/**
 * 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.processing.face.feature;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;

import org.openimaj.feature.FeatureVectorProvider;
import org.openimaj.feature.FloatFV;
import org.openimaj.image.FImage;
import org.openimaj.image.feature.dense.binarypattern.ExtendedLocalBinaryPattern;
import org.openimaj.image.feature.dense.binarypattern.UniformBinaryPattern;
import org.openimaj.image.processing.face.alignment.FaceAligner;
import org.openimaj.image.processing.face.alignment.IdentityAligner;
import org.openimaj.image.processing.face.detection.DetectedFace;
import org.openimaj.io.IOUtils;

/**
 * A {@link FacialFeature} built from decomposing the face image into
 * (non-overlapping) blocks and building histograms of the
 * {@link ExtendedLocalBinaryPattern}s for each block and then concatenating to
 * form the final feature.
 * 
 * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
 */
public class LocalLBPHistogram implements FacialFeature, FeatureVectorProvider<FloatFV> {
        /**
         * A {@link FacialFeatureExtractor} for building {@link LocalLBPHistogram}s.
         * 
         * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
         * 
         * @param <T>
         *            Type of {@link DetectedFace}.
         */
        public static class Extractor<T extends DetectedFace> implements FacialFeatureExtractor<LocalLBPHistogram, T> {
                FaceAligner<T> aligner;
                int blocksX = 25;
                int blocksY = 25;
                int samples = 8;
                int radius = 1;

                /**
                 * Construct with a {@link IdentityAligner}
                 */
                public Extractor() {
                        this.aligner = new IdentityAligner<T>();
                }

                /**
                 * Construct with the given aligner.
                 * 
                 * @param aligner
                 *            the aligner
                 */
                public Extractor(FaceAligner<T> aligner) {
                        this.aligner = aligner;
                }

                /**
                 * Construct with the given aligner, parameters describing how the image
                 * is broken into blocks and parameters describing the radius of the LBP
                 * extraction circle, and how many samples are made.
                 * 
                 * @param aligner
                 *            The face aligner
                 * @param blocksX
                 *            The number of blocks in the x-direction
                 * @param blocksY
                 *            The number of blocks in the y-direction
                 * @param samples
                 *            The number of samples around the circle for the
                 *            {@link ExtendedLocalBinaryPattern}
                 * @param radius
                 *            the radius used for the {@link ExtendedLocalBinaryPattern}
                 *            .
                 */
                public Extractor(FaceAligner<T> aligner, int blocksX, int blocksY, int samples, int radius) {
                        this.aligner = aligner;
                        this.blocksX = blocksX;
                        this.blocksY = blocksY;
                        this.samples = samples;
                        this.radius = radius;
                }

                @Override
                public LocalLBPHistogram extractFeature(T detectedFace) {
                        final LocalLBPHistogram f = new LocalLBPHistogram();

                        final FImage face = aligner.align(detectedFace);
                        final FImage mask = aligner.getMask();

                        f.initialise(face, mask, blocksX, blocksY, samples, radius);

                        return f;
                }

                @Override
                public void readBinary(DataInput in) throws IOException {
                        final String alignerClass = in.readUTF();
                        aligner = IOUtils.newInstance(alignerClass);
                        aligner.readBinary(in);

                        blocksX = in.readInt();
                        blocksY = in.readInt();
                        radius = in.readInt();
                        samples = in.readInt();
                }

                @Override
                public byte[] binaryHeader() {
                        return this.getClass().getName().getBytes();
                }

                @Override
                public void writeBinary(DataOutput out) throws IOException {
                        out.writeUTF(aligner.getClass().getName());
                        aligner.writeBinary(out);

                        out.writeInt(blocksX);
                        out.writeInt(blocksY);
                        out.writeInt(radius);
                        out.writeInt(samples);
                }

                @Override
                public String toString() {
                        return String.format("LocalLBPHistogram.Factory[blocksX=%d,blocksY=%d,samples=%d,radius=%d]", blocksX,
                                        blocksY, samples, radius);
                }
        }

        float[][][] histograms;
        transient FloatFV featureVector;

        protected void initialise(FImage face, FImage mask, int blocksX, int blocksY, int samples, int radius) {
                final int[][] pattern = ExtendedLocalBinaryPattern.calculateLBP(face, radius, samples);
                final boolean[][][] maps = UniformBinaryPattern.extractPatternMaps(pattern, samples);

                final int bx = face.width / blocksX;
                final int by = face.height / blocksY;
                histograms = new float[blocksY][blocksX][maps.length];

                // build histogram
                for (int p = 0; p < maps.length; p++) {
                        for (int y = 0; y < blocksY; y++) {
                                for (int x = 0; x < blocksX; x++) {

                                        for (int j = 0; j < by; j++) {
                                                for (int i = 0; i < bx; i++) {
                                                        if (maps[p][y * by + j][x * bx + i])
                                                                histograms[y][x][p]++;
                                                }
                                        }
                                }
                        }
                }

                // normalise
                for (int y = 0; y < blocksY; y++) {
                        for (int x = 0; x < blocksX; x++) {
                                float count = 0;
                                for (int p = 0; p < maps.length; p++) {
                                        count += histograms[y][x][p];
                                }
                                for (int p = 0; p < maps.length; p++) {
                                        histograms[y][x][p] /= count;
                                }
                        }
                }

                updateFeatureVector();
        }

        protected void updateFeatureVector() {
                featureVector = new FloatFV(histograms.length * histograms[0].length * histograms[0][0].length);

                int i = 0;
                for (int y = 0; y < histograms.length; y++) {
                        for (int x = 0; x < histograms[0].length; x++) {
                                for (int p = 0; p < histograms[0][0].length; p++) {
                                        featureVector.values[i] = histograms[y][x][p];
                                        i++;
                                }
                        }
                }
        }

        @Override
        public byte[] binaryHeader() {
                return "LBPH".getBytes();
        }

        @Override
        public void readBinary(DataInput in) throws IOException {
                final int by = in.readInt();
                final int bx = in.readInt();
                final int p = in.readInt();

                histograms = new float[by][bx][p];

                for (int j = 0; j < by; j++) {
                        for (int i = 0; i < bx; i++) {
                                for (int k = 0; k < p; k++) {
                                        histograms[j][i][k] = in.readFloat();
                                }
                        }
                }
                updateFeatureVector();
        }

        @Override
        public void writeBinary(DataOutput out) throws IOException {
                out.writeInt(histograms.length);
                out.writeInt(histograms[0].length);
                out.writeInt(histograms[0][0].length);

                for (final float[][] hist1 : histograms) {
                        for (final float[] hist2 : hist1) {
                                for (final float h : hist2) {
                                        out.writeFloat(h);
                                }
                        }
                }
        }

        @Override
        public FloatFV getFeatureVector() {
                if (featureVector == null)
                        updateFeatureVector();

                return featureVector;
        }
}