//
//  SCVideoPlayer.m
//  SCAudioVideoRecorder
//
//  Created by Simon CORSIN on 8/30/13.
//  Copyright (c) 2013 rFlex. All rights reserved.
//

#import "SCPlayer.h"
#import "SCWeakSelectorTarget.h"

////////////////////////////////////////////////////////////
// PRIVATE DEFINITION
/////////////////////

@interface SCPlayer() <AVPlayerItemOutputPullDelegate, AVPlayerItemOutputPushDelegate> {
    CADisplayLink *_displayLink;
    AVPlayerItemVideoOutput *_videoOutput;
    AVPlayerItem *_oldItem;
    Float64 _itemsLoopLength;
    id _timeObserver;
    BOOL _rendererWasSetup;
    CGAffineTransform _rendererTransform;
}

@end


////////////////////////////////////////////////////////////
// IMPLEMENTATION
/////////////////////

@implementation SCPlayer

static char* StatusChanged = "StatusContext";
static char* ItemChanged = "CurrentItemContext";

- (id)init {
    self = [super init];
    
    if (self) {
        _shouldSuppressPlayerRendering = YES;
        [self addObserver:self forKeyPath:@"currentItem" options:NSKeyValueObservingOptionNew context:ItemChanged];
    }
    
    return self;
}

- (void)dealloc {
    [self endSendingPlayMessages];
    
    [self unsetupDisplayLink];
    [self unsetupVideoOutputToItem:self.currentItem];
    [self removeObserver:self forKeyPath:@"currentItem"];
    [self removeOldObservers];
    [self endSendingPlayMessages];
}

- (void)beginSendingPlayMessages {
    if (!self.isSendingPlayMessages) {
        __weak SCPlayer *myWeakSelf = self;
        
        _timeObserver = [self addPeriodicTimeObserverForInterval:CMTimeMake(1, 24) queue:dispatch_get_main_queue() usingBlock:^(CMTime time) {
            SCPlayer *mySelf = myWeakSelf;
            id<SCPlayerDelegate> delegate = mySelf.delegate;
            if ([delegate respondsToSelector:@selector(player:didPlay:loopsCount:)]) {
                int itemsLoopLength = 1;
                
                if (mySelf != nil) {
                    itemsLoopLength = mySelf->_itemsLoopLength;
                }
                Float64 ratio = 1.0 / itemsLoopLength;
                CMTime currentTime = CMTimeMultiplyByFloat64(time, ratio);
                
                NSInteger loopCount = CMTimeGetSeconds(time) / (CMTimeGetSeconds(mySelf.currentItem.duration) / (Float64)itemsLoopLength);
                
                [delegate player:mySelf didPlay:currentTime loopsCount:loopCount];
            }
        }];
    }
}

- (void)endSendingPlayMessages {
    if (_timeObserver != nil) {
        [self removeTimeObserver:_timeObserver];
        _timeObserver = nil;
    }
}

- (void)playReachedEnd:(NSNotification*)notification {
    if (notification.object == self.currentItem) {
        if (_loopEnabled) {
            [self seekToTime:kCMTimeZero];
            if ([self isPlaying]) {
                [self play];
            }
        }
        id<SCPlayerDelegate> delegate = self.delegate;
        if ([delegate respondsToSelector:@selector(player:didReachEndForItem:)]) {
            [delegate player:self didReachEndForItem:self.currentItem];
        }
    }
}

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
    if (context == ItemChanged) {
        [self initObserver];
    } else if (context == StatusChanged) {
        void (^block)() = ^{
            id<SCPlayerDelegate> delegate = self.delegate;
            
            if ([delegate respondsToSelector:@selector(player:itemReadyToPlay:)]) {
                [delegate player:self itemReadyToPlay:self.currentItem];
            }
        };
        if ([NSThread isMainThread]) {
            block();
        } else {
            dispatch_async(dispatch_get_main_queue(), block);
        }
    }
}

- (void)removeOldObservers {
    if (_oldItem != nil) {
        [[NSNotificationCenter defaultCenter] removeObserver:self name:AVPlayerItemDidPlayToEndTimeNotification object:_oldItem];
        [_oldItem removeObserver:self forKeyPath:@"status"];
        
        [self unsetupVideoOutputToItem:_oldItem];
        
        _oldItem = nil;
    }
}

- (void)outputMediaDataWillChange:(AVPlayerItemOutput *)sender {
    _displayLink.paused = NO;
}

