/*
 *
 * MariaDB Client for Java
 *
 * Copyright (c) 2012-2014 Monty Program Ab.
 * Copyright (c) 2015-2020 MariaDB Corporation Ab.
 *
 * This library is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation; either version 2.1 of the License, or (at your option)
 * any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along
 * with this library; if not, write to Monty Program Ab info@montyprogram.com.
 *
 * This particular MariaDB Client for Java file is work
 * derived from a Drizzle-JDBC. Drizzle-JDBC file which is covered by subject to
 * the following copyright and notice provisions:
 *
 * Copyright (c) 2009-2011, Marcus Eriksson
 *
 * 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 driver nor the names of its contributors may not 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 org.mariadb.jdbc.internal.io.input;

import static org.mariadb.jdbc.internal.io.TraceObject.COMPRESSED_PROTOCOL_COMPRESSED_PACKET;
import static org.mariadb.jdbc.internal.io.TraceObject.COMPRESSED_PROTOCOL_NOT_COMPRESSED_PACKET;

import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
import java.util.Arrays;
import java.util.zip.DataFormatException;
import java.util.zip.Inflater;
import org.mariadb.jdbc.internal.com.read.Buffer;
import org.mariadb.jdbc.internal.io.LruTraceCache;
import org.mariadb.jdbc.internal.io.TraceObject;
import org.mariadb.jdbc.internal.logging.Logger;
import org.mariadb.jdbc.internal.logging.LoggerFactory;
import org.mariadb.jdbc.internal.util.Utils;

public class DecompressPacketInputStream implements PacketInputStream {

  private static final int REUSABLE_BUFFER_LENGTH = 1024;
  private static final int MAX_PACKET_SIZE = 0xffffff;
  private static final Logger logger = LoggerFactory.getLogger(DecompressPacketInputStream.class);
  private final byte[] header = new byte[7];
  private final byte[] reusableArray = new byte[REUSABLE_BUFFER_LENGTH];
  private final InputStream inputStream;
  private final int maxQuerySizeToLog;
  // compress packet can contain multiple standard packet
  private byte[] cacheData = new byte[0];
  private int cachePos;
  private int cacheEnd;
  private int packetSeq;
  private int compressPacketSeq;
  private String serverThreadLog = "";
  private LruTraceCache traceCache = null;
  private long threadId;

  public DecompressPacketInputStream(InputStream in, int maxQuerySizeToLog, long threadId) {
    inputStream = in;
    this.maxQuerySizeToLog = maxQuerySizeToLog;
    this.threadId = threadId;
  }

  @Override
  public Buffer getPacket(boolean reUsable) throws IOException {
    return new Buffer(getPacketArray(reUsable));
  }

  /**
   * Get next packet. Packet can be compressed, and if so, can contain many standard packet.
   *
   * @param reUsable if can use existing reusable buffer to avoid creating array
   * @return array packet.
   * @throws IOException if socket exception occur.
   */
  public byte[] getPacketArray(boolean reUsable) throws IOException {

    byte[] cachePacket = getNextCachePacket();
    if (cachePacket != null) {
      return cachePacket;
    }

    // loop until having the whole packet
    do {
      // Read 7 byte header
      readBlocking(header, 7);

      int compressedLength =
          (header[0] & 0xff) + ((header[1] & 0xff) << 8) + ((header[2] & 0xff) << 16);
      compressPacketSeq = header[3] & 0xff;
      int decompressedLength =
          (header[4] & 0xff) + ((header[5] & 0xff) << 8) + ((header[6] & 0xff) << 16);

      byte[] rawBytes;
      if (reUsable && decompressedLength == 0 && compressedLength < REUSABLE_BUFFER_LENGTH) {
        rawBytes = reusableArray;
      } else {
        rawBytes = new byte[decompressedLength != 0 ? decompressedLength : compressedLength];
      }

      readCompressBlocking(rawBytes, compressedLength, decompressedLength);

      if (traceCache != null) {
        int length = decompressedLength != 0 ? decompressedLength : compressedLength;
        traceCache.put(
            new TraceObject(
                false,
                decompressedLength == 0
                    ? COMPRESSED_PROTOCOL_NOT_COMPRESSED_PACKET
                    : COMPRESSED_PROTOCOL_COMPRESSED_PACKET,
                threadId,
                Arrays.copyOfRange(header, 0, 7),
                Arrays.copyOfRange(rawBytes, 0, length > 1000 ? 1000 : length)));
      }

      if (logger.isTraceEnabled()) {
        int length = decompressedLength != 0 ? decompressedLength : compressedLength;
        logger.trace(
            "read {} {}{}",
            (decompressedLength == 0 ? "uncompress" : "compress"),
            serverThreadLog,
            Utils.hexdump(maxQuerySizeToLog - 7, 0, length, header, rawBytes));
      }

      cache(rawBytes, decompressedLength == 0 ? compressedLength : decompressedLength);
      byte[] packet = getNextCachePacket();
      if (packet != null) {
        return packet;
      }

    } while (true);
  }

  private void readCompressBlocking(byte[] arr, int compressedLength, int decompressedLength)
      throws IOException {
    if (decompressedLength != 0) {

      byte[] compressedBuffer = new byte[compressedLength];
      // Read compress content
      readBlocking(compressedBuffer, compressedLength);

