package org.bukkit.scheduler;

import org.bukkit.Bukkit;
import org.bukkit.plugin.Plugin;

/**
 * This class is provided as an easy way to handle scheduling tasks.
 */
public abstract class BukkitRunnable implements Runnable
{
	private int taskId = -1;

	/**
	 * Attempts to cancel this task.
	 *
	 * @throws IllegalStateException if task was not scheduled yet
	 */
	public synchronized void cancel() throws IllegalStateException
	{
		Bukkit.getScheduler().cancelTask(getTaskId());
	}

	/**
	 * Schedules this in the Bukkit scheduler to run on next tick.
	 *
	 * @param plugin the reference to the plugin scheduling task
	 * @return a BukkitTask that contains the id number
	 * @throws IllegalArgumentException if plugin is null
	 * @throws IllegalStateException    if this was already scheduled
	 * @see BukkitScheduler#runTask(Plugin, Runnable)
	 */
	public synchronized BukkitTask runTask(Plugin plugin) throws IllegalArgumentException, IllegalStateException
	{
		checkState();
		return setupId(Bukkit.getScheduler().runTask(plugin, this));
	}

	/**
	 * <b>Asynchronous tasks should never access any API in Bukkit. Great care
	 * should be taken to assure the thread-safety of asynchronous tasks.</b>
	 * <p>
	 * Schedules this in the Bukkit scheduler to run asynchronously.
	 *
	 * @param plugin the reference to the plugin scheduling task
	 * @return a BukkitTask that contains the id number
	 * @throws IllegalArgumentException if plugin is null
	 * @throws IllegalStateException    if this was already scheduled
	 * @see BukkitScheduler#runTaskAsynchronously(Plugin, Runnable)
	 */
	public synchronized BukkitTask runTaskAsynchronously(Plugin plugin) throws IllegalArgumentException, IllegalStateException
	{
		checkState();
		return setupId(Bukkit.getScheduler().runTaskAsynchronously(plugin, this));
	}

	/**
	 * Schedules this to run after the specified number of server ticks.
	 *
	 * @param plugin the reference to the plugin scheduling task
	 * @param delay  the ticks to wait before running the task
	 * @return a BukkitTask that contains the id number
	 * @throws IllegalArgumentException if plugin is null
	 * @throws IllegalStateException    if this was already scheduled
	 * @see BukkitScheduler#runTaskLater(Plugin, Runnable, long)
	 */
	public synchronized BukkitTask runTaskLater(Plugin plugin, long delay) throws IllegalArgumentException, IllegalStateException
	{
		checkState();
		return setupId(Bukkit.getScheduler().runTaskLater(plugin, this, delay));
	}

	/**
	 * <b>Asynchronous tasks should never access any API in Bukkit. Great care
	 * should be taken to assure the thread-safety of asynchronous tasks.</b>
	 * <p>
	 * Schedules this to run asynchronously after the specified number of
	 * server ticks.
	 *
	 * @param plugin the reference to the plugin scheduling task
	 * @param delay  the ticks to wait before running the task
	 * @return a BukkitTask that contains the id number
	 * @throws IllegalArgumentException if plugin is null
	 * @throws IllegalStateException    if this was already scheduled
	 * @see BukkitScheduler#runTaskLaterAsynchronously(Plugin, Runnable, long)
	 */
	public synchronized BukkitTask runTaskLaterAsynchronously(Plugin plugin, long delay) throws IllegalArgumentException, IllegalStateException
	{
		checkState();
		return setupId(Bukkit.getScheduler().runTaskLaterAsynchronously(plugin, this, delay));
	}

	/**
	 * Schedules this to repeatedly run until cancelled, starting after the
	 * specified number of server ticks.
	 *
	 * @param plugin the reference to the plugin scheduling task
	 * @param delay  the ticks to wait before running the task
	 * @param period the ticks to wait between runs
	 * @return a BukkitTask that contains the id number
	 * @throws IllegalArgumentException if plugin is null
	 * @throws IllegalStateException    if this was already scheduled
	 * @see BukkitScheduler#runTaskTimer(Plugin, Runnable, long, long)
	 */
	public synchronized BukkitTask runTaskTimer(Plugin plugin, long delay, long period) throws IllegalArgumentException, IllegalStateException
	{
		checkState();
		return setupId(Bukkit.getScheduler().runTaskTimer(plugin, this, delay, period));
	}

	/**
	 * <b>Asynchronous tasks should never access any API in Bukkit. Great care
	 * should be taken to assure the thread-safety of asynchronous tasks.</b>
	 * <p>
	 * Schedules this to repeatedly run asynchronously until cancelled,
	 * starting after the specified number of server ticks.
	 *
	 * @param plugin the reference to the plugin scheduling task
	 * @param delay  the ticks to wait before running the task for the first
	 *               time
	 * @param period the ticks to wait between runs
	 * @return a BukkitTask that contains the id number
	 * @throws IllegalArgumentException if plugin is null
	 * @throws IllegalStateException    if this was already scheduled
	 * @see BukkitScheduler#runTaskTimerAsynchronously(Plugin, Runnable, long,
	 * long)
	 */
	public synchronized BukkitTask runTaskTimerAsynchronously(Plugin plugin, long delay, long period) throws IllegalArgumentException, IllegalStateException
	{
		checkState();
		return setupId(Bukkit.getScheduler().runTaskTimerAsynchronously(plugin, this, delay, period));
	}

	/**
	 * Gets the task id for this runnable.
	 *
	 * @return the task id that this runnable was scheduled as
	 * @throws IllegalStateException if task was not scheduled yet
	 */
	public synchronized int getTaskId() throws IllegalStateException
	{
		final int id = taskId;
		if(id == -1)
		{
			throw new IllegalStateException("Not scheduled yet");
		}
		return id;
	}

	private void checkState()
	{
		if(taskId != -1)
		{
			throw new IllegalStateException("Already scheduled as " + taskId);
		}
	}

	private BukkitTask setupId(final BukkitTask task)
	{
		this.taskId = task.getTaskId();
		return task;
	}
}