/**
 * =============================================================================
 *
 * ORCID (R) Open Source
 * http://orcid.org
 *
 * Copyright (c) 2012-2014 ORCID, Inc.
 * Licensed under an MIT-Style License (MIT)
 * http://orcid.org/open-source-license
 *
 * This copyright and license information (including a link to the full license)
 * shall be included in its entirety in all copies or substantial portion of
 * the software.
 *
 * =============================================================================
 */
package org.orcid.core.cron.impl;

import java.util.Calendar;
import java.util.Date;
import java.util.Map;

import javax.annotation.Resource;

import org.orcid.core.cron.StatisticsGeneratorCronJob;
import org.orcid.core.manager.StatisticsGeneratorManager;
import org.orcid.core.manager.StatisticsManager;
import org.orcid.core.manager.read_only.StatisticsManagerReadOnly;
import org.orcid.statistics.jpa.entities.StatisticKeyEntity;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class StatisticsGeneratorCronJobImpl implements StatisticsGeneratorCronJob {

    private static final Logger LOG = LoggerFactory.getLogger(StatisticsGeneratorCronJobImpl.class);

    @Resource
    private StatisticsGeneratorManager statisticsGeneratorManager;

    @Resource
    private StatisticsManager statisticsManager;

    @Resource
    private StatisticsManagerReadOnly statisticsManagerReadOnly;
    
    private long halfHourInMillis = 30 * 60 * 1000;

    private long hourInMillis = halfHourInMillis * 2;

    private long dayInMillis = 24 * hourInMillis;

    private long weekInMillis = dayInMillis * 7;

    /**
     * Cron job that will generate statistics and store them on database
     */
    @Override
    public void generateStatistics() {
        LOG.debug("About to run statistics generator thread");
        boolean run = false;
        StatisticKeyEntity lastStatisticsKey = statisticsManagerReadOnly.getLatestKey();

        if (lastStatisticsKey != null && lastStatisticsKey.getGenerationDate() != null) {
            Date lastTimeJobRuns = lastStatisticsKey.getGenerationDate();
            boolean isTimeToRun = isFridayNearMidnight();
            long offset = System.currentTimeMillis() - lastTimeJobRuns.getTime();
            LOG.info("Last time the statistics were generated: {}", lastTimeJobRuns);
            LOG.info("Is time to run the scheduler? {}", isTimeToRun);

            if (offset > weekInMillis || (isTimeToRun && offset > halfHourInMillis)) {
                run = true;
            }

        } else {
            run = true;
            LOG.warn("There are no statistics generated yet.");
        }

        if (run) {
            Map<String, Long> statistics = statisticsGeneratorManager.generateStatistics();
            statisticsManager.saveStatistics(statistics);           
            LOG.info("Last time the statistics cron job ran: {}", new Date());            
        }
    }

    /**
     * @return true if it is Friday 11:30 PM or later, false otherwise.
     */
    public boolean isFridayNearMidnight() {
        Calendar c = Calendar.getInstance();
        int dayOfWeek = c.get(Calendar.DAY_OF_WEEK);
        // If it is friday
        if (dayOfWeek == Calendar.FRIDAY) {
            // And it is 11 PM
            if (c.get(Calendar.HOUR_OF_DAY) == 23) {
                // And it is later than 11:30 pm
                if (c.get(Calendar.MINUTE) >= 30) {
                    return true;
                }
            }
        }

        return false;
    }
}