      Inflater inflater = new Inflater();
      inflater.setInput(compressedBuffer);
      try {
        int actualUncompressBytes = inflater.inflate(arr);
        if (actualUncompressBytes != decompressedLength) {
          throw new IOException(
              "Invalid exception length after decompression "
                  + actualUncompressBytes
                  + ",expected "
                  + decompressedLength);
        }
      } catch (DataFormatException dfe) {
        throw new IOException(dfe);
      } finally {
        inflater.end();
      }

    } else {
      // Read standard content
      readBlocking(arr, compressedLength);
    }
  }

  private void readBlocking(byte[] arr, int length) throws IOException {
    int remaining = length;
    int off = 0;
    do {
      int count = inputStream.read(arr, off, remaining);
      if (count < 0) {
        throw new EOFException(
            "unexpected end of stream, read "
                + (length - remaining)
                + " bytes from "
                + length
                + " (socket was closed by server)");
      }
      remaining -= count;
      off += count;
    } while (remaining > 0);
  }

  private void cache(byte[] rawBytes, int length) {
    if (cachePos >= cacheEnd) {
      cacheData = rawBytes;
      cachePos = 0;
      cacheEnd = length;
    } else {
      // must add to cache
      byte[] newCache = new byte[length + cacheEnd - cachePos];
      System.arraycopy(cacheData, cachePos, newCache, 0, cacheEnd - cachePos);
      System.arraycopy(rawBytes, 0, newCache, cacheEnd - cachePos, length);
      cacheData = newCache;
      cachePos = 0;
      cacheEnd = newCache.length;
    }
  }

  private byte[] getNextCachePacket() {
    int packetOffset = 0;

    // if packet is not totally fetch, return null
    while (cacheEnd > cachePos + 4 + packetOffset * (MAX_PACKET_SIZE + 4)) {
      int lastPacketLength =
          (cacheData[cachePos + packetOffset * (MAX_PACKET_SIZE + 4)] & 0xff)
              + ((cacheData[cachePos + packetOffset * (MAX_PACKET_SIZE + 4) + 1] & 0xff) << 8)
              + ((cacheData[cachePos + packetOffset * (MAX_PACKET_SIZE + 4) + 2] & 0xff) << 16);
      if (lastPacketLength == MAX_PACKET_SIZE) {
        packetOffset += 1;
      } else if (cacheEnd
          >= cachePos + 4 + packetOffset * (MAX_PACKET_SIZE + 4) + lastPacketLength) {
        // packet is totally fetched.

        // if packet was less than 16M
        if (packetOffset == 0) {
          packetSeq = cacheData[cachePos + 3];

          if (cacheEnd - (cachePos + 4) >= lastPacketLength) {
            byte[] packet = new byte[lastPacketLength];
            System.arraycopy(cacheData, cachePos + 4, packet, 0, lastPacketLength);

            if (logger.isTraceEnabled()) {
              logger.trace(
                  "read packet: seq={} len={} {}{}",
                  packetSeq,
                  lastPacketLength,
                  serverThreadLog,
                  Utils.hexdump(maxQuerySizeToLog, cachePos + 4, lastPacketLength, cacheData));
            }

            cachePos += 4 + lastPacketLength;
            return packet;
          }
        } else {
          byte[] packet = new byte[lastPacketLength + packetOffset * MAX_PACKET_SIZE];
          int offset = 0;
          do {
            lastPacketLength =
                (cacheData[cachePos] & 0xff)
                    + ((cacheData[cachePos + 1] & 0xff) << 8)
                    + ((cacheData[cachePos + 2] & 0xff) << 16);
            packetSeq = cacheData[cachePos + 3];
            System.arraycopy(cacheData, cachePos + 4, packet, offset, lastPacketLength);
            offset += lastPacketLength;

            if (logger.isTraceEnabled()) {
              logger.trace(
                  "read packet: seq={} len={} {}{}",
                  packetSeq,
                  lastPacketLength,
                  serverThreadLog,
                  Utils.hexdump(maxQuerySizeToLog, cachePos + 4, lastPacketLength, cacheData));
            }

            cachePos += 4 + lastPacketLength;

          } while (lastPacketLength == MAX_PACKET_SIZE);
          return packet;
        }
      } else {
        return null;
      }
    }
    return null;
  }

  @Override
  public int getLastPacketSeq() {
    return packetSeq;
  }

  @Override
  public int getCompressLastPacketSeq() {
    return compressPacketSeq;
  }

  @Override
  public void close() throws IOException {
    inputStream.close();
  }

  /**
   * Set server thread id.
   *
   * @param serverThreadId current server thread id.
   * @param isMaster is server master
   */
  public void setServerThreadId(long serverThreadId, Boolean isMaster) {
    this.serverThreadLog =
        "conn=" + serverThreadId + ((isMaster != null) ? "(" + (isMaster ? "M" : "S") + ")" : "");
  }

  public void setTraceCache(LruTraceCache traceCache) {
    this.traceCache = traceCache;
  }

  public InputStream getInputStream() {
    return inputStream;
  }
}
