/*
 *  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.tools.zip;

import java.io.File;
import java.io.FileOutputStream;
import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.RandomAccessFile;
import java.io.UnsupportedEncodingException;
import java.util.Date;
import java.util.Hashtable;
import java.util.Vector;
import java.util.zip.CRC32;
import java.util.zip.Deflater;
import java.util.zip.ZipException;

/**
 * Reimplementation of {@link java.util.zip.ZipOutputStream
 * java.util.zip.ZipOutputStream} that does handle the extended functionality of
 * this package, especially internal/external file attributes and extra fields
 * with different layouts for local file data and central directory entries.
 * 
 * <p>
 * This class will try to use {@link java.io.RandomAccessFile RandomAccessFile}
 * when you know that the output is going to go to a file.
 * </p>
 * 
 * <p>
 * If RandomAccessFile cannot be used, this implementation will use a Data
 * Descriptor to store size and CRC information for {@link #DEFLATED DEFLATED}
 * entries, this means, you don't need to calculate them yourself. Unfortunately
 * this is not possible for the {@link #STORED STORED} method, here setting the
 * CRC and uncompressed size information is required before
 * {@link #putNextEntry putNextEntry} can be called.
 * </p>
 * 
 */
public class ZipOutputStream extends FilterOutputStream {

  /**
   * Compression method for deflated entries.
   * 
   * @since 1.1
   */
  public static final int DEFLATED = java.util.zip.ZipEntry.DEFLATED;

  /**
   * Default compression level for deflated entries.
   * 
   * @since Ant 1.7
   */
  public static final int DEFAULT_COMPRESSION = Deflater.DEFAULT_COMPRESSION;

  /**
   * Compression method for stored entries.
   * 
   * @since 1.1
   */
  public static final int STORED = java.util.zip.ZipEntry.STORED;

  /**
   * Current entry.
   * 
   * @since 1.1
   */
  private ZipEntry entry;

  /**
   * The file comment.
   * 
   * @since 1.1
   */
  private String comment = "";

  /**
   * Compression level for next entry.
   * 
   * @since 1.1
   */
  private int level = DEFAULT_COMPRESSION;

  /**
   * Has the compression level changed when compared to the last entry?
   * 
   * @since 1.5
   */
  private boolean hasCompressionLevelChanged = false;

  /**
   * Default compression method for next entry.
   * 
   * @since 1.1
   */
  private int method = java.util.zip.ZipEntry.DEFLATED;

  /**
   * List of ZipEntries written so far.
   * 
   * @since 1.1
   */
  private Vector entries = new Vector();

  /**
   * CRC instance to avoid parsing DEFLATED data twice.
   * 
   * @since 1.1
   */
  private CRC32 crc = new CRC32();

  /**
   * Count the bytes written to out.
   * 
   * @since 1.1
   */
  private long written = 0;

  /**
   * Data for local header data
   * 
   * @since 1.1
   */
  private long dataStart = 0;

  /**
   * Offset for CRC entry in the local file header data for the current entry
   * starts here.
   * 
   * @since 1.15
   */
  private long localDataStart = 0;

  /**
   * Start of central directory.
   * 
   * @since 1.1
   */
  private long cdOffset = 0;

  /**
   * Length of central directory.
   * 
   * @since 1.1
   */
  private long cdLength = 0;

  /**
   * Helper, a 0 as ZipShort.
   * 
   * @since 1.1
   */
  private static final byte[] ZERO = { 0, 0 };

  /**
   * Helper, a 0 as ZipLong.
   * 
   * @since 1.1
   */
  private static final byte[] LZERO = { 0, 0, 0, 0 };

  /**
   * Holds the offsets of the LFH starts for each entry.
   * 
   * @since 1.1
   */
  private Hashtable offsets = new Hashtable();

