/*******************************************************************************
 * Copyright (c) 2011 Ziver Koc
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 ******************************************************************************/
package zutil.net.threaded;

import java.io.File;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.cert.CertificateException;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.net.ssl.SSLServerSocketFactory;

import zutil.log.LogUtil;


/**
 * A simple network server that handles TCP communication
 * 
 * @author Ziver
 */
public abstract class ThreadedTCPNetworkServer extends Thread{
	private static final Logger logger = LogUtil.getLogger();
	
	public final int port;
	private File keyStore;
	private String keyStorePass;

	/**
	 * Creates a new instance of the sever
	 * 
	 * @param 	port 		The port that the server should listen to
	 */
	public ThreadedTCPNetworkServer(int port){
		this(port, null, null);
	}
	/**
	 * Creates a new instance of the sever
	 * 
	 * @param 	port 		The port that the server should listen to
	 * @param 	sslCert 	If this is not null then the server will use SSL connection with this keyStore file path
	 * @param 	sslCert 	If this is not null then the server will use a SSL connection with the given certificate
	 */
	public ThreadedTCPNetworkServer(int port, File keyStore, String keyStorePass){	
		this.port = port;
		this.keyStorePass = keyStorePass;
		this.keyStore = keyStore;
	}


	public void run(){
		ServerSocket ss = null;
		try{
			if(keyStorePass != null && keyStore != null){
				registerCertificate(keyStore, keyStorePass);
				ss = initSSL( port );
			}
			else{
				ss = new ServerSocket( port );
			}

			while(true){
				Socket s = ss.accept();
				ThreadedTCPNetworkServerThread t = getThreadInstance( s );
				if( t!=null )
					new Thread( t ).start();
				else{
					logger.severe("Unable to instantiate ThreadedTCPNetworkServerThread, closing connection!");
					s.close();
				}
			}
		} catch(Exception e) {
			logger.log(Level.SEVERE, null, e);
		} finally {
			if( ss!=null ){
				try{
					ss.close();
				}catch(IOException e){ logger.log(Level.SEVERE, null, e); }
			}	
		}
	}

	/**
	 * This method returns an new instance of the ThreadedTCPNetworkServerThread
	 * that will handle the newly made connection, if an null value is returned
	 * then the ThreadedTCPNetworkServer will close the new connection.
	 * 
	 * @param 		s 		is an new connection to an host
	 * @return 				a new instance of an thread or null
	 */
	protected abstract ThreadedTCPNetworkServerThread getThreadInstance( Socket s );

	/**
	 * Initiates a SSLServerSocket
	 * 
	 * @param 		port 	The port to listen to
	 * @return 				The SSLServerSocket
	 */
	private ServerSocket initSSL(int port) throws IOException{
		SSLServerSocketFactory sslserversocketfactory =
			(SSLServerSocketFactory) SSLServerSocketFactory.getDefault();
		return sslserversocketfactory.createServerSocket(port);

	}

	/**
	 * Registers the given cert file to the KeyStore
	 * 
	 * @param 		certFile 	The cert file
	 */
	protected void registerCertificate(File keyStore, String keyStorePass) throws CertificateException, IOException, KeyStoreException, NoSuchProviderException, NoSuchAlgorithmException{
		System.setProperty("javax.net.ssl.keyStore", keyStore.getAbsolutePath());
		System.setProperty("javax.net.ssl.keyStorePassword", keyStorePass);
	}
	
	/**
	 * Stops the server and interrupts its internal thread. 
	 * This is a permanent action that will not be able to recover from
	 */
	public void close(){
		this.interrupt();
	}
}