package io.github.evacchi;

import org.drools.model.Index;
import org.drools.model.Model;
import org.drools.model.Rule;
import org.drools.model.Variable;
import org.drools.model.impl.ModelImpl;
import org.drools.modelcompiler.builder.KieBaseBuilder;
import org.kie.api.KieBase;
import org.kie.api.runtime.KieSession;
import org.kie.api.runtime.rule.FactHandle;

import static org.drools.model.DSL.*;
import static org.drools.model.PatternDSL.*;

public class A {
    public static void main( String[] args ) {
        Result result = new Result();
        Variable<Person> markV = declarationOf( Person.class );
        Variable<Person> olderV = declarationOf(Person.class );

        Rule rule = rule("beta" )
                .build(
                        pattern(markV)
                                .expr("exprA", p -> p.getName().equals( "Mark" ),
                                      alphaIndexedBy(String.class, Index.ConstraintType.EQUAL, 1, p -> p.getName(), "Mark" ),
                                      reactOn( "name", "age" )),
                        pattern(olderV)
                                .expr("exprB", p -> !p.getName().equals("Mark"),
                                      alphaIndexedBy( String.class, Index.ConstraintType.NOT_EQUAL, 1, p -> p.getName(), "Mark" ),
                                      reactOn( "name" ))
                                .expr("exprC", markV, (p1, p2) -> p1.getAge() > p2.getAge(),
                                      betaIndexedBy( int.class, Index.ConstraintType.GREATER_THAN, 0, p -> p.getAge(), p -> p.getAge() ),
                                      reactOn( "age" )),
                        on(olderV, markV).execute((p1, p2) -> result.setValue( p1.getName() + " is older than " + p2.getName()))
                );

        Model model = new ModelImpl().addRule(rule );
        KieBase kieBase = null; //KieBaseBuilder.createKieBaseFromModel(model );

        KieSession ksession = kieBase.newKieSession();

        Person mark = new Person("Mark", 37);
        Person edson = new Person("Edson", 35);
        Person mario = new Person("Mario", 40);

        FactHandle markFH = ksession.insert(mark);
        FactHandle edsonFH = ksession.insert(edson);
        FactHandle marioFH = ksession.insert(mario);

        ksession.fireAllRules();
        if (!"Mario is older than Mark".equals( result.getValue() )) {
            throw new IllegalStateException();
        }

        result.setValue( null );
        ksession.delete( marioFH );
        ksession.fireAllRules();
        if (result.getValue() != null) {
            throw new IllegalStateException();
        }

        mark.setAge( 34 );
        ksession.update( markFH, mark, "age" );

        ksession.fireAllRules();
        if (!"Edson is older than Mark".equals( result.getValue() )) {
            throw new IllegalStateException();
        }
    }
}