
if(![whitelistIdentifiers containsObject:bundleIdentifier]) return;

[_mediaKeyAppList removeObject:psnv];
[_mediaKeyAppList insertObject:psnv atIndex:0];
[self mediaKeyAppListChanged];
}
-(void)appTerminated:(ProcessSerialNumber)psn;
{
NSValue *psnv = [NSValue valueWithBytes:&psn objCType:@encode(ProcessSerialNumber)];
[_mediaKeyAppList removeObject:psnv];
[self mediaKeyAppListChanged];
}

static pascal OSStatus appSwitched (EventHandlerCallRef nextHandler, EventRef evt, void* userData)
{
SPMediaKeyTap *self = (id)userData;

ProcessSerialNumber newSerial;
GetFrontProcess(&newSerial);

[self appIsNowFrontmost:newSerial];

return CallNextEventHandler(nextHandler, evt);
}

static pascal OSStatus appTerminated (EventHandlerCallRef nextHandler, EventRef evt, void* userData)
{
SPMediaKeyTap *self = (id)userData;

ProcessSerialNumber deadPSN;

GetEventParameter(
evt,
kEventParamProcessID,
typeProcessSerialNumber,
NULL,
sizeof(deadPSN),
NULL,
&deadPSN
);

[self appTerminated:deadPSN];
return CallNextEventHandler(nextHandler, evt);
}

@end