  /**
   * The encoding to use for filenames and the file comment.
   * 
   * <p>
   * For a list of possible values see <a
   * href="http://java.sun.com/j2se/1.5.0/docs/guide/intl/encoding.doc.html"
   * >http://java.sun.com/j2se/1.5.0/docs/guide/intl/encoding.doc.html</a>.
   * Defaults to the platform's default character encoding.
   * </p>
   * 
   * @since 1.3
   */
  private String encoding = null;

  // CheckStyle:VisibilityModifier OFF - bc

  /**
   * This Deflater object is used for output.
   * 
   * <p>
   * This attribute is only protected to provide a level of API backwards
   * compatibility. This class used to extend
   * {@link java.util.zip.DeflaterOutputStream DeflaterOutputStream} up to
   * Revision 1.13.
   * </p>
   * 
   * @since 1.14
   */
  protected Deflater def = new Deflater(level, true);

  /**
   * This buffer servers as a Deflater.
   * 
   * <p>
   * This attribute is only protected to provide a level of API backwards
   * compatibility. This class used to extend
   * {@link java.util.zip.DeflaterOutputStream DeflaterOutputStream} up to
   * Revision 1.13.
   * </p>
   * 
   * @since 1.14
   */
  protected byte[] buf = new byte[512];

  // CheckStyle:VisibilityModifier ON

  /**
   * Optional random access output.
   * 
   * @since 1.14
   */
  private RandomAccessFile raf = null;

  /**
   * Creates a new ZIP OutputStream filtering the underlying stream.
   * 
   * @param out
   *          the outputstream to zip
   * @since 1.1
   */
  public ZipOutputStream(OutputStream out) {
    super(out);
  }

  /**
   * Creates a new ZIP OutputStream writing to a File. Will use random access if
   * possible.
   * 
   * @param file
   *          the file to zip to
   * @since 1.14
   * @throws IOException
   *           on error
   */
  public ZipOutputStream(File file) throws IOException {
    super(null);

    try {
      raf = new RandomAccessFile(file, "rw");
      raf.setLength(0);
    } catch (IOException e) {
      if (raf != null) {
        try {
          raf.close();
        } catch (IOException inner) {
          // ignore
        }
        raf = null;
      }
      out = new FileOutputStream(file);
    }
  }

  /**
   * This method indicates whether this archive is writing to a seekable stream
   * (i.e., to a random access file).
   * 
   * <p>
   * For seekable streams, you don't need to calculate the CRC or uncompressed
   * size for {@link #STORED} entries before invoking {@link #putNextEntry}.
   * 
   * @return true if seekable
   * @since 1.17
   */
  public boolean isSeekable() {
    return raf != null;
  }

  /**
   * The encoding to use for filenames and the file comment.
   * 
   * <p>
   * For a list of possible values see <a
   * href="http://java.sun.com/j2se/1.5.0/docs/guide/intl/encoding.doc.html"
   * >http://java.sun.com/j2se/1.5.0/docs/guide/intl/encoding.doc.html</a>.
   * Defaults to the platform's default character encoding.
   * </p>
   * 
   * @param encoding
   *          the encoding value
   * @since 1.3
   */
  public void setEncoding(String encoding) {
    this.encoding = encoding;
  }

  /**
   * The encoding to use for filenames and the file comment.
   * 
   * @return null if using the platform's default character encoding.
   * 
   * @since 1.3
   */
  public String getEncoding() {
    return encoding;
  }

  /**
   * Finishs writing the contents and closes this as well as the underlying
   * stream.
   * 
   * @since 1.1
   * @throws IOException
   *           on error
   */
  public void finish() throws IOException {
    closeEntry();
    cdOffset = written;
    for (int i = 0, entriesSize = entries.size(); i < entriesSize; i++) {
      writeCentralFileHeader((ZipEntry) entries.elementAt(i));
    }
    cdLength = written - cdOffset;
    writeCentralDirectoryEnd();
    offsets.clear();
    entries.removeAllElements();
  }

