/**
    * 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.overtime.daily.rule.service;
  
  import org.apache.log4j.Logger;
  import org.kuali.hr.job.Job;
  import org.kuali.hr.time.assignment.Assignment;
  import org.kuali.hr.time.overtime.daily.rule.DailyOvertimeRule;
  import org.kuali.hr.time.overtime.daily.rule.dao.DailyOvertimeRuleDao;
  import org.kuali.hr.time.service.base.TkServiceLocator;
  import org.kuali.hr.time.timeblock.TimeBlock;
  import org.kuali.hr.time.timeblock.TimeHourDetail;
  import org.kuali.hr.time.timesheet.TimesheetDocument;
  import org.kuali.hr.time.util.TKUtils;
  import org.kuali.hr.time.util.TkConstants;
  import org.kuali.hr.time.util.TkTimeBlockAggregate;
  
  import java.math.BigDecimal;
  import java.sql.Date;
  import java.util.*;
  
  public class DailyOvertimeRuleServiceImpl implements DailyOvertimeRuleService {
  
      private static final Logger LOG = Logger.getLogger(DailyOvertimeRuleServiceImpl.class);
  
  	private DailyOvertimeRuleDao dailyOvertimeRuleDao = null;
  
  	public void saveOrUpdate(DailyOvertimeRule dailyOvertimeRule) {
  		dailyOvertimeRuleDao.saveOrUpdate(dailyOvertimeRule);
  	}
  
  	public void saveOrUpdate(List<DailyOvertimeRule> dailyOvertimeRules) {
  		dailyOvertimeRuleDao.saveOrUpdate(dailyOvertimeRules);
  	}
  
  	@Override
  	/**
  	 * Search for the valid Daily Overtime Rule, wild cards are allowed on
  	 * location
  	 * paytype
  	 * department
  	 * workArea
  	 *
  	 * asOfDate is required.
  	 */
  	public DailyOvertimeRule getDailyOvertimeRule(String location, String paytype, String dept, Long workArea, Date asOfDate) {
  		DailyOvertimeRule dailyOvertimeRule = null;
  
  		//		l, p, d, w
  		if (dailyOvertimeRule == null)
  			dailyOvertimeRule = dailyOvertimeRuleDao.findDailyOvertimeRule(location, paytype, dept, workArea, asOfDate);
  
  		//		l, p, d, -1
  		if (dailyOvertimeRule == null)
  			dailyOvertimeRule = dailyOvertimeRuleDao.findDailyOvertimeRule(location, paytype, dept, -1L, asOfDate);
  
  		//		l, p, *, w
  		if (dailyOvertimeRule == null)
  			dailyOvertimeRule = dailyOvertimeRuleDao.findDailyOvertimeRule(location, paytype, "%", workArea, asOfDate);
  
  		//		l, p, *, -1
  		if (dailyOvertimeRule == null)
  			dailyOvertimeRule = dailyOvertimeRuleDao.findDailyOvertimeRule(location, paytype, "%", -1L, asOfDate);
  
  		//		l, *, d, w
  		if (dailyOvertimeRule == null)
  			dailyOvertimeRule = dailyOvertimeRuleDao.findDailyOvertimeRule(location, "%", dept, workArea, asOfDate);
  
  		//		l, *, d, -1
  		if (dailyOvertimeRule == null)
  			dailyOvertimeRule = dailyOvertimeRuleDao.findDailyOvertimeRule(location, "%", dept, -1L, asOfDate);
  
  		//		l, *, *, w
  		if (dailyOvertimeRule == null)
  			dailyOvertimeRule = dailyOvertimeRuleDao.findDailyOvertimeRule(location, "%", "%", workArea, asOfDate);
  
  		//		l, *, *, -1
  		if (dailyOvertimeRule == null)
  			dailyOvertimeRule = dailyOvertimeRuleDao.findDailyOvertimeRule(location, "%", "%", -1L, asOfDate);
  
  		//		*, p, d, w
  		if (dailyOvertimeRule == null)
  			dailyOvertimeRule = dailyOvertimeRuleDao.findDailyOvertimeRule("%", paytype, dept, workArea, asOfDate);
  
  		//		*, p, d, -1
  		if (dailyOvertimeRule == null)
 			dailyOvertimeRule = dailyOvertimeRuleDao.findDailyOvertimeRule("%", paytype, dept, -1L, asOfDate);
 
