/**
 * 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.sampling;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.NoSuchElementException;

import org.openimaj.image.Image;
import org.openimaj.math.geometry.shape.Rectangle;

/**
 * A {@link RectangleSampler} provides an easy way to generate a sliding window
 * of rectangle over an image or other domain.
 * 
 * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
 * 
 */
public class RectangleSampler implements Iterable<Rectangle> {
        float minx;
        float maxx;
        float miny;
        float maxy;
        float stepx;
        float stepy;
        float width;
        float height;

        /**
         * Construct the sampler with the given parameters
         * 
         * @param minx
         *            starting x-ordinate
         * @param maxx
         *            finishing x-ordinate
         * @param miny
         *            starting y-ordinate
         * @param maxy
         *            finishing y-ordinate
         * @param stepx
         *            step size in x direction
         * @param stepy
         *            step size in y direction
         * @param width
         *            width of sample window
         * @param height
         *            height of sample window
         */
        public RectangleSampler(float minx, float maxx, float miny, float maxy, float stepx, float stepy, float width,
                        float height)
        {
                setBounds(minx, maxx, miny, maxy);
                this.stepx = stepx;
                this.stepy = stepy;
                this.width = width;
                this.height = height;
        }

        /**
         * Construct the sampler with the given parameters
         * 
         * @param bounds
         *            the bounds in which the window must remain; it will start in
         *            the top-left corner
         * @param stepx
         *            step size in x direction
         * @param stepy
         *            step size in y direction
         * @param width
         *            width of sample window
         * @param height
         *            height of sample window
         */
        public RectangleSampler(Rectangle bounds, float stepx, float stepy, float width, float height)
        {
                setBounds(bounds);
                this.stepx = stepx;
                this.stepy = stepy;
                this.width = width;
                this.height = height;
        }

        /**
         * Construct the sampler with the given parameters
         * 
         * @param img
         *            the image from which to set the sampler bounds (will be set to
         *            the complete image)
         * @param stepx
         *            step size in x direction
         * @param stepy
         *            step size in y direction
         * @param width
         *            width of sample window
         * @param height
         *            height of sample window
         */
        public RectangleSampler(Image<?, ?> img, float stepx, float stepy, float width, float height)
        {
                setBounds(img);
                this.stepx = stepx;
                this.stepy = stepy;
                this.width = width;
                this.height = height;
        }

        /**
         * Adjust the bounds of the sampler
         * 
         * @param minx
         *            starting x-ordinate
         * @param maxx
         *            finishing x-ordinate
         * @param miny
         *            starting y-ordinate
         * @param maxy
         *            finishing y-ordinate
         */
        public void setBounds(float minx, float maxx, float miny, float maxy) {
                this.minx = minx;
                this.maxx = maxx;
                this.miny = miny;
                this.maxy = maxy;
        }

        /**
         * Adjust the bounds of the sampler
         * 
         * @param r
         *            the new bounds rectangle
         */
        public void setBounds(Rectangle r) {
                if (r == null)
                        return;

                this.minx = r.x;
                this.maxx = r.x + r.width;
                this.miny = r.y;
                this.maxy = r.y + r.height;
        }

        /**
         * Adjust the bounds of the sampler
         * 
         * @param img
         *            the image to determine the bounds from
         */
        public void setBounds(Image<?, ?> img) {
                if (img == null)
                        return;

                setBounds(img.getBounds());
        }

        /**
         * Get a list of all the rectangles that can be produced by this sampler
         * 
         * @return all the rectangles
         */
        public List<Rectangle> allRectangles() {
                final List<Rectangle> list = new ArrayList<Rectangle>();

                for (final Rectangle r : this)
                        list.add(r);

                return list;
        }

        @Override
        public Iterator<Rectangle> iterator() {
                return new Iterator<Rectangle>() {
                        float x = minx;
                        float y = miny;

                        @Override
                        public boolean hasNext() {
                                if (x + width <= maxx && y + height <= maxy)
                                        return true;

                                return false;
                        }

                        @Override
                        public Rectangle next() {
                                if (y + height > maxy)
                                        throw new NoSuchElementException();

                                float nextX = x + stepx;
                                float nextY = y;
                                if (nextX + width > maxx) {
                                        nextX = minx;
                                        nextY += stepy;
                                }

                                final Rectangle r = new Rectangle(x, y, width, height);

                                x = nextX;
                                y = nextY;

                                return r;
                        }

                        @Override
                        public void remove() {
                                throw new UnsupportedOperationException("Removal is not supported!");
                        }
                };
        }

        /**
         * Create an iterator to extract sub-images from an image based on the
         * rectangles defined by this sampler.
         * 
         * @param image
         *            the image to extract from
         * @return an iterator over the extracted sub-images.
         */
        public <I extends Image<?, I>> Iterator<I> subImageIterator(final I image) {
                return new Iterator<I>() {
                        Iterator<Rectangle> inner = iterator();

                        @Override
                        public boolean hasNext() {
                                return inner.hasNext();
                        }

                        @Override
                        public I next() {
                                final Rectangle r = inner.next();

                                return image.extractROI(r);
                        }

                        @Override
                        public void remove() {
                                throw new UnsupportedOperationException("Removal is not supported!");
                        }
                };
        }
}