/**
 * Copyright (c) 2012, The National Archives <pronom@nationalarchives.gsi.gov.uk>
 * 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 The National Archives 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 HOLDER 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 uk.gov.nationalarchives.droid.command.archive;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;

import org.apache.commons.compress.archivers.tar.TarArchiveEntry;
import org.apache.commons.compress.archivers.tar.TarArchiveInputStream;

import uk.gov.nationalarchives.droid.command.ResultPrinter;
import uk.gov.nationalarchives.droid.command.action.CommandExecutionException;
import uk.gov.nationalarchives.droid.container.ContainerSignatureDefinitions;
import uk.gov.nationalarchives.droid.core.BinarySignatureIdentifier;
import uk.gov.nationalarchives.droid.core.interfaces.IdentificationRequest;
import uk.gov.nationalarchives.droid.core.interfaces.IdentificationResultCollection;
import uk.gov.nationalarchives.droid.core.interfaces.RequestIdentifier;
import uk.gov.nationalarchives.droid.core.interfaces.resource.RequestMetaData;
import uk.gov.nationalarchives.droid.core.interfaces.resource.TarEntryIdentificationRequest;

/**
 * Identifier for files held in a TAR archive.
 * 
 * @author rbrennan
 */
public class TarArchiveContentIdentifier {

    private BinarySignatureIdentifier binarySignatureIdentifier;
    private ContainerSignatureDefinitions containerSignatureDefinitions;
    private String path;
    private String slash;
    private String slash1;
    private File tmpDir;
    
    /**
     * 
     * @param binarySignatureIdentifier     binary signature identifier
     * @param containerSignatureDefinitions container signatures
     * @param path                          current archive path 
     * @param slash                         local path element delimiter
     * @param slash1                        local first container prefix delimiter
     */
    public TarArchiveContentIdentifier(final BinarySignatureIdentifier binarySignatureIdentifier,
            final ContainerSignatureDefinitions containerSignatureDefinitions,
            final String path, final String slash, final String slash1) {
    
        synchronized (this) {
            this.binarySignatureIdentifier = binarySignatureIdentifier;
            this.containerSignatureDefinitions = containerSignatureDefinitions;
            this.path = path;
            this.slash = slash;
            this.slash1 = slash1;
            if (tmpDir == null) {
                tmpDir = new File(System.getProperty("java.io.tmpdir"));
            }
        }
    }
    
    /**
     * @param uri The URI of the file to identify
     * @param request The Identification Request
     * @throws CommandExecutionException When an exception happens during execution
     * @throws CommandExecutionException When an exception happens during archive access
     */
    public void identify(final URI uri, final IdentificationRequest request)
        throws CommandExecutionException {
        
        final String newPath = "tar:" + slash1 + path + request.getFileName() + "!" + slash;
        slash1 = "";
        InputStream tarIn = null; 
        try {
            tarIn = request.getSourceInputStream(); 
            final TarArchiveInputStream in = new TarArchiveInputStream(tarIn);
            try {
                TarArchiveEntry entry = null; 
                while ((entry = (TarArchiveEntry) in.getNextTarEntry()) != null) {
                    String name = entry.getName();
                    if (!entry.isDirectory()) {
                        final RequestMetaData metaData = new RequestMetaData(1L, 2L, name);
                        final RequestIdentifier identifier = new RequestIdentifier(uri);
                        final TarEntryIdentificationRequest tarRequest =
                            new TarEntryIdentificationRequest(metaData, identifier, tmpDir);
                        tarRequest.open(in);
                        final IdentificationResultCollection tarResults =
                                binarySignatureIdentifier.matchBinarySignatures(tarRequest);
                        final ResultPrinter resultPrinter =
                                new ResultPrinter(binarySignatureIdentifier,
                                    containerSignatureDefinitions, newPath, slash, slash1, true);
                        resultPrinter.print(tarResults, tarRequest);
                    }
                }
            } finally {
                if (in != null) {
                    in.close();
                }
            }
        } catch (IOException ioe) {
            System.err.println(ioe + " (" + newPath + ")"); // continue after corrupt archive 
        } finally {
            if (tarIn != null) {
                try {
                    tarIn.close();
                } catch (IOException ioe) {
                    throw new CommandExecutionException(ioe.getMessage(), ioe);
                }
            }
        }
    }
}
