/**
    * 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.morphology;
  
  import java.util.HashSet;
  import java.util.Set;
  
  import org.openimaj.image.FImage;
  import org.openimaj.image.pixel.ConnectedComponent;
  import org.openimaj.image.pixel.Pixel;
  import org.openimaj.image.processor.KernelProcessor;
  import org.openimaj.image.processor.connectedcomponent.ConnectedComponentProcessor;
  import org.openimaj.math.geometry.shape.Rectangle;
  
  /**
   * Morphological hit-and-miss transform of connected 
   * components and (assumed binary) FImages.
   * 
   * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
   */
  public class HitAndMiss implements ConnectedComponentProcessor, KernelProcessor<Float, FImage> {
  	/**
  	 * Hit and miss operator for detecting convex corners
  	 */
  	public final static HitAndMiss CONVEX_CORNERS;
  	static {
  		CONVEX_CORNERS = new HitAndMiss(
  				new StructuringElement(
  						new Pixel[] {new Pixel(0,-1), new Pixel(0,0), new Pixel(1,0)}, 
  						new Pixel[] {new Pixel(-1,0), new Pixel(-1,1), new Pixel(0,1)}),
  						new StructuringElement(
  								new Pixel[] {new Pixel(0,-1), new Pixel(0,0), new Pixel(-1,0)}, 
  								new Pixel[] {new Pixel(1,0), new Pixel(1,1), new Pixel(0,1)}),
  								new StructuringElement(
  										new Pixel[] {new Pixel(-1,0), new Pixel(0,0), new Pixel(0,1)}, 
  										new Pixel[] {new Pixel(0,-1), new Pixel(1,-1), new Pixel(1,0)}),
  										new StructuringElement(
  												new Pixel[] {new Pixel(0,1), new Pixel(0,0), new Pixel(1,0)}, 
  												new Pixel[] {new Pixel(-1,-1), new Pixel(0,-1), new Pixel(-1,0)})
  		);
  	}
  
  	protected Set<Pixel> outputPixels = new HashSet<Pixel>();
  	protected StructuringElement [] elements;
  	protected int cx;
  	protected int cy;
  	protected int sw=0;
  	protected int sh=0;
  
  	/**
  	 * Construct a hit and miss operator with the given
  	 * structuring elements.
  	 * @param ses the structuring elements
  	 */
  	public HitAndMiss(StructuringElement... ses) {
  		this.elements = ses;
  
  		for (StructuringElement se : ses) {
  			int [] sz = se.size();
  
  			if (sw < sz[0]) sw = sz[0];
  			if (sh < sz[1]) sh = sz[1];
  		}
  		cx = sw/2;
  		cy = sw/2;
  	}
  
  	@Override
  	public void process(ConnectedComponent cc) {
  		//hit and miss transform; doesn't affect original pixels.
  		outputPixels.clear();
  
 		for (StructuringElement element : elements) {
 			Set<Pixel> pixels = cc.getPixels();
 			int [] se_size = element.size();
 			Rectangle cc_bb = cc.calculateRegularBoundingBox();
 			for (int j=(int) (cc_bb.y-se_size[1]); j<=cc_bb.y+se_size[1]+cc_bb.height; j++) {
 				for (int i=(int) (cc_bb.x-se_size[0]); i<=cc_bb.x+se_size[0]+cc_bb.width; i++) {
 					Pixel p = new Pixel(i, j);
 
 					if (element.matches(p, pixels)) {
 						outputPixels.add(p);
 					}
 				}
 			}
 		}
 	}
 
 	/**
 	 * Get the pixels selected by the hit and miss operator
 	 * @return a list of selected pixels
 	 */
 	public Set<Pixel> getPixels() {
 		return outputPixels;
 	}
 
 	@Override
 	public int getKernelHeight() {
 		return sh;
 	}
 
 	@Override
 	public int getKernelWidth() {
 		return sw;
 	}
 
 	@Override
 	public Float processKernel(FImage patch) {
 
 		for (StructuringElement element : elements) {
 			int count = 0;
 			for (Pixel p : element.positive) {
 				int px = cx - p.x;
 				int py = cy - p.y;
 				if (px>=0 && py>=0 && px<sw && py<sh && patch.pixels[py][px] == 1)
 					count++;
 			}
 
 			for (Pixel p : element.negative) {
 				int px = cx - p.x;
 				int py = cy - p.y;
 				if (px>=0 && py>=0 && px<sw && py<sh && patch.pixels[py][px] == 0)
 					count++;
 			}
 			
 			if (count == element.positive.size()+element.negative.size()) return 1f;
 		}
 
 		return 0f;
 	}
 }