/*
 * Copyright (c) 2017, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
 *
 * WSO2 Inc. licenses this file to you 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.
 */

package org.wso2.carbon.event.simulator.core.service;

import org.apache.commons.io.FilenameUtils;
import org.osgi.framework.BundleContext;
import org.osgi.service.component.annotations.Activate;
import org.osgi.service.component.annotations.Component;
import org.osgi.service.component.annotations.Reference;
import org.osgi.service.component.annotations.ReferenceCardinality;
import org.osgi.service.component.annotations.ReferencePolicy;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.wso2.carbon.deployment.engine.Artifact;
import org.wso2.carbon.deployment.engine.ArtifactType;
import org.wso2.carbon.deployment.engine.Deployer;
import org.wso2.carbon.deployment.engine.exception.CarbonDeploymentException;
import org.wso2.carbon.event.simulator.core.exception.CSVFileDeploymentException;
import org.wso2.carbon.event.simulator.core.internal.generator.csv.util.FileStore;
import org.wso2.carbon.event.simulator.core.internal.util.EventSimulatorConstants;
import org.wso2.carbon.stream.processor.common.EventStreamService;
import org.wso2.carbon.stream.processor.common.SimulationDependencyListener;

import java.io.File;
import java.net.MalformedURLException;
import java.net.URL;

/**
 * CSVFileDeployer is responsible for all simulation related CSV deployment tasks
 */
@Component(
        name = "csv-file-deployer",
        immediate = true,
        service = org.wso2.carbon.deployment.engine.Deployer.class
)
public class CSVFileDeployer implements Deployer {
    private static final Logger log = LoggerFactory.getLogger(CSVFileDeployer.class);
    private ArtifactType artifactType = new ArtifactType<>(EventSimulatorConstants.CSV_FILE_EXTENSION);
    private SimulationDependencyListener simulationDependencyListener;
    private URL directoryLocation;

    /**
     * deployCSVFile() is used to deploy csv files copied to directory 'csv-files'
     *
     * @param file file copied to directory
     */
    private void deployCSVFile(File file) throws Exception {
        String fileName = file.getName();
        if (!fileName.startsWith(".") && !FilenameUtils.isExtension(fileName,
                EventSimulatorConstants.TEMP_FILE_EXTENSION)) {
            if (FilenameUtils.isExtension(fileName, EventSimulatorConstants.CSV_FILE_EXTENSION)) {
                FileStore.getFileStore().addFile(fileName);
                log.info("Deployed CSV file '" + fileName + "'.");
            } else {
                throw new CSVFileDeploymentException("Error: File extension not supported for file name "
                        + file.getName() + ". Support only ." + EventSimulatorConstants.CSV_FILE_EXTENSION + " .");
            }
        }
    }

    @Activate
    protected void activate(BundleContext bundleContext) {
        // Nothing to do.
    }

    /**
     * init() is used to initialize csvFileDeployer
     */
    @Override
    public void init() {
        try {
            directoryLocation = new URL("file:" + EventSimulatorConstants.DIRECTORY_CSV_FILES);
            log.info("CSV file deployer initiated.");
        } catch (MalformedURLException e) {
            log.error("Error while initializing simulation CSV directoryLocation "
                    + EventSimulatorConstants.DIRECTORY_CSV_FILES, e);
        }
    }

    /**
     * deploy() is used to deploy a csv file added
     *
     * @param artifact csv file added
     * @return name of csv file
     */
    @Override
    public Object deploy(Artifact artifact) throws CarbonDeploymentException {
        try {
            deployCSVFile(artifact.getFile());
            broadcastDeploy();
        } catch (Exception e) {
            throw new CarbonDeploymentException(e.getMessage(), e);
        }
        return artifact.getFile().getName();
    }

    /**
     * undeploy() is called when a csv file is deleted
     *
     * @param key name of the csv file deleted
     */
    @Override
    public void undeploy(Object key) throws CarbonDeploymentException {
        try {
            String fileName = (String) key;
            if (FileStore.getFileStore().checkExists(fileName)) {
                FileStore.getFileStore().deleteFile(fileName);
                log.info("Undeployed CSV file '" + fileName + "'.");
                broadcastDelete();
            }
        } catch (Exception e) {
            throw new CarbonDeploymentException(e.getMessage(), e);
        }
    }

    @Override
    public Object update(Artifact artifact) throws CarbonDeploymentException {
        // Nothing to do.
        return artifact.getName();
    }

    @Override
    public URL getLocation() {
        return directoryLocation;
    }

    @Override
    public ArtifactType getArtifactType() {
        return artifactType;
    }

    /**
     * broadcastDeploy() is used to notify simulationDependencyListeners about a deployment
     */
    private void broadcastDeploy() {
        if (simulationDependencyListener != null) {
            simulationDependencyListener.onDeploy();
        }
    }


    /**
     * broadcastDelete() is used to notify simulationDependencyListeners about a delete
     */
    private void broadcastDelete() {
        if (simulationDependencyListener != null) {
            simulationDependencyListener.onDelete();
        }
    }

    @Reference(
            name = "event.stream.service",
            service = EventStreamService.class,
            cardinality = ReferenceCardinality.MANDATORY,
            policy = ReferencePolicy.DYNAMIC,
            unbind = "unsetEventStreamService"
    )
    protected void setEventStreamService(EventStreamService eventStreamService) {
        if (log.isDebugEnabled()) {
            log.debug("@Reference(bind) EventStreamService");
        }

    }

    protected void unsetEventStreamService(EventStreamService eventStreamService) {
        if (log.isDebugEnabled()) {
            log.debug("@Reference(unbind) EventStreamService");
        }

    }

    /**
     * This bind method will be called when SimulationDependencyListener OSGi service is registered.
     */
    @Reference(
            name = "csv.dependency.resolver",
            service = SimulationDependencyListener.class,
            cardinality = ReferenceCardinality.MULTIPLE,
            policy = ReferencePolicy.DYNAMIC,
            unbind = "unsubscribeFromListener"
    )
    protected void subscribeToListener(SimulationDependencyListener simulationDependencyListener) {
        this.simulationDependencyListener = simulationDependencyListener;
    }

    protected void unsubscribeFromListener(SimulationDependencyListener simulationDependencyListener) {
        this.simulationDependencyListener = null;
    }
}
