package org.kuali.student.enrollment.class2.population.rule;
   
   import org.kuali.rice.core.api.criteria.PredicateFactory;
   import org.kuali.rice.core.api.criteria.QueryByCriteria;
   import org.kuali.rice.core.api.resourceloader.GlobalResourceLoader;
   import org.kuali.rice.krad.maintenance.MaintenanceDocument;
   import org.kuali.rice.krad.rules.MaintenanceDocumentRuleBase;
   import org.kuali.rice.krad.util.GlobalVariables;
   import org.kuali.student.enrollment.class2.population.dto.PopulationWrapper;
  import org.kuali.student.enrollment.class2.population.util.PopulationConstants;
  import org.kuali.student.r2.common.dto.ContextInfo;
  import org.kuali.student.r2.common.util.ContextUtils;
  import org.kuali.student.r2.core.constants.PopulationServiceConstants;
  import org.kuali.student.r2.core.population.dto.PopulationInfo;
  import org.kuali.student.r2.core.population.service.PopulationService;
  
  import javax.xml.namespace.QName;
  import java.util.List;
  
  /**
   * This class does business validation for Populations
   *
   * @author Kuali Student Team
   */
  public class PopulationWrapperRule extends MaintenanceDocumentRuleBase {
      private transient PopulationService populationService;
  
      @Override
      protected boolean processGlobalSaveDocumentBusinessRules(MaintenanceDocument document) {
          return true;
      }
  
      /**
       * Main entry for validating populations.
       *
       * @param document
       * @return if this document contains valid population information
       */
      @Override
      protected boolean processCustomRouteDocumentBusinessRules(MaintenanceDocument document) {
  
          boolean isValid = super.processCustomRouteDocumentBusinessRules(document);
          PopulationWrapper newWrapper = (PopulationWrapper) document.getNewMaintainableObject().getDataObject();
          //Rule:  population Name has to be unique for creating a new population
          if (document.isNew()) {
              isValid &= populationNameUniqueCheck(newWrapper);
          }
          else if(document.isEdit()){
              PopulationWrapper oldWrapper = (PopulationWrapper) document.getOldMaintainableObject().getDataObject(); 
              if (!oldWrapper.getPopulationInfo().getName().equalsIgnoreCase(newWrapper.getPopulationInfo().getName())) {
                  isValid &= populationNameUniqueCheck(newWrapper);
              }             
          }
  
          String operationType = newWrapper.getPopulationRuleInfo().getTypeKey();
          //Rule:
          //by Union - must select at least 2 DIFFERENT populations in order to create
          //by Intersection - must select at least 2 DIFFERENT populations in order to create
          if (operationType.equals(PopulationServiceConstants.POPULATION_RULE_TYPE_UNION_KEY)){
              isValid &= needTwoChildPopulations(newWrapper, "Union" );
          }
          else if (operationType.equals(PopulationServiceConstants.POPULATION_RULE_TYPE_INTERSECTION_KEY)){
  
              isValid &= needTwoChildPopulations(newWrapper, "Intersection" );
          }
          else if (operationType.equals(PopulationServiceConstants.POPULATION_RULE_TYPE_EXCLUSION_KEY)){
              //Rule:
              //by Exclusion - must select one reference population and at least one other DIFFERENT population in order to create
              isValid &= checkReferenceAndChildPopulations(newWrapper);
          }
          return isValid;
      }
  
      protected boolean checkReferenceAndChildPopulations(PopulationWrapper wrapper){
          boolean isValid  = true;
          List<PopulationInfo> populationInfoList = wrapper.getChildPopulations();
          String referenceId = wrapper.getReferencePopulation().getId();
          if(populationInfoList == null || populationInfoList.isEmpty()){
              isValid = false;
              GlobalVariables.getMessageMap().putError("document.newMaintainableObject.dataObject.operationType",
                      PopulationConstants.POPULATION_MSG_ERROR_NEED_ONE_POPULATIONS, "Exclusion");
          }else{
              // the ref population cannot be in the  source populations.
              if(this.containsPopulation(populationInfoList,referenceId)){
                  isValid = false;
                  GlobalVariables.getMessageMap().putError("document.newMaintainableObject.dataObject.operationType",
                          PopulationConstants.POPULATION_MSG_ERROR_REF_NOT_ALLOWED_IN_SOURCE_POPULATIONS, "Exclusion");
              }
  
