package org.bouncycastle.bcpg;

import java.io.ByteArrayOutputStream;
import java.io.IOException;

/**
 * Basic type for a symmetric encrypted session key packet
 */
public class SymmetricKeyEncSessionPacket 
	extends ContainedPacket
{
	private int			version;
	private int			encAlgorithm;
	private S2K		s2k;
	private byte[]	secKeyData;
	
	public SymmetricKeyEncSessionPacket( 
		BCPGInputStream  in)
		throws IOException
	{
		version = in.read();
		encAlgorithm = in.read();

		s2k = new S2K(in);
    	
    	if (in.available() != 0)
    	{
			secKeyData = new byte[in.available()];
			in.readFully(secKeyData, 0, secKeyData.length);
    	}
	}
	
	public SymmetricKeyEncSessionPacket(
		int		encAlgorithm,
		S2K		s2k,
		byte[]	secKeyData)
	{
		this.version = 4;
		this.encAlgorithm = encAlgorithm;
		this.s2k = s2k;
		this.secKeyData = secKeyData;
	}
	
    /**
     * @return int
     */
    public int getEncAlgorithm()
    {
        return encAlgorithm;
    }

    /**
     * @return S2K
     */
    public S2K getS2K()
    {
        return s2k;
    }

    /**
     * @return byte[]
     */
    public byte[] getSecKeyData()
    {
        return secKeyData;
    }

    /**
     * @return int
     */
    public int getVersion()
    {
        return version;
    }
    
    public void encode(
    	BCPGOutputStream	out)
    	throws IOException
    {
    	ByteArrayOutputStream	bOut = new ByteArrayOutputStream();
    	BCPGOutputStream			pOut = new BCPGOutputStream(bOut);
    	
    	pOut.write(version);
    	pOut.write(encAlgorithm);
    	pOut.writeObject(s2k);
    	
    	if (secKeyData != null)
    	{
    		pOut.write(secKeyData);
    	}
    	
    	out.writePacket(SYMMETRIC_KEY_ENC_SESSION, bOut.toByteArray(), true);
    }
}
