/*
 * 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.commons.compress.archivers.zip;

import static org.apache.commons.compress.archivers.zip.ZipConstants.DWORD;
import static org.apache.commons.compress.archivers.zip.ZipConstants.WORD;

import java.util.zip.ZipException;

import org.apache.commons.compress.utils.ByteUtils;

/**
 * Holds size and other extended information for entries that use Zip64 features.
 *
 * <p>
 * Currently Commons Compress doesn't support encrypting the central directory so the note in APPNOTE.TXT about masking doesn't apply.
 * </p>
 *
 * <p>
 * The implementation relies on data being read from the local file header and assumes that both size values are always present.
 * </p>
 *
 * @see <a href="https://www.pkware.com/documents/casestudies/APPNOTE.TXT">PKWARE APPNOTE.TXT, section 4.5.3</a>
 *
 * @since 1.2
 * @NotThreadSafe
 */
public class Zip64ExtendedInformationExtraField implements ZipExtraField {

    static final ZipShort HEADER_ID = new ZipShort(0x0001);

    private static final String LFH_MUST_HAVE_BOTH_SIZES_MSG = "Zip64 extended information must contain" + " both size values in the local file header.";
    private ZipEightByteInteger size, compressedSize, relativeHeaderOffset;
    private ZipLong diskStart;

    /**
     * Stored in {@link #parseFromCentralDirectoryData parseFromCentralDirectoryData} so it can be reused when ZipFile calls {@link #reparseCentralDirectoryData
     * reparseCentralDirectoryData}.
     *
     * <p>
     * Not used for anything else
     * </p>
     *
     * @since 1.3
     */
    private byte[] rawCentralDirectoryData;

    /**
     * This constructor should only be used by the code that reads archives inside of Commons Compress.
     */
    public Zip64ExtendedInformationExtraField() {
    }

    /**
     * Creates an extra field based on the original and compressed size.
     *
     * @param size           the entry's original size
     * @param compressedSize the entry's compressed size
     *
     * @throws IllegalArgumentException if size or compressedSize is null
     */
    public Zip64ExtendedInformationExtraField(final ZipEightByteInteger size, final ZipEightByteInteger compressedSize) {
        this(size, compressedSize, null, null);
    }

    /**
     * Creates an extra field based on all four possible values.
     *
     * @param size                 the entry's original size
     * @param compressedSize       the entry's compressed size
     * @param relativeHeaderOffset the entry's offset
     * @param diskStart            the disk start
     *
     * @throws IllegalArgumentException if size or compressedSize is null
     */
    public Zip64ExtendedInformationExtraField(final ZipEightByteInteger size, final ZipEightByteInteger compressedSize,
            final ZipEightByteInteger relativeHeaderOffset, final ZipLong diskStart) {
        this.size = size;
        this.compressedSize = compressedSize;
        this.relativeHeaderOffset = relativeHeaderOffset;
        this.diskStart = diskStart;
    }

    private int addSizes(final byte[] data) {
        int off = 0;
        if (size != null) {
            System.arraycopy(size.getBytes(), 0, data, 0, DWORD);
            off += DWORD;
        }
        if (compressedSize != null) {
            System.arraycopy(compressedSize.getBytes(), 0, data, off, DWORD);
            off += DWORD;
        }
        return off;
    }

    @Override
    public byte[] getCentralDirectoryData() {
        final byte[] data = new byte[getCentralDirectoryLength().getValue()];
        int off = addSizes(data);
        if (relativeHeaderOffset != null) {
            System.arraycopy(relativeHeaderOffset.getBytes(), 0, data, off, DWORD);
            off += DWORD;
        }
        if (diskStart != null) {
            System.arraycopy(diskStart.getBytes(), 0, data, off, WORD);
            off += WORD; // NOSONAR - assignment as documentation
        }
        return data;
    }

    @Override
    public ZipShort getCentralDirectoryLength() {
        return new ZipShort((size != null ? DWORD : 0) + (compressedSize != null ? DWORD : 0) + (relativeHeaderOffset != null ? DWORD : 0)
                + (diskStart != null ? WORD : 0));
    }

    /**
     * The compressed size stored in this extra field.
     *
     * @return The compressed size stored in this extra field.
     */
    public ZipEightByteInteger getCompressedSize() {
        return compressedSize;
    }

    /**
     * The disk start number stored in this extra field.
     *
     * @return The disk start number stored in this extra field.
     */
    public ZipLong getDiskStartNumber() {
        return diskStart;
    }

    @Override
    public ZipShort getHeaderId() {
        return HEADER_ID;
    }

    @Override
    public byte[] getLocalFileDataData() {
        if (size != null || compressedSize != null) {
            if (size == null || compressedSize == null) {
                throw new IllegalArgumentException(LFH_MUST_HAVE_BOTH_SIZES_MSG);
            }
            final byte[] data = new byte[2 * DWORD];
            addSizes(data);
            return data;
        }
        return ByteUtils.EMPTY_BYTE_ARRAY;
    }

    @Override
    public ZipShort getLocalFileDataLength() {
        return new ZipShort(size != null ? 2 * DWORD : 0);
    }

    /**
     * The relative header offset stored in this extra field.
     *
     * @return The relative header offset stored in this extra field.
     */
    public ZipEightByteInteger getRelativeHeaderOffset() {
        return relativeHeaderOffset;
    }

