/**
 * Copyright (C) 2009 eXo Platform SAS.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */

package org.exoplatform.webui.application.portlet;

import java.io.IOException;
import java.util.Locale;
import java.util.ResourceBundle;

import javax.portlet.ActionRequest;
import javax.portlet.ActionResponse;
import javax.portlet.EventRequest;
import javax.portlet.EventResponse;
import javax.portlet.PortletConfig;
import javax.portlet.PortletContext;
import javax.portlet.PortletRequest;
import javax.portlet.PortletResponse;
import javax.portlet.RenderRequest;
import javax.portlet.RenderResponse;
import javax.portlet.ResourceRequest;
import javax.portlet.ResourceResponse;

import org.exoplatform.commons.utils.PortalPrinter;
import org.exoplatform.commons.utils.Safe;
import org.exoplatform.resolver.ApplicationResourceResolver;
import org.exoplatform.resolver.PortletResourceResolver;
import org.exoplatform.services.log.ExoLogger;
import org.exoplatform.services.log.Log;
import org.exoplatform.web.application.ApplicationLifecycle;
import org.exoplatform.web.application.RequestContext;
import org.exoplatform.webui.application.StateManager;
import org.exoplatform.webui.application.WebuiApplication;
import org.exoplatform.webui.application.WebuiRequestContext;
import org.exoplatform.webui.core.UIApplication;
import org.exoplatform.webui.core.UIComponent;
import org.exoplatform.webui.core.UIPortletApplication;
import org.exoplatform.webui.event.Event;
import org.exoplatform.webui.event.Event.Phase;

/**
 * May 26, 2006
 *
 * A portlet application. Every call made to a portlet deployed in eXo PC - and using eXo web framework - is going through this
 * class
 */
public class PortletApplication extends WebuiApplication {

    protected static Log log = ExoLogger.getLogger(PortletApplication.class);

    public static final String PORTLET_EVENT_VALUE = "portletEventValue";

    /**
     * The configuration parameter of this portlet
     */
    private PortletConfig portletConfig_;

    /**
     * The id of this portlet
     */
    private String applicationId_;

    /**
     * This constructor has 2 purposes: 1) recreate the application id 2) configure the resource resolver to look in different
     * UIR scheme (here app: and par:)
     */
    public PortletApplication(PortletConfig config) {
        portletConfig_ = config;
        PortletContext pcontext = config.getPortletContext();
        String contextName = pcontext.getPortletContextName();
        applicationId_ = contextName + "/" + config.getPortletName();

        ApplicationResourceResolver resolver = new ApplicationResourceResolver();
        resolver.addResourceResolver(new PortletResourceResolver(pcontext, "app:"));
        resolver.addResourceResolver(new PortletResourceResolver(pcontext, "par:"));
        setResourceResolver(resolver);
    }

    public String getApplicationId() {
        return applicationId_;
    }

    public String getApplicationName() {
        return portletConfig_.getPortletName();
    }

    public String getApplicationGroup() {
        return portletConfig_.getPortletContext().getPortletContextName();
    }

    @Override
    public String getApplicationType() {
        return JSR168_APPLICATION_TYPE;
    }

    public ResourceBundle getResourceBundle(Locale locale) {
        return portletConfig_.getResourceBundle(locale);
    }

    @SuppressWarnings("unused")
    public ResourceBundle getOwnerResourceBundle(String username, Locale locale) {
        return null;
    }

    public String getApplicationInitParam(String name) {
        return portletConfig_.getInitParameter(name);
    }

