/*
 * Copyright 1999-2015 dangdang.com.
 * <p>
 * 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.
 * </p>
 */

package io.elasticjob.cloud.executor;

import io.elasticjob.cloud.api.ElasticJob;
import io.elasticjob.cloud.executor.JobExecutorFactory;
import io.elasticjob.cloud.executor.JobFacade;
import io.elasticjob.cloud.executor.ShardingContexts;
import io.elasticjob.cloud.config.JobRootConfiguration;
import io.elasticjob.cloud.exception.JobSystemException;
import lombok.RequiredArgsConstructor;
import lombok.Setter;
import org.apache.mesos.ExecutorDriver;
import org.apache.mesos.Protos;
import org.quartz.CronScheduleBuilder;
import org.quartz.CronTrigger;
import org.quartz.Job;
import org.quartz.JobBuilder;
import org.quartz.JobDetail;
import org.quartz.JobExecutionContext;
import org.quartz.JobExecutionException;
import org.quartz.Scheduler;
import org.quartz.SchedulerException;
import org.quartz.TriggerBuilder;
import org.quartz.impl.StdSchedulerFactory;
import org.quartz.plugins.management.ShutdownHookPlugin;

import java.util.Properties;
import java.util.concurrent.ConcurrentHashMap;

/**
 * 常驻作业调度器.
 * 
 * @author zhangliang
 * @author caohao
 */
@RequiredArgsConstructor
public final class DaemonTaskScheduler {
    
    public static final String ELASTIC_JOB_DATA_MAP_KEY = "elasticJob";
    
    private static final String JOB_FACADE_DATA_MAP_KEY = "jobFacade";
    
    private static final String EXECUTOR_DRIVER_DATA_MAP_KEY = "executorDriver";
    
    private static final String TASK_ID_DATA_MAP_KEY = "taskId";
    
    private static final ConcurrentHashMap<String, Scheduler> RUNNING_SCHEDULERS = new ConcurrentHashMap<>(1024, 1);
    
    private final ElasticJob elasticJob;
    
    private final JobRootConfiguration jobRootConfig;
    
    private final JobFacade jobFacade;
    
    private final ExecutorDriver executorDriver;
    
    private final Protos.TaskID taskId;
    
    /**
     * 初始化作业.
     */
    public void init() {
        JobDetail jobDetail = JobBuilder.newJob(DaemonJob.class).withIdentity(jobRootConfig.getTypeConfig().getCoreConfig().getJobName()).build();
        jobDetail.getJobDataMap().put(ELASTIC_JOB_DATA_MAP_KEY, elasticJob);
        jobDetail.getJobDataMap().put(JOB_FACADE_DATA_MAP_KEY, jobFacade);
        jobDetail.getJobDataMap().put(EXECUTOR_DRIVER_DATA_MAP_KEY, executorDriver);
        jobDetail.getJobDataMap().put(TASK_ID_DATA_MAP_KEY, taskId);
        try {
            scheduleJob(initializeScheduler(), jobDetail, taskId.getValue(), jobRootConfig.getTypeConfig().getCoreConfig().getCron());
        } catch (final SchedulerException ex) {
            throw new JobSystemException(ex);
        }
    }
    
    private Scheduler initializeScheduler() throws SchedulerException {
        StdSchedulerFactory factory = new StdSchedulerFactory();
        factory.initialize(getBaseQuartzProperties());
        return factory.getScheduler();
    }
    
    private Properties getBaseQuartzProperties() {
        Properties result = new Properties();
        result.put("org.quartz.threadPool.class", org.quartz.simpl.SimpleThreadPool.class.getName());
        result.put("org.quartz.threadPool.threadCount", "1");
        result.put("org.quartz.scheduler.instanceName", taskId.getValue());
        if (!jobRootConfig.getTypeConfig().getCoreConfig().isMisfire()) {
            result.put("org.quartz.jobStore.misfireThreshold", "1");
        }
        result.put("org.quartz.plugin.shutdownhook.class", ShutdownHookPlugin.class.getName());
        result.put("org.quartz.plugin.shutdownhook.cleanShutdown", Boolean.TRUE.toString());
        return result;
    }
    
    private void scheduleJob(final Scheduler scheduler, final JobDetail jobDetail, final String triggerIdentity, final String cron) {
        try {
            if (!scheduler.checkExists(jobDetail.getKey())) {
                scheduler.scheduleJob(jobDetail, createTrigger(triggerIdentity, cron));
            }
            scheduler.start();
            RUNNING_SCHEDULERS.putIfAbsent(scheduler.getSchedulerName(), scheduler);
        } catch (final SchedulerException ex) {
            throw new JobSystemException(ex);
        }
    }
    
    private CronTrigger createTrigger(final String triggerIdentity, final String cron) {
        return TriggerBuilder.newTrigger().withIdentity(triggerIdentity).withSchedule(CronScheduleBuilder.cronSchedule(cron).withMisfireHandlingInstructionDoNothing()).build();
    }
    
    /**
     * 停止任务调度.
     * 
     * @param taskID 任务主键
     */
    public static void shutdown(final Protos.TaskID taskID) {
        Scheduler scheduler = RUNNING_SCHEDULERS.remove(taskID.getValue());
        if (null != scheduler) {
            try {
                scheduler.shutdown();
            } catch (final SchedulerException ex) {
                throw new JobSystemException(ex);
            }
        }
    }
    
    /**
     * 常驻作业.
     * 
     * @author zhangliang
     */
    public static final class DaemonJob implements Job {
        
        @Setter
        private ElasticJob elasticJob;
        
        @Setter
        private JobFacade jobFacade;
        
        @Setter
        private ExecutorDriver executorDriver;
    
        @Setter
        private Protos.TaskID taskId;
        
        @Override
        public void execute(final JobExecutionContext context) throws JobExecutionException {
            ShardingContexts shardingContexts = jobFacade.getShardingContexts();
            int jobEventSamplingCount = shardingContexts.getJobEventSamplingCount();
            int currentJobEventSamplingCount = shardingContexts.getCurrentJobEventSamplingCount();
            if (jobEventSamplingCount > 0 && ++currentJobEventSamplingCount < jobEventSamplingCount) {
                shardingContexts.setCurrentJobEventSamplingCount(currentJobEventSamplingCount);
                jobFacade.getShardingContexts().setAllowSendJobEvent(false);
                JobExecutorFactory.getJobExecutor(elasticJob, jobFacade).execute();
            } else {
                jobFacade.getShardingContexts().setAllowSendJobEvent(true);
                executorDriver.sendStatusUpdate(Protos.TaskStatus.newBuilder().setTaskId(taskId).setState(Protos.TaskState.TASK_RUNNING).setMessage("BEGIN").build());
                JobExecutorFactory.getJobExecutor(elasticJob, jobFacade).execute();
                executorDriver.sendStatusUpdate(Protos.TaskStatus.newBuilder().setTaskId(taskId).setState(Protos.TaskState.TASK_RUNNING).setMessage("COMPLETE").build());
                shardingContexts.setCurrentJobEventSamplingCount(0);
            }
        }
    }
}