 		//		*, p, *, w
 		if (dailyOvertimeRule == null)
 			dailyOvertimeRule = dailyOvertimeRuleDao.findDailyOvertimeRule("%", paytype, "%", workArea, asOfDate);
 
 		//		*, p, *, -1
 		if (dailyOvertimeRule == null)
 			dailyOvertimeRule = dailyOvertimeRuleDao.findDailyOvertimeRule("%", paytype, "%", -1L, asOfDate);
 
 		//		*, *, d, w
 		if (dailyOvertimeRule == null)
 			dailyOvertimeRule = dailyOvertimeRuleDao.findDailyOvertimeRule("%", "%", dept, workArea, asOfDate);
 
 		//		*, *, d, -1
 		if (dailyOvertimeRule == null)
 			dailyOvertimeRule = dailyOvertimeRuleDao.findDailyOvertimeRule("%", "%", dept, -1L, asOfDate);
 
 		//		*, *, *, w
 		if (dailyOvertimeRule == null)
 			dailyOvertimeRule = dailyOvertimeRuleDao.findDailyOvertimeRule("%", "%", "%", workArea, asOfDate);
 
 		//		*, *, *, -1
 		if (dailyOvertimeRule == null)
 			dailyOvertimeRule = dailyOvertimeRuleDao.findDailyOvertimeRule("%", "%", "%", -1L, asOfDate);
 
 		return dailyOvertimeRule;
 	}
 
 
 
 	public void setDailyOvertimeRuleDao(DailyOvertimeRuleDao dailyOvertimeRuleDao) {
 		this.dailyOvertimeRuleDao = dailyOvertimeRuleDao;
 	}
 
 	/**
 	 * Provides a key used to store and look up Daily Overtime Rules.
 	 * @param assignment
 	 * @return
 	 */
 	private String getIdentifyingKey(Assignment assignment) {
 		StringBuffer keybuf = new StringBuffer();
 		Job job = assignment.getJob();
 
 		keybuf.append(job.getLocation()).append('_');
 		keybuf.append(job.getHrPayType()).append('_');
 		keybuf.append(job.getDept()).append('_');
 		keybuf.append(assignment.getWorkArea());
 
 		return keybuf.toString();
 	}
 
 	private Assignment getIdentifyingKey(TimeBlock block, Date asOfDate, String principalId) {
 		List<Assignment> lstAssign = TkServiceLocator.getAssignmentService().getAssignments(principalId, asOfDate);
 
 		for(Assignment assign : lstAssign){
 			if((assign.getJobNumber().compareTo(block.getJobNumber()) == 0) && (assign.getWorkArea().compareTo(block.getWorkArea()) == 0)){
 				return assign;
 			}
 		}
 		return null;
 	}
 
 
 	public void processDailyOvertimeRules(TimesheetDocument timesheetDocument, TkTimeBlockAggregate timeBlockAggregate){
 		Map<DailyOvertimeRule, List<Assignment>> mapDailyOvtRulesToAssignment = new HashMap<DailyOvertimeRule, List<Assignment>>();
 
 		for(Assignment assignment : timesheetDocument.getAssignments()) {
 			Job job = assignment.getJob();
 			DailyOvertimeRule dailyOvertimeRule = getDailyOvertimeRule(job.getLocation(), job.getHrPayType(), job.getDept(), assignment.getWorkArea(), timesheetDocument.getAsOfDate());
 
 			if(dailyOvertimeRule !=null) {
 				if(mapDailyOvtRulesToAssignment.containsKey(dailyOvertimeRule)){
 					List<Assignment> lstAssign = mapDailyOvtRulesToAssignment.get(dailyOvertimeRule);
 					lstAssign.add(assignment);
 					mapDailyOvtRulesToAssignment.put(dailyOvertimeRule, lstAssign);
 				}  else {
 					List<Assignment> lstAssign = new ArrayList<Assignment>();
 					lstAssign.add(assignment);
 					mapDailyOvtRulesToAssignment.put(dailyOvertimeRule, lstAssign);
 				}
 			}
 		}
 
 		//Quick bail
 		if(mapDailyOvtRulesToAssignment.isEmpty()){
 			return;
 		}
 
 		// TODO: We iterate Day by Day
 		for(List<TimeBlock> dayTimeBlocks : timeBlockAggregate.getDayTimeBlockList()){
 
 			if (dayTimeBlocks.size() == 0)
 				continue;
 
