/*
 * 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.
 */
package org.apache.tika.zip.utils;

import java.io.EOFException;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.nio.file.Files;
import java.util.zip.ZipException;

import org.apache.commons.compress.archivers.zip.ZipArchiveEntry;
import org.apache.commons.compress.archivers.zip.ZipArchiveInputStream;
import org.apache.commons.compress.archivers.zip.ZipArchiveOutputStream;
import org.apache.commons.io.IOUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class ZipSalvager {

    private static final Logger LOG = LoggerFactory.getLogger(ZipSalvager.class);

    /**
     * This streams the broken zip and rebuilds a new zip that
     * is at least a valid zip file.  The contents of the final stream
     * may be truncated, but the result should be a valid zip file.
     * <p>
     * This does nothing fancy to fix the underlying broken zip.
     *
     * @param brokenZip
     * @param salvagedZip
     */
    public static void salvageCopy(InputStream brokenZip, File salvagedZip) {
        try (ZipArchiveOutputStream outputStream = new ZipArchiveOutputStream(salvagedZip)) {
            ZipArchiveInputStream zipArchiveInputStream = new ZipArchiveInputStream(brokenZip);
            ZipArchiveEntry zae = zipArchiveInputStream.getNextZipEntry();
            while (zae != null) {
                try {
                    if (!zae.isDirectory() && zipArchiveInputStream.canReadEntryData(zae)) {
                        //create a new ZAE and copy over only the name so that
                        //if there is bad info (e.g. CRC) in brokenZip's zae, that
                        //won't be propagated or cause an exception
                        outputStream.putArchiveEntry(new ZipArchiveEntry(zae.getName()));
                        //this will copy an incomplete stream...so there
                        //could be truncation of the xml/contents, but the zip file
                        //should be intact.
                        boolean successfullyCopied = false;
                        try {
                            IOUtils.copy(zipArchiveInputStream, outputStream);
                            successfullyCopied = true;
                        } catch (IOException e) {
                            //this can hit a "truncated ZipFile" IOException
                        }
                        outputStream.flush();
                        outputStream.closeArchiveEntry();
                        if (!successfullyCopied) {
                            break;
                        }
                    }
                    zae = zipArchiveInputStream.getNextZipEntry();
                } catch (ZipException | EOFException e) {
                    break;
                }

            }
            outputStream.flush();
            outputStream.finish();


        } catch (IOException e) {
            LOG.warn("problem fixing zip", e);
        }
    }

    public static void salvageCopy(File brokenZip, File salvagedZip) throws IOException {
        try (InputStream is = Files.newInputStream(brokenZip.toPath())) {
            salvageCopy(is, salvagedZip);
        }
    }
}
