/**
 * 
 */
package proxy;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.UnknownHostException;


/**
 * 代理、請求響應抽象類
 * @author liwen
 *
 */
public abstract class ProxyMsg {

	/**
	 * 
	 */
	public ProxyMsg() {
		// TODO Auto-generated constructor stub
	}

	/** Host as an IP address */
	   public InetAddress ip=null;
	   /** SOCKS version, or version of the response for SOCKS4*/
	   public int version;
	   /** Port field of the request/response*/
	   public int port;
	   /** Request/response code as an int*/
	   public int command;
	   /** Host as string.*/
	   public String host=null;
	   /** User field for SOCKS4 request messages*/
	   public String user=null;

	   ProxyMsg(int command,InetAddress ip,int port){
	      this.command = command;
	      this.ip      = ip;
	      this.port    = port;
	   }



	   /**
	     Initialises Message from the stream. Reads server response from
	     given stream.
	     @param in Input stream to read response from.
	     @throws SocksException If server response code is not SOCKS_SUCCESS(0), or
	     if any error with protocol occurs.
	     @throws IOException If any error happens with I/O.
	   */
	   public abstract void read(InputStream in)throws Exception;


	   /**
	     Initialises Message from the stream. Reads server response or client 
	     request from given stream.
	     
	     @param in Input stream to read response from.
	     @param clinetMode If true read server response, else read client request.
	     @throws SocksException If server response code is not SOCKS_SUCCESS(0) and
	     reading in client mode, or if any error with protocol occurs.
	     @throws IOException If any error happens with I/O.
	   */
	   public abstract void read(InputStream in,boolean client_mode)
	   throws Exception;


	   /**
	    Writes the message to the stream.
	    @param out Output stream to which message should be written.
	   */
	   public abstract void write(OutputStream out)throws Exception;

	   /**
	    Get the Address field of this message as InetAddress object.
	    @return Host address or null, if one can't be determined.
	   */
	   public InetAddress getInetAddress() throws UnknownHostException{
	     return ip;
	   }


	   /**
	    Get string representaion of this message.
	    @return string representation of this message.
	   */
	   public String toString(){
	      return 
	      "Proxy Message:\n"+
	      "Version:"+ version+"\n"+
	      "Command:"+ command+"\n"+
	      "IP:     "+ ip+"\n"+
	      "Port:   "+ port+"\n"+
	      "User:   "+ user+"\n" ;
	   }

//	Package methods
////////////////	//

	   static final String bytes2IPV4(byte[] addr,int offset){
	      String hostName = ""+(addr[offset] & 0xFF);
	      for(int i = offset+1;i<offset+4;++i)
	        hostName+="."+(addr[i] & 0xFF);
	      return hostName;
	   }

	   static final String bytes2IPV6(byte[] addr,int offset){
	     //Have no idea how they look like!
	     return null;
	   }

}