- (void)renderVideo:(CFTimeInterval)hostFrameTime {
    CMTime outputItemTime = [_videoOutput itemTimeForHostTime:hostFrameTime];
    
    if ([_videoOutput hasNewPixelBufferForItemTime:outputItemTime]) {
        
        SCImageView *renderer = self.SCImageView;

        if (renderer != nil) {
            if (!_rendererWasSetup) {
                renderer.preferredCIImageTransform = _rendererTransform;

                id<SCPlayerDelegate> delegate = self.delegate;
                if ([delegate respondsToSelector:@selector(player:didSetupSCImageView:)]) {
                    [delegate player:self didSetupSCImageView:renderer];
                }
                
                _rendererWasSetup = YES;
            }
            
            CMTime time;
            CVPixelBufferRef pixelBuffer = [_videoOutput copyPixelBufferForItemTime:outputItemTime itemTimeForDisplay:&time];
            
            if (pixelBuffer != nil) {
                CIImage *inputImage = [CIImage imageWithCVPixelBuffer:pixelBuffer];
                
                renderer.CIImageTime = CMTimeGetSeconds(outputItemTime);
                renderer.CIImage = inputImage;

                CVPixelBufferRelease(pixelBuffer);
            }
        }
    }
}

- (void)replaceCurrentItemWithPlayerItem:(AVPlayerItem *)item {
    _itemsLoopLength = 1;
    
    [super replaceCurrentItemWithPlayerItem:item];
    [self suspendDisplay];
}

- (void)willRenderFrame:(CADisplayLink *)sender {
    CFTimeInterval nextFrameTime = sender.timestamp + sender.duration;
    
    [self renderVideo:nextFrameTime];
}

- (void)suspendDisplay {
    _displayLink.paused = YES;
    [_videoOutput requestNotificationOfMediaDataChangeWithAdvanceInterval:0.1];
}

- (void)setupDisplayLink {
    if (_displayLink == nil) {
        SCWeakSelectorTarget *target = [[SCWeakSelectorTarget alloc] initWithTarget:self targetSelector:@selector(willRenderFrame:)];
        
        _displayLink = [CADisplayLink displayLinkWithTarget:target selector:target.handleSelector];
        _displayLink.frameInterval = 1;
        
        [self setupVideoOutputToItem:self.currentItem];
        
        [_displayLink addToRunLoop:[NSRunLoop mainRunLoop] forMode:NSRunLoopCommonModes];
        
        [self suspendDisplay];
    }
    _rendererWasSetup = NO;
}

- (void)unsetupDisplayLink {
    if (_displayLink != nil) {
        [_displayLink invalidate];
        _displayLink = nil;
        
        [self unsetupVideoOutputToItem:self.currentItem];
        
        _videoOutput = nil;
    }
}

- (void)setupVideoOutputToItem:(AVPlayerItem *)item {
    if (_displayLink != nil && item != nil && _videoOutput == nil) {
        NSDictionary *pixBuffAttributes = @{(id)kCVPixelBufferPixelFormatTypeKey: @(kCVPixelFormatType_420YpCbCr8BiPlanarFullRange)};
        _videoOutput = [[AVPlayerItemVideoOutput alloc] initWithPixelBufferAttributes:pixBuffAttributes];
        [_videoOutput setDelegate:self queue:dispatch_get_main_queue()];
        _videoOutput.suppressesPlayerRendering = self.shouldSuppressPlayerRendering;
        
        [item addOutput:_videoOutput];
        
        _displayLink.paused = NO;
        
        CGAffineTransform transform = CGAffineTransformIdentity;
        SCImageView *renderer = self.SCImageView;
        
        NSArray *videoTracks = [item.asset tracksWithMediaType:AVMediaTypeVideo];

        if (videoTracks.count > 0) {
            AVAssetTrack *track = videoTracks.firstObject;

            transform = track.preferredTransform;

            // Return the video if it is upside down
            if (transform.b == 1 && transform.c == -1) {
                transform = CGAffineTransformRotate(transform, M_PI);
            }

            if (self.autoRotate) {
                CGSize videoSize = track.naturalSize;
                CGSize viewSize =  [renderer frame].size;
                CGRect outRect = CGRectApplyAffineTransform(CGRectMake(0, 0, videoSize.width, videoSize.height), transform);

                BOOL viewIsWide = viewSize.width / viewSize.height > 1;
                BOOL videoIsWide = outRect.size.width / outRect.size.height > 1;
                    
                if (viewIsWide != videoIsWide) {
                    transform = CGAffineTransformRotate(transform, M_PI_2);
                }
            }
        }
        _rendererTransform = transform;
        _rendererWasSetup = NO;
    }
}

