/*-
 * ============LICENSE_START=======================================================
 * ONAP
 * ================================================================================
 * Copyright (C) 2018-2019 AT&T Intellectual Property. All rights reserved.
 * ================================================================================
 * 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.drools.util;

import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.stream.Collectors;
import lombok.NonNull;
import org.drools.compiler.kie.builder.impl.InternalKieModule;
import org.drools.compiler.kproject.models.KieModuleModelImpl;
import org.kie.api.KieServices;
import org.kie.api.builder.KieBuilder;
import org.kie.api.builder.KieFileSystem;
import org.kie.api.builder.Message;
import org.kie.api.builder.ReleaseId;
import org.kie.api.builder.model.KieModuleModel;
import org.kie.api.definition.KiePackage;
import org.kie.api.definition.rule.Rule;
import org.kie.api.runtime.KieContainer;
import org.kie.api.runtime.KieSession;
import org.kie.scanner.KieMavenRepository;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Kie related utilities.
 */
public class KieUtils {

    private static final Logger logger = LoggerFactory.getLogger(KieUtils.class);

    private KieUtils() {
        // Utility class
    }

    /**
     * Installs a rules artifact in the local maven repository.
     */
    public static ReleaseId installArtifact(File kmodule, File pom, String drlKJarPath, @NonNull List<File> drls)
    throws IOException {
        KieModuleModel kieModule = KieModuleModelImpl.fromXML(kmodule);

        final KieFileSystem kieFileSystem = KieServices.Factory.get().newKieFileSystem();
        kieFileSystem.writeKModuleXML(kieModule.toXML());
        kieFileSystem.writePomXML(new String(Files.readAllBytes(pom.toPath())));
        for (File drl : drls) {
            kieFileSystem.write(drlKJarPath + drl.getName(), new String(Files.readAllBytes(drl.toPath())));
        }

        KieBuilder kieBuilder = build(kieFileSystem);
        return getReleaseId(kieBuilder, pom);
    }

    /**
     * Installs a rules artifact in the local maven repository.
     */
    public static ReleaseId installArtifact(File kmodule, File pom, String drlKJarPath, File drl)
    throws IOException {
        return installArtifact(kmodule, pom, drlKJarPath, Collections.singletonList(drl));
    }

    private static ReleaseId getReleaseId(KieBuilder kieBuilder, File pomFile) {
        ReleaseId releaseId = kieBuilder.getKieModule().getReleaseId();
        KieMavenRepository
            .getKieMavenRepository()
            .installArtifact(releaseId,
                (InternalKieModule) kieBuilder.getKieModule(),
                pomFile);
        return releaseId;
    }

    /**
     * Get Knowledge Bases.
     */
    public static List<String> getBases(KieContainer container) {
        return new ArrayList<>(container.getKieBaseNames());
    }

    /**
     * Get Packages.
     */
    public static List<KiePackage> getPackages(KieContainer container) {
        return getBases(container).stream()
            .flatMap(base -> container.getKieBase(base).getKiePackages().stream())
            .collect(Collectors.toList());
    }

    /**
     * Get Package Names.
     */
    public static List<String> getPackageNames(KieContainer container) {
        return getPackages(container).stream()
            .map(KiePackage::getName)
            .collect(Collectors.toList());
    }

    /**
     * Get Rules.
     */
    public static List<Rule> getRules(KieContainer container) {
        return getPackages(container).stream()
            .flatMap(kiePackage -> kiePackage.getRules().stream())
            .collect(Collectors.toList());
    }

    /**
     * Get Rule Names.
     */
    public static List<String> getRuleNames(KieContainer container) {
        return getRules(container).stream()
            .map(Rule::getName)
            .collect(Collectors.toList());
    }

    /**
     * Get Facts.
     */
    public static List<Object> getFacts(KieSession session) {
        return session.getFactHandles().stream()
            .map(session::getObject)
            .collect(Collectors.toList());
    }

    /**
     * Create Container.
     */
    public static KieContainer createContainer(ReleaseId releaseId) {
        return KieServices.Factory.get().newKieContainer(releaseId);
    }

    private static KieBuilder build(KieFileSystem kieFileSystem) {
        KieBuilder kieBuilder = KieServices.Factory.get().newKieBuilder(kieFileSystem);
        List<Message> messages = kieBuilder.buildAll().getResults().getMessages();
        if (messages != null && !messages.isEmpty()) {
            throw new IllegalArgumentException(messages.toString());
        }
        return kieBuilder;
    }
}