package org.kuali.rice.krms.framework.engine;

 import java.util.ArrayList;

 import java.util.Collections;

 import java.util.List;

 import java.util.Map;

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

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

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

 import org.kuali.rice.krms.api.repository.LogicalOperator;

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

 public final class CompoundProposition implements Proposition {

     private static final ResultLogger LOG = ResultLogger.getInstance();

         private final LogicalOperator logicalOperator;

         private final List<Proposition> propositions;

         public CompoundProposition(LogicalOperator logicalOperator, List<Proposition> propositions) {

                 if (propositions == null || propositions.isEmpty()) {

                         throw new IllegalArgumentException("Propositions must be non-null and non-empty.");

                 }

                 if (logicalOperator == null) {

                         throw new IllegalArgumentException("Logical operator must be non-null.");

                 }

                 this.logicalOperator = logicalOperator;

                 this.propositions = new ArrayList<Proposition>(propositions);

         }

         @Override

         public PropositionResult evaluate(ExecutionEnvironment environment) {

                 PropositionResult result = evaluateInner(environment);

                 // handle compound proposition result logging

                 if (LOG.isEnabled(environment)) { 

             LOG.logResult(new BasicResult(ResultEvent.PropositionEvaluated, this, environment, result.getResult()));

         }

                 return result;

         }

     /**

      * This method handles the evaluation logic

      * 

      * @param environment

      * @return

      */

     private PropositionResult evaluateInner(ExecutionEnvironment environment) {

             boolean collatedResult;

             boolean evaluateAll = environment.getExecutionOptions().getFlag(ExecutionFlag.EVALUATE_ALL_PROPOSITIONS);

         if (logicalOperator == LogicalOperator.AND) {

             collatedResult = true;

                         for (Proposition proposition : propositions) {

                                 PropositionResult singleResult = proposition.evaluate(environment);

                                 logPropositionResult(proposition, singleResult, environment);

                                 if (!singleResult.getResult()) {

                                         collatedResult = false;

                                         if(!evaluateAll) break;

                                 }

                         }

                         return new PropositionResult(collatedResult);

                 } else if (logicalOperator == LogicalOperator.OR) {

                     collatedResult = false;

                         for (Proposition proposition : propositions) {

                             PropositionResult singleResult = proposition.evaluate(environment);

                                 logPropositionResult(proposition, singleResult, environment);

                                 if (!singleResult.getResult()) {

                                         collatedResult = true;

                                         if(!evaluateAll) break;

                                 }

                         }

                         return new PropositionResult(collatedResult);

                 }

                 throw new IllegalStateException("Invalid logical operator: " + logicalOperator);

     }

     /*

      * only log if the proposition is not compound

      * and have the compound proposition log its own result

      */

     public void logPropositionResult(Proposition proposition, PropositionResult propositionResult, ExecutionEnvironment environment) {

             if(!proposition.isCompound()) {

             LOG.logResult(new BasicResult(propositionResult.getExecutionDetails(), ResultEvent.PropositionEvaluated, proposition, environment, propositionResult.getResult()));                

             }

     }

     @Override

     public List<Proposition> getChildren() {

         return Collections.unmodifiableList(propositions);

     }

     @Override

     public boolean isCompound() {

         return true;

     }

 }