/*
 * 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.servlet;

import java.security.SecureRandom;

import javax.servlet.http.HttpSession;

import org.apache.log4j.Logger;
import org.wamblee.cache.Cache;
import org.wamblee.general.BeanKernel;
import org.wamblee.photos.model.Album;
import org.wamblee.photos.model.authorization.AuthorizedAlbum;
import org.wamblee.security.authorization.AuthorizationService;

/**
 * Wrapper class for a session that provides a type-safe interface to the
 * session for the photos application.
 */
public class PhotoSession {

    private static final Logger LOGGER = Logger.getLogger(PhotoSession.class);

    /**
     * Attribute key for the photo album in the session.
     */
    private static final String ALBUM_KEY = "album";

    /**
     * Http session.
     */
    private HttpSession _session;

    /**
     * Constructs the wrapper.
     * 
     * @param aSession
     *            Session.
     */
    public PhotoSession(HttpSession aSession) {
        _session = aSession;
    }

    /**
     * Retrieves the album from the session.
     * 
     * @return Photo album.
     */
    public Album getAlbum() {
        return (Album) _session.getAttribute(ALBUM_KEY);
    }

    /**
     * Performs session initialization.
     * 
     * @param aAlbum
     *            Configured photo album.
     */
    public void sessionCreated() {
        LOGGER.info("Initializing album with authorized entries");
        
        // NOTE: In some circumstances the container reuses the session id for the next 
        //       session it creates, so we have to make it unique by adding a random number 
        //       to the end. 
        
        _session.setAttribute(ALBUM_KEY, new AuthorizedAlbum(
                getConfiguredAlbum(), getAuthorizationService(), BeanKernel
                        .getBeanFactory().find("authorizedPhotoCache",
                                Cache.class), _session.getId() + "/" + new SecureRandom().nextInt()));
    }

    /**
     * Performs session cleanup.
     */
    public void sessionDestroyed() {
        LOGGER.info("Unsubscribing the authorized album");
        _session.removeAttribute(ALBUM_KEY);
    }

    /**
     * Prepares the session for passivation.
     * 
     */
    public void sessionWillPassivate() {
        sessionDestroyed();
    }

    /**
     * Initializes the session after activation.
     * 
     */
    public void sessionDidActivate() {
        sessionCreated();
    }

    /**
     * Gets the configured photo album.
     * 
     * @return Album to use.
     */
    private Album getConfiguredAlbum() {
        return BeanKernel.getBeanFactory().find(Album.class);
    }

    /**
     * Gets the authorization service.
     * 
     * @return Authorization service.
     */
    private AuthorizationService getAuthorizationService() {
        return BeanKernel.getBeanFactory().find(AuthorizationService.class);
    }
}