package com.lashpoint.quartz;

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

import org.quartz.JobExecutionContext;
import org.quartz.JobExecutionException;
import org.quartz.SchedulerException;
import org.quartz.SimpleTrigger;

import com.lashpoint.twitter.quartz.RescheduleException;

public abstract class RetriableTrigger extends SimpleTrigger {
	/**
	 * 
	 */
	private static final long serialVersionUID = 2986291750485640660L;
	
	private static final int DELAY_CEILING = 600; // 15 minutes
	private static final int DELAY_EXP_BASE = 2; // Delays will be a power of 2
	
	public RetriableTrigger(String name, Date startDate) {
		super(name, startDate, null, 0, 0);
	}
	
	@Override
	public boolean hasAdditionalProperties() {
		return true;
	}
	
	@Override
	public int executionComplete(JobExecutionContext context,
			JobExecutionException result) {
		if (shouldReschedule(context, result)) {
			try {
    			SimpleTrigger nextTrigger = createTriggerForReschedule(context,
    					result);
    			if (nextTrigger != null) {
					context.getScheduler().rescheduleJob(getName(), getGroup(),
							nextTrigger);
					
					return INSTRUCTION_NOOP;
				}
			}			
			catch (SchedulerException e) {
				throw new RescheduleException(e);
			}
		}
		
		return INSTRUCTION_DELETE_TRIGGER;
	}
	
	protected abstract boolean shouldReschedule(JobExecutionContext context,
			JobExecutionException result);
	
	protected SimpleTrigger createTriggerForReschedule(JobExecutionContext context,
			JobExecutionException result) {
		try {
			SimpleTrigger trigger = getClass().newInstance();
			
			Calendar nextFireTime = Calendar.getInstance();
			nextFireTime.add(Calendar.SECOND, Math.min(DELAY_CEILING,
					(int)Math.pow(DELAY_EXP_BASE, getTimesTriggered())));
			
			trigger.setStartTime(nextFireTime.getTime());
			trigger.setJobName(getJobName());
			trigger.setJobGroup(getJobGroup());
			trigger.setTimesTriggered(getTimesTriggered());
			
			return trigger;
		}
		catch (InstantiationException e) {
			throw new RescheduleException(e);
		}
		catch (IllegalAccessException e) {
			throw new RescheduleException(e);
		}
	}
}