- (void)unsetupVideoOutputToItem:(AVPlayerItem *)item {
    if (_videoOutput != nil && item != nil) {
        if ([item.outputs containsObject:_videoOutput]) {
            [item removeOutput:_videoOutput];
        }
        _videoOutput = nil;
    }
}

- (void)initObserver {
    [self removeOldObservers];
    
    if (self.currentItem != nil) {
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(playReachedEnd:) name:AVPlayerItemDidPlayToEndTimeNotification object:self.currentItem];
        _oldItem = self.currentItem;
        [self.currentItem addObserver:self forKeyPath:@"status" options:NSKeyValueObservingOptionNew context:StatusChanged];
        
        [self setupVideoOutputToItem:self.currentItem];
    }
    
    
    id<SCPlayerDelegate> delegate = self.delegate;
    if ([delegate respondsToSelector:@selector(player:didChangeItem:)]) {
        [delegate player:self didChangeItem:self.currentItem];
    }
}

- (CMTime)playableDuration {
    AVPlayerItem * item = self.currentItem;
    CMTime playableDuration = kCMTimeZero;
    
    if (item.status != AVPlayerItemStatusFailed) {
        for (NSValue *value in item.loadedTimeRanges) {
            CMTimeRange timeRange = [value CMTimeRangeValue];
            
            playableDuration = CMTimeAdd(playableDuration, timeRange.duration);
        }
    }
    
    return playableDuration;
}

- (void)setShouldSuppressPlayerRendering:(BOOL)shouldSuppressPlayerRendering
{
    _shouldSuppressPlayerRendering = shouldSuppressPlayerRendering;
    
    _videoOutput.suppressesPlayerRendering = shouldSuppressPlayerRendering;
}

- (void)setItemByStringPath:(NSString *)stringPath {
    [self setItemByUrl:[NSURL URLWithString:stringPath]];
}

- (void)setItemByUrl:(NSURL *)url {
    [self setItemByAsset:[AVURLAsset URLAssetWithURL:url options:nil]];
}

- (void)setItemByAsset:(AVAsset *)asset {
    [self setItem:[AVPlayerItem playerItemWithAsset:asset]];
}

- (void)setItem:(AVPlayerItem *)item {
    [self replaceCurrentItemWithPlayerItem:item];
}

- (void)setSmoothLoopItemByStringPath:(NSString *)stringPath smoothLoopCount:(NSUInteger)loopCount {
    [self setSmoothLoopItemByUrl:[NSURL URLWithString:stringPath] smoothLoopCount:loopCount];
}

- (void)setSmoothLoopItemByUrl:(NSURL *)url smoothLoopCount:(NSUInteger)loopCount {
    [self setSmoothLoopItemByAsset:[AVURLAsset URLAssetWithURL:url options:nil] smoothLoopCount:loopCount];
}

- (void)setSmoothLoopItemByAsset:(AVAsset *)asset smoothLoopCount:(NSUInteger)loopCount {
    AVMutableComposition * composition = [AVMutableComposition composition];
    
    CMTimeRange timeRange = CMTimeRangeMake(kCMTimeZero, asset.duration);
    
    for (NSUInteger i = 0; i < loopCount; i++) {
        [composition insertTimeRange:timeRange ofAsset:asset atTime:composition.duration error:nil];
    }
    
    [self setItemByAsset:composition];
    
    _itemsLoopLength = loopCount;
}

- (BOOL)isPlaying {
    return self.rate > 0;
}

- (void)setLoopEnabled:(BOOL)loopEnabled {
    _loopEnabled = loopEnabled;
    
    self.actionAtItemEnd = loopEnabled ? AVPlayerActionAtItemEndNone : AVPlayerActionAtItemEndPause;
}

- (void)setSCImageView:(SCImageView *)SCImageView {
    _SCImageView = SCImageView;

    if (SCImageView == nil) {
        [self unsetupDisplayLink];
    } else {
        [self setupDisplayLink];
    }
}

- (CMTime)itemDuration {
    Float64 ratio = 1.0 / _itemsLoopLength;
    
    return CMTimeMultiply(self.currentItem.duration, ratio);
}

- (BOOL)isSendingPlayMessages {
    return _timeObserver != nil;
}

- (void)setAutoRotate:(BOOL)autoRotate {
    _autoRotate = autoRotate;
}

+ (SCPlayer*)player {
    return [SCPlayer new];
}

@end