    /**
     * The processAction() method is the one modelled according to the Portlet API specification
     *
     * The process is quite simple and here are te different steps done in the method:
     *
     * 1) The current instance of the WebuiRequestContext (stored in a ThreadLocal in the class) is referenced 2) A new request
     * context of type PortletRequestContext (which extends the class WebuiRequestContext) is created as a child of the current
     * context instance 3) The new context is place inside the ThreadLocal and hence overides its parent one there, only for the
     * portlet request lifeciclye 4) The method onStartRequest() is called in all the ApplicationLifecycle objects referenced in
     * the webui configuration XML file 5) The StateManager object (in case of portlet it is an object of type
     * ParentAppStateManager) is used to get the RootComponent also referenced in the XML configuration file 6) The methods
     * processDecode(UIApplication, WebuiRequestContext) and processAction(UIApplication, WebuiRequestContext) are then called
     * 7) Finally, a flag, to tell that the processAction phase was done, in the context is set to true and the parent context
     * is restored in the Threadlocal
     */
    public void processAction(ActionRequest req, ActionResponse res) throws Exception {
        WebuiRequestContext parentAppRequestContext = WebuiRequestContext.getCurrentInstance();
        PortletRequestContext context = createRequestContext(req, res, parentAppRequestContext);
        WebuiRequestContext.setCurrentInstance(context);
        try {
            for (ApplicationLifecycle<RequestContext> lifecycle : getApplicationLifecycle()) {
                lifecycle.onStartRequest(this, context);
            }
            StateManager sm = getStateManager();
            UIApplication uiApp = sm.restoreUIRootComponent(context);
            context.setUIApplication(uiApp);
            uiApp.processDecode(context);
            if (!context.isResponseComplete() && !context.getProcessRender()) {
                uiApp.processAction(context);
            }

            // Store ui root
            sm.storeUIRootComponent(context);
        } finally {
            context.setAppLifecycleStarted(true);
            WebuiRequestContext.setCurrentInstance(parentAppRequestContext);
        }
    }

    /**
     * This method is called when a JSR 286 event is targeting the current portlet.
     *
     * The event is transformed in a WebUI event using the convention that the 286 event name will target the
     * EventNameActionListener class of one of the UIComponent in the portlet uicomponent tree
     *
     * The event value is passed as an attribute of the PortletRequestContext
     */
    public void processEvent(EventRequest req, EventResponse res) throws Exception {
        WebuiRequestContext parentAppRequestContext = WebuiRequestContext.getCurrentInstance();
        PortletRequestContext context = createRequestContext(req, res, parentAppRequestContext);
        WebuiRequestContext.setCurrentInstance(context);
        try {
            for (ApplicationLifecycle<RequestContext> lifecycle : getApplicationLifecycle()) {
                lifecycle.onStartRequest(this, context);
            }
            StateManager sm = getStateManager();
            UIApplication uiApp = sm.restoreUIRootComponent(context);
            context.setUIApplication(uiApp);
            javax.portlet.Event portletEvent = req.getEvent();
            context.setAttribute(PORTLET_EVENT_VALUE, portletEvent.getValue());
            Event<UIComponent> uiEvent = uiApp.createEvent(portletEvent.getName(), Phase.PROCESS, context);
            uiEvent.broadcast();

            // Store ui root
            sm.storeUIRootComponent(context);
        } finally {
            context.setAppLifecycleStarted(true);
            WebuiRequestContext.setCurrentInstance(parentAppRequestContext);
        }
    }

    /**
     * This method is called when a JSR 286 serveResource lifecycle method is targeting the current portlet.
     *
     * 1) The current instance of the WebuiRequestContext (stored in a ThreadLocal in the class) is referenced 2) A new request
     * context of type PortletRequestContext (which extends the class WebuiRequestContext) is created as a child of the current
     * context instance 3) The new context is place inside the ThreadLocal and hence overides its parent one there, only for the
     * portlet request lifecycle 4) The method onStartRequest() is called in all the ApplicationLifecycle objects referenced in
     * the webui configuration XML file 5) The StateManager object (in case of portlet it is an object of type
     * ParentAppStateManager) is used to get the RootComponent also referenced in the XML configuration file 6) The method
     * serveResource of UIPortletApplication is called 7) Finally, the method onEndRequest() is called on every
     * ApplicationLifecycle referenced in the portlet configuration XML file and the parent WebuiRequestContext is restored
     */
    public void serveResource(ResourceRequest req, ResourceResponse res) throws Exception {
        WebuiRequestContext parentAppRequestContext = WebuiRequestContext.getCurrentInstance();
        PortletRequestContext context = createRequestContext(req, res, parentAppRequestContext);
        WebuiRequestContext.setCurrentInstance(context);
        try {
            for (ApplicationLifecycle<RequestContext> lifecycle : getApplicationLifecycle()) {
                lifecycle.onStartRequest(this, context);
            }
            StateManager sm = getStateManager();
            UIApplication uiApp = sm.restoreUIRootComponent(context);
            context.setUIApplication(uiApp);
            if (uiApp instanceof UIPortletApplication) {
                ((UIPortletApplication) uiApp).serveResource(context);
            }

