/**
 * Copyright (c) 2011, The University of Southampton and the individual contributors.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 *   *  Redistributions of source code must retain the above copyright notice,
 *      this list of conditions and the following disclaimer.
 *
 *   *  Redistributions in binary form must reproduce the above copyright notice,
 *      this list of conditions and the following disclaimer in the documentation
 *      and/or other materials provided with the distribution.
 *
 *   *  Neither the name of the University of Southampton nor the names of its
 *      contributors may be used to endorse or promote products derived from this
 *      software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.openimaj.video.processing.effects;

import java.util.LinkedList;

import org.openimaj.image.FImage;
import org.openimaj.image.MBFImage;
import org.openimaj.image.processing.convolution.FGaussianConvolve;
import org.openimaj.image.processing.convolution.FImageConvolveSeparable;
import org.openimaj.image.processing.resize.ResizeProcessor;
import org.openimaj.video.Video;
import org.openimaj.video.processor.VideoProcessor;

/**
 * {@link VideoProcessor} that produces a slit-scan effect based on the time-map
 * in a greyscale image.
 *
 *      @author Sina Samangooei (ss@ecs.soton.ac.uk)
 *      @author David Dupplaw (dpd@ecs.soton.ac.uk)
 */
public class GreyscaleSlitScanProcessor extends VideoProcessor<MBFImage>
{
        /** The list of previous images */
        private final LinkedList<MBFImage> cache = new LinkedList<MBFImage>();

        /** The kernel to blur with */
        private final float[] blurKern = FGaussianConvolve.makeKernel( 0.5f );

        /** The number of images in the cache -> more = slower */
        private int cacheSize = 240;

        /** The timemap image */
        private FImage timemapImage = null;

        /** First time through we'll always fix the timemap */
        private boolean needToFixTimemap = true;

        /**
         *      Default constructor for using the video processor in an ad-hoc manner. Uses a default
         *      cache size of 240 steps.
         *
         *      @param timemap The time map image
         */
        public GreyscaleSlitScanProcessor( final FImage timemap )
        {
                this( timemap, 240 );
        }

        /**
         * Default constructor for using the video processor in an ad-hoc manner.
         *
         * @param timemap The time map image
         * @param cacheSize The number of frames to retain for creating the slitscan
         *            effect
         */
        public GreyscaleSlitScanProcessor( final FImage timemap, final int cacheSize )
        {
                this.cacheSize = cacheSize;
                this.timemapImage = timemap;
        }

        /**
         * Constructor for creating a video processor which is chainable.
         *
         * @param video The video to process
         * @param timemap the time map
         * @param cacheSize The number of frames to retain for creating the slitscan
         *            effect
         */
        public GreyscaleSlitScanProcessor( final Video<MBFImage> video, final FImage timemap, final int cacheSize )
        {
                super( video );
                this.cacheSize = cacheSize;
                this.timemapImage = timemap;
        }

        /**
         * Default constructor for using the video processor in an ad-hoc manner.
         *
         * @param cacheSize
         *            The number of frames to retain for creating the slitscan
         *            effect
         */
        public GreyscaleSlitScanProcessor( final int cacheSize )
        {
                this.cacheSize = cacheSize;
        }

        /**
         * Constructor for creating a video processor which is chainable.
         *
         * @param video The video to process
         * @param cacheSize The number of frames to retain for creating the slitscan
         *            effect
         */
        public GreyscaleSlitScanProcessor( final Video<MBFImage> video, final int cacheSize )
        {
                super( video );
                this.cacheSize = cacheSize;
        }

        @Override
        public MBFImage processFrame( final MBFImage frame )
        {
                this.addToCache( frame );

                if( this.timemapImage == null || this.timemapImage.getWidth() != frame.getWidth() ||
                                this.timemapImage.getHeight() != frame.getHeight() )
                        this.needToFixTimemap = true;

                if( this.needToFixTimemap )
                        this.fixTimemapImage( frame.getWidth(), frame.getHeight() );

                final int height = frame.getHeight();
                final int width = frame.getWidth();

                for( int y = 0; y < height; y++ )
                {
                        for( int x = 0; x < width; x++ )
                        {
                                int index = (int)this.timemapImage.pixels[y][x];
                                if( index >= this.cache.size() )
                                        index = this.cache.size()-1;

                                final MBFImage cacheImage = this.cache.get( index );
                                frame.setPixel( x, y, cacheImage.getPixel(x,y) );
                        }
                }

                for( final FImage f : frame.bands )
                {
                        FImageConvolveSeparable.convolveVertical( f, this.blurKern );
                }

                if( this.cache.size() >= this.cacheSize ) this.cache.removeLast();

                return frame;
        }

        /**
         *      Fixes the timemap image to be the same width/height as the given value.
         *      Will generate a default one if the image is null
         *
         *      @param width The width to resize the timemap to
         *      @param height The height to resize the timemap to
         */
        private void fixTimemapImage( final int width, final int height )
    {
                // Resize the timemap
                this.timemapImage = ResizeProcessor.resample( this.timemapImage, width, height );

                // Resample the colours to the number of cache sizes.
                for( int y = 0; y < this.timemapImage.getHeight(); y++ )
                        for( int x = 0; x < this.timemapImage.getWidth(); x++ )
                                this.timemapImage.pixels[y][x] = (float)
                                        (Math.floor( this.timemapImage.pixels[y][x] * this.cacheSize));
                this.needToFixTimemap = false;
    }

        private void addToCache( final MBFImage frame )
        {
                final MBFImage f = frame.clone();
                this.cache.addFirst( f );
        }
}