/*
 * TeleStax, Open Source Cloud Communications
 * Copyright 2011-2016, TeleStax Inc. and individual contributors
 * by the @authors tag.
 *
 * This program is free software: you can redistribute it and/or modify
 * under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation; either version 3 of
 * the License, or (at your option) any later version.
 *
 * This program 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>
 */

package org.jdiameter.client.impl.transport.tls.netty;

import java.util.List;

import org.jdiameter.api.AvpDataException;
import org.jdiameter.client.api.parser.IMessageParser;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.ByteToMessageDecoder;

/**
 *
 * @author <a href="mailto:jqayyum@gmail.com"> Jehanzeb Qayyum </a>
 */
public class DiameterMessageDecoder extends ByteToMessageDecoder {
  private static final Logger logger = LoggerFactory.getLogger(DiameterMessageDecoder.class);

  protected final IMessageParser parser;
  protected final TLSClientConnection parentConnection;

  public DiameterMessageDecoder(TLSClientConnection parentConnection, IMessageParser parser) {
    this.parser = parser;
    this.parentConnection = parentConnection;
  }

  @Override
  protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) {
    logger.debug("Decode message size: {}", in.readableBytes());

    if (in.readableBytes() >= 4) {
      int first = in.getInt(in.readerIndex());
      byte version = (byte) (first >> 24);
      if (version != 1) {
        return;
      }

      int messageLength = (first & 0xFFFFFF);
      if (in.readableBytes() < messageLength) {
        return;
      }

      logger.debug("Decoding message version: {}, length: {}", version, messageLength);

      byte[] bytes = new byte[messageLength];
      in.readBytes(bytes);
      try {
        out.add(this.parser.createMessage(bytes));
      } catch (AvpDataException e) {
        logger.error(e.getMessage(), e);

        this.parentConnection.onAvpDataException(e);
      }
    }
  }
}