package org.openslx.imagemaster.session;

import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.UUID;

import org.apache.log4j.Logger;
import org.openslx.imagemaster.thrift.iface.SessionData;
import org.openslx.imagemaster.util.Hash;

/**
 * Class for managing active user sessions. This class and all its function are
 * (supposed to be) thread-safe.
 */
public class SessionManager
{
	private static Logger log = Logger.getLogger( SessionManager.class );

	// Map of currently known sessions
	private static final Map<String, Session> sessions = new LinkedHashMap<>();
	private static final Thread gcThread;

	public static SessionData addSession( Session session )
	{
		final String authToken = Hash.md5( UUID.randomUUID().toString() );
		final String sessionId = Hash.sha256( UUID.randomUUID().toString() );

		synchronized ( sessions ) {
			sessions.put( authToken, session );
			sessions.put( sessionId, session );
		}
		return new SessionData( sessionId, authToken, session.getSatelliteAddress() );
	}

	public static Session getSessionFromToken( String token )
	{
		if ( token == null || token.length() != 64 )
			return null;
		final Session session;
		synchronized ( sessions ) {
			session = sessions.get( token );
		}
		if ( session == null || session.timedOut() ) {
			return null;
		}
		return session;
	}

	static {
		gcThread = new Thread( new Runnable() {

			@Override
			public void run()
			{
				for ( ;; ) {
					try {
						Thread.sleep( 1800L * 1000L );
					} catch ( InterruptedException e ) {
					}
					synchronized ( sessions ) {
						Iterator<Session> it = sessions.values().iterator();
						while ( it.hasNext() ) {
							final Session s = it.next();
							if ( s.timedOut() ) {
								it.remove();
							}
						}
					}
				}
			}
		} );
		gcThread.start();
	}

	public static Object getSessionFromSessionId( String sessionId )
	{
		if ( sessionId == null || sessionId.length() != 32 )
			return null;
		final Session session;
		synchronized ( sessions ) {
			session = sessions.get( sessionId );
		}
		if ( session == null || session.timedOut() ) {
			return null;
		}
		return session;
	}

}