/**
    * Copyright 2004-2013 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.opensource.org/licenses/ecl2.php
    *
   * 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.hr.time.timezone.service;
  
  import java.util.List;
  
  import org.apache.commons.lang.ObjectUtils;
  import org.apache.commons.lang.StringUtils;
  import org.joda.time.DateTime;
  import org.joda.time.DateTimeZone;
  import org.kuali.hr.job.Job;
  import org.kuali.hr.location.Location;
  import org.kuali.hr.time.principal.PrincipalHRAttributes;
  import org.kuali.hr.time.service.base.TkServiceLocator;
  import org.kuali.hr.time.timeblock.TimeBlock;
  import org.kuali.hr.time.util.TKContext;
  import org.kuali.hr.time.util.TKUtils;
  import org.kuali.rice.krad.util.GlobalVariables;
  
  public class TimezoneServiceImpl implements TimezoneService {
  
      @Override
      public String getUserTimezone(String principalId) {
          PrincipalHRAttributes principalCalendar = TkServiceLocator.getPrincipalHRAttributeService().getPrincipalCalendar(principalId, TKUtils.getCurrentDate());
          if(principalCalendar != null && principalCalendar.getTimezone() != null){
              return principalCalendar.getTimezone();
          }
          List<Job> jobs = TkServiceLocator.getJobService().getJobs(principalId, TKUtils.getCurrentDate());
          if (jobs.size() > 0) {
              // Grab the location off the first job in the list
              Location location = TkServiceLocator.getLocationService().getLocation(jobs.get(0).getLocation(), TKUtils.getCurrentDate());
              if (location!=null){
                  if(StringUtils.isNotBlank(location.getTimezone())){
                      return location.getTimezone();
                  }
              }
          }
          return TKUtils.getSystemTimeZone();
      }
  
      /**
  	 * Used to determine if an override condition exists for a user timezone
  	 */
  	@Override
  	public String getUserTimezone() {
  		String timezone = "";
  		if (GlobalVariables.getUserSession() != null) {
  			timezone = getUserTimezone(GlobalVariables.getUserSession().getPrincipalId());
  		}
          return timezone;
  	}
  
      @Override
      public DateTimeZone getUserTimezoneWithFallback() {
          String tzid = getUserTimezone();
          if (StringUtils.isEmpty(tzid)) {
              return TKUtils.getSystemDateTimeZone();
          } else {
              return DateTimeZone.forID(tzid);
          }
      }
  
      private DateTimeZone getUserTimezoneWithFallback(String principalId) {
          String tzid = getUserTimezone(principalId);
          if (StringUtils.isEmpty(tzid)) {
              return TKUtils.getSystemDateTimeZone();
          } else {
              return DateTimeZone.forID(tzid);
          }
      }
  
  	/**
  	 * Translation needed for UI Display
  	 * @param timeBlocks
  	 * @param timezone
  	 * @return timeblock list modified with times offset for timezone
  	 */
  	public List<TimeBlock> translateForTimezone(List<TimeBlock> timeBlocks, DateTimeZone timezone){
  		for(TimeBlock tb : timeBlocks){
  			//No need for translation if it matches the current timezone
  			if(ObjectUtils.equals(timezone, TKUtils.getSystemDateTimeZone())){
  				tb.setBeginTimeDisplay(new DateTime(tb.getBeginTimestamp()));
  				tb.setEndTimeDisplay(new DateTime(tb.getEndTimestamp()));
  			}
  			else {
  				tb.setBeginTimeDisplay(new DateTime(tb.getBeginTimestamp(), timezone));
 				tb.setEndTimeDisplay(new DateTime(tb.getEndTimestamp(), timezone));
 			}
 		}
 		return timeBlocks;
 	}
 
     public void translateForTimezone(List<TimeBlock> timeBlocks) {
         if (timeBlocks.isEmpty()) {
             translateForTimezone(timeBlocks, getUserTimezoneWithFallback());
         }
         else {
             translateForTimezone(timeBlocks, getUserTimezoneWithFallback(timeBlocks.get(0).getPrincipalId()));
         }
     }
 
 	@Override
 	public boolean isSameTimezone() {
 		String userTimezone = getUserTimezone();
 		if(StringUtils.isNotBlank(userTimezone)) {
 			return StringUtils.equals(TKUtils.getSystemTimeZone(), userTimezone);
 		}
 		return true;
 	}
 	
 	
 	public long getTimezoneOffsetFromServerTime(DateTimeZone dtz){
 		long systemOffsetUTC = TKUtils.getSystemDateTimeZone().getOffset(null);
 		long tzOffsetUTC = dtz.getOffset(null);
 		return tzOffsetUTC - systemOffsetUTC;
 	}
 
 
 
 }