package pl.org.bpmn;

import java.io.File;

import pl.org.bpmn.Model;
import org.drools.KnowledgeBase;
import org.drools.KnowledgeBaseFactory;
import org.drools.builder.KnowledgeBuilder;
import org.drools.builder.KnowledgeBuilderError;
import org.drools.builder.KnowledgeBuilderErrors;
import org.drools.builder.KnowledgeBuilderFactory;
import org.drools.builder.ResourceType;
import org.drools.io.ResourceFactory;
import org.drools.runtime.StatelessKnowledgeSession;

public class RuleRunner {

	public static String runRules(Model modelRyzyka) throws Exception {

		KnowledgeBase kbase = readKnowledgeBase();
		StatelessKnowledgeSession ksession = kbase.newStatelessKnowledgeSession();
		ksession.execute(modelRyzyka);
		System.out.println("Done firing.. --> result = " + modelRyzyka.Ryzyko);
		return modelRyzyka.Ryzyko;
	}

	private static KnowledgeBase readKnowledgeBase() throws Exception {
		KnowledgeBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder();
		kbuilder.add(
				ResourceFactory.newClassPathResource("rules" 
				        + File.separator + "rules.drl"),
				ResourceType.DRL);
		KnowledgeBuilderErrors errors = kbuilder.getErrors();
		if (errors.size() > 0) {
			for (KnowledgeBuilderError error : errors) {
				System.err.println(error);
			}
			throw new IllegalArgumentException("Could not parse knowledge.");
		}
		KnowledgeBase kbase = KnowledgeBaseFactory.newKnowledgeBase();
		kbase.addKnowledgePackages(kbuilder.getKnowledgePackages());
		return kbase;
	}

}