  /**
   * Writes all necessary data for this entry.
   * 
   * @since 1.1
   * @throws IOException
   *           on error
   */
  public void closeEntry() throws IOException {
    if (entry == null) {
      return;
    }

    long realCrc = crc.getValue();
    crc.reset();

    if (entry.getMethod() == DEFLATED) {
      def.finish();
      while (!def.finished()) {
        deflate();
      }

      entry.setSize(adjustToLong(def.getTotalIn()));
      entry.setCompressedSize(adjustToLong(def.getTotalOut()));
      entry.setCrc(realCrc);

      def.reset();

      written += entry.getCompressedSize();
    } else if (raf == null) {
      if (entry.getCrc() != realCrc) {
        throw new ZipException("bad CRC checksum for entry " + entry.getName()
            + ": " + Long.toHexString(entry.getCrc()) + " instead of "
            + Long.toHexString(realCrc));
      }

      if (entry.getSize() != written - dataStart) {
        throw new ZipException("bad size for entry " + entry.getName() + ": "
            + entry.getSize() + " instead of " + (written - dataStart));
      }
    } else { /* method is STORED and we used RandomAccessFile */
      long size = written - dataStart;

      entry.setSize(size);
      entry.setCompressedSize(size);
      entry.setCrc(realCrc);
    }

    // If random access output, write the local file header containing
    // the correct CRC and compressed/uncompressed sizes
    if (raf != null) {
      long save = raf.getFilePointer();

      raf.seek(localDataStart);
      writeOut(ZipLong.getBytes(entry.getCrc()));
      writeOut(ZipLong.getBytes(entry.getCompressedSize()));
      writeOut(ZipLong.getBytes(entry.getSize()));
      raf.seek(save);
    }

    writeDataDescriptor(entry);
    entry = null;
  }

  /**
   * Begin writing next entry.
   * 
   * @param ze
   *          the entry to write
   * @since 1.1
   * @throws IOException
   *           on error
   */
  public void putNextEntry(ZipEntry ze) throws IOException {
    closeEntry();

    entry = ze;
    entries.addElement(entry);

    if (entry.getMethod() == -1) { // not specified
      entry.setMethod(method);
    }

    if (entry.getTime() == -1) { // not specified
      entry.setTime(System.currentTimeMillis());
    }

    // Size/CRC not required if RandomAccessFile is used
    if (entry.getMethod() == STORED && raf == null) {
      if (entry.getSize() == -1) {
        throw new ZipException("uncompressed size is required for"
            + " STORED method when not writing to a" + " file");
      }
      if (entry.getCrc() == -1) {
        throw new ZipException("crc checksum is required for STORED"
            + " method when not writing to a file");
      }
      entry.setCompressedSize(entry.getSize());
    }

    if (entry.getMethod() == DEFLATED && hasCompressionLevelChanged) {
      def.setLevel(level);
      hasCompressionLevelChanged = false;
    }
    writeLocalFileHeader(entry);
  }

  /**
   * Set the file comment.
   * 
   * @param comment
   *          the comment
   * @since 1.1
   */
  public void setComment(String comment) {
    this.comment = comment;
  }

  /**
   * Sets the compression level for subsequent entries.
   * 
   * <p>
   * Default is Deflater.DEFAULT_COMPRESSION.
   * </p>
   * 
   * @param level
   *          the compression level.
   * @throws IllegalArgumentException
   *           if an invalid compression level is specified.
   * @since 1.1
   */
  public void setLevel(int level) {
    if (level < Deflater.DEFAULT_COMPRESSION
        || level > Deflater.BEST_COMPRESSION) {
      throw new IllegalArgumentException("Invalid compression level: " + level);
    }
    hasCompressionLevelChanged = (this.level != level);
    this.level = level;
  }

