<?php

/*
 *
 *  ____            _        _   __  __ _                  __  __ ____
 * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
 * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
 * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
 * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * @author PocketMine Team
 * @link http://www.pocketmine.net/
 *
 *
*/

declare(strict_types=1);

namespace pocketmine\level;

use pocketmine\block\Block;
use pocketmine\level\format\Chunk;
use pocketmine\math\Vector3;

/**
 * If you want to keep chunks loaded and receive notifications on a specific area,
 * extend this class and register it into Level. This will also tick chunks.
 *
 * Register Level->registerChunkLoader($this, $chunkX, $chunkZ)
 * Unregister Level->unregisterChunkLoader($this, $chunkX, $chunkZ)
 *
 * WARNING: When moving this object around in the world or destroying it,
 * be sure to free the existing references from Level, otherwise you'll leak memory.
 */
interface ChunkLoader{

	/**
	 * Returns the ChunkLoader id.
	 * Call Level::generateChunkLoaderId($this) to generate and save it
	 */
	public function getLoaderId() : int;

	/**
	 * Returns if the chunk loader is currently active
	 */
	public function isLoaderActive() : bool;

	/**
	 * @return Position
	 */
	public function getPosition();

	/**
	 * @return float
	 */
	public function getX();

	/**
	 * @return float
	 */
	public function getZ();

	/**
	 * @return Level
	 */
	public function getLevel();

	/**
	 * This method will be called when a Chunk is replaced by a new one
	 *
	 * @return void
	 */
	public function onChunkChanged(Chunk $chunk);

	/**
	 * This method will be called when a registered chunk is loaded
	 *
	 * @return void
	 */
	public function onChunkLoaded(Chunk $chunk);

	/**
	 * This method will be called when a registered chunk is unloaded
	 *
	 * @return void
	 */
	public function onChunkUnloaded(Chunk $chunk);

	/**
	 * This method will be called when a registered chunk is populated
	 * Usually it'll be sent with another call to onChunkChanged()
	 *
	 * @return void
	 */
	public function onChunkPopulated(Chunk $chunk);

	/**
	 * This method will be called when a block changes in a registered chunk
	 *
	 * @param Block|Vector3 $block
	 *
	 * @return void
	 */
	public function onBlockChanged(Vector3 $block);

}
