/**
 * 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.feature.local.list;

import java.io.BufferedInputStream;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;

import org.openimaj.data.RandomData;
import org.openimaj.feature.local.LocalFeature;
import org.openimaj.feature.local.LocationFilter;
import org.openimaj.io.IOUtils;

/**
 * An in-memory list of local features.
 * 
 * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
 * 
 * @param <T>
 *            the type of local feature
 */
public class MemoryLocalFeatureList<T extends LocalFeature<?, ?>> extends ArrayList<T> implements LocalFeatureList<T> {
        private static final long serialVersionUID = 1L;

        protected int cached_veclen = -1;

        /**
         * Construct an empty feature list
         */
        public MemoryLocalFeatureList() {
        }

        /**
         * Construct an empty list with the given feature-vector length.
         * 
         * @param veclen
         *            the expected length of the feature vectors of each local
         *            feature.
         */
        public MemoryLocalFeatureList(int veclen) {
                super();
                this.cached_veclen = veclen;
        }

        /**
         * Construct a local feature list from the given collection of local
         * features.
         * 
         * @param c
         *            Collection of local feature to add to the list instance.
         */
        public MemoryLocalFeatureList(Collection<? extends T> c) {
                super(c);
                if (size() > 0)
                        cached_veclen = this.get(0).getFeatureVector().length();
        }

        /**
         * Construct an empty list with the given feature-vector length and
         * pre-allocate the underlying array with space for initialCapacity local
         * features. The list will automatically grow once initialCapacity is
         * reached.
         * 
         * @param veclen
         *            the expected length of the feature vectors of each local
         *            feature.
         * @param initialCapacity
         *            the initial capacity of the list.
         */
        public MemoryLocalFeatureList(int veclen, int initialCapacity) {
                super(initialCapacity);
                this.cached_veclen = veclen;
        }

        /**
         * Create a MemoryLocalFeatureList by reading all the local features from
         * the specified file.
         * 
         * @param <T>
         *            the type of local feature
         * @param keypointFile
         *            the file from which to read the features
         * @param clz
         *            the class of local feature
         * @return a new MemoryLocalFeatureList populated with features from the
         *         file
         * @throws IOException
         *             if an error occurs reading the file
         */
        public static <T extends LocalFeature<?, ?>> MemoryLocalFeatureList<T> read(File keypointFile, Class<T> clz)
                        throws IOException
        {
                final boolean isBinary = IOUtils.isBinary(keypointFile, LocalFeatureList.BINARY_HEADER);
                final MemoryLocalFeatureList<T> list = new MemoryLocalFeatureList<T>();

                if (isBinary) {
                        LocalFeatureListUtils.readBinary(keypointFile, list, clz);
                } else {
                        LocalFeatureListUtils.readASCII(keypointFile, list, clz);
                }

                return list;
        }

        /**
         * Create a MemoryLocalFeatureList by reading all the local features from
         * the specified stream.
         * 
         * @param <T>
         *            the type of local feature
         * @param stream
         *            the input stream from which to read the features
         * @param clz
         *            the class of local feature
         * @return a new MemoryLocalFeatureList populated with features from the
         *         file
         * @throws IOException
         *             if an error occurs reading the file
         */
        public static <T extends LocalFeature<?, ?>> MemoryLocalFeatureList<T> read(InputStream stream, Class<T> clz)
                        throws IOException
        {
                return read(new BufferedInputStream(stream), clz);
        }

        /**
         * Create a MemoryLocalFeatureList by reading all the local features from
         * the specified stream.
         * 
         * @param <T>
         *            the type of local feature
         * @param stream
         *            the input stream from which to read the features
         * @param clz
         *            the class of local feature
         * @return a new MemoryLocalFeatureList populated with features from the
         *         file
         * @throws IOException
         *             if an error occurs reading the file
         */
        public static <T extends LocalFeature<?, ?>> MemoryLocalFeatureList<T> read(BufferedInputStream stream, Class<T> clz)
                        throws IOException
        {
                final boolean isBinary = IOUtils.isBinary(stream, LocalFeatureList.BINARY_HEADER);
                final MemoryLocalFeatureList<T> list = new MemoryLocalFeatureList<T>();

