/*
 * Copyright 1999-2002,2004 The Apache Software Foundation.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.cocoon.portal.coplet.adapter.impl;

import org.apache.avalon.framework.service.ServiceException;
import org.apache.cocoon.ProcessingException;
import org.apache.cocoon.portal.application.PortalApplicationConfigFactory;
import org.apache.cocoon.portal.coplet.CopletData;
import org.apache.cocoon.portal.coplet.CopletFactory;
import org.apache.cocoon.portal.coplet.CopletInstanceData;
import org.apache.cocoon.portal.event.Event;
import org.apache.cocoon.portal.event.impl.CopletLinkEvent;
import org.apache.cocoon.portal.layout.CompositeLayout;
import org.apache.cocoon.portal.layout.Item;
import org.apache.cocoon.portal.layout.LayoutFactory;
import org.apache.cocoon.portal.layout.NamedItem;
import org.apache.cocoon.portal.layout.impl.CopletLayout;
import org.apache.cocoon.portal.profile.ProfileManager;
import org.apache.cocoon.portal.transformation.ProxyTransformer;
import org.apache.cocoon.xml.XMLUtils;
import org.xml.sax.ContentHandler;
import org.xml.sax.SAXException;

/**
 * This coplet adapter is used to connect to external applications that are plugged into the portal
 *
 * @author <a href="mailto:gerald.kahrer@rizit.at">Gerald Kahrer</a>
 * 
 * @version CVS $Id: ApplicationCopletAdapter.java,v 1.4 2004/03/05 13:02:10 bdelacretaz Exp $
 */
public class ApplicationCopletAdapter extends CachingURICopletAdapter {

    public void streamContent(
        final CopletInstanceData coplet,
        final String uri,
        final ContentHandler contentHandler)
        throws SAXException {
        try {
            super.streamContent(coplet, uri, contentHandler);
        }
        catch (SAXException se) {
            getLogger().error(
                "ApplicationCopletAdapter: Exception while getting coplet resource",
                se);

            renderErrorContent(coplet, contentHandler);
        }
    }

    /**
     * This adapter listens for CopletLinkEvents. If it catches one the link uri is saved in
     * the coplet instance data for further handling in the ProxyTransformer.
     * There is a special CopletLinkEvent with the uri "createNewCopletInstance", which is the
     * trigger to create a new instance of the one that is the target of the event.
     */
    public void handleCopletInstanceEvent(Event e) {
        super.handleCopletInstanceEvent(e);
        
        if ( e instanceof CopletLinkEvent ) {
            CopletLinkEvent event = (CopletLinkEvent) e;
            CopletInstanceData coplet = (CopletInstanceData) event.getTarget();
            String link = event.getLink();
    
            if ("createNewCopletInstance".equals(link)) {
                try {
                    createNewInstance(coplet);
                }
                catch (ProcessingException ex) {
                    getLogger().error("Could not create new coplet instance", ex);
                }
            }
            else {
                // this is a normal link event, so save the url in the instance data
                // for ProxyTransformer
                coplet.setAttribute(ProxyTransformer.LINK, event.getLink());
            }
        }
    }

    /**
     * Creates a new instance of the given coplet. Also a new named item in the tab layout is
     * created to show the data of the new coplet instance in the portal.
     * @param 	coplet	the coplet instance data
     * @trows	ProcessingException if something fails in the creation process
     */
    private void createNewInstance(CopletInstanceData coplet)
        throws ProcessingException {
        ProfileManager profileManager = null;
        try {
            profileManager =
                (ProfileManager) this.manager.lookup(ProfileManager.ROLE);

            CopletData copletData = coplet.getCopletData();

            LayoutFactory lfac =
                (LayoutFactory) this.manager.lookup(LayoutFactory.ROLE);

            CopletLayout copletLayout =
                (CopletLayout) lfac.newInstance("coplet");

            CopletFactory cfac =
                (CopletFactory) manager.lookup(CopletFactory.ROLE);

            CopletInstanceData newCoplet = cfac.newInstance(copletData);

            copletLayout.setCopletInstanceData(newCoplet);
            profileManager.register(copletLayout);

            NamedItem newItem = new NamedItem();
            newItem.setLayout(copletLayout);

            CompositeLayout tabLayout =
                (CompositeLayout) profileManager.getPortalLayout(
                    "portalApplications", null);

            newItem.setName(getNewInstanceTabName(tabLayout));
            tabLayout.addItem(newItem);
        } catch (ServiceException ce) {
            throw new ProcessingException(
                "Unable to lookup profile manager.",
                ce);
        }
        catch (Exception e) {
            throw new ProcessingException(e);
        }
        finally {
            this.manager.release(profileManager);
        }
    }

    /**
     * Returns the name of the new named item in the tab layout
     * @return String the name of the new item
     */
    private String getNewInstanceTabName(CompositeLayout layout) {
        Integer data = (Integer) layout.getAspectData("tab");
        Item selectedItem = (NamedItem) layout.getItem(data.intValue());

        if (selectedItem instanceof NamedItem) {
            return ((NamedItem) selectedItem).getName();
        }
        else {
            return ("New");
        }
    }

    /**
     * Sets the application configuration in the coplet instance data.
     * @param	coplet the coplet instance data
     */
    private void setApplicationConfig(CopletInstanceData coplet) {
        try {
            PortalApplicationConfigFactory factory =
                PortalApplicationConfigFactory.getInstance(resolver);

            coplet.setAttribute(
                ProxyTransformer.CONFIG,
                factory.getConfig(coplet.getCopletData().getId()));
        }
        catch (ProcessingException pe) {
            getLogger().error(
                "Error while getting portal application configuration for coplet "
                    + coplet.getId(),
                pe);
        }
    }

    /**
     * Called when user logs in to the portal.
     */
    public void login(CopletInstanceData coplet) {
        getLogger().info("ApplicationCopletAdapter:login");
        setApplicationConfig(coplet);
    }

    /**
     * Called when user logs out from the portal.
     */
    public void logout(CopletInstanceData coplet) {
        getLogger().info("ApplicationCopletAdapter:logout");
    }

    /**
     * Render the error content for a coplet
     * @param coplet
     * @param handler
     * @return True if the error content has been rendered, otherwise false
     * @throws SAXException
     */
    protected boolean renderErrorContent(
        CopletInstanceData coplet,
        ContentHandler handler)
        throws SAXException {
        handler.startDocument();
        XMLUtils.startElement(handler, "p");
        XMLUtils.data(
            handler,
            "ApplicationCopletAdapter: Can't get content for coplet "
                + coplet.getId()
                + ". Look up the logs.");
        XMLUtils.endElement(handler, "p");
        handler.endDocument();

        return true;
    }

}