 			// 1: ... bucketing by (DailyOvertimeRule -> List<TimeBlock>)
 			Map<DailyOvertimeRule,List<TimeBlock>> dailyOvtRuleToDayTotals = new HashMap<DailyOvertimeRule,List<TimeBlock>>();
 			for(TimeBlock timeBlock : dayTimeBlocks) {
 				Assignment assign = this.getIdentifyingKey(timeBlock, timesheetDocument.getAsOfDate(), timesheetDocument.getPrincipalId());
 				for(DailyOvertimeRule dr : mapDailyOvtRulesToAssignment.keySet()){
 					List<Assignment> lstAssign = mapDailyOvtRulesToAssignment.get(dr);
 
                     // for this kind of operation to work, equals() and hashCode() need to
                     // be over ridden for the object of comparison.
 					if(lstAssign.contains(assign)){
                         // comparison here will always work, because we're comparing
                         // against our existing instantiation of the object.
 						if(dailyOvtRuleToDayTotals.get(dr) != null){
 							List<TimeBlock> lstTimeBlock = dailyOvtRuleToDayTotals.get(dr);
 							lstTimeBlock.add(timeBlock);
 							dailyOvtRuleToDayTotals.put(dr, lstTimeBlock);
 						} else {
 							List<TimeBlock> lstTimeBlock = new ArrayList<TimeBlock>();
 							lstTimeBlock.add(timeBlock);
 							dailyOvtRuleToDayTotals.put(dr, lstTimeBlock);
 						}
 					}
 				}
 			}
 
 			for(DailyOvertimeRule dr : mapDailyOvtRulesToAssignment.keySet() ){
 				Set<String> fromEarnGroup = TkServiceLocator.getEarnCodeGroupService().getEarnCodeListForEarnCodeGroup(dr.getFromEarnGroup(), TKUtils.getTimelessDate(timesheetDocument.getCalendarEntry().getEndPeriodDateTime()));
 				List<TimeBlock> blocksForRule = dailyOvtRuleToDayTotals.get(dr);
 				if (blocksForRule == null || blocksForRule.size() == 0)
 					continue; // skip to next rule and check for valid blocks.
 				sortTimeBlocksNatural(blocksForRule);
 
 				// 3: Iterate over the timeblocks, apply the rule when necessary.
 				BigDecimal hours = BigDecimal.ZERO;
 				List<TimeBlock> applicationList = new LinkedList<TimeBlock>();
 				TimeBlock previous = null;
 				for (TimeBlock block : blocksForRule) {
 					if (exceedsMaxGap(previous, block, dr.getMaxGap())) {
 						apply(hours, applicationList, dr, fromEarnGroup);
 						applicationList.clear();
 						hours = BigDecimal.ZERO;
 						previous = null; // reset our chain
 					} else {
 						previous = block; // build up our chain
 					}
                     applicationList.add(block);
 					for (TimeHourDetail thd : block.getTimeHourDetails())
 						if (fromEarnGroup.contains(thd.getEarnCode()))
 							hours = hours.add(thd.getHours(), TkConstants.MATH_CONTEXT);
 				}
 				// when we run out of blocks, we may have more to apply.
 				apply(hours, applicationList, dr, fromEarnGroup);
 			}
 		}
 	}
 
 	/**
 	 * Reverse sorts blocks and applies hours to matching earn codes in the
 	 * time hour detail entries.
 	 *
 	 * @param hours Total number of Daily Overtime Hours to apply.
 	 * @param blocks Time blocks found to need rule application.
 	 * @param rule The rule we are applying.
 	 * @param earnGroup Earn group we've already loaded for this rule.
 	 */
 	private void apply(BigDecimal hours, List<TimeBlock> blocks, DailyOvertimeRule rule, Set<String> earnGroup) {
 		sortTimeBlocksInverse(blocks);
 		if (blocks != null && blocks.size() > 0)
 			if (hours.compareTo(rule.getMinHours()) >= 0) {
                 BigDecimal remaining = hours.subtract(rule.getMinHours(), TkConstants.MATH_CONTEXT);
 				for (TimeBlock block : blocks) {
 					remaining = applyOvertimeToTimeBlock(block, rule.getEarnCode(), earnGroup, remaining);
                 }
                 if (remaining.compareTo(BigDecimal.ZERO) > 0) {
                     LOG.warn("Hours remaining that were unapplied in DailyOvertimeRule.");
                 }
             }
 	}
 
