/**
 * Copyright (c) 2010 Yahoo! Inc. 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. See accompanying LICENSE file.
 */
package org.apache.oozie.service;

import org.apache.hadoop.conf.Configuration;
import org.apache.oozie.command.bundle.BundlePurgeXCommand;
import org.apache.oozie.command.coord.CoordPurgeCommand;
import org.apache.oozie.command.coord.CoordPurgeXCommand;
import org.apache.oozie.command.wf.PurgeCommand;
import org.apache.oozie.command.wf.PurgeXCommand;
import org.apache.oozie.service.CallableQueueService;
import org.apache.oozie.service.SchedulerService;
import org.apache.oozie.service.Service;
import org.apache.oozie.service.Services;

/**
 * The PurgeService schedules purging of completed jobs and associated action older than a specified age for workflow, coordinator and bundle.
 */
public class PurgeService implements Service {

    public static final String CONF_PREFIX = Service.CONF_PREFIX + "PurgeService.";
    /**
     * Age of completed jobs to be deleted, in days.
     */
    public static final String CONF_OLDER_THAN = CONF_PREFIX + "older.than";
    public static final String COORD_CONF_OLDER_THAN = CONF_PREFIX + "coord.older.than";
    public static final String BUNDLE_CONF_OLDER_THAN = CONF_PREFIX + "bundle.older.than";
    /**
     * Time interval, in seconds, at which the purge jobs service will be scheduled to run.
     */
    public static final String CONF_PURGE_INTERVAL = CONF_PREFIX + "purge.interval";
    public static final String PURGE_LIMIT = CONF_PREFIX + "purge.limit";

    private static boolean useXCommand = true;

    /**
     * PurgeRunnable is the runnable which is scheduled to run at the configured interval. PurgeCommand is queued to
     * remove completed jobs and associated actions older than the configured age for workflow, coordinator and bundle.
     */
    static class PurgeRunnable implements Runnable {
        private int olderThan;
        private int coordOlderThan;
        private int bundleOlderThan;
        private int limit;

        public PurgeRunnable(int olderThan, int coordOlderThan, int bundleOlderThan, int limit) {
            this.olderThan = olderThan;
            this.coordOlderThan = coordOlderThan;
            this.bundleOlderThan = bundleOlderThan;
            this.limit = limit;
        }

        public void run() {
            if (useXCommand) {
                Services.get().get(CallableQueueService.class).queue(new PurgeXCommand(olderThan, limit));
                Services.get().get(CallableQueueService.class).queue(new CoordPurgeXCommand(coordOlderThan, limit));
                Services.get().get(CallableQueueService.class).queue(new BundlePurgeXCommand(bundleOlderThan, limit));
            } else {
                Services.get().get(CallableQueueService.class).queue(new PurgeCommand(olderThan, limit));
                Services.get().get(CallableQueueService.class).queue(new CoordPurgeCommand(coordOlderThan, limit));
            }
        }

    }

    /**
     * Initializes the {@link PurgeService}.
     *
     * @param services services instance.
     */
    @Override
    public void init(Services services) {
        Configuration conf = services.getConf();
        Runnable purgeJobsRunnable = new PurgeRunnable(conf.getInt(
                CONF_OLDER_THAN, 30), conf.getInt(COORD_CONF_OLDER_THAN, 7), conf.getInt(BUNDLE_CONF_OLDER_THAN, 7),
                                      conf.getInt(PURGE_LIMIT, 100));
        services.get(SchedulerService.class).schedule(purgeJobsRunnable, 10, conf.getInt(CONF_PURGE_INTERVAL, 3600),
                                                      SchedulerService.Unit.SEC);

        if (Services.get().getConf().getBoolean(USE_XCOMMAND, true) == false) {
            useXCommand = false;
        }
    }

    /**
     * Destroy the Purge Jobs Service.
     */
    @Override
    public void destroy() {
    }

    /**
     * Return the public interface for the purge jobs service.
     *
     * @return {@link PurgeService}.
     */
    @Override
    public Class<? extends Service> getInterface() {
        return PurgeService.class;
    }
}