/*
 * ====================================================================
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */

package org.apache.http.nio.entity;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.RandomAccessFile;
import java.nio.channels.FileChannel;

import org.apache.http.entity.AbstractHttpEntity;
import org.apache.http.entity.ContentType;
import org.apache.http.nio.ContentEncoder;
import org.apache.http.nio.ContentEncoderChannel;
import org.apache.http.nio.FileContentEncoder;
import org.apache.http.nio.IOControl;
import org.apache.http.util.Args;

A self contained, repeatable non-blocking entity that retrieves its content
from a file. This class is mostly used to stream large files of different
types, so one needs to supply the content type of the file to make sure
the content can be correctly recognized and processed by the recipient.
Since:
4.0/**
 * A self contained, repeatable non-blocking entity that retrieves its content
 * from a file. This class is mostly used to stream large files of different
 * types, so one needs to supply the content type of the file to make sure
 * the content can be correctly recognized and processed by the recipient.
 *
 * @since 4.0
 */
@SuppressWarnings("deprecation")
public class NFileEntity extends AbstractHttpEntity
                         implements HttpAsyncContentProducer, ProducingNHttpEntity {

    private final File file;
    private RandomAccessFile accessfile;
    private FileChannel fileChannel;
    private long idx = -1;
    private boolean useFileChannels;

    
Creates new instance of NFileEntity from the given source File with the given content type. If useFileChannels is set to true, the entity will try to use FileContentEncoder interface to stream file content directly from the file channel. 
Params:
file – the source file.
contentType – the content type of the file.
useFileChannels – flag whether the direct transfer from the file
  channel should be attempted.
Since:
4.2/**
     * Creates new instance of NFileEntity from the given source {@link File}
     * with the given content type. If {@code useFileChannels} is set to
     * {@code true}, the entity will try to use {@link FileContentEncoder}
     * interface to stream file content directly from the file channel.
     *
     * @param file the source file.
     * @param contentType the content type of the file.
     * @param useFileChannels flag whether the direct transfer from the file
     *   channel should be attempted.
     *
     * @since 4.2
     */
    public NFileEntity(final File file, final ContentType contentType, final boolean useFileChannels) {
        Args.notNull(file, "File");
        this.file = file;
        this.useFileChannels = useFileChannels;
        if (contentType != null) {
            setContentType(contentType.toString());
        }
    }

    
Since:
4.2/**
     * @since 4.2
     */
    public NFileEntity(final File file) {
        Args.notNull(file, "File");
        this.file = file;
    }
    
Creates new instance of NFileEntity from the given source File with the given content type. 
Params:
file – the source file.
contentType – the content type of the file.
Since:
4.2/**
     * Creates new instance of NFileEntity from the given source {@link File}
     * with the given content type.
     *
     * @param file the source file.
     * @param contentType the content type of the file.
     *
     * @since 4.2
     */
    public NFileEntity(final File file, final ContentType contentType) {
        this(file, contentType, true);
    }

    
Deprecated:
(4.2) use NFileEntity(File, ContentType, boolean)/**
     * @deprecated (4.2) use {@link #NFileEntity(File, ContentType, boolean)}
     */
    @Deprecated
    public NFileEntity(final File file, final String contentType, final boolean useFileChannels) {
        Args.notNull(file, "File");
        this.file = file;
        this.useFileChannels = useFileChannels;
        setContentType(contentType);
    }

    
Deprecated:
(4.2) use NFileEntity(File, ContentType)/**
     * @deprecated (4.2) use {@link #NFileEntity(File, ContentType)}
     */
    @Deprecated
    public NFileEntity(final File file, final String contentType) {
        this(file, contentType, true);
    }

    
{@inheritDoc}
Since:
4.2/**
     * {@inheritDoc}
     *
     * @since 4.2
     */
    @Override
    public void close() throws IOException {
        if (accessfile != null) {
            accessfile.close();
        }
        accessfile = null;
        fileChannel = null;
    }

    
{@inheritDoc}
Deprecated:
(4.2) use close()/**
     * {@inheritDoc}
     *
     * @deprecated (4.2) use {@link #close()}
     */
    @Override
    @Deprecated
    public void finish() throws IOException {
        close();
    }

    @Override
    public long getContentLength() {
        return file.length();
    }

    @Override
    public boolean isRepeatable() {
        return true;
    }

    @Override
    public void produceContent(final ContentEncoder encoder, final IOControl ioControl)
            throws IOException {
        if (accessfile == null) {
            accessfile = new RandomAccessFile(this.file, "r");
        }
        if (fileChannel == null) {
            fileChannel = accessfile.getChannel();
            idx = 0;
        }

        final long transferred;
        if (useFileChannels && encoder instanceof FileContentEncoder) {
            transferred = ((FileContentEncoder)encoder)
                .transfer(fileChannel, idx, Long.MAX_VALUE);
        } else {
            transferred = fileChannel.
                transferTo(idx, Long.MAX_VALUE, new ContentEncoderChannel(encoder));
        }
        if (transferred > 0) {
            idx += transferred;
        }
        if (idx >= fileChannel.size()) {
            encoder.complete();
            close();
        }
    }

    @Override
    public boolean isStreaming() {
        return false;
    }

    @Override
    public InputStream getContent() throws IOException {
        return new FileInputStream(this.file);
    }

    @Override
    public void writeTo(final OutputStream outStream) throws IOException {
        Args.notNull(outStream, "Output stream");
        final InputStream inStream = new FileInputStream(this.file);
        try {
            final byte[] tmp = new byte[4096];
            int l;
            while ((l = inStream.read(tmp)) != -1) {
                outStream.write(tmp, 0, l);
            }
            outStream.flush();
        } finally {
            inStream.close();
        }
    }

}