            // Store ui root
            sm.storeUIRootComponent(context);
        } finally {
            try {
                for (ApplicationLifecycle<RequestContext> lifecycle : getApplicationLifecycle()) {
                    lifecycle.onEndRequest(this, context);
                }
            } catch (Exception exception) {
                log.error("Error while trying to call onEndRequest of the portlet ApplicationLifecycle", exception);
            }
            WebuiRequestContext.setCurrentInstance(parentAppRequestContext);
        }
    }

    /**
     * The render method business logic is quite similar to the processAction() one.
     *
     * 1) A PortletRequestContext object is created (or extracted from the cache if it already exists) and initialized 2) The
     * PortletRequestContext replaces the parent one in the WebuiRequestContext ThreadLocal object 3) If the portal has already
     * called the portlet processAction() then the call to all onStartRequest of the ApplicationLifecycle has already been made,
     * otherwise we call them 4) The ParentStateManager is also used to get the UIApplication, as we have seen it delegates the
     * call to the PortalStateManager which caches the UI component root associated with the current application 5) the
     * processRender() method of the UIPortletApplucaton is called 6) Finally, the method onEndRequest() is called on every
     * ApplicationLifecycle referenced in the portlet configuration XML file and the parent WebuiRequestContext is restored
     *
     */
    public void render(RenderRequest req, RenderResponse res) throws Exception {
        WebuiRequestContext parentAppRequestContext = WebuiRequestContext.getCurrentInstance();
        PortletRequestContext context = createRequestContext(req, res, parentAppRequestContext);
        WebuiRequestContext.setCurrentInstance(context);
        try {
            if (!context.isAppLifecycleStarted()) {
                for (ApplicationLifecycle<RequestContext> lifecycle : getApplicationLifecycle()) {
                    lifecycle.onStartRequest(this, context);
                }
            }
            StateManager sm = getStateManager();
            UIApplication uiApp = sm.restoreUIRootComponent(context);
            context.setUIApplication(uiApp);
            if (!context.isResponseComplete()) {
                UIPortletApplication uiPortletApp = (UIPortletApplication) uiApp;
                uiPortletApp.processRender(this, context);
            }
            uiApp.setLastAccessApplication(System.currentTimeMillis());

            // Store ui root
            sm.storeUIRootComponent(context);
        } finally {

            // Close the writer
            Safe.close(context.getWriter());

            //
            try {
                for (ApplicationLifecycle<RequestContext> lifecycle : getApplicationLifecycle()) {
                    lifecycle.onEndRequest(this, context);
                }
            } catch (Exception exception) {
                log.error("Error while trying to call onEndRequest of the portlet ApplicationLifecycle", exception);
            }
            WebuiRequestContext.setCurrentInstance(parentAppRequestContext);
        }
    }

    /**
     * In this method we try to get the PortletRequestContext object from the attribute map of the parent WebuiRequestContext.
     *
     * If it is not cached then we create a new instance, if it is cached then we init it with the correct writer, request and
     * response objects
     *
     * We finally cache it in the parent attribute map
     *
     */
    private PortletRequestContext createRequestContext(PortletRequest req, PortletResponse res,
            WebuiRequestContext parentAppRequestContext) throws IOException {
        String attributeName = getApplicationId() + "$PortletRequest";
        PortletRequestContext context = (PortletRequestContext) parentAppRequestContext.getAttribute(attributeName);
        PortalPrinter w = null;
        if (res instanceof RenderResponse) {
            RenderResponse renderRes = (RenderResponse) res;
            renderRes.setContentType("text/html; charset=UTF-8");
            w = new PortalPrinter(renderRes.getPortletOutputStream(), true, 0);
        }
        if (context != null) {
            context.init(w, req, res);
        } else {
            context = new PortletRequestContext(parentAppRequestContext, this, w, req, res);
            parentAppRequestContext.setAttribute(attributeName, context);
        }
        return context;
    }
}
