package org.kuali.student.r2.core.statement.util;

 import org.joda.time.DateTime;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

 import org.kuali.student.r2.core.statement.dto.ReqComponentInfo;

 import java.util.ArrayList;

 import java.util.Arrays;

 import java.util.Collections;

 import java.util.HashMap;

 import java.util.List;

 import java.util.Map;

 /**

  * @author alubbers

  *

  * This class contains utility methods to evaluate agendas using the KRMS engine

  *

  */

 public class RulesEvaluationUtil {

     private List<TermResolver<?>> termResolvers;

     private ExecutionOptions executionOptions;

     private Map<String, String> contextQualifiers;

     private SelectionCriteria selectionCriteria;

     public List<TermResolver<?>> getTermResolvers() {

         return termResolvers;

     }

     public void setTermResolvers(List<TermResolver<?>> termResolvers) {

         this.termResolvers = termResolvers;

     }

     public ExecutionOptions getExecutionOptions() {

         return executionOptions;

     }

     public void setExecutionOptions(ExecutionOptions executionOptions) {

         this.executionOptions = executionOptions;

     }

     public Map<String, String> getContextQualifiers() {

         return contextQualifiers;

     }

     public void setContextQualifiers(Map<String, String> contextQualifiers) {

         this.contextQualifiers = contextQualifiers;

     }

     public SelectionCriteria getSelectionCriteria() {

         return selectionCriteria;

     }

     public void setSelectionCriteria(SelectionCriteria selectionCriteria) {

         this.selectionCriteria = selectionCriteria;

     }

     public RulesEvaluationUtil() {

         executionOptions = new ExecutionOptions();

         executionOptions.setFlag(ExecutionFlag.LOG_EXECUTION, true);

         executionOptions.setFlag(ExecutionFlag.EVALUATE_ALL_PROPOSITIONS, true);

         contextQualifiers = new HashMap<String, String>();

         contextQualifiers.put("docTypeName", "Course.PreRequisities");

         Map<String, String> empty = Collections.emptyMap();

         selectionCriteria = SelectionCriteria.createCriteria(new DateTime(), contextQualifiers, empty);

     }

     private ProviderBasedEngine buildEngine(Agenda agenda) {

         Context context = new BasicContext(Arrays.asList(agenda), termResolvers);

         ContextProvider contextProvider = new ManualContextProvider(context);

         ProviderBasedEngine engine = new ProviderBasedEngine();

         engine.setContextProvider(contextProvider);

         return engine;

     }

     public EngineResults executeAgenda(Agenda agenda, Map<String, Object> executionFacts) {

         Engine engine = buildEngine(agenda);

         EngineResults results = engine.execute(selectionCriteria, executionFacts, executionOptions);

         return results;

     }

     public List<ReqComponentInfo> getFailedRequirementsFromEngineResults(EngineResults results, Map<Proposition, ReqComponentInfo> reqComponentPropositionMap) {

         List<ReqComponentInfo> failedRequirements = new ArrayList<ReqComponentInfo>();

         List<ResultEvent> events = results.getResultsOfType(ResultEvent.PROPOSITION_EVALUATED);

         for (ResultEvent e : events) {

             if (!e.getResult()) {

                 Proposition prop = (Proposition) e.getSource();

                 failedRequirements.add(reqComponentPropositionMap.get(prop));

             }

         }

         return failedRequirements;

     }

 }