  /**
   * Sets the default compression method for subsequent entries.
   * 
   * <p>
   * Default is DEFLATED.
   * </p>
   * 
   * @param method
   *          an <code>int</code> from java.util.zip.ZipEntry
   * @since 1.1
   */
  public void setMethod(int method) {
    this.method = method;
  }

  /**
   * Writes bytes to ZIP entry.
   * 
   * @param b
   *          the byte array to write
   * @param offset
   *          the start position to write from
   * @param length
   *          the number of bytes to write
   * @throws IOException
   *           on error
   */
  public void write(byte[] b, int offset, int length) throws IOException {
    if (entry.getMethod() == DEFLATED) {
      if (length > 0) {
        if (!def.finished()) {
          def.setInput(b, offset, length);
          while (!def.needsInput()) {
            deflate();
          }
        }
      }
    } else {
      writeOut(b, offset, length);
      written += length;
    }
    crc.update(b, offset, length);
  }

  /**
   * Writes a single byte to ZIP entry.
   * 
   * <p>
   * Delegates to the three arg method.
   * </p>
   * 
   * @param b
   *          the byte to write
   * @since 1.14
   * @throws IOException
   *           on error
   */
  public void write(int b) throws IOException {
    byte[] buff = new byte[1];
    buff[0] = (byte) (b & 0xff);
    write(buff, 0, 1);
  }

  /**
   * Closes this output stream and releases any system resources associated with
   * the stream.
   * 
   * @exception IOException
   *              if an I/O error occurs.
   * @since 1.14
   */
  public void close() throws IOException {
    finish();

    if (raf != null) {
      raf.close();
    }
    if (out != null) {
      out.close();
    }
  }

  /**
   * Flushes this output stream and forces any buffered output bytes to be
   * written out to the stream.
   * 
   * @exception IOException
   *              if an I/O error occurs.
   * @since 1.14
   */
  public void flush() throws IOException {
    if (out != null) {
      out.flush();
    }
  }

  /*
   * Various ZIP constants
   */
  /**
   * local file header signature
   * 
   * @since 1.1
   */
  protected static final byte[] LFH_SIG = ZipLong.getBytes(0X04034B50L);

  /**
   * data descriptor signature
   * 
   * @since 1.1
   */
  protected static final byte[] DD_SIG = ZipLong.getBytes(0X08074B50L);

  /**
   * central file header signature
   * 
   * @since 1.1
   */
  protected static final byte[] CFH_SIG = ZipLong.getBytes(0X02014B50L);

  /**
   * end of central dir signature
   * 
   * @since 1.1
   */
  protected static final byte[] EOCD_SIG = ZipLong.getBytes(0X06054B50L);

  /**
   * Writes next block of compressed data to the output stream.
   * 
   * @throws IOException
   *           on error
   * 
   * @since 1.14
   */
  protected final void deflate() throws IOException {
    int len = def.deflate(buf, 0, buf.length);
    if (len > 0) {
      writeOut(buf, 0, len);
    }
  }

  /**
   * Writes the local file header entry
   * 
   * @param ze
   *          the entry to write
   * @throws IOException
   *           on error
   * 
   * @since 1.1
   */
  protected void writeLocalFileHeader(ZipEntry ze) throws IOException {
    offsets.put(ze, ZipLong.getBytes(written));

    writeOut(LFH_SIG);
    written += 4;

    // store method in local variable to prevent multiple method calls
    final int zipMethod = ze.getMethod();

    // version needed to extract
    // general purpose bit flag
    if (zipMethod == DEFLATED && raf == null) {
      // requires version 2 as we are going to store length info
      // in the data descriptor
      writeOut(ZipShort.getBytes(20));

      // bit3 set to signal, we use a data descriptor
      writeOut(ZipShort.getBytes(8));
    } else {
      writeOut(ZipShort.getBytes(10));
      writeOut(ZERO);
    }
    written += 4;

    // compression method
    writeOut(ZipShort.getBytes(zipMethod));
    written += 2;

    // last mod. time and date
    writeOut(toDosTime(ze.getTime()));
    written += 4;

