/*
 * Copyright 2000-2004 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.jetspeed.services.forward;

// java
import java.util.Map;
import java.util.Iterator;
import java.util.Collection;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.TreeMap;
import java.util.Map.Entry;
import java.io.File;
import java.io.FileReader;
import javax.servlet.ServletConfig;

// turbine, services
import org.apache.turbine.util.RunData;
import org.apache.turbine.util.DynamicURI;
import org.apache.turbine.services.resources.ResourceService;
import org.apache.turbine.services.TurbineBaseService;
import org.apache.turbine.services.TurbineServices;
import org.apache.turbine.services.InitializationException;
import org.apache.turbine.services.servlet.TurbineServlet;

// marshaling
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.exolab.castor.mapping.Mapping;
import org.exolab.castor.xml.Unmarshaller;
import org.apache.xml.serialize.OutputFormat;
import org.xml.sax.InputSource;

// jetspeed
import org.apache.jetspeed.services.logging.JetspeedLogFactoryService;
import org.apache.jetspeed.services.logging.JetspeedLogger;
import org.apache.jetspeed.util.template.JetspeedLink;
import org.apache.jetspeed.util.template.JetspeedLinkFactory;

// forwarding configuration
import org.apache.jetspeed.services.forward.configuration.ForwardsConfiguration;
import org.apache.jetspeed.services.forward.configuration.Forward;
import org.apache.jetspeed.services.forward.configuration.Page;
import org.apache.jetspeed.services.forward.configuration.Pane;
import org.apache.jetspeed.services.forward.configuration.Portlet;
import org.apache.jetspeed.services.forward.configuration.PortletForward;
import org.apache.jetspeed.services.forward.configuration.QueryParam;


/**
 * <P>This is the implementation of the Jetspeed Forward services.
 *    The interface defines methods for forwarding navigation to 
 *    other pages or panes in the portal. The Forward service
 *    provides an abstraction, by removing the hard-coding of
 *    portal resources in your actions. Instead, all forward targets
 *    are defined in a centralized configuration file. By using the 
 *    forward service, you use logical forward names in your java code.</P>
 *
 * @see org.apache.jetspeed.om.profile.Profile
 * @author <a href="mailto:david@bluesunrise.com">David Sean Taylor</a>
 * @version $Id: JetspeedForwardService.java,v 1.7 2004/02/23 03:51:09 jford Exp $
 */

public class JetspeedForwardService extends TurbineBaseService
                                    implements ForwardService
{
    /**
     * Static initialization of the logger for this class
     */    
    private static final JetspeedLogger logger = JetspeedLogFactoryService.getLogger(JetspeedForwardService.class.getName());
    
    // configuration keys
    protected final static String CONFIG_MAPPING = "mapping";
    protected final static String CONFIG_DIRECTORY = "directory";

    // configuration parameters
    protected String mapping =                 // the forwards XML-Java mapping 
               "/WEB-INF/conf/forwards-mapping.xml";

    protected String directory =                // the location of forwards definitions
                      "/WEB-INF/conf/forwards/";

    /** the Castor mapping file name */
    protected Mapping mapper = null;

    /** the output format for pretty printing when saving registries */
    protected OutputFormat format = null;


    // Forward definitions
    protected Map forwards = new HashMap();
    
    // Portlet Forward definitions
    protected Map portletForwards = new TreeMap();


    protected final static String KEY_DELIMITER = ":";

    /**
     * This is the early initialization method called by the
     * Turbine <code>Service</code> framework
     * @param conf The <code>ServletConfig</code>
     * @exception throws a <code>InitializationException</code> if the service
     * fails to initialize
     */
    public synchronized void init(ServletConfig conf) throws InitializationException
    {

        // already initialized
        if (getInit()) return;

        try
        {
            // get configuration parameters from Jetspeed Resources
            ResourceService serviceConf = ((TurbineServices)TurbineServices.getInstance())
                                                         .getResources(ForwardService.SERVICE_NAME);

            this.mapping = serviceConf.getString(CONFIG_MAPPING, this.mapping);

            this.directory = serviceConf.getString(CONFIG_DIRECTORY, this.directory);

            this.mapping = TurbineServlet.getRealPath(this.mapping);
            this.directory = TurbineServlet.getRealPath(this.directory);

            loadForwards();

        }
        catch (Exception e)
        {
            logger.error("ForwardService: Failed to load ", e);
        }

        // initialization done
        setInit(true);

     }



    /**
     * This is the shutdown method called by the
     * Turbine <code>Service</code> framework
     */
    public void shutdown()
    {
    }

