package de.tudarmstadt.informatik.hostage;

import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.Iterator;

import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSocket;
import javax.net.ssl.SSLSocketFactory;

import android.content.Context;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import de.tudarmstadt.informatik.hostage.handler.AbstractHandler;
import de.tudarmstadt.informatik.hostage.handler.ByteArrayHandlerImpl;
import de.tudarmstadt.informatik.hostage.handler.StringHandlerImpl;
import de.tudarmstadt.informatik.hostage.net.MyServerSocketFactory;
import de.tudarmstadt.informatik.hostage.protocol.Protocol;
import de.tudarmstadt.informatik.hostage.protocol.SSLProtocol;
import de.tudarmstadt.informatik.hostage.ui.MainActivity;
import de.tudarmstadt.informatik.hostage.wrapper.ByteArray;
/**
 * Protocol listener class:<br>
 * Creates a Socket on the port of a given protocol and listens for incoming connections.<br>
 * For each connection creates a Socket and instantiate an {@link AbstractHandler}.
 * @author Mihai Plasoianu 
 *
 */
public class HoneyListener implements Runnable {

	private ArrayList<AbstractHandler> handlers = new ArrayList<AbstractHandler>();

	/**
	 * Determines the amount of active handlers.
	 * @return The number of active handlers.
	 */
	public int getHandlerCount() {
		return handlers.size();
	}

	private Protocol protocol;
	private ServerSocket server;
	private Thread thread;

	private HoneyService service;
	// Shared Preferences
	private SharedPreferences pref;

	// Editor for Shared preferences
	private Editor editor;

	private boolean running = false;

	/**
	 * Determines if the service is running.
	 * @return True if the service is running, else false.
	 */
	public boolean isRunning() {
		return running;
	}

	/**
	 * Constructor for the class. Instantiate class variables.
	 * @param service The Background service that started the listener. 
	 * @param protocol The Protocol on which the listener is running.
	 */
	public HoneyListener(HoneyService service, Protocol protocol) {
		this.service = service;
		this.protocol = protocol;
		pref = service.getApplicationContext().getSharedPreferences(
				MainActivity.SESSION_DATA, Context.MODE_PRIVATE);
		editor = pref.edit();
	}

	@Override
	public void run() {
		while (!thread.isInterrupted()) {
			addHandler();
		}
		for (AbstractHandler handler : handlers) {
			handler.kill();
		}
	}

	/**
	 * Starts the listener. Creates a server socket runs itself in a new Thread and notifies the background service.
	 */
	public void start() {
		try {
			server = new MyServerSocketFactory().createServerSocket(protocol
					.getPort());
			(this.thread = new Thread(this)).start();
			editor.putBoolean(protocol + MainActivity.LISTENER, true);
			editor.commit();
			service.notifyUI(protocol.toString(), MainActivity.LISTENER);
			running = true;
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	/**
	 * Stops the listener. Closes the server socket, interrupts the Thread its running in and notifies the background service.
	 */
	public void stop() {
		try {
			server.close();
			thread.interrupt();
			editor.putBoolean(protocol + MainActivity.LISTENER, false);
			editor.commit();
			service.notifyUI(protocol.toString(), MainActivity.LISTENER);
			running = false;
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	/**
	 * Determine the name of the protocol the listener is running on.
	 * @return Name of the protocol
	 */
	public String getProtocolName() {
		return protocol.toString();
	}

	/**
	 * Remove all terminated handlers from its internal ArrayList.
	 */
	public void refreshHandlers() {
		for (Iterator<AbstractHandler> iterator = handlers.iterator(); iterator
				.hasNext();) {
			AbstractHandler handler = iterator.next();
			if (handler.isTerminated()) {
				iterator.remove();
			}
		}
	}

	/**
	 * Waits for an incoming connection, accepts it and starts a {@link AbstractHandler}
	 */
	private void addHandler() {
		try {
			Socket client = server.accept();
			if (protocol.isSecure()) {
				startSecureHandler(client);
			} else {
				startHandler(client);
			}
			int handlerCount = pref.getInt(protocol
					+ MainActivity.HANDLER_COUNT, 0);
			editor.putInt(protocol + MainActivity.HANDLER_COUNT,
					handlerCount + 1);
			editor.commit();
			service.notifyUI(protocol.toString(), MainActivity.HANDLER_COUNT);
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	/**
	 * Creates a SSLSocket out of the given socket and starts a {@link AbstractHandler}.
	 * @param client The socket with the accepted connection.
	 * @throws Exception
	 */
	private void startSecureHandler(Socket client) throws Exception {
		SSLContext sslContext = ((SSLProtocol) protocol).getSSLContext();
		SSLSocketFactory factory = sslContext.getSocketFactory();
		SSLSocket sslClient = (SSLSocket) factory.createSocket(client, null,
				client.getPort(), false);
		sslClient.setUseClientMode(false);
		handlers.add(newInstance(service, this, protocol.getClass()
				.newInstance(), sslClient));
	}

	/**
	 * Starts a {@link AbstractHandler} with the given socket.
	 * @param client The socket with the accepted connection.
	 * @throws Exception
	 */
	private void startHandler(Socket client) throws Exception {
		handlers.add(newInstance(service, this, protocol.getClass()
				.newInstance(), client));
	}

	/**
	 * Creates a new instance of an {@link AbstractHandler}.
	 * @param service The background service
	 * @param listener The listener that created the handler
	 * @param protocol The Protocol the handler will run on
	 * @param client The Socket the handler uses
	 * @return A Instance of a {@link AbstractHandler} with the specified parameter.
	 */
	private AbstractHandler newInstance(HoneyService service,
			HoneyListener listener, Protocol protocol, Socket client) {
		if (protocol.getType().equals(String.class)) {
			return new StringHandlerImpl(service, listener, protocol, client);
		} else if (protocol.getType().equals(ByteArray.class)) {
			return new ByteArrayHandlerImpl(service, listener, protocol, client);
		} else {
			return null;
		}
	}
}