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 android.util.Log;
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;

/**
 * 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 HoneyHandler}.
 * 
 * @author Mihai Plasoianu
 * 
 */
public class HoneyListener implements Runnable {

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

	/**
	 * 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;
	private ConnectionRegister conReg;

	// 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();
		conReg = new ConnectionRegister(service);
	}

	public void run() {
		while (!thread.isInterrupted()) {
			addHandler();
		}
		for (HoneyHandler 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();
			Log.i("BugSearch", "Open ServerSocket - ServerSocket is: " + ((server == null) ? "null" : "not null"));
			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 {
			Log.i("BugSearch", "Closing ServerSocket - ServerSocket is: " + ((server == null) ? "null" : "not null"));
			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<HoneyHandler> iterator = handlers.iterator(); iterator
				.hasNext();) {
			HoneyHandler handler = iterator.next();
			if (handler.isTerminated()) {
				conReg.closeConnection();
				iterator.remove();
			}
		}
	}

	/**
	 * Waits for an incoming connection, accepts it and starts a
	 * {@link HoneyHandler}
	 */
	private void addHandler() {
		if (conReg.isConnectionFree()) {
			try {
				Socket client = server.accept();
				conReg.newOpenConnection();
				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 HoneyHandler}.
	 * 
	 * @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 HoneyHandler} 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 HoneyHandler}.
	 * 
	 * @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 HoneyHandler} with the specified
	 *         parameter.
	 */
	private HoneyHandler newInstance(HoneyService service,
			HoneyListener listener, Protocol protocol, Socket client) {
		return new HoneyHandler(service, listener, protocol, client);
	}
}