/*-
 * ============LICENSE_START=======================================================
 * ONAP
 * ================================================================================
 * Copyright (C) 2020-2021 AT&T Intellectual Property. All rights reserved.
 * Modifications Copyright (C) 2023 Nordix Foundation.
 * ================================================================================
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      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.
 * ============LICENSE_END=========================================================
 */

package org.onap.policy.controlloop.common.rules.test;

import static org.assertj.core.api.Assertions.assertThat;
import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertSame;
import static org.junit.jupiter.api.Assertions.assertTrue;
import static org.mockito.ArgumentMatchers.any;
import static org.mockito.ArgumentMatchers.eq;
import static org.mockito.Mockito.doAnswer;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;

import ch.qos.logback.classic.Logger;
import java.io.File;
import java.util.LinkedList;
import java.util.List;
import java.util.Properties;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.TimeUnit;
import java.util.stream.Collectors;
import org.junit.jupiter.api.AfterAll;
import org.junit.jupiter.api.BeforeAll;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.kie.api.definition.rule.Rule;
import org.kie.api.event.rule.AfterMatchFiredEvent;
import org.kie.api.event.rule.AgendaEventListener;
import org.kie.api.event.rule.BeforeMatchFiredEvent;
import org.kie.api.event.rule.MatchCancelledEvent;
import org.kie.api.event.rule.MatchCreatedEvent;
import org.kie.api.event.rule.ObjectDeletedEvent;
import org.kie.api.event.rule.ObjectInsertedEvent;
import org.kie.api.event.rule.ObjectUpdatedEvent;
import org.kie.api.event.rule.RuleRuntimeEventListener;
import org.kie.api.runtime.KieSession;
import org.kie.api.runtime.rule.Match;
import org.onap.policy.common.utils.test.log.logback.ExtractAppender;
import org.onap.policy.controlloop.ControlLoopEvent;
import org.onap.policy.controlloop.drl.legacy.ControlLoopParams;
import org.onap.policy.controlloop.eventmanager.ControlLoopEventManager;
import org.onap.policy.drools.controller.DroolsController;
import org.onap.policy.drools.persistence.SystemPersistence;
import org.onap.policy.drools.system.PolicyController;
import org.onap.policy.drools.system.PolicyControllerFactory;
import org.onap.policy.drools.system.PolicyEngine;
import org.onap.policy.models.tosca.authorative.concepts.ToscaPolicy;
import org.slf4j.LoggerFactory;

class RulesTest {
    private static final String EXPECTED_EXCEPTION = "expected exception";
    private static final String CONTROLLER_NAME = "rulesTest";
    private static final String POLICY_FILE = "src/test/resources/tosca-policy.json";
    private static final String MY_POLICY = "operational.restart";
    private static final String RESOURCE_DIR = "src/test/resources";
    private static final String MY_RULE_NAME = "my-rule-name";
    private static final String MY_TEXT = "my text";

    /**
     * Used to attach an appender to the class' logger.
     */
    private static final Logger logger = (Logger) LoggerFactory.getLogger(Rules.class);
    private static final ExtractAppender appender = new ExtractAppender();

    private final PolicyEngine engine = mock(PolicyEngine.class);
    private final SystemPersistence repo = mock(SystemPersistence.class);
    private final PolicyController controller = mock(PolicyController.class);
    private final KieSession kieSession = mock(KieSession.class);
    private final PolicyControllerFactory controllerFactory = mock(PolicyControllerFactory.class);
    private final DroolsController drools = mock(DroolsController.class);

    private List<Object> facts;
    private List<RuleRuntimeEventListener> ruleListeners;
    private List<AgendaEventListener> agendaListeners;
    private Properties properties;
    private boolean installed;

    private Rules rules;

    /**
     * Attaches the appender to the logger.
     */
    @BeforeAll
    public static void setUpBeforeClass() throws Exception {
        /*
         * Attach appender to the logger.
         */
        appender.setContext(logger.getLoggerContext());
        appender.start();

        logger.addAppender(appender);
    }

    /**
     * Stops the appender.
     */
    @AfterAll
    public static void tearDownAfterClass() {
        appender.stop();
    }

    /**
     * Sets up.
     */
    @BeforeEach
    public void setUp() {
        facts = new LinkedList<>();
        ruleListeners = new LinkedList<>();
        agendaListeners = new LinkedList<>();
        installed = false;
        properties = new Properties();

        when(engine.createPolicyController(any(), any())).thenReturn(controller);
        when(repo.getControllerProperties(CONTROLLER_NAME)).thenReturn(properties);
        when(controller.getDrools()).thenReturn(drools);

        when(drools.facts(eq(CONTROLLER_NAME), any())).thenAnswer(args -> {
            var clazz = args.getArgument(1);
            return facts.stream().filter(obj -> obj.getClass() == clazz).collect(Collectors.toList());
        });