    /**
     * The uncompressed size stored in this extra field.
     *
     * @return The uncompressed size stored in this extra field.
     */
    public ZipEightByteInteger getSize() {
        return size;
    }

    @Override
    public void parseFromCentralDirectoryData(final byte[] buffer, int offset, final int length) throws ZipException {
        // store for processing in reparseCentralDirectoryData
        rawCentralDirectoryData = new byte[length];
        System.arraycopy(buffer, offset, rawCentralDirectoryData, 0, length);

        // if there is no size information in here, we are screwed and
        // can only hope things will get resolved by LFH data later
        // But there are some cases that can be detected
        // * all data is there
        // * length == 24 -> both sizes and offset
        // * length % 8 == 4 -> at least we can identify the diskStart field
        if (length >= 3 * DWORD + WORD) {
            parseFromLocalFileData(buffer, offset, length);
        } else if (length == 3 * DWORD) {
            size = new ZipEightByteInteger(buffer, offset);
            offset += DWORD;
            compressedSize = new ZipEightByteInteger(buffer, offset);
            offset += DWORD;
            relativeHeaderOffset = new ZipEightByteInteger(buffer, offset);
        } else if (length % DWORD == WORD) {
            diskStart = new ZipLong(buffer, offset + length - WORD);
        }
    }

    @Override
    public void parseFromLocalFileData(final byte[] buffer, int offset, final int length) throws ZipException {
        if (length == 0) {
            // no local file data at all, may happen if an archive
            // only holds a ZIP64 extended information extra field
            // inside the central directory but not inside the local
            // file header
            return;
        }
        if (length < 2 * DWORD) {
            throw new ZipException(LFH_MUST_HAVE_BOTH_SIZES_MSG);
        }
        size = new ZipEightByteInteger(buffer, offset);
        offset += DWORD;
        compressedSize = new ZipEightByteInteger(buffer, offset);
        offset += DWORD;
        int remaining = length - 2 * DWORD;
        if (remaining >= DWORD) {
            relativeHeaderOffset = new ZipEightByteInteger(buffer, offset);
            offset += DWORD;
            remaining -= DWORD;
        }
        if (remaining >= WORD) {
            diskStart = new ZipLong(buffer, offset);
            offset += WORD; // NOSONAR - assignment as documentation
            remaining -= WORD; // NOSONAR - assignment as documentation
        }
    }

    /**
     * Parses the raw bytes read from the central directory extra field with knowledge which fields are expected to be there.
     *
     * <p>
     * All four fields inside the zip64 extended information extra field are optional and must only be present if their corresponding entry inside the central
     * directory contains the correct magic value.
     * </p>
     *
     * @param hasUncompressedSize     flag to read from central directory
     * @param hasCompressedSize       flag to read from central directory
     * @param hasRelativeHeaderOffset flag to read from central directory
     * @param hasDiskStart            flag to read from central directory
     * @throws ZipException on error
     */
    public void reparseCentralDirectoryData(final boolean hasUncompressedSize, final boolean hasCompressedSize, final boolean hasRelativeHeaderOffset,
            final boolean hasDiskStart) throws ZipException {
        if (rawCentralDirectoryData != null) {
            final int expectedLength = (hasUncompressedSize ? DWORD : 0) + (hasCompressedSize ? DWORD : 0) + (hasRelativeHeaderOffset ? DWORD : 0)
                    + (hasDiskStart ? WORD : 0);
            if (rawCentralDirectoryData.length < expectedLength) {
                throw new ZipException("Central directory zip64 extended" + " information extra field's length" + " doesn't match central directory"
                        + " data.  Expected length " + expectedLength + " but is " + rawCentralDirectoryData.length);
            }
            int offset = 0;
            if (hasUncompressedSize) {
                size = new ZipEightByteInteger(rawCentralDirectoryData, offset);
                offset += DWORD;
            }
            if (hasCompressedSize) {
                compressedSize = new ZipEightByteInteger(rawCentralDirectoryData, offset);
                offset += DWORD;
            }
            if (hasRelativeHeaderOffset) {
                relativeHeaderOffset = new ZipEightByteInteger(rawCentralDirectoryData, offset);
                offset += DWORD;
            }
            if (hasDiskStart) {
                diskStart = new ZipLong(rawCentralDirectoryData, offset);
                offset += WORD; // NOSONAR - assignment as documentation
            }
        }
    }

    /**
     * The uncompressed size stored in this extra field.
     *
     * @param compressedSize The uncompressed size stored in this extra field.
     */
    public void setCompressedSize(final ZipEightByteInteger compressedSize) {
        this.compressedSize = compressedSize;
    }

    /**
     * The disk start number stored in this extra field.
     *
     * @param ds The disk start number stored in this extra field.
     */
    public void setDiskStartNumber(final ZipLong ds) {
        diskStart = ds;
    }

    /**
     * The relative header offset stored in this extra field.
     *
     * @param rho The relative header offset stored in this extra field.
     */
    public void setRelativeHeaderOffset(final ZipEightByteInteger rho) {
        relativeHeaderOffset = rho;
    }

    /**
     * The uncompressed size stored in this extra field.
     *
     * @param size The uncompressed size stored in this extra field.
     */
    public void setSize(final ZipEightByteInteger size) {
        this.size = size;
    }
}