/**
 * 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.image.pixel.statistics;

import org.openimaj.feature.FeatureVectorProvider;
import org.openimaj.image.MBFImage;
import org.openimaj.math.statistics.distribution.MultidimensionalHistogram;
import org.openimaj.util.pair.Pair;

/**
 * A multidimensional histogram calculated from image pixels (assumes image is
 * in 0-1 range)
 * 
 * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
 * 
 */
public class HistogramModel extends AbstractPixelStatisticsModel
                implements
                FeatureVectorProvider<MultidimensionalHistogram>
{
        private static final long serialVersionUID = 1L;

        /**
         * The histogram data
         */
        public MultidimensionalHistogram histogram;

        /**
         * Construct with the given number of bins per dimension
         * 
         * @param nbins
         *            the number of bins in each dimension for the histograms
         */
        public HistogramModel(int... nbins) {
                super(nbins.length);

                assert (nbins.length > 0);

                histogram = new MultidimensionalHistogram(nbins);
        }

        @Override
        public void estimateModel(MBFImage... images) {
                reset();
                for (final MBFImage im : images) {
                        accum(im);
                }
                histogram.normalise();
        }

        protected void reset() {
                for (int i = 0; i < histogram.values.length; i++)
                        histogram.values[i] = 0;
        }

        /**
         * For a given index, map to the range of colours which could map to it
         * 
         * @param index
         * @return start/end colour
         */
        public Pair<float[]> colourRange(int index) {
                final int[] coord = this.histogram.getCoordinates(index);
                final float[] start = new float[coord.length];
                final float[] end = new float[coord.length];
                final int[] nbins = histogram.nbins;
                for (int i = 0; i < coord.length; i++) {
                        start[i] = (float) coord[i] / (float) nbins[i];
                        end[i] = ((float) coord[i] + 1) / nbins[i];
                }
                return new Pair<float[]>(start, end);
        }

        /**
         * For a given index, get the average colour which would map to it
         * 
         * @param index
         * @return start/end colour
         */
        public float[] colourAverage(int index) {
                final int[] coord = this.histogram.getCoordinates(index);
                final float[] average = new float[coord.length];
                final int[] nbins = histogram.nbins;
                for (int i = 0; i < coord.length; i++) {
                        final float start = (float) coord[i] / (float) nbins[i];
                        final float end = ((float) coord[i] + 1) / nbins[i];
                        average[i] = (start + end) / 2f;
                }

                return average;
        }

        protected void accum(MBFImage im) {
                final int height = im.getHeight();
                final int width = im.getWidth();
                final int[] bins = new int[ndims];

                final float[][][] bands = new float[im.numBands()][][];
                for (int i = 0; i < bands.length; i++)
                        bands[i] = im.getBand(i).pixels;

                final int[] nbins = histogram.nbins;
                final double[] values = histogram.values;

                for (int y = 0; y < height; y++) {
                        for (int x = 0; x < width; x++) {
                                for (int i = 0; i < ndims; i++) {
                                        bins[i] = (int) (bands[i][y][x] * (nbins[i]));
                                        if (bins[i] >= nbins[i])
                                                bins[i] = nbins[i] - 1;
                                }

                                int bin = 0;
                                for (int i = 0; i < ndims; i++) {
                                        int f = 1;
                                        for (int j = 0; j < i; j++)
                                                f *= nbins[j];

                                        bin += f * bins[i];
                                }

                                values[bin]++;
                        }
                }
        }

        @Override
        public String toString() {
                return histogram.toString();
        }

        @Override
        public HistogramModel clone() {
                final HistogramModel model = new HistogramModel();
                model.histogram = histogram.clone();
                model.ndims = ndims;
                return model;
        }

        @Override
        public MultidimensionalHistogram getFeatureVector() {
                return histogram;
        }
}