/*
 * Copyright 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.struts.faces.application;


import java.io.IOException;
import javax.faces.FactoryFinder;
import javax.faces.application.ViewHandler;
import javax.faces.component.UICommand;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.context.FacesContextFactory;
import javax.faces.event.ActionEvent;
import javax.faces.lifecycle.Lifecycle;
import javax.faces.lifecycle.LifecycleFactory;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.struts.Globals;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.config.FormBeanConfig;
import org.apache.struts.config.ForwardConfig;
import org.apache.struts.faces.Constants;
import org.apache.struts.faces.component.FormComponent;
import org.apache.struts.faces.util.HttpServletRequestWrapper;
import org.apache.struts.tiles.TilesRequestProcessor;


/**
 * <p>Concrete implementation of <code>RequestProcessor</code> that
 * implements the standard Struts request processing lifecycle on a
 * request that was received as an <code>ActionEvent</code> by our
 * associated <code>ActionListener</code>.  It replaces the request processor
 * instance normally configured by Struts+Tiles, so it must support non-Faces
 * requests as well.</p>
 *
 * @version $Rev: 56770 $ $Date: 2004-11-06 18:15:35 +0000 (Sat, 06 Nov 2004) $
 */

public class FacesTilesRequestProcessor extends TilesRequestProcessor {


    // ------------------------------------------------------ Instance Variables


    /**
     * <p>The log instance for this class.</p>
     */
    protected static Log log =
        LogFactory.getLog(FacesTilesRequestProcessor.class);



    // ------------------------------------------------------- Protected Methods


    /**
     * <p>Set up a Faces Request if we are not already processing one.  Next,
     * create a new view if the specified <code>uri</code> is different from
     * the current view identifier.  Finally, cause the new view to be
     * rendered, and call <code>FacesContext.responseComplete()</code> to
     * indicate that this has already been done.</p>
     *
     * @param uri Context-relative path to forward to
     * @param request Current page request
     * @param response Current page response
     *
     * @exception IOException if an input/output error occurs
     * @exception ServletException if a servlet error occurs
     */
    protected void doForward(String uri,
                             HttpServletRequest request,
                             HttpServletResponse response)
        throws IOException, ServletException {

        if (log.isDebugEnabled()) {
            log.debug("doForward(" + uri + ")");
        }

        // Remove the current ActionEvent (if any)
        request.removeAttribute(Constants.ACTION_EVENT_KEY);

        // Process a Struts controller request normally
        if (isStrutsRequest(uri)) {
            if (response.isCommitted()) {
                if (log.isTraceEnabled()) {
                    log.trace("  super.doInclude(" + uri + ")");
                }
                super.doInclude(uri, request, response);
            } else {
                if (log.isTraceEnabled()) {
                    log.trace("  super.doForward(" + uri + ")");
                }
                super.doForward(uri, request, response);
            }
            return;
        }

        // Create a FacesContext for this request if necessary
        LifecycleFactory lf = (LifecycleFactory)
            FactoryFinder.getFactory(FactoryFinder.LIFECYCLE_FACTORY);
        Lifecycle lifecycle = // FIXME - alternative lifecycle ids
            lf.getLifecycle(LifecycleFactory.DEFAULT_LIFECYCLE);
        boolean created = false;
        FacesContext context = FacesContext.getCurrentInstance();
        if (context == null) {
            if (log.isTraceEnabled()) {
                log.trace("  Creating new FacesContext for '" + uri + "'");
            }
            created = true;
            FacesContextFactory fcf = (FacesContextFactory)
                FactoryFinder.getFactory(FactoryFinder.FACES_CONTEXT_FACTORY);
            HttpServletRequestWrapper wrapper = new HttpServletRequestWrapper(request, uri);
            context = fcf.getFacesContext(servlet.getServletContext(), wrapper,
                                          response, lifecycle); 
            // Comment out the previous three lines and uncomment
            // the following two lines to test eliminating the wrapper
            // context = fcf.getFacesContext(servlet.getServletContext(),
            //                               request, response, lifecycle);
        }

        // Create a new view root
        ViewHandler vh = context.getApplication().getViewHandler();
        if (log.isTraceEnabled()) {
            log.trace("  Creating new view for '" + uri + "'");
        }
        context.setViewRoot(vh.createView(context, uri));

        // Cause the view to be rendered
        if (log.isTraceEnabled()) {
            log.trace("  Rendering view for '" + uri + "'");
        }
        lifecycle.render(context);
        if (created) {
            if (log.isTraceEnabled()) {
                log.trace("  Releasing context for '" + uri + "'");
            }
            context.release();
        } else {
            if (log.isTraceEnabled()) {
                log.trace("  Rendering completed");
            }
        }

    }


    // Override default processing to provide logging
    protected void internalModuleRelativeForward
        (String uri, HttpServletRequest request, HttpServletResponse response)
        throws IOException, ServletException {

        if (log.isTraceEnabled()) {
            log.trace("Performing internal module relative forward to '" +
                      uri + "'");
        }
        super.internalModuleRelativeForward(uri, request, response);

    }


    // Override default processing to provide logging
    protected Action processActionCreate(HttpServletRequest request,
                                         HttpServletResponse response,
                                         ActionMapping mapping)
        throws IOException {

        if (log.isTraceEnabled()) {
            log.trace("Performing standard action create");
        }
        Action result = super.processActionCreate(request, response, mapping);
        if (log.isDebugEnabled()) {
            log.debug("Standard action create returned " +
                      result.getClass().getName() + " instance");
        }
        return (result);

    }


    // Override default processing to provide logging
    protected ActionForm processActionForm(HttpServletRequest request,
                                           HttpServletResponse response,
                                           ActionMapping mapping) {
        if (log.isTraceEnabled()) {
            log.trace("Performing standard action form processing");
            String attribute = mapping.getAttribute();
            if (attribute != null) {
                String name = mapping.getName();
                FormBeanConfig fbc = moduleConfig.findFormBeanConfig(name);
                if (fbc != null) {
                    if ("request".equals(mapping.getScope())) {
                        log.trace("  Bean in request scope = " +
                                  request.getAttribute(attribute));
                    } else {
                        log.trace("  Bean in session scope = " +
                                  request.getSession().getAttribute(attribute));
                    }
                } else {
                    log.trace("  No FormBeanConfig for '" + name + "'");
                }
            } else {
                log.trace("  No form bean for this action");
            }
        }
        ActionForm result =
            super.processActionForm(request, response, mapping);
        if (log.isDebugEnabled()) {
            log.debug("Standard action form returned " +
                      result);
        }
        return (result);
        

    }