              if(populationInfoList.size() > 1 ){     //Two or more
                  if(this.hasDuplicates(populationInfoList)){
                      isValid = false;
                      GlobalVariables.getMessageMap().putError("document.newMaintainableObject.dataObject.operationType",
                              PopulationConstants.POPULATION_MSG_ERROR_NEED_TWO_DIFFERENT_POPULATIONS, "Exclusion");
                  }
              }
          }
  
          return isValid;
     }
 
     protected boolean containsPopulation(List<PopulationInfo> populationInfoList, String populationId){
         if(populationInfoList!=null){
             for(PopulationInfo population : populationInfoList){
                 if(population.getId().equalsIgnoreCase(populationId)){
                     return true;
                 }
             }
         }
         return false;
     }
 
     protected boolean hasDuplicates(List<PopulationInfo> populationInfoList){
         //Compare and make sure there is no duplication
         for (int i= 0; i < populationInfoList.size(); i++) {
             for (int j= 0; j < populationInfoList.size(); j++) {
                 if (i != j && populationInfoList.get(i).getId().equals(populationInfoList.get(j).getId())){
                     return true;
                 }
             }
         }
         return false;
     }
 
     /**
      * Validates that a wrapper has at least two unique child populations
      * @param wrapper
      * @param operation PoplulationType type key (union,intersection/exclusion)
      * @return
      */
     protected boolean needTwoChildPopulations (PopulationWrapper wrapper, String operation){
         boolean isValid  = true;
         List<PopulationInfo> populationInfoList = wrapper.getChildPopulations();
 
         if(populationInfoList.size() > 1 ){     //Two or more
             for (PopulationInfo populationInfo: populationInfoList) {
                 int duplicateCntr = 0;
                 for (PopulationInfo populationInfo1: populationInfoList) {
                     if (populationInfo.getId().equals(populationInfo1.getId())){
                         duplicateCntr++;
                     }
                     if ( duplicateCntr > 1 ) {   //No duplicates
                         isValid = false;
                         break;
                     }
                 }
                 if ( !isValid ){
                     break;
                 }
             }
         } else {
             isValid = false;
         }
         if ( !isValid ){
             GlobalVariables.getMessageMap().putError("document.newMaintainableObject.dataObject.operationType",
                     PopulationConstants.POPULATION_MSG_ERROR_NEED_TWO_DIFFERENT_POPULATIONS, operation);
         }
 
         return isValid;
     }
 
     /**
      * Validates that the population name has not already been used
      * @param wrapper
      * @return if the population name is unique for the application
      */
     protected boolean populationNameUniqueCheck(PopulationWrapper wrapper){
         boolean isNameUnique = true;
 
         String popName = wrapper.getPopulationInfo().getName();
 
         QueryByCriteria.Builder qbcBuilder = QueryByCriteria.Builder.create();
         qbcBuilder.setPredicates(PredicateFactory.equal("name", popName));
         QueryByCriteria criteria = qbcBuilder.build();
         ContextInfo context = ContextUtils.getContextInfo();
         try {
             List<PopulationInfo> populationInfoList = getPopulationService().searchForPopulations(criteria, context);
             if (populationInfoList.size()>0){
                 putFieldError(PopulationConstants.PopulationWrapper.POPULATION_NAME, PopulationConstants.POPULATION_MSG_ERROR_NAME_IS_NOT_UNIQUE, popName);
                 isNameUnique = false;
             }                 
         } catch (Exception e) {
             throw new RuntimeException("PopulationWrapperRule exception. ", e);
         }
         return isNameUnique;
     }
 
     private PopulationService getPopulationService() {
         if(populationService == null) {
             populationService = (PopulationService) GlobalResourceLoader.getService(new QName(PopulationServiceConstants.NAMESPACE, "PopulationService"));
         }
         return populationService;
     }
     
 }