 
 	/**
 	 * Method to apply (if applicable) overtime additions to the indiciated TimeBlock.  TimeBlock
 	 * earn code is checked against the convertFromEarnCodes Set.
 	 *
 	 * @param block
 	 * @param otEarnCode
 	 * @param convertFromEarnCodes
 	 * @param otHours
 	 *
 	 * @return The amount of overtime hours remaining to be applied.  (BigDecimal is immutable)
 	 */
 	private BigDecimal applyOvertimeToTimeBlock(TimeBlock block, String otEarnCode, Set<String> convertFromEarnCodes, BigDecimal otHours) {
 		BigDecimal applied = BigDecimal.ZERO;
 
 		if (otHours.compareTo(BigDecimal.ZERO) <= 0)
 			return BigDecimal.ZERO;
 
 		List<TimeHourDetail> details = block.getTimeHourDetails();
 		List<TimeHourDetail> addDetails = new LinkedList<TimeHourDetail>();
 		for (TimeHourDetail detail : details) {
 			if (convertFromEarnCodes.contains(detail.getEarnCode())) {
 				// n = detailHours - otHours
 				BigDecimal n = detail.getHours().subtract(otHours, TkConstants.MATH_CONTEXT);
 				// n >= 0 (meaning there are greater than or equal amount of Detail hours vs. OT hours, so apply all OT hours here)
 				// n < = (meaning there were more OT hours than Detail hours, so apply only the # of hours in detail and update applied.
 				if (n.compareTo(BigDecimal.ZERO) >= 0) {
 					// if
 					applied = otHours;
 				} else {
 					applied = detail.getHours();
 				}
 
 				// Make a new TimeHourDetail with the otEarnCode with "applied" hours
 				TimeHourDetail timeHourDetail = new TimeHourDetail();
 				timeHourDetail.setHours(applied);
 				timeHourDetail.setEarnCode(otEarnCode);
 				timeHourDetail.setTkTimeBlockId(block.getTkTimeBlockId());
 
 				// Decrement existing matched FROM earn code.
 				detail.setHours(detail.getHours().subtract(applied, TkConstants.MATH_CONTEXT));
 				addDetails.add(timeHourDetail);
 			}
 		}
 
 		if (addDetails.size() > 0) {
 			details.addAll(addDetails);
 			block.setTimeHourDetails(details);
 		}
 
 		return otHours.subtract(applied);
 	}
 
 
 	// TODO : Refactor this Copy-Pasta mess to util/comparator classes.
 
 	private void sortTimeBlocksInverse(List<TimeBlock> blocks) {
 		Collections.sort(blocks, new Comparator<TimeBlock>() { // Sort the Time Blocks
 			public int compare(TimeBlock tb1, TimeBlock tb2) {
 				if (tb1 != null && tb2 != null)
 					return -1 * tb1.getBeginTimestamp().compareTo(tb2.getBeginTimestamp());
 				return 0;
 			}
 		});
 	}
 
 
 	private void sortTimeBlocksNatural(List<TimeBlock> blocks) {
 		Collections.sort(blocks, new Comparator<TimeBlock>() { // Sort the Time Blocks
 			public int compare(TimeBlock tb1, TimeBlock tb2) {
 				if (tb1 != null && tb2 != null)
 					return tb1.getBeginTimestamp().compareTo(tb2.getBeginTimestamp());
 				return 0;
 			}
 		});
 	}
 
 	/**
 	 * Does the difference between the previous time blocks clock out time and the
 	 * current time blocks clock in time exceed the max gap?
 	 *
 	 * @param previous If null, false is returned.
 	 * @param current
 	 * @param maxGap
 	 * @return
 	 */
 	boolean exceedsMaxGap(TimeBlock previous, TimeBlock current, BigDecimal maxGap) {
 		if (previous == null)
 			return false;
 
 		long difference = current.getBeginTimestamp().getTime() - previous.getEndTimestamp().getTime();
 		BigDecimal gapHours = TKUtils.convertMillisToHours(difference);
 		BigDecimal cmpGapHrs = TKUtils.convertMinutesToHours(maxGap);
 		return (gapHours.compareTo(cmpGapHrs) > 0);
 	}
 
 	@Override
 	public DailyOvertimeRule getDailyOvertimeRule(String tkDailyOvertimeRuleId) {
 		return dailyOvertimeRuleDao.getDailyOvertimeRule(tkDailyOvertimeRuleId);
 	}
 }