        // notify listeners when objects are added to drools
        when(drools.offer(any())).thenAnswer(args -> {
            var object = args.getArgument(0);
            notifyInserted(object);

            if (!(object instanceof ToscaPolicy)) {
                return true;
            }

            // "insert" Params objects associated with the policy (i.e., mimic the rules)
            var policy = (ToscaPolicy) object;
            var params = new ControlLoopParams();
            params.setToscaPolicy(policy);
            notifyInserted(params);

            return true;
        });

        when(drools.delete(any())).thenAnswer(args -> {
            var clazz = args.getArgument(0);
            facts.removeIf(obj -> obj.getClass() == clazz);
            return null;
        });

        // handle rule listener registration and deregistration with the kieSession
        doAnswer(args -> {
            ruleListeners.add(args.getArgument(0));
            return null;
        }).when(kieSession).addEventListener(any(RuleRuntimeEventListener.class));

        doAnswer(args -> {
            ruleListeners.remove(args.getArgument(0));
            return null;
        }).when(kieSession).removeEventListener(any(RuleRuntimeEventListener.class));

        // handle agenda listener registration and deregistration with the kieSession
        doAnswer(args -> {
            agendaListeners.add(args.getArgument(0));
            return null;
        }).when(kieSession).addEventListener(any(AgendaEventListener.class));

        rules = new MyRules();

        rules.configure(RESOURCE_DIR);
        rules.start();
    }

    @Test
    void testRules() {
        assertEquals(CONTROLLER_NAME, rules.getControllerName());

        assertSame(engine, rules.getPdpd());
        assertSame(repo, rules.getPdpdRepo());
        assertSame(controller, rules.getController());
    }

    @Test
    void testStart() throws Exception {
        verify(repo).setConfigurationDir("src/test/resources/config");
        assertTrue(installed);
        verify(engine).configure(any(Properties.class));
        verify(engine).createPolicyController(CONTROLLER_NAME, properties);
        verify(engine).start();

        verify(kieSession).addEventListener(any(RuleRuntimeEventListener.class));
        verify(kieSession).addEventListener(any(AgendaEventListener.class));
    }

    @Test
    void testDestroy() {
        rules.destroy();

        verify(controllerFactory).shutdown(CONTROLLER_NAME);
        verify(engine).stop();
    }

    @Test
    void testResetFacts() {
        rules.resetFacts();

        verify(drools).delete(ToscaPolicy.class);
        verify(drools).delete(ControlLoopParams.class);
        verify(drools).delete(ControlLoopEventManager.class);
        verify(drools).delete(ControlLoopEvent.class);
    }

    @Test
    void testSetupPolicyFromTemplate_testGetPolicyFromTemplate() throws InterruptedException {
        rules.setupPolicyFromTemplate("tosca-template.json", MY_POLICY);

        assertThatIllegalArgumentException()
                        .isThrownBy(() -> rules.setupPolicyFromTemplate("missing-file.json", "a-policy"));

        // check interrupt case
        checkInterrupt(() -> rules.setupPolicyFromTemplate("tosca-template.json", MY_POLICY),
                        "policy operational.restart");
    }

    @Test
    void testSetupPolicyFromFile_testGetPolicyFromFile_testSetupPolicy() throws InterruptedException {
        assertNotNull(rules.setupPolicyFromFile(POLICY_FILE));

        assertThatIllegalArgumentException().isThrownBy(() -> rules.setupPolicyFromFile("missing-file.json"));

        // check interrupt case
        checkInterrupt(() -> rules.setupPolicyFromFile(POLICY_FILE), "policy " + POLICY_FILE);
    }

    @Test
    void testRuleListenerLogger() {
        var rule = mock(Rule.class);
        when(rule.getName()).thenReturn(MY_RULE_NAME);

        // insertions - with and without rule name
        var insert = mock(ObjectInsertedEvent.class);
        when(insert.getObject()).thenReturn(MY_TEXT);
        checkLogging("inserted", () -> ruleListeners.forEach(listener -> listener.objectInserted(insert)));
        when(insert.getRule()).thenReturn(rule);
        checkLogging("inserted", () -> ruleListeners.forEach(listener -> listener.objectInserted(insert)));

        // updates - with and without rule name
        var update = mock(ObjectUpdatedEvent.class);
        when(update.getObject()).thenReturn(MY_TEXT);
        checkLogging("updated", () -> ruleListeners.forEach(listener -> listener.objectUpdated(update)));
        when(update.getRule()).thenReturn(rule);
        checkLogging("updated", () -> ruleListeners.forEach(listener -> listener.objectUpdated(update)));

