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*/
/**
 * 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.
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 *      this list of conditions and the following disclaimer in the documentation
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 *      contributors may be used to endorse or promote products derived from this
 *      software without specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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package org.openimaj.ml.clustering.kmeans;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Scanner;

import org.openimaj.ml.clustering.LongCentroidsResult;
import org.openimaj.ml.clustering.SpatialClusters;
import org.openimaj.ml.clustering.assignment.hard.HierarchicalLongHardAssigner;

/** 
 * The result of a {@link HierarchicalLongKMeans} clustering operation.
 *
 * @author Sina Samangooei (ss@ecs.soton.ac.uk)
 * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
 */
public class HierarchicalLongKMeansResult implements SpatialClusters<long[]> {
        /**
         * HierarchicalLongKMeans tree node
         *
         * The number of children is not bigger than the HierarchicalLongKMeans K parameter
         **/
        public static class Node {
                /** {@link LongCentroidsResult} for this node */
                public LongCentroidsResult result;

                /** Node children (if any) */
                public Node[] children;
        }
        
        private static final String HEADER = SpatialClusters.CLUSTER_HEADER + "H" +"Long".charAt(0) + "KM";
        
        /** Data dimensionality */
        int M;

        /** K clusters per node */
        int K;
        
        /** Depth of the tree */
        int depth;
        
        /** Tree root node */
        Node root;

        protected HierarchicalLongKMeansResult() {}

        @Override
        public int numDimensions() {
                return M;
        }
        
        /**
         * Get the number of clusters per node
         * @return number of clusters per node
         */
        public int getK() {
                return K;
        }

        /**
         * Get the depth of the cluster tree
         * @return the depth of the cluster tree
         */
        public int getDepth() {
                return depth;
        }

        /**
         * Get the root node of the tree
         * @return the root node of the tree
         */
        public Node getRoot() {
                return root;
        }

        private static int ipow(int x, int y) {
                int sum = 1;
                for (int i=0; i<y; i++) 
                        sum *= x;
                return sum;
        }

        /**
         * Translates a path down the KDTree as a cluster index. This allows the specification of K and the depth
         * @param path
         * @param depth
         * @param K
         * @return cluster index
         */
        public static int getIndex(int [] path, int depth, int K) {
                int idx = 0;

                for (int i=0; i<depth; i++) 
                        idx += path[i] * ipow(K, depth-1-i);

                return idx;
        }

        /**
         * Translates a path down the KDTree as a cluster index. 
         * @param path
         * @return cluster index
         */
        public int getIndex(int [] path) {
                return getIndex(path, depth, K);
        }

        /**
         * Given an index, what was the path down the hierarchy that lead to it. Allows the specification of
         * depth and number of clusters. 
         * @param index
         * @param depth
         * @param K
         * @return a hierarchy path
         */
        public static int [] getPath(int index, int depth, int K) {
                int [] path = new int[depth];

                for (int i=0; i<depth; i++) {
                        int v = ipow(K, depth-1-i);

                        for (int j=0; j<K; j++) {       
                                int vp = v * j;
                                int vpn = v * (j+1);

                                if (index < vpn) {
                                        path[i] = j;
                                        index -= vp;
                                        break;
                                }
                        }
                }

                return path;
        }

        /**
         * Given an index, what was the path down the hierarchy that lead to it. Assumes the class depth and K.
         * @param index
         * @return a hierarchy path
         */
        public int [] getPath(int index) {
                return getPath(index, depth, K);
        }

        private int countLeaves(Node node) {
                int count = 0;
                if (node.children == null) {
                        count = node.result.numClusters();
                } else {
                        for (int i=0; i<node.result.numClusters(); i++) {
                                count += countLeaves(node.children[i]);
                        }
                }
                return count;
        }

        /**
         * Count number of active leaf nodes.
         * @return number of nodes.
         */
        public int countActiveLeafNodes() {
                return countLeaves(root);
        }
        
        @Override
        public String toString() {
                String s = "";
                s += String.format("Number of dimensions:               %d\n", M);
                s += String.format("Number of clusters:                 %d\n", K);
                s += String.format("Number of levels:                   %d\n", depth);
                s += String.format("Maximum number of leaf nodes:       %d\n", ipow(K, depth));
                s += String.format("Number of leaf active nodes:        %d", countActiveLeafNodes());
                return s;
        }

