/**
 * 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.analysis.watershed;

import java.util.HashMap;
import java.util.Map;

import org.apache.log4j.Logger;
import org.openimaj.image.analysis.watershed.event.ComponentStackMergeListener;
import org.openimaj.util.tree.TreeNode;
import org.openimaj.util.tree.TreeNodeImpl;


/**
 *      A listener that listens to the watershed algorithm progress and
 *      creates a region tree as the processing takes place.
 *
 *      @author David Dupplaw (dpd@ecs.soton.ac.uk)
 *      @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
 *      
 */
public class MergeTreeBuilder implements ComponentStackMergeListener
{
        Logger logger = Logger.getLogger(MergeTreeBuilder.class);
        
        /** This is the tree we build */
        private TreeNode<Component> tree = null;
        
        /** 
         *      Because we're creating components to store the history,
         *  the components that are being processed by the algorithm
         *  are not the same as those in our tree, so we must provide
         *  a map so that we can join up the tree afterwards. 
         */
        private Map<Component,TreeNode<Component>> map = null;

        /**
         *      Default constructor
         */
        public MergeTreeBuilder()
        {
                map = new HashMap<Component, TreeNode<Component>>();
        }
        
        /** 
         *      {@inheritDoc}
         *      @see org.openimaj.image.analysis.watershed.event.ComponentStackMergeListener#componentsMerged(org.openimaj.image.analysis.watershed.Component, org.openimaj.image.analysis.watershed.Component)
         */
        @Override
        public void componentsMerged( Component c1, Component c2 )
        {
                logger.debug( "Map: "+map );
                logger.debug( "Component c1: "+c1 );
                logger.debug( "Component c2: "+c2 );
                
                // Create a tree node for the component if it doesn't
                // exist already
                TreeNode<Component> c1xtn = map.get( c1 );
                if( c1xtn == null )
                {
                        logger.debug( "c1 not found" );
                        c1xtn = new TreeNodeImpl<Component>();
                        Component c1x = c1.clone();
                        c1xtn.setValue( c1x );
                        map.put( c1, c1xtn );
                }

                // Add all the pixels from c2 into our copy of c1
                c1xtn.getValue().merge( c2 );

                // Create a tree node for the second component
                // if it doesn't exist already
                TreeNode<Component> c2xtn = map.get( c2 );
                if( c2xtn == null )
                {
                        logger.debug( "c2 not found" );
                        c2xtn = new TreeNodeImpl<Component>();
                        Component c2x = c2.clone();
                        c2xtn.setValue( c2x );
                        map.put( c2, c2xtn );
                }

                logger.debug("Linking "+c1xtn+" and "+c2xtn );

                // Link the tree nodes
                c1xtn.addChild( c2xtn );
                this.tree = c1xtn;
        }

        /**
         *      {@inheritDoc}
         *      @see org.openimaj.image.analysis.watershed.event.ComponentStackMergeListener#componentPromoted(org.openimaj.image.analysis.watershed.Component)
         */
        @Override
        public void componentPromoted( Component c1 )
        {               
                TreeNode<Component> c1xtn_old = map.get( c1 );

                Component c1x = c1.clone();
                
                TreeNode<Component> c1xtn = new TreeNodeImpl<Component>();
                c1xtn.setValue( c1x );
                
                map.put( c1, c1xtn );

                if( c1xtn_old != null )
                        c1xtn.addChild( c1xtn_old );
        }
        
        /**
         *      Return the tree that has been built.
         *      @return the tree
         */
        public TreeNode<Component> getTree()
        {
                return tree;
        }
}