/*
 * Copyright 2005 the original author or authors.
 * 
 * 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.wamblee.photos.tapestry;

import java.security.AccessController;

import javax.security.auth.Subject;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.tapestry.BaseComponent;
import org.apache.tapestry.IRequestCycle;
import org.apache.tapestry.RedirectException;

/**
 * Border component providing general page layout and functions available on every page. 
 */
public class Border extends BaseComponent {
    
    private static final Log LOG = LogFactory.getLog(Border.class);
    
    private static final String LOGOUT_URL = "logout.jsp";
   
    /**
     * Checks if the user is logged in. 
     * @return True if the user is logged in. 
     */
    public boolean isLoggedIn() {
        return getEngine().getUser() != null; 
    }
    
    public String getCurrentUser() { 
        return getEngine().getUser().getName(); 
    }
    
    /** 
     * @return True if the user is logged in and is an administrator.  
     */
    public boolean isAdministrator() { 
        String adminGroup = getEngine().getAdministratorGroup();
        return getEngine().getUser().isInGroup(adminGroup);
    }
    
    /**
     * Gets a reference to the home page. 
     * @return Home page reference. 
     */
    public AlbumPageRef getHome() {
        return new AlbumPageRef(1, 0, "/", true);
    }
    
    public void editProfile(IRequestCycle aCycle) { 
        aCycle.activate(EditProfilePage.PAGE_NAME);
    }
    
    /**
     * Logout the user. 
     * @param aCycle Request cycle. 
     */
    public void logout(IRequestCycle aCycle) {
        
        LOG.info("User '" + Subject.getSubject(AccessController.getContext()) + "' logging out");
        // An alternative is to restart the engine but this solution is fragile since Tapestry itself
        // tries to access the session after that in some case and this leads to an error since
        // tapestry already invalidated the session. Therefore, we just redirect to a JSP which 
        // invalidates the session and forwards back to the home page of the application. 
        // In this way, the logout functionality completely bypasses Tapestry. 
        throw new RedirectException(LOGOUT_URL);
    }
    
    public void viewAdminPage(IRequestCycle aCycle) { 
        aCycle.activate(AdminPage.PAGE_NAME);
    }
    
    private PhotosEngine getEngine() { 
        return (PhotosEngine)getPage().getEngine(); 
    }
}