        /**
         * Total number of leaves assuming leaves = K^depth
         * @return number of leaves
         */
        public int countLeafs() {
                return ipow(K, depth);
        }

        @Override
        public int numClusters() {
                return this.countLeafs();
        }
        
        @Override
        public boolean equals(Object o) {
                if(!(o instanceof HierarchicalLongKMeansResult)) return false;
                
                HierarchicalLongKMeansResult other = (HierarchicalLongKMeansResult) o;
                
                return other.countActiveLeafNodes() == this.countActiveLeafNodes() && 
                                other.getDepth() == this.getDepth() &&
                                other.getK() == this.getK() &&
                                other.numDimensions() == this.numDimensions();
        }
        
        /**
         * Given a path, get the cluster centroid associated with the cluster index of the path.  
         * @param path
         * @return the centroid of a given path
         */
        public long [] getClusterCentroid(int [] path) {
                Node node = root;
                
                for (int i=0; i<path.length-1; i++) {
                        node = node.children[path[i]];
                }
                
                return node.result.getCentroids()[path[path.length-1]];
        }
        
        @Override
        public String asciiHeader() {
                return "ASCII"+HEADER;
        }

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

        @Override
        public void readASCII(Scanner reader) throws IOException {
                M = Integer.parseInt(reader.nextLine());
                K = Integer.parseInt(reader.nextLine());
                depth = Integer.parseInt(reader.nextLine());

                root = readNode(this,reader);
        }
        
        private Node readNode(HierarchicalLongKMeansResult hLongkm, Scanner reader) throws IOException {
                String line;
                
                while ((line = reader.nextLine()).length()==0) {/*do nothing*/}
                
                char type = line.charAt(0);

                //read result data
                Node node = new Node();
                node.result = new LongCentroidsResult();
                node.result.readASCII(reader);
                
                if (type == 'I') {
                        node.children = new Node[node.result.numClusters()];

                        for (int i=0; i<node.result.numClusters(); i++) {
                                node.children[i] = readNode(hLongkm,reader);
                        }
                } else {
                        node.children = null;
                }

                return node ;
        }
        
        @Override
        public void readBinary(DataInput dis) throws IOException {
                M = dis.readInt();
                K = dis.readInt();
                depth = dis.readInt();

                root = readNodeB(this,dis);
        }
        
        private Node readNodeB(HierarchicalLongKMeansResult hLongkm, DataInput dis) throws IOException {
                Node node = new Node();
                char type = (char) dis.readByte();

                //read result data
                node.result = new LongCentroidsResult();
                node.result.readBinary(dis);
                
                if (type == 'I') {
                        node.children = new Node[node.result.numClusters()];

                        for (int i=0; i<node.result.numClusters(); i++) {
                                node.children[i] = readNodeB(hLongkm, dis);
                        }
                } else {
                        node.children = null;
                }

                return node ;
        }
        
        @Override
        public void writeASCII(PrintWriter writer) throws IOException {
                writer.format("%d\n", this.M);
                writer.format("%d\n", this.K);
                writer.format("%d\n", this.depth);

                writeNodeASCII(writer, this.root);
        }
        
        private void writeNodeASCII(PrintWriter writer, final Node node) throws IOException {
                //write node type
                if (node.children == null) 
                        writer.write("L\n"); //intermediate
                else
                        writer.write("I\n"); //leaf

                //write result data
                node.result.writeASCII(writer); // node.result.writeASCII(writer, false);
                writer.flush();
                //write children
                if (node.children != null) {
                        for (int i=0; i<node.result.numClusters(); i++) {
                                writeNodeASCII(writer, node.children[i]);
                        }
                }
        }
        
        @Override
        public void writeBinary(DataOutput dos) throws IOException {    
                dos.writeInt(this.M);
                dos.writeInt(this.K);
                dos.writeInt(this.depth);
        
                writeNodeB(dos, this.root);
        }
        
        private void writeNodeB(DataOutput dos, Node node) throws IOException {
                //write node type
                char type;
                if (node.children == null) 
                        type='L'; //intermediate
                else
                        type='I'; //leaf
                dos.writeByte(type);

                //write result data
                node.result.writeBinary(dos);

                //write children
                if (node.children != null) {
                        for (int i=0; i<node.result.numClusters(); i++) {
                                writeNodeB(dos, node.children[i]);
                        }
                }
        }
        
        @Override
        public HierarchicalLongHardAssigner defaultHardAssigner() {
                return new HierarchicalLongHardAssigner(this);
        }
}