    // CRC
    // compressed length
    // uncompressed length
    localDataStart = written;
    if (zipMethod == DEFLATED || raf != null) {
      writeOut(LZERO);
      writeOut(LZERO);
      writeOut(LZERO);
    } else {
      writeOut(ZipLong.getBytes(ze.getCrc()));
      writeOut(ZipLong.getBytes(ze.getSize()));
      writeOut(ZipLong.getBytes(ze.getSize()));
    }
    written += 12;

    // file name length
    byte[] name = getBytes(ze.getName());
    writeOut(ZipShort.getBytes(name.length));
    written += 2;

    // extra field length
    byte[] extra = ze.getLocalFileDataExtra();
    writeOut(ZipShort.getBytes(extra.length));
    written += 2;

    // file name
    writeOut(name);
    written += name.length;

    // extra field
    writeOut(extra);
    written += extra.length;

    dataStart = written;
  }

  /**
   * Writes the data descriptor entry.
   * 
   * @param ze
   *          the entry to write
   * @throws IOException
   *           on error
   * 
   * @since 1.1
   */
  protected void writeDataDescriptor(ZipEntry ze) throws IOException {
    if (ze.getMethod() != DEFLATED || raf != null) {
      return;
    }
    writeOut(DD_SIG);
    writeOut(ZipLong.getBytes(entry.getCrc()));
    writeOut(ZipLong.getBytes(entry.getCompressedSize()));
    writeOut(ZipLong.getBytes(entry.getSize()));
    written += 16;
  }

  /**
   * Writes the central file header entry.
   * 
   * @param ze
   *          the entry to write
   * @throws IOException
   *           on error
   * 
   * @since 1.1
   */
  protected void writeCentralFileHeader(ZipEntry ze) throws IOException {
    writeOut(CFH_SIG);
    written += 4;

    // version made by
    writeOut(ZipShort.getBytes((ze.getPlatform() << 8) | 20));
    written += 2;

    // version needed to extract
    // general purpose bit flag
    if (ze.getMethod() == DEFLATED && raf == null) {
      // requires version 2 as we are going to store length info
      // in the data descriptor
      writeOut(ZipShort.getBytes(20));

      // bit3 set to signal, we use a data descriptor
      writeOut(ZipShort.getBytes(8));
    } else {
      writeOut(ZipShort.getBytes(10));
      writeOut(ZERO);
    }
    written += 4;

    // compression method
    writeOut(ZipShort.getBytes(ze.getMethod()));
    written += 2;

    // last mod. time and date
    writeOut(toDosTime(ze.getTime()));
    written += 4;

    // CRC
    // compressed length
    // uncompressed length
    writeOut(ZipLong.getBytes(ze.getCrc()));
    writeOut(ZipLong.getBytes(ze.getCompressedSize()));
    writeOut(ZipLong.getBytes(ze.getSize()));
    written += 12;

    // file name length
    byte[] name = getBytes(ze.getName());
    writeOut(ZipShort.getBytes(name.length));
    written += 2;

    // extra field length
    byte[] extra = ze.getCentralDirectoryExtra();
    writeOut(ZipShort.getBytes(extra.length));
    written += 2;

    // file comment length
    String comm = ze.getComment();
    if (comm == null) {
      comm = "";
    }
    byte[] commentB = getBytes(comm);
    writeOut(ZipShort.getBytes(commentB.length));
    written += 2;

    // disk number start
    writeOut(ZERO);
    written += 2;

    // internal file attributes
    writeOut(ZipShort.getBytes(ze.getInternalAttributes()));
    written += 2;

    // external file attributes
    writeOut(ZipLong.getBytes(ze.getExternalAttributes()));
    written += 4;

    // relative offset of LFH
    writeOut((byte[]) offsets.get(ze));
    written += 4;

    // file name
    writeOut(name);
    written += name.length;

