/**
 * 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.tools.clusterquantiser.samplebatch;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.DataInput;
import java.io.DataInputStream;
import java.io.DataOutput;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import org.openimaj.io.IOUtils;
import org.openimaj.io.ReadWriteableBinary;
import org.openimaj.tools.clusterquantiser.FileType;

/**
 * A batch of samples
 * 
 * @author Sina Samangooei (ss@ecs.soton.ac.uk)
 */
public class SampleBatch implements ReadWriteableBinary {
        /**
         * Header for SampleBatch files
         */
        public static final byte[] HEADER = "SAMPLEBATCH".getBytes();

        private FileType type;
        private File sampleSource;
        private int startIndex;
        private int endIndex;
        private int[] relativeIndexList;
        
        /**
         * Default constructor
         */
        public SampleBatch(){
                
        }
        /**
         * Default constructor
         * @param type
         * @param sampleSource
         * @param startIndex
         * @param endIndex
         * @param relativeIndexList
         */
        public SampleBatch(FileType type, File sampleSource, int startIndex, int endIndex, int[] relativeIndexList){
                this.endIndex = endIndex;
                this.startIndex = startIndex;
                this.type = type;
                this.sampleSource = sampleSource;
                this.relativeIndexList = relativeIndexList;
        }
        
        /**
         * Default constructor
         * @param type
         * @param sampleSource
         * @param startIndex
         * @param endIndex
         */
        public SampleBatch(FileType type, File sampleSource, int startIndex,int endIndex) {
                this.type = type;
                this.startIndex = startIndex;
                this.endIndex = endIndex;
                this.sampleSource = sampleSource;
                this.relativeIndexList = null;
        }

        /**
         * @return the stored samples
         * @throws IOException
         */
        public byte[][] getStoredSamples() throws IOException{
                byte [][] f  = null;
                if(relativeIndexList == null){
                        f = type.readFeatures(sampleSource);
                }
                else
                {
                        f = type.readFeatures(sampleSource, relativeIndexList);
                }
                return f;
        }
        
        /**
         * Get the stored samples
         * @param indices
         * @return the stored samples
         * @throws IOException
         */
        public byte[][] getStoredSamples(int[] indices) throws IOException{
                byte [][] f  = null;
                int[] corrected = new int[indices.length];
                for(int i = 0; i < corrected.length;i++) corrected[i] = this.relativeIndexList == null ? indices[i] : this.relativeIndexList[indices[i]];
                f = type.readFeatures(sampleSource, corrected);
                return f;
        }
        
        /**
         * Get the stored samples
         * @param interestedStart
         * @param interestedEnd
         * @return the stored samples
         * @throws IOException
         */
        public byte[][] getStoredSamples(int interestedStart, int interestedEnd) throws IOException {
                int[] interestedList = new int[interestedEnd - interestedStart];
                int j = 0;
                for(int i = interestedStart; i < interestedEnd; i++,j++)
                        interestedList[j] = this.relativeIndexList == null ? j : this.relativeIndexList[j]; 
                return type.readFeatures(sampleSource, interestedList);
        }
        
        /**
         * @return the start index of the batch
         */
        public int getStartIndex() {
                return startIndex;
        }
        
        /**
         * @return the end index of the batch
         */
        public int getEndIndex() {
                return endIndex;
        }
        
        /**
         * Write batches to a file
         * @param sampleBatches
         * @param sampleBatchOut
         */
        public static void writeSampleBatches(List<SampleBatch> sampleBatches,File sampleBatchOut) {
                DataOutputStream dos = null;
                try{
                        FileOutputStream fos = new FileOutputStream(sampleBatchOut);
                        BufferedOutputStream bos = new BufferedOutputStream(fos);
                        dos = new DataOutputStream(bos);
                        dos.writeInt(sampleBatches.size());
                        for(SampleBatch sb : sampleBatches){
                                IOUtils.writeBinary(bos, sb);
                                dos.flush();
                        }
                        
                } catch (IOException e) {
                        e.printStackTrace();
                }
                finally{
                        try {
                                dos.close();
                        } catch (IOException e) {
                                e.printStackTrace();
                        }
                }
        }
        
        /**
         * Read batches from a file
         * @param sampleBatchOut
         * @return batches
         */
        public static List<SampleBatch> readSampleBatches(File sampleBatchOut) {
                FileInputStream fis = null;
                List<SampleBatch> sbl = new ArrayList<SampleBatch>();
                try{
                        fis = new FileInputStream(sampleBatchOut);
                        DataInputStream dis = new DataInputStream(new BufferedInputStream(fis));
                        int toRead = dis.readInt();
                        for(int i = 0; i < toRead; i++){
                                dis.read(new byte[SampleBatch.HEADER.length]);
                                SampleBatch sb = new SampleBatch();
                                sb.readBinary(dis);
                                sbl.add(sb);
                                System.err.printf("\r%8d / %8d", i, toRead);
                        }
                } catch (IOException e) {
                }
                finally{
                        try {
                                fis.close();
                        } catch (IOException e) {
                                
                        }
                }
                System.out.println(" Done!");
                return sbl;
        }
        
        @Override
        public boolean equals(Object o){
                if(!(o instanceof SampleBatch)) return false;
                SampleBatch sbo = (SampleBatch) o;
                
                return  sbo.endIndex == this.endIndex && 
                                sbo.startIndex == this.startIndex && 
                                Arrays.equals(sbo.relativeIndexList, this.relativeIndexList) &&
                                sbo.sampleSource.getAbsolutePath().equals(this.sampleSource.getAbsolutePath()) &&
                                sbo.type.equals(this.type);
        }
        
        /**
         * @return list of relative indices
         */
        public int[] getRelativeIndexList() {
                return this.relativeIndexList;
        }
        
        @Override
        public String toString(){
                String out = "";
                out += "|" + this.startIndex + "->" + this.endIndex + "| == " + (this.endIndex - this.startIndex);
                return out;
                
        }

        @Override
        public void writeBinary(DataOutput out) throws IOException {
                out.writeInt(type.ordinal());
                out.writeInt(sampleSource.getAbsolutePath().length());
                byte[] path = sampleSource.getAbsolutePath().getBytes();
                out.write(path, 0, path.length);
                out.writeInt(startIndex);
                out.writeInt(endIndex);
                if(relativeIndexList == null)
                        out.writeInt(0);
                else
                {
                        out.writeInt(relativeIndexList.length);
                        for(int i = 0; i < relativeIndexList.length; i++){
                                out.writeInt(relativeIndexList[i]);
                        }
                }
                
        }

        @Override
        public void readBinary(DataInput in) throws IOException {
                type = FileType.values()[in.readInt()];
                int pathLen = in.readInt();
                byte[] path = new byte[pathLen];
                in.readFully(path, 0, pathLen);
                sampleSource = new File(new String(path));
                startIndex = in.readInt();
                endIndex = in.readInt();
                int nRelativeIndexList = in.readInt();
                if(nRelativeIndexList == 0){
                        relativeIndexList  = null;
                }
                else{
                        relativeIndexList = new int[nRelativeIndexList];
                        for(int i = 0 ; i < nRelativeIndexList; i++){
                                relativeIndexList[i] = in.readInt();
                        }
                }
        }

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