    /**
     *  Forward to a specific forward by name.
     *  All parameters are resolved statically (via the forward definition)
     *
     * @param rundata The turbine rundata context for this request.     
     * @param forwardName Forward to this abstract forward name.
     * @return DynamicURI the full link to the referenced page
     */
    public DynamicURI forward(RunData rundata, String forwardName)
    {
        return forwardInternal(rundata, forwardName, null, null);
    }

    /**
     *  Forward to a specific forward by name.
     *  Parameters are resolved both statically and dynamically, with the 
     *  dynamic parameter overriding the static parameter definitions.
     *
     * @param rundata The turbine rundata context for this request.     
     * @param forwardName Forward to this abstract forward name.
     * @param parameters The dynamic Validation Parameters used in creating validation forwards
     * @return DynamicURI the full link to the referenced page
     */
    public DynamicURI forwardDynamic(RunData rundata, String forwardName, Map parameters)
    {
        return forwardInternal(rundata, forwardName, null, parameters);        
    }

    /**
     * Internal implementation of Forward used by both forwards and portlet forwards.
     *
     * @param rundata The turbine rundata context for this request.     
     * @param name Forward to this abstract forward name.
     * @param staticParams Map of static query parameters from PortletForward 
     *                     overriding the static Forwards query parameters
     * @param dynamicParams Map of dynamic query parameters overriding both
     *                     static PortletForward parameters and static Forwards query parameters     
     * @return DynamicURI the full link to the referenced page     
     */
    private DynamicURI forwardInternal(RunData rundata, 
                                   String  forwardName,
                                   Map staticParams,
                                   Map dynamicParams)
    {
        DynamicURI duri = null;
        Forward forward = null;

        try
        {
            JetspeedLink link = JetspeedLinkFactory.getInstance(rundata);
            int rootType = JetspeedLink.DEFAULT;
            int elementType = JetspeedLink.DEFAULT;
            String rootValue = null;
            String pageName = null;
            String elementValue = null;
            String actionName = null;
            String templateName = null;
            String mediaType = null;
            String language = null;
            String country = null;


            forward = (Forward)this.forwards.get(forwardName);
            if (null != forward)
            {
                Pane pane = forward.getPane();
                if (null != pane)
                {
                    elementValue = pane.getId();
                    elementType = JetspeedLink.PANE_ID;
                    if (elementValue == null)
                    {
                        elementValue = pane.getName();
                        elementType = JetspeedLink.PANE_NAME;
                    }                    
                }
                else // can't have both portlet and pane
                {
                    Portlet portlet = forward.getPortlet();
                    if (null != portlet)
                    {
                        elementValue = portlet.getId();
                        elementType = JetspeedLink.PORTLET_ID;
                        if (elementValue == null)
                        {
                            elementValue = portlet.getName();
                            elementType = JetspeedLink.PORTLET_NAME;
                        }                    
                        actionName = portlet.getAction();
                    }
                }

                Page page = forward.getPage();
                if (null != page)
                {
                    pageName = page.getName();

                    String user = page.getUser();
                    if (user != null)
                    {
                        rootType = JetspeedLink.USER;
                        rootValue = user;
                    }
                    else 
                    {
                        String role = page.getRole();
                        if (role != null)
                        {
                            rootType = JetspeedLink.ROLE;
                            rootValue = role;
                        }
                        else
                        {
                            String group = page.getGroup();
                            if (group != null)
                            {
                                rootType = JetspeedLink.GROUP;
                                rootValue = group;
                            }
                            else
                            {
                                rootType = JetspeedLink.CURRENT;
                            }
                        }
                    }
                }

                duri = link.getLink(rootType, 
                             rootValue, 
                             pageName, 
                             elementType, 
                             elementValue, 
                             actionName,  
                             templateName, // not yet implemented
                             mediaType,    // not yet implemented 
                             language,     // not yet implemented
                             country);     // not yet implemented 

            }
            else
            {
                // forward not found, log it and return to home page
                // TODO: perhaps this could be configurable to go to a default error page
                logger.error("Forward not found, going to Home Page:" + forwardName);
                duri = link.getHomePage();
    
            }
    
            if (null == duri)
            {
                duri = link.getPage();
            }

            Map baseQueryParams = null;
            if (null != forward)
            {
                baseQueryParams = forward.getQueryParams();
            }
            setQueryParams(duri, baseQueryParams, staticParams, dynamicParams);

            rundata.setRedirectURI(duri.toString());
            JetspeedLinkFactory.putInstance(link);
        }
        catch (Throwable t)
        {
            logger.error("Exception in Forward",t);
        }
        return duri;
    }