/**
 * 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.alignment;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import org.openimaj.image.FImage;
import org.openimaj.image.processing.face.detection.CLMDetectedFace;
import org.openimaj.image.processing.face.detection.CLMFaceDetector.Configuration;
import org.openimaj.image.processing.face.tracking.clm.CLMFaceTracker;
import org.openimaj.image.processing.transform.PiecewiseMeshWarp;
import org.openimaj.io.IOUtils;
import org.openimaj.math.geometry.shape.Shape;
import org.openimaj.math.geometry.shape.Triangle;
import org.openimaj.util.pair.Pair;

/**
 * <p>
 * An aligner that warps a {@link CLMDetectedFace} to the neutral pose
 * (reference shape) of the {@link Configuration}.
 * </p>
 * <p>
 * Implementors of subclasses of this should note that if the triangles of the
 * configuration are changed that the reference triangles must be recomputed.
 * </p>
 *
 * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
 */
public class CLMAligner implements FaceAligner<CLMDetectedFace> {
        protected Configuration config;
        protected int size = 100;
        protected transient List<Triangle> referenceTriangles;
        protected transient FImage mask;

        /**
         * Construct a new {@link CLMAligner} using the default
         * {@link Configuration} and default size of 100 pixels.
         */
        public CLMAligner() {
                config = new Configuration();
                loadReference();
        }

        /**
         * Construct a new {@link CLMAligner} using the default
         * {@link Configuration} and given size for the aligned output image.
         *
         * @param size
         *            the output facial patch size
         */
        public CLMAligner(int size) {
                this.size = size;
                config = new Configuration();
                loadReference();
        }

        /**
         * Construct a new {@link CLMAligner} using the provided
         * {@link Configuration} and default size of 100 pixels.
         *
         * @param size
         *            the output facial patch size
         * @param config
         *            the configuration
         */
        public CLMAligner(int size, Configuration config) {
                this.size = size;
                this.config = config;
                loadReference();
        }

        protected void loadReference() {
                referenceTriangles = CLMFaceTracker.getTriangles(config.referenceShape, null, this.config.triangles);

                mask = new FImage(size, size);

                for (final Triangle t : referenceTriangles) {
                        // magic numbers chosen to scale and centre the face
                        // with a small border
                        t.scale(0.3f * size);
                        t.translate(0.5f * size, 0.45f * size);

                        mask.drawShapeFilled(t, 1f);
                }
        }

        @Override
        public void readBinary(DataInput in) throws IOException {
                config = IOUtils.read(in);
                loadReference();
        }

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

        @Override
        public void writeBinary(DataOutput out) throws IOException {
                IOUtils.write(config, out);
        }

        @Override
        public FImage align(CLMDetectedFace face) {
                if (face == null)
                        return null;

                final List<Triangle> triangles = CLMFaceTracker.getTriangles(
                                face.getShapeMatrix(), face.getVisibility(), this.config.triangles);
                final List<Pair<Shape>> matches = computeMatches(triangles);

                final PiecewiseMeshWarp<Float, FImage> pmw = new PiecewiseMeshWarp<Float, FImage>(matches);

                return pmw.transform(face.getFacePatch(), size, size);
        }

        @Override
        public FImage getMask() {
                return mask;
        }

        private List<Pair<Shape>> computeMatches(List<Triangle> triangles) {
                final List<Pair<Shape>> mtris = new ArrayList<Pair<Shape>>();

                for (int i = 0; i < triangles.size(); i++) {
                        final Triangle t1 = triangles.get(i);
                        final Triangle t2 = referenceTriangles.get(i);

                        if (t1 != null && t2 != null) {
                                mtris.add(new Pair<Shape>(t1, t2));
                        }
                }

                return mtris;
        }
}