package org.bukkit.event.block;

import org.bukkit.block.Block;
import org.bukkit.block.BlockFace;
import org.bukkit.event.HandlerList;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

/**
 * Called when a piston extends
 */
public class BlockPistonExtendEvent extends BlockPistonEvent
{
	private static final HandlerList handlers = new HandlerList();
	private final int length;
	private List<Block> blocks;

	public BlockPistonExtendEvent(final Block block, final int length, final BlockFace direction)
	{
		super(block, direction);

		this.length = length;
	}

	/**
	 * Get the amount of blocks which will be moved while extending.
	 *
	 * @return the amount of moving blocks
	 */
	public int getLength()
	{
		return this.length;
	}

	/**
	 * Get an immutable list of the blocks which will be moved by the
	 * extending.
	 *
	 * @return Immutable list of the moved blocks.
	 */
	public List<Block> getBlocks()
	{
		if(blocks == null)
		{
			ArrayList<Block> tmp = new ArrayList<Block>();
			for(int i = 0; i < this.getLength(); i++)
			{
				tmp.add(block.getRelative(getDirection(), i + 1));
			}
			blocks = Collections.unmodifiableList(tmp);
		}
		return blocks;
	}

	@Override
	public HandlerList getHandlers()
	{
		return handlers;
	}

	public static HandlerList getHandlerList()
	{
		return handlers;
	}
}