package org.argeo.slc.web.mvc;

import java.io.Serializable;
import java.util.List;
import java.util.Vector;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.argeo.slc.SlcException;
import org.argeo.slc.msg.event.SlcEvent;
import org.argeo.slc.msg.event.SlcEventListener;
import org.argeo.slc.msg.event.SlcEventListenerDescriptor;
import org.argeo.slc.msg.event.SlcEventListenerRegister;
import org.springframework.web.context.request.RequestContextHolder;

public class WebSlcEventListenerRegister implements SlcEventListenerRegister,
		Serializable {
	private final static Log log = LogFactory
			.getLog(WebSlcEventListenerRegister.class);
	public final static String ATTR_EVENT_LISTENER = "slcEventListener";

	static final long serialVersionUID = 1l;

	transient private SlcEventListener eventListener = null;

	private String clientId = null;

	/** Synchronized */
	private List<SlcEventListenerDescriptor> descriptors = new Vector<SlcEventListenerDescriptor>();

	public synchronized void addEventListenerDescriptor(
			SlcEventListenerDescriptor eventListenerDescriptor) {
		if (descriptors.contains(eventListenerDescriptor))
			descriptors.remove(eventListenerDescriptor);
		descriptors.add(eventListenerDescriptor);
	}

	public synchronized void removeEventListenerDescriptor(
			SlcEventListenerDescriptor eventListenerDescriptor) {
		descriptors.remove(eventListenerDescriptor);
	}

	// public synchronized List<SlcEventListenerDescriptor> getDescriptorsCopy()
	// {
	// return new ArrayList<SlcEventListenerDescriptor>(descriptors);
	// }

	public SlcEvent listen(SlcEventListener eventListener, Long timeout) {
		checkClientId();
		this.eventListener = eventListener;
		return this.eventListener.listen(clientId, descriptors, timeout);
	}

	public void init() {
		clientId = getSessionId();
		checkClientId();

		if (log.isDebugEnabled())
			log.debug("Initialized web event listener " + clientId);
	}

	public void close() {
		checkClientId();
		if (eventListener != null)
			eventListener.close(clientId);

		if (log.isDebugEnabled())
			log.debug("Closed web event listener " + clientId);
	}

	protected void checkClientId() {
		String sessionId = getSessionId();
		if (clientId == null || !clientId.equals(sessionId))
			throw new SlcException("Client id " + clientId
					+ " not consistent with web session id " + sessionId);
	}

	protected String getSessionId() {
		return RequestContextHolder.currentRequestAttributes().getSessionId();
	}

	public String getClientId() {
		return clientId;
	}

}