/**

  * Copyright 2011 The Kuali Foundation Licensed under the

  * Educational Community 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.osedu.org/licenses/ECL-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.kuali.mobility.admin.service;

 import java.util.Calendar;

 import java.util.Date;

 import java.util.List;

 import java.util.concurrent.ConcurrentHashMap;

 import java.util.concurrent.ConcurrentMap;

 import org.kuali.mobility.admin.dao.AdminDao;

 import org.kuali.mobility.admin.entity.HomeScreen;

 import org.kuali.mobility.admin.entity.Tool;

 import org.springframework.beans.factory.annotation.Autowired;

 import org.springframework.stereotype.Service;

 import org.springframework.transaction.annotation.Transactional;

 /**

  * Service for actually performing administrative tasks

  * @author Kuali Mobility Team (moblitiy.collab@kuali.org)

  */

 @Service(value = "AdminService")

 public class AdminServiceImpl implements AdminService {

         private static org.apache.log4j.Logger LOG = org.apache.log4j.Logger.getLogger(AdminServiceImpl.class);

         private static final int HOMESCREEN_UPDATE_INTERVAL = 5; //5 min

         private static ConcurrentMap<String, HomeScreen> homeScreens;

         private static Thread homeScreenReloaderThread = null;

         static {

                 homeScreens = new ConcurrentHashMap<String, HomeScreen>();

         } 

         @Autowired

     private AdminDao adminDao;

         @Override

         public void startCache() {

                 homeScreenReloaderThread = new Thread(new HomeScreenReloader());

                 homeScreenReloaderThread.setDaemon(true);

                 homeScreenReloaderThread.start();

     }

         @Override

     public void stopCache() {

             homeScreenReloaderThread.interrupt();

             homeScreenReloaderThread = null;

     }

         @Transactional(readOnly = true)

         public HomeScreen getCachedHomeScreenByAlias(String alias) {

                 return getHomeScreenByAlias(alias);

                 /* TODO: Add caching back in when publishing works properly

                 HomeScreen homeScreen = homeScreens.get(alias);

                 if (homeScreen == null) {

                         LOG.warn("Cannot find homeScreen with alias: " + alias + " in the cache. Fetching from database");

                         return getHomeScreenByAlias(alias);

                 }

                 return homeScreen;

                 */

          }

         @Transactional

         @Override

         public List<HomeScreen> getAllHomeScreens() {

                 return adminDao.getAllHomeScreens();

         }

         @Transactional

         @Override

         public HomeScreen getHomeScreenById(long homeScreenId) {

                 return adminDao.getHomeScreenById(homeScreenId);

         }

         @Transactional

         @Override

         public HomeScreen getHomeScreenByAlias(String alias) {

                 return adminDao.getHomeScreenByAlias(alias);

         }

         @Transactional

         @Override

         public Long saveHomeScreen(HomeScreen homeScreen) {

                 return adminDao.saveHomeScreen(homeScreen);

         }

         @Transactional

         @Override

         public void deleteHomeScreenById(long homeScreenId) {

                 adminDao.deleteHomeScreenById(homeScreenId);

         }

         @Transactional

         @Override

         public List<Tool> getAllTools() {

                 return adminDao.getAllTools();

         }

         @Transactional

         @Override

         public Tool getToolById(long toolId) {

                 return adminDao.getToolById(toolId);

         }

         @Transactional

         @Override

         public Long saveTool(Tool tool) {

                 return adminDao.saveTool(tool);

         }

         @Transactional

         @Override

         public void deleteToolById(long toolId) {

                 adminDao.deleteToolById(toolId);

         }

         /**

          * Class to be used as the cache reloader background thread.

          * @author Kuali Mobility Team (moblitiy.collab@kuali.org)

          *

          */

         private class HomeScreenReloader implements Runnable {

                 /**

                  * Main entry point for the cache reloader

                  */

         public void run() {    

             Calendar updateCalendar = Calendar.getInstance();

             Date nextCacheUpdate = new Date();

             // Cache loop

             while (true) {

                 Date now = new Date();

                 if (now.after(nextCacheUpdate)) {

                     try {

                             reloadHomeScreens();        

                     } catch (Exception e) {

                             LOG.error("Error reloading home screen cache.", e);

                     }

                     updateCalendar.add(Calendar.MINUTE, HOMESCREEN_UPDATE_INTERVAL);

                     nextCacheUpdate = new Date(updateCalendar.getTimeInMillis());

                 }

                 try {

                     Thread.sleep(1000 * 60);

                 } catch (InterruptedException e) {

                     LOG.error("Error:", e);

                 }

             }

         }

         /**

          * Does the actual work of updating the home screens

          */

                 private void reloadHomeScreens() {

                         List<HomeScreen> names = adminDao.getAllHomeScreens();

                         for (HomeScreen homeScreen : names) {

                                 homeScreens.put(homeScreen.getAlias(), adminDao.getHomeScreenByAlias(homeScreen.getAlias()));

                         }                        

                 }

         }

 }