/*

     File: StopNGoDocument.m

 Abstract: Document that captures stills to a QuickTime movie

  Version: 1.0

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 */

#import "StopNGoDocument.h"

#define DEFAULT_FRAMES_PER_SECOND   5.0

@implementation StopNGoDocument

@synthesize outputURL;

- (BOOL)setupAVCapture

{

    NSError *error = nil;

    session = [AVCaptureSession new];

    [session setSessionPreset:AVCaptureSessionPresetPhoto];

    // Select a video device, make an input

    for (AVCaptureDevice *device in [AVCaptureDevice devices]) {

        if ([device hasMediaType:AVMediaTypeVideo] || [device hasMediaType:AVMediaTypeMuxed]) {

            AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:&error];

            if (error) {

                [session release];

                NSLog(@"deviceInputWithDevice failed with error %@", [error localizedDescription]);

                return NO;

            }

            if ([session canAddInput:input])

                [session addInput:input];

            break;

        }

    }

    // Make a still image output

    stillImageOutput = [AVCaptureStillImageOutput new];

    if ([session canAddOutput:stillImageOutput])

        [session addOutput:stillImageOutput];

    // Make a preview layer so we can see the visual output of an AVCaptureSession

    previewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session];

    [previewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill];

    [previewLayer setFrame:[previewView bounds]];

    [[previewLayer connection] setAutomaticallyAdjustsVideoMirroring:NO];

    [[previewLayer connection] setVideoMirrored:YES];

    // add the preview layer to the hierarchy

    CALayer *rootLayer = [previewView layer];

    [rootLayer setBackgroundColor:CGColorGetConstantColor(kCGColorBlack)];

    [rootLayer addSublayer:previewLayer];

    // start the capture session running, note this is an async operation

    // status is provided via notifications such as AVCaptureSessionDidStartRunningNotification/AVCaptureSessionDidStopRunningNotification

    [session startRunning];

    return YES;

}

- (BOOL)setupAssetWriterForURL:(NSURL *)fileURL formatDescription:(CMFormatDescriptionRef)formatDescription

{

    NSError *error = nil;

    // allocate the writer object with our output file URL

    assetWriter = [[AVAssetWriter alloc] initWithURL:fileURL fileType:AVFileTypeQuickTimeMovie error:&error];

    if (error) {

        NSLog(@"AVAssetWriter initWithURL failed with error %@", [error localizedDescription]);

        return NO;

    }

    // initialized a new input for video to receive sample buffers for writing

    // passing nil for outputSettings instructs the input to pass through appended samples, doing no processing before they are written

    videoInput = [[AVAssetWriterInput alloc] initWithMediaType:AVMediaTypeVideo outputSettings:nil]; // passthru

    [videoInput setExpectsMediaDataInRealTime:YES];

    if ([assetWriter canAddInput:videoInput])

        [assetWriter addInput:videoInput];

    // initiates a sample-writing at time 0

    nextPresentationTime = kCMTimeZero;

    [assetWriter startWriting];

    [assetWriter startSessionAtSourceTime:nextPresentationTime];

    return YES;

}

- (IBAction)takePicture:(id)sender

{

    // initiate a still image capture, return immediately

    // the completionHandler is called when a sample buffer has been captured

    AVCaptureConnection *stillImageConnection = [stillImageOutput connectionWithMediaType:AVMediaTypeVideo];

    [stillImageOutput captureStillImageAsynchronouslyFromConnection:stillImageConnection 

                                                  completionHandler:^(CMSampleBufferRef imageDataSampleBuffer, NSError *__strong error) {

        // set up the AVAssetWriter using the format description from the first sample buffer captured

        if (!assetWriter) {

            CMFormatDescriptionRef formatDescription = CMSampleBufferGetFormatDescription(imageDataSampleBuffer);

            if ( NO == [self setupAssetWriterForURL:self.outputURL formatDescription:formatDescription] ) return;

            [self setFileURL:self.outputURL];

            [self setFileType:@"mov"];

        }

        // re-time the sample buffer

        CMSampleTimingInfo timingInfo = kCMTimingInfoInvalid;

        timingInfo.duration = frameDuration;

        timingInfo.presentationTimeStamp = nextPresentationTime;

        CMSampleBufferRef sbufWithNewTiming = NULL;

        OSStatus err = CMSampleBufferCreateCopyWithNewTiming(kCFAllocatorDefault, 

                                                             imageDataSampleBuffer, 

                                                             1, // numSampleTimingEntries

                                                             &timingInfo, 

                                                             &sbufWithNewTiming);

        if (err) {

            NSLog(@"CMSampleBufferCreateCopyWithNewTiming failed with error %d", err);

            return;

        }

        // append the sample buffer if we can and increment presnetation time

        if ( [videoInput isReadyForMoreMediaData] ) {

            if ([videoInput appendSampleBuffer:sbufWithNewTiming]) {

                nextPresentationTime = CMTimeAdd(frameDuration, nextPresentationTime);

            }

            else {

                NSError *error = [assetWriter error];

                NSLog(@"failed to append sbuf: %@", [error localizedDescription]);

            }

        }

        // release the copy of the sample buffer we made

        CFRelease(sbufWithNewTiming);

    }];

}

- (void)teardownAssetWriter

{

    if (assetWriter) {

        [videoInput markAsFinished];

        [assetWriter finishWriting];

        [[NSWorkspace sharedWorkspace] openURL:[assetWriter outputURL]];

        [videoInput release];

        [assetWriter release];

        videoInput = nil;

        assetWriter = nil;

    }

    self.outputURL = nil;

}

- (IBAction)startStop:(id)sender

{

    if (started) {

        // finish

        [self teardownAssetWriter];

        [takePictureButton setEnabled:NO];

        [sender setTitle:@"Start"];

    }

    else {

        NSSavePanel *savePanel = [NSSavePanel savePanel];

        [savePanel setTitle:@"Choose QuickTime movie location..."];

        [savePanel setAllowedFileTypes:[NSArray arrayWithObject:AVFileTypeQuickTimeMovie]];

        NSInteger result = [savePanel runModal];

        if ( result != NSFileHandlingPanelOKButton )

            return;

        self.outputURL = [savePanel URL];

        [[NSFileManager defaultManager] removeItemAtURL:self.outputURL error:nil];

        [takePictureButton setEnabled:YES];

        [sender setTitle:@"Stop"];

    }

    started = !started;

}

- (void)close

{

    [self teardownAssetWriter];

    [session stopRunning];

    [previewLayer removeFromSuperlayer];

    [previewLayer setSession:nil];

    [previewLayer release];

    [stillImageOutput release];

    [session release];

    [super close];

}

- (float)framesPerSecond

{

    return (float)((1.0 / CMTimeGetSeconds(frameDuration)));

}

- (void)setFramesPerSecond:(float)framesPerSecond

{

    frameDuration = CMTimeMakeWithSeconds( 1.0 / framesPerSecond, 90000);

}

- (IBAction)togglePreviewMirrored:(id)sender

{

    [[previewLayer connection] setVideoMirrored:[(NSButton *)sender state]];

}

- (id)init

{

    self = [super init];

    if (self) {

        frameDuration = CMTimeMakeWithSeconds(1. / DEFAULT_FRAMES_PER_SECOND, 90000);

    }

    return self;

}

- (NSString *)windowNibName

{

    return @"StopNGoDocument";

}

- (void)windowControllerDidLoadNib:(NSWindowController *)aController

{

    [super windowControllerDidLoadNib:aController];

    [self setupAVCapture];

}

@end