// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.vespa.config.server.maintenance;

import com.google.inject.Inject;
import com.yahoo.cloud.config.ConfigserverConfig;
import com.yahoo.component.AbstractComponent;
import com.yahoo.concurrent.maintenance.Maintainer;
import com.yahoo.vespa.config.server.ApplicationRepository;
import com.yahoo.vespa.config.server.ConfigServerBootstrap;
import com.yahoo.vespa.config.server.application.ConfigConvergenceChecker;
import com.yahoo.vespa.curator.Curator;
import com.yahoo.vespa.flags.FlagSource;

import java.time.Clock;
import java.time.Duration;
import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;

/**
 * Maintenance jobs of the config server.
 * Each maintenance job is a singleton instance of its implementing class, created and owned by this,
 * and running its own dedicated thread. {@link ConfigServerBootstrap} is injected into this class, so
 * no maintainers will run until bootstrapping is done
 *
 * @author hmusum
 */
public class ConfigServerMaintenance extends AbstractComponent {

    private final List<Maintainer> maintainers = new CopyOnWriteArrayList<>();

    @Inject
    public ConfigServerMaintenance(ConfigServerBootstrap configServerBootstrap,
                                   ConfigserverConfig configserverConfig,
                                   ApplicationRepository applicationRepository,
                                   Curator curator,
                                   FlagSource flagSource,
                                   ConfigConvergenceChecker convergence) {
        DefaultTimes defaults = new DefaultTimes(configserverConfig);
        maintainers.add(new TenantsMaintainer(applicationRepository, curator, flagSource, defaults.defaultInterval, Clock.systemUTC()));
        maintainers.add(new FileDistributionMaintainer(applicationRepository, curator, defaults.defaultInterval, flagSource));
        maintainers.add(new SessionsMaintainer(applicationRepository, curator, Duration.ofSeconds(30), flagSource));
        maintainers.add(new ApplicationPackageMaintainer(applicationRepository, curator, Duration.ofSeconds(30), flagSource));
        maintainers.add(new ReindexingMaintainer(applicationRepository, curator, flagSource, Duration.ofMinutes(3), convergence, Clock.systemUTC()));
    }

    @Override
    public void deconstruct() {
        maintainers.forEach(Maintainer::shutdown);
        maintainers.forEach(Maintainer::awaitShutdown);
    }

    /*
     * Default values from config. If one of the values needs to be changed, add the value to
     * configserver-config.xml in the config server application directory and restart the config server
     */
    private static class DefaultTimes {

        private final Duration defaultInterval;

        DefaultTimes(ConfigserverConfig configserverConfig) {
            this.defaultInterval = Duration.ofMinutes(configserverConfig.maintainerIntervalMinutes());
        }
    }

}