/**

  * 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.student.process.poc.krms.proposition;

 import org.kuali.rice.krms.api.engine.ExecutionEnvironment;

 import org.kuali.rice.krms.api.engine.ResultEvent;

 import org.kuali.rice.krms.api.engine.Term;

 import org.kuali.rice.krms.framework.engine.PropositionResult;

 import org.kuali.rice.krms.framework.engine.result.BasicResult;

 import org.kuali.student.common.util.krms.RulesExecutionConstants;

 import org.kuali.student.common.util.krms.proposition.AbstractLeafProposition;

 import org.kuali.student.r2.core.atp.dto.MilestoneInfo;

 import org.kuali.student.r2.core.exemption.dto.DateOverrideInfo;

 import org.kuali.student.r2.core.exemption.infc.DateOverride;

 import java.util.Collections;

 import java.util.Date;

 import java.util.HashMap;

 import java.util.List;

 import java.util.Map;

 /**

  * This proposition evaluates a check of a particular date against the dates of a given Milestone.

  * Caveat: the comparisons are all exclusive by default.  If the inclusive field is set to true, then an inclusive comparison is performed

  *

  * @author alubbers

  */

 public class MilestoneDateComparisonProposition extends AbstractLeafProposition implements ExemptionAwareProposition {

     private boolean exemptionUsed = false;

     private final Term milestonesTerm;

     public enum DateComparisonType {

         BETWEEN, BEFORE, AFTER

     }

     private final Term comparisonDateTerm;

     private final DateOverride dateOverride;

     private final DateComparisonType comparisonType;

     private final String milestoneType;

     private final String atpKey;

     private final Boolean inclusive;

     public MilestoneDateComparisonProposition(String comparisonDateTermKey, DateComparisonType comparisonType, String milestoneType, String atpKey, Boolean inclusive, DateOverride dateOverrideInfo) {

         this.comparisonDateTerm = new Term(comparisonDateTermKey);

         this.comparisonType = comparisonType;

         this.milestoneType = milestoneType;

         this.inclusive = inclusive;

         this.dateOverride = dateOverrideInfo;

         this.atpKey = atpKey;

         Map<String, String> termParametersMap = new HashMap<String, String>(2);

         termParametersMap.put(RulesExecutionConstants.MILESTONE_TYPE_TERM_PROPERTY, milestoneType);

         termParametersMap.put(RulesExecutionConstants.MILESTONE_ATP_KEY_TERM_PROPERTY, atpKey);

         milestonesTerm = new Term(RulesExecutionConstants.MILESTONES_BY_TYPE_TERM_NAME, termParametersMap);

     }

     public Term getComparisonDateTerm() {

         return comparisonDateTerm;

     }

     public DateComparisonType getComparisonType() {

         return comparisonType;

     }

     public String getMilestoneType() {

         return milestoneType;

     }

     public Boolean getInclusive() {

         return inclusive;

     }

     public DateOverride getDateOverride() {

         return dateOverride;

     }

     @Override

     public PropositionResult evaluate(ExecutionEnvironment environment) {

         // resolve the list of Milestones from the given Milestone type key

         List<MilestoneInfo> milestones = environment.resolveTerm(milestonesTerm, this);

         Date comparisonDate = environment.resolveTerm(comparisonDateTerm, this);

         boolean dateCompareResult = true;

         for(MilestoneInfo milestone : milestones) {

             dateCompareResult = compareDateToMilestone(comparisonDate, milestone.getStartDate(), milestone.getEndDate());

             if(dateCompareResult) {

                 break;

             }

         }

         if(dateOverride != null) {

            if(dateCompareResult) {

                exemptionUsed = false;

            }

            else {

                // set the proposition result equal to the comparison of the date and the dates from the override

                dateCompareResult = compareDateToMilestone(comparisonDate, dateOverride.getEffectiveEndDate(), dateOverride.getEffectiveEndDate());

                // it should be up to the caller what happens when the comparison fails even when the exemption information was checked

                // so we set the exemptionUsed to true no matter what the actual comparison result was

                exemptionUsed = true;

            }

         }

         PropositionResult result = new PropositionResult(dateCompareResult);

         environment.getEngineResults().addResult(new BasicResult(ResultEvent.PropositionEvaluated, this, environment, result.getResult()));

         return result;

     }

     private boolean compareDateToMilestone(Date comparisonDate, Date startDate, Date endDate) {

         boolean dateCompareResult;

         switch (comparisonType) {

             case BEFORE: {

                 dateCompareResult = comparisonDate.before(endDate);

                 if(inclusive && !dateCompareResult) {

                     dateCompareResult = comparisonDate.equals(endDate);

                 }

                 break;

             }

             case AFTER: {

                 dateCompareResult = comparisonDate.after(startDate);

                 if(inclusive && !dateCompareResult) {

                     dateCompareResult = comparisonDate.equals(startDate);

                 }

                 break;

             }

             case BETWEEN: {

                 dateCompareResult = comparisonDate.after(startDate) && comparisonDate.before(endDate);

                 if(inclusive && !dateCompareResult) {

                     dateCompareResult = comparisonDate.equals(startDate) || comparisonDate.equals(endDate);

                 }

                 break;

             }

             default: {

                 throw new RuntimeException("Invalid comparisonType when evaluating a MilestoneDateComparisonProposition: " + comparisonType);

             }

         }

         return dateCompareResult;

     }

     public boolean isExemptionUsed() {

         return exemptionUsed;

     }

 }