/*******************************************************************************
 * Copyright (c) 2010 IBM Corporation and others All rights reserved. This
 * program and the accompanying materials are made available under the terms of
 * the Eclipse Public License v1.0 which accompanies this distribution, and is
 * available at http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors: IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.wst.jsdt.debug.transport.socket;

import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.HashMap;
import java.util.Map;

import org.eclipse.wst.jsdt.debug.transport.Connection;
import org.eclipse.wst.jsdt.debug.transport.Constants;
import org.eclipse.wst.jsdt.debug.transport.ListenerKey;
import org.eclipse.wst.jsdt.debug.transport.TransportService;

/**
 * Implementation of a {@link TransportService} that using a {@link Socket} for communication
 * 
 * @since 1.0
 */
public abstract class SocketTransportService implements TransportService {

	/**
	 * Map of {@link ListenerKey} to {@link ServerSocket}s
	 */
	private Map listeners = new HashMap();

	/* (non-Javadoc)
	 * @see org.eclipse.wst.jsdt.debug.transport.TransportService#startListening(java.lang.String)
	 */
	public synchronized ListenerKey startListening(String address) throws IOException {
		String host = null;
		int port = 0;
		if (address != null) {
			String[] strings = address.split(Constants.COLON);
			if (strings.length == 2) {
				host = strings[0];
				port = Integer.parseInt(strings[1]);
			} else {
				port = Integer.parseInt(strings[0]);
			}
		}
		if (host == null) {
			host = Constants.LOCALHOST;
		}
		ListenerKey key = new SocketListenerKey(host + Constants.COLON + port);
		ServerSocket serverSocket = new ServerSocket(port);
		listeners.put(key, serverSocket);
		return key;

	};

	/* (non-Javadoc)
	 * @see org.eclipse.wst.jsdt.debug.transport.TransportService#stopListening(org.eclipse.wst.jsdt.debug.transport.TransportService.ListenerKey)
	 */
	public void stopListening(ListenerKey key) throws IOException {
		ServerSocket serverSocket = (ServerSocket) listeners.remove(key);
		if (serverSocket != null) {
			serverSocket.close();
		}
	}

	/**
	 * Returns the {@link ServerSocket} mapped to the given {@link ListenerKey} or 
	 * <code>null</code> if the mapping does not exist
	 * 
	 * @param key the {@link ListenerKey} to get the {@link ServerSocket} for
	 * @return the mapped {@link ServerSocket} or <code>null</code>
	 */
	public final ServerSocket getServerSocket(ListenerKey key) {
		synchronized (listeners) {
			return (ServerSocket) listeners.get(key);
		}
	}
	
	/* (non-Javadoc)
	 * @see org.eclipse.wst.jsdt.debug.transport.TransportService#accept(org.eclipse.wst.jsdt.debug.transport.TransportService.ListenerKey, long, long)
	 */
	public Connection accept(ListenerKey key, long attachTimeout, long handshakeTimeout) throws IOException {
		ServerSocket serverSocket = getServerSocket(key);
		if (serverSocket == null) {
			throw new IllegalStateException("Accept failed. Not listening for address: key.address()"); //$NON-NLS-1$
		}
		int timeout = (int) attachTimeout;
		if (timeout > 0) {
			if (timeout > Integer.MAX_VALUE) {
				timeout = Integer.MAX_VALUE; // approximately 25 days!
			}
			serverSocket.setSoTimeout(timeout);
		}
		Connection connection = getConnection(serverSocket.accept());
		handleAccept(connection);
		return connection;
	}

	/**
	 * This method allows implementors to perform specific actions immediately following
	 * a successful accept for {@link Socket} communication (the socket has been successfully opened).
	 * 
	 * @param connection the connection that just opened
	 * @throws IOException
	 */
	public abstract void handleAccept(Connection connection) throws IOException;
	
	/**
	 * Returns the {@link SocketConnection} for the given {@link Socket}.
	 * <br><br>
	 * This method cannot return <code>null</code>, if a connection cannot be created
	 * an {@link IOException} must be thrown.
	 * 
	 * @param socket the socket to get the connection for
	 * @return the {@link SocketConnection} for the given {@link Socket}, never <code>null</code>
	 * @throws IOException
	 */
	public abstract SocketConnection getConnection(Socket socket) throws IOException;
	
	/* (non-Javadoc)
	 * @see org.eclipse.wst.jsdt.debug.transport.TransportService#attach(java.lang.String, long, long)
	 */
	public Connection attach(String address, long attachTimeout, long handshakeTimeout) throws IOException {
		String host = null;
		int port = 0;
		if (address != null) {
			String[] strings = address.split(Constants.COLON);
			if (strings.length == 2) {
				host = strings[0];
				port = Integer.parseInt(strings[1]);
			} else {
				port = Integer.parseInt(strings[0]);
			}
		}
		if (host == null) {
			host = Constants.LOCALHOST;
		}
		Connection connection = getConnection(new Socket(host, port));
		handleAttach(connection);
		return connection;
	}
	
	/**
	 * This method allows implementors to perform specific actions immediately following
	 * a successful attach for {@link Socket} communication (the socket has been successfully opened).
	 * 
	 * @param connection the connection that just opened
	 * @throws IOException
	 */
	public abstract void handleAttach(Connection connection) throws IOException;
}