    // extra field
    writeOut(extra);
    written += extra.length;

    // file comment
    writeOut(commentB);
    written += commentB.length;
  }

  /**
   * Writes the &quot;End of central dir record&quot;.
   * 
   * @throws IOException
   *           on error
   * 
   * @since 1.1
   */
  protected void writeCentralDirectoryEnd() throws IOException {
    writeOut(EOCD_SIG);

    // disk numbers
    writeOut(ZERO);
    writeOut(ZERO);

    // number of entries
    byte[] num = ZipShort.getBytes(entries.size());
    writeOut(num);
    writeOut(num);

    // length and location of CD
    writeOut(ZipLong.getBytes(cdLength));
    writeOut(ZipLong.getBytes(cdOffset));

    // ZIP file comment
    byte[] data = getBytes(comment);
    writeOut(ZipShort.getBytes(data.length));
    writeOut(data);
  }

  /**
   * Smallest date/time ZIP can handle.
   * 
   * @since 1.1
   */
  private static final byte[] DOS_TIME_MIN = ZipLong.getBytes(0x00002100L);

  /**
   * Convert a Date object to a DOS date/time field.
   * 
   * @param time
   *          the <code>Date</code> to convert
   * @return the date as a <code>ZipLong</code>
   * @since 1.1
   */
  protected static ZipLong toDosTime(Date time) {
    return new ZipLong(toDosTime(time.getTime()));
  }

  /**
   * Convert a Date object to a DOS date/time field.
   * 
   * <p>
   * Stolen from InfoZip's <code>fileio.c</code>
   * </p>
   * 
   * @param t
   *          number of milliseconds since the epoch
   * @return the date as a byte array
   * @since 1.26
   */
  protected static byte[] toDosTime(long t) {
    Date time = new Date(t);
    int year = time.getYear() + 1900;
    if (year < 1980) {
      return DOS_TIME_MIN;
    }
    int month = time.getMonth() + 1;
    long value = ((year - 1980) << 25) | (month << 21) | (time.getDate() << 16)
        | (time.getHours() << 11) | (time.getMinutes() << 5)
        | (time.getSeconds() >> 1);
    return ZipLong.getBytes(value);
  }

  /**
   * Retrieve the bytes for the given String in the encoding set for this
   * Stream.
   * 
   * @param name
   *          the string to get bytes from
   * @return the bytes as a byte array
   * @throws ZipException
   *           on error
   * 
   * @since 1.3
   */
  protected byte[] getBytes(String name) throws ZipException {
    if (encoding == null) {
      return name.getBytes();
    } else {
      try {
        return name.getBytes(encoding);
      } catch (UnsupportedEncodingException uee) {
        throw new ZipException(uee.getMessage());
      }
    }
  }

  /**
   * Write bytes to output or random access file.
   * 
   * @param data
   *          the byte array to write
   * @throws IOException
   *           on error
   * 
   * @since 1.14
   */
  protected final void writeOut(byte[] data) throws IOException {
    writeOut(data, 0, data.length);
  }

  /**
   * Write bytes to output or random access file.
   * 
   * @param data
   *          the byte array to write
   * @param offset
   *          the start position to write from
   * @param length
   *          the number of bytes to write
   * @throws IOException
   *           on error
   * 
   * @since 1.14
   */
  protected final void writeOut(byte[] data, int offset, int length)
      throws IOException {
    if (raf != null) {
      raf.write(data, offset, length);
    } else {
      out.write(data, offset, length);
    }
  }

  /**
   * Assumes a negative integer really is a positive integer that has wrapped
   * around and re-creates the original value.
   * 
   * @param i
   *          the value to treat as unsigned int.
   * @return the unsigned int as a long.
   * @since 1.34
   */
  protected static long adjustToLong(int i) {
    if (i < 0) {
      return 2 * ((long) Integer.MAX_VALUE) + 2 + i;
    } else {
      return i;
    }
  }

}