/*
 * Copyright 2015 Red Hat, Inc. and/or its affiliates.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
*/

package org.drools.compiler.integrationtests;

import org.drools.compiler.integrationtests.DynamicRulesChangesTest.Fire;
import org.drools.compiler.integrationtests.DynamicRulesChangesTest.Room;
import org.drools.compiler.integrationtests.DynamicRulesChangesTest.Sprinkler;
import org.drools.core.impl.InternalKnowledgeBase;
import org.drools.core.impl.StatefulKnowledgeSessionImpl;
import org.junit.Test;
import org.kie.api.io.ResourceType;
import org.kie.api.runtime.KieSession;
import org.kie.api.runtime.rule.FactHandle;
import org.kie.internal.KnowledgeBaseFactory;
import org.kie.internal.builder.KnowledgeBuilder;
import org.kie.internal.builder.KnowledgeBuilderFactory;
import org.kie.internal.io.ResourceFactory;

import java.util.ArrayList;
import java.util.List;

import static org.junit.Assert.assertEquals;

public class SegmentMemoryPrototypeTest {
    private static final String DRL =
            "import " +  DynamicRulesChangesTest.class.getCanonicalName() + "\n " +
            "global java.util.List events\n" +
            "rule \"Raise the alarm when we have one or more fires\"\n" +
            "when\n" +
            "    exists DynamicRulesChangesTest.Fire()\n" +
            "then\n" +
            "    insert( new DynamicRulesChangesTest.Alarm() );\n" +
            "    events.add( \"Raise the alarm\" );\n" +
            "end" +
            "\n" +
            "rule \"When there is a fire turn on the sprinkler\"\n" +
            "when\n" +
            "    $fire: DynamicRulesChangesTest.Fire($room : room)\n" +
            "    $sprinkler : DynamicRulesChangesTest.Sprinkler( room == $room, on == false )\n" +
            "then\n" +
            "    modify( $sprinkler ) { setOn( true ) };\n" +
            "    events.add( \"Turn on the sprinkler for room \" + $room.getName() );\n" +
            "end" +
            "\n" +
            "rule \"When the fire is gone turn off the sprinkler\"\n" +
            "when\n" +
            "    $room : DynamicRulesChangesTest.Room( )\n" +
            "    $sprinkler : DynamicRulesChangesTest.Sprinkler( room == $room, on == true )\n" +
            "    not DynamicRulesChangesTest.Fire( room == $room )\n" +
            "then\n" +
            "    modify( $sprinkler ) { setOn( false ) };\n" +
            "    events.add( \"Turn off the sprinkler for room \" + $room.getName() );\n" +
            "end" +
            "\n" +
            "rule \"Cancel the alarm when all the fires have gone\"\n" +
            "when\n" +
            "    not DynamicRulesChangesTest.Fire()\n" +
            "    $alarm : DynamicRulesChangesTest.Alarm()\n" +
            "then\n" +
            "    retract( $alarm );\n" +
            "    events.add( \"Cancel the alarm\" );\n" +
            "end" +
            "\n" +
            "rule \"Status output when things are ok\"\n" +
            "when\n" +
            "    not DynamicRulesChangesTest.Fire()\n" +
            "    not DynamicRulesChangesTest.Alarm()\n" +
            "    not DynamicRulesChangesTest.Sprinkler( on == true )\n" +
            "then\n" +
            "    events.add( \"Everything is ok\" );\n" +
            "end";

    @Test
    public void testSegmentMemoryPrototype() throws Exception {
        KnowledgeBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder();
        kbuilder.add( ResourceFactory.newByteArrayResource(DRL.getBytes()),
                      ResourceType.DRL );

        InternalKnowledgeBase kbase = (InternalKnowledgeBase) KnowledgeBaseFactory.newKnowledgeBase();
        kbase.addKnowledgePackages( kbuilder.getKnowledgePackages() );

        KieSession ksession = kbase.newKieSession();
        checkKieSession(ksession);

        // Create a 2nd KieSession (that will use segment memory prototype) and check that it works as the former one
        KieSession ksession2 = kbase.newKieSession();
        checkKieSession(ksession2);
    }

    @Test
    public void testSessionCache() throws Exception {
        KnowledgeBuilder kbuilder = KnowledgeBuilderFactory.newKnowledgeBuilder();
        kbuilder.add( ResourceFactory.newByteArrayResource(DRL.getBytes()),
                      ResourceType.DRL );

        InternalKnowledgeBase kbase = (InternalKnowledgeBase) KnowledgeBaseFactory.newKnowledgeBase();
        kbase.addKnowledgePackages( kbuilder.getKnowledgePackages() );

        StatefulKnowledgeSessionImpl ksession = (StatefulKnowledgeSessionImpl)kbase.newKieSession();
        checkKieSession(ksession);

        ksession.dispose();
        ksession.reset();
        checkKieSession(ksession);
    }

    private void checkKieSession(KieSession ksession) {
        final List<String> events = new ArrayList<String>();

        ksession.setGlobal("events", events);

        // phase 1
        Room room1 = new Room("Room 1");
        ksession.insert(room1);
        FactHandle fireFact1 = ksession.insert(new Fire(room1));
        ksession.fireAllRules();
        assertEquals(1, events.size());

        // phase 2
        Sprinkler sprinkler1 = new Sprinkler(room1);
        ksession.insert(sprinkler1);
        ksession.fireAllRules();
        assertEquals(2, events.size());

        // phase 3
        ksession.delete(fireFact1);
        ksession.fireAllRules();
        assertEquals(5, events.size());
    }
}