        // deletions - with and without rule name
        var delete = mock(ObjectDeletedEvent.class);
        when(delete.getOldObject()).thenReturn(MY_TEXT);
        checkLogging("deleted", () -> ruleListeners.forEach(listener -> listener.objectDeleted(delete)));
        when(delete.getRule()).thenReturn(rule);
        checkLogging("deleted", () -> ruleListeners.forEach(listener -> listener.objectDeleted(delete)));
    }

    @Test
    void testAgendaListenerLogger() {
        var rule = mock(Rule.class);
        when(rule.getName()).thenReturn(MY_RULE_NAME);

        var match = mock(Match.class);
        when(match.getRule()).thenReturn(rule);

        // create
        var create = mock(MatchCreatedEvent.class);
        when(create.getMatch()).thenReturn(match);
        checkLogging("match created", () -> agendaListeners.forEach(listener -> listener.matchCreated(create)));

        // cancel
        var cancel = mock(MatchCancelledEvent.class);
        when(cancel.getMatch()).thenReturn(match);
        checkLogging("match cancelled", () -> agendaListeners.forEach(listener -> listener.matchCancelled(cancel)));

        // before-fire
        var before = mock(BeforeMatchFiredEvent.class);
        when(before.getMatch()).thenReturn(match);
        // @formatter:off
        checkLogging("before match fired",
            () -> agendaListeners.forEach(listener -> listener.beforeMatchFired(before)));
        // @formatter:on

        // after-fire
        var after = mock(AfterMatchFiredEvent.class);
        when(after.getMatch()).thenReturn(match);
        checkLogging("after match fired", () -> agendaListeners.forEach(listener -> listener.afterMatchFired(after)));
    }

    @Test
    void testMakePdpd_testMakePdpdRepo() {
        // need rules that makes real objects
        rules = new Rules(CONTROLLER_NAME);

        assertNotNull(rules.getPdpd());
        assertNotNull(rules.getPdpdRepo());
    }

    private void checkInterrupt(Runnable command, String expectedMsg) throws InterruptedException {
        rules = new MyRules() {
            @Override
            protected ToscaPolicy setupPolicy(ToscaPolicy policy) throws InterruptedException {
                throw new InterruptedException(EXPECTED_EXCEPTION);
            }
        };
        rules.configure(RESOURCE_DIR);
        rules.start();

        BlockingQueue<IllegalArgumentException> exceptions = new LinkedBlockingQueue<>();

        var thread = new Thread(() -> {
            try {
                command.run();
            } catch (IllegalArgumentException e) {
                exceptions.add(e);
            }
        });

        thread.setDaemon(true);
        thread.start();

        assertThat(exceptions.poll(10, TimeUnit.SECONDS)).isNotNull().hasMessage(expectedMsg)
                        .hasCauseInstanceOf(InterruptedException.class);
    }

    private void checkLogging(String expectedMsg, Runnable command) {
        appender.clearExtractions();
        command.run();
        var messages = appender.getExtracted();
        assertEquals(1, messages.size());
        assertThat(messages.get(0)).contains(expectedMsg);
    }

    protected void notifyInserted(Object object) {
        // add it to our list
        facts.add(object);

        // increase code coverage by adding random objects
        var event0 = mock(ObjectInsertedEvent.class);
        when(event0.getObject()).thenReturn(new Object());
        ruleListeners.forEach(listener -> listener.objectInserted(event0));

        // increase code coverage by adding a random object
        var event = mock(ObjectInsertedEvent.class);
        when(event.getObject()).thenReturn(object);

        if (object instanceof ToscaPolicy) {
            // increase code coverage by associating it with a random rule
            var rule = mock(Rule.class);
            when(rule.getName()).thenReturn(MY_RULE_NAME);
            when(event.getRule()).thenReturn(rule);
        }

        ruleListeners.forEach(listener -> listener.objectInserted(event));
    }

    private class MyRules extends Rules {
        public MyRules() {
            super(CONTROLLER_NAME);
        }

        @Override
        protected PolicyEngine makeEngine() {
            return engine;
        }

        @Override
        protected SystemPersistence makePdpdRepo() {
            return repo;
        }

        @Override
        protected KieSession getKieSession() {
            return kieSession;
        }

        @Override
        protected PolicyControllerFactory getControllerFactory() {
            return controllerFactory;
        }

        @Override
        protected void installArtifact(File kmoduleFile, File pomFile, String resourceDir, List<File> ruleFiles) {
            installed = true;
        }
    }
}