/*

     File: GSDocument.m

 Abstract: Main document

  Version: 1.3

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 */

#import "GSDocument.h"

#import <AVFoundation/AVFoundation.h>

#import "GSPlayerView.h"

static void *GSPlayerItemStatusContext = &GSPlayerItemStatusContext;

NSString* const GSMouseDownNotification = @"GSMouseDownNotification";

NSString* const GSMouseUpNotification = @"GSMouseUpNotification";

@interface GSTimeSliderCell : NSSliderCell

@end

@interface GSTimeSlider : NSSlider

@end

// Custom NSSlider and NSSliderCell subclasses to track scrubbing

@implementation GSTimeSliderCell

- (void)stopTracking:(NSPoint)lastPoint at:(NSPoint)stopPoint inView:(NSView *)controlView mouseIsUp:(BOOL)flag

{

    if (flag) {

        [[NSNotificationCenter defaultCenter] postNotificationName:GSMouseUpNotification object:self];

    }

    [super stopTracking:lastPoint at:stopPoint inView:controlView mouseIsUp:flag];

}

@end

@implementation GSTimeSlider

- (void)mouseDown:(NSEvent *)theEvent

{

    [[NSNotificationCenter defaultCenter] postNotificationName:GSMouseDownNotification object:self];

    [super mouseDown:theEvent];

}

@end

@interface GSDocument ()

@property (nonatomic, assign) IBOutlet GSPlayerView *playerView;

@property (nonatomic, assign) IBOutlet NSButton *playPauseButton;

@property (nonatomic, assign) IBOutlet GSTimeSlider *currentTimeSlider;

@property (nonatomic, assign) IBOutlet NSColorWell *chromaKeyColorWell;

@property double currentTime;

@property (readonly) double duration;

- (IBAction)togglePlayPause:(id)sender;

@end

@implementation GSDocument

{

    AVPlayer *_player;

    AVPlayerItem *_currentPlayerItem;

    float _playRateToRestore;

    id _observer;

}

#pragma mark -

- (id)init

{

    self = [super init];

    if (self)

    {

        _player = [[AVPlayer alloc] init];

        [self addTimeObserverToPlayer];

    }

    return self;

}

- (void)dealloc

{

    [[NSNotificationCenter defaultCenter] removeObserver:self name:AVPlayerItemDidPlayToEndTimeNotification object:nil];

    [[NSNotificationCenter defaultCenter] removeObserver:self name:GSMouseDownNotification object:nil];

    [[NSNotificationCenter defaultCenter] removeObserver:self name:GSMouseUpNotification object:nil];

    [_player removeTimeObserver:_observer];

    _player = nil;

    _currentPlayerItem = nil;

}

#pragma mark -

- (NSString *)windowNibName

{

    return @"GSDocument";

}

- (void)windowControllerDidLoadNib:(NSWindowController *)windowController

{

    [super windowControllerDidLoadNib:windowController];

    _currentPlayerItem = [_player currentItem];

    self.playerView.playerItem = _currentPlayerItem;

    [self.currentTimeSlider setDoubleValue:0.0];

    [self addObserver:self forKeyPath:@"self.player.currentItem.status" options:NSKeyValueObservingOptionNew context:GSPlayerItemStatusContext];

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(playerItemDidPlayToEndTime:) name:AVPlayerItemDidPlayToEndTimeNotification object:_currentPlayerItem];

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(beginScrubbing:) name:GSMouseDownNotification object:self.currentTimeSlider];

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(endScrubbing:) name:GSMouseUpNotification object:self.currentTimeSlider.cell];

}

- (void)close

{

    self.playerView = nil;

    self.playPauseButton = nil;

    self.currentTimeSlider = nil;

    self.chromaKeyColorWell = nil;

    [self removeObserver:self forKeyPath:@"self.player.currentItem.status"];

    [super close];

}

#pragma mark -

- (BOOL)readFromURL:(NSURL *)url ofType:(NSString *)typeName error:(NSError *__autoreleasing *)outError

{

    AVPlayerItem *playerItem = [AVPlayerItem playerItemWithURL:url];

    if (playerItem)

    {

        [_player replaceCurrentItemWithPlayerItem:playerItem];

        return YES;

    }

    return NO;

}

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context

{

    if (context == GSPlayerItemStatusContext) {

        AVPlayerStatus status = [change[NSKeyValueChangeNewKey] integerValue];

        if (status == AVPlayerItemStatusReadyToPlay) {

            self.playerView.videoLayer.controlTimebase = _player.currentItem.timebase;

        }

    }

    else {

        [super observeValueForKeyPath:keyPath ofObject:object change:change context:context];

    }

}

#pragma mark -

- (IBAction)togglePlayPause:(id)sender

{

    if (CMTIME_COMPARE_INLINE([[_player currentItem] currentTime], >=, [[_player currentItem] duration]))

        [[_player currentItem] seekToTime:kCMTimeZero];

    [_player setRate:([_player rate] == 0.0f ? 1.0f : 0.0f)];

    [(NSButton *)sender setTitle:([_player rate] == 0.0f ? @"Play" : @"Pause")];

}

+ (NSSet *)keyPathsForValuesAffectingDuration

{

    return [NSSet setWithObjects:@"player.currentItem", @"player.currentItem.status", nil];

}

- (double)duration

{

    AVPlayerItem *playerItem = [_player currentItem];

    if ([playerItem status] == AVPlayerItemStatusReadyToPlay)

        return CMTimeGetSeconds([[playerItem asset] duration]);

    else

        return 0.f;

}

- (double)currentTime

{

    return CMTimeGetSeconds([_player currentTime]);

}

- (void)setCurrentTime:(double)time

{

    // Flush the previous enqueued sample buffers for display while scrubbing

    [self.playerView.videoLayer flush];

    [_player seekToTime:CMTimeMakeWithSeconds(time, 1)];

}

#pragma mark -

- (void)playerItemDidPlayToEndTime:(NSNotification *)notification

{

    [(NSButton *)self.playPauseButton setTitle:([_player rate] == 0.0f ? @"Play" : @"Pause")];

}

- (void)addTimeObserverToPlayer

{

    if (_observer)

        return;

    // __weak is used to ensure that a retain cycle between the document, player and notification block is not formed.

    __weak GSDocument* weakSelf = self;

    _observer = [_player addPeriodicTimeObserverForInterval:CMTimeMakeWithSeconds(1, 10) queue:dispatch_get_main_queue() usingBlock:

                          ^(CMTime time) {

                              [weakSelf syncScrubber];

                          }];

}

- (void)removeTimeObserverFromPlayer

{

    if (_observer)

    {

        [_player removeTimeObserver:_observer];

        _observer = nil;

    }

}

#pragma mark - Scrubbing Utilities

- (void)beginScrubbing:(NSNotification*)notification

{

    _playRateToRestore = [_player rate];

    [self removeTimeObserverFromPlayer];

    [_player setRate:0.0];

}

- (void)endScrubbing:(NSNotification*)notification

{

    [_player setRate:_playRateToRestore];

    [self addTimeObserverToPlayer];

}

- (void)syncScrubber

{

    double time = CMTimeGetSeconds([_player currentTime]);

    [self.currentTimeSlider setDoubleValue:time];

}

@end