/*

     File: AVSEAddWatermarkCommand.m

 Abstract: A subclass of AVSECommand which handles CALayer. This tool adds a title layer (CALayer) on top of an existing AVMutableComposition or an AVAsset.

  Version: 1.0

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 */

#import "AVSEAddWatermarkCommand.h"

@implementation AVSEAddWatermarkCommand

@synthesize mutableComposition;

@synthesize mutableVideoComposition;

@synthesize watermarkLayer;

- (void)performWithAsset:(AVAsset*)asset 

{

    watermarkLayer = nil;

    CGSize videoSize;

    // Check if a composition already exists, else create a composition using the input asset

    if(!mutableComposition){

        AVAssetTrack *videoTrack = nil;

        AVAssetTrack *audioTrack = nil;

        // Check if the asset contains video and audio tracks

        if ([[asset tracksWithMediaType:AVMediaTypeVideo] count] != 0) {

            videoTrack = [[asset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];

        }

        if ([[asset tracksWithMediaType:AVMediaTypeAudio] count] != 0) {

            audioTrack = [[asset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0];

        }

        CMTime insertionPoint = kCMTimeZero;

        NSError * error = nil;

        mutableComposition = [AVMutableComposition composition];

        // Insert the video and audio tracks from AVAsset 

        if (videoTrack != nil) {

            AVMutableCompositionTrack *vtrack = [mutableComposition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];

            [vtrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, [asset duration]) ofTrack:videoTrack atTime:insertionPoint error:&error];

        }

        if (audioTrack != nil) {

            AVMutableCompositionTrack *atrack = [mutableComposition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];

            [atrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, [asset duration]) ofTrack:audioTrack atTime:insertionPoint error:&error];

        }

    }

    // Check if the input asset contains only audio

    if ([[mutableComposition tracksWithMediaType:AVMediaTypeVideo] count] != 0) {

        if(!mutableVideoComposition){

            // build a pass through video composition

            mutableVideoComposition = [AVMutableVideoComposition videoComposition];

            mutableVideoComposition.frameDuration = CMTimeMake(1, 30); // 30 fps

            mutableVideoComposition.renderSize = mutableComposition.naturalSize;

            AVMutableVideoCompositionInstruction *passThroughInstruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];

            passThroughInstruction.timeRange = CMTimeRangeMake(kCMTimeZero, [mutableComposition duration]);

            AVAssetTrack *videoTrack = [[mutableComposition tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];

            AVMutableVideoCompositionLayerInstruction *passThroughLayer = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:videoTrack];

            passThroughInstruction.layerInstructions = [NSArray arrayWithObject:passThroughLayer];

            mutableVideoComposition.instructions = [NSArray arrayWithObject:passThroughInstruction];

        }

        videoSize = mutableVideoComposition.renderSize;

        watermarkLayer = [self watermarkLayerForSize:videoSize];

    }

    // Notify AVSEDocument class to reload the player view with the changes

    [[NSNotificationCenter defaultCenter] 

     postNotificationName:AVSEReloadNotification

     object:self];

}

- (CALayer*)watermarkLayerForSize:(CGSize)videoSize

{

    // Create a layer for the title animation

    CALayer *_watermarkLayer = [CALayer layer];

    // Create a layer for the text of the title.

    CATextLayer *titleLayer = [CATextLayer layer];

    titleLayer.string = @"AVSE";

    titleLayer.font = (__bridge void*)[NSFont fontWithName:@"Helvetica" size:videoSize.height/6] ;

    titleLayer.shadowOpacity = 0.5;

    titleLayer.alignmentMode = kCAAlignmentCenter;

    titleLayer.bounds = CGRectMake(0, 0, videoSize.width/2, videoSize.height/2);

    // Add it to the overall layer.

    [_watermarkLayer addSublayer:titleLayer];

    [_watermarkLayer setAutoresizingMask:kCALayerWidthSizable | kCALayerHeightSizable];

    return _watermarkLayer;

}

@end