                if (isBinary) {
                        LocalFeatureListUtils.readBinary(stream, list, clz);
                } else {
                        LocalFeatureListUtils.readASCII(stream, list, clz);
                }

                return list;
        }

        /**
         * Create a MemoryLocalFeatureList by reading all the local features from
         * the specified {@link DataInput}. Reading of the header is skipped, and it
         * is assumed that the data is in binary format.
         * 
         * @param <T>
         *            the type of local feature
         * @param in
         *            the data input from which to read the features
         * @param clz
         *            the class of local feature
         * @return a new MemoryLocalFeatureList populated with features from the
         *         file
         * @throws IOException
         *             if an error occurs reading the file
         */
        public static <T extends LocalFeature<?, ?>> MemoryLocalFeatureList<T> readNoHeader(DataInput in, Class<T> clz)
                        throws IOException
        {
                final MemoryLocalFeatureList<T> list = new MemoryLocalFeatureList<T>();

                LocalFeatureListUtils.readBinary(in, list, clz);

                return list;
        }

        @SuppressWarnings("unchecked")
        @Override
        public <Q> Q[] asDataArray(Q[] a) {
                if (a.length < size()) {
                        System.out.println(a.getClass());
                        a = (Q[]) Array.newInstance(a.getClass().getComponentType(), size());
                }

                int i = 0;
                for (final T t : this) {
                        a[i++] = (Q) t.getFeatureVector().getVector();
                }

                return a;
        }

        @Override
        public MemoryLocalFeatureList<T> randomSubList(int nelem) {
                MemoryLocalFeatureList<T> kl;

                if (nelem > size()) {
                        kl = new MemoryLocalFeatureList<T>(this);
                        Collections.shuffle(kl);
                } else {
                        final int[] rnds = RandomData.getUniqueRandomInts(nelem, 0, this.size());
                        kl = new MemoryLocalFeatureList<T>(cached_veclen);

                        for (final int idx : rnds)
                                kl.add(this.get(idx));
                }

                return kl;
        }

        @Override
        public void writeBinary(DataOutput out) throws IOException {
                resetVecLength();
                LocalFeatureListUtils.writeBinary(out, this);
        }

        @Override
        public void writeASCII(PrintWriter out) throws IOException {
                resetVecLength();
                LocalFeatureListUtils.writeASCII(out, this);
        }

        @Override
        public byte[] binaryHeader() {
                return LocalFeatureList.BINARY_HEADER;
        }

        @Override
        public String asciiHeader() {
                return "";
        }

        /*
         * @see org.openimaj.feature.local.list.LocalFeatureList#vecLength()
         */
        @Override
        public int vecLength() {
                resetVecLength();

                if (cached_veclen == -1) {
                        if (size() > 0) {
                                cached_veclen = get(0).getFeatureVector().length();
                        }
                }
                return cached_veclen;
        }

        /**
         * Reset the internal feature vector length to the length of the first
         * feature. You must call this if you change the length of the features
         * within the list.
         */
        public void resetVecLength() {
                if (size() > 0) {
                        cached_veclen = get(0).getFeatureVector().length();
                }
        }

        /**
         * Create a new list by applying a {@link LocationFilter} to all the
         * elements of this list. Only items which are accepted by the filter will
         * be added to the new list.
         * 
         * @param locationFilter
         *            the location filter
         * @return a filtered list
         */
        public MemoryLocalFeatureList<T> filter(LocationFilter locationFilter) {
                final MemoryLocalFeatureList<T> newlist = new MemoryLocalFeatureList<T>();
                for (final T t : this) {
                        if (locationFilter.accept(t.getLocation()))
                                newlist.add(t);
                }
                return newlist;
        }

        @Override
        public MemoryLocalFeatureList<T> subList(int fromIndex, int toIndex) {
                return new MemoryLocalFeatureList<T>(super.subList(fromIndex, toIndex));
        }
}