<?php
/**
*
* This file is part of the phpBB Forum Software package.
*
* @copyright (c) phpBB Limited <https://www.phpbb.com>
* @license GNU General Public License, version 2 (GPL-2.0)
*
* For full copyright and license information, please see
* the docs/CREDITS.txt file.
*
*/

namespace phpbb\extension;

/**
* Provides a set of items found in extensions.
*
* This abstract class is essentially a wrapper around item-specific
* finding logic. It handles storing the extension manager via constructor
* for the finding logic to use to find the items, and provides an
* iterator interface over the items found by the finding logic.
*
* Items could be anything, for example template paths or cron task names.
* Derived classes completely define what the items are.
*/
abstract class provider implements \IteratorAggregate
{
	/**
	* Array holding all found items
	* @var array|null
	*/
	protected $items = null;

	/**
	* An extension manager to search for items in extensions
	* @var \phpbb\extension\manager
	*/
	protected $extension_manager;

	/**
	* Constructor. Loads all available items.
	*
	* @param \phpbb\extension\manager $extension_manager phpBB extension manager
	*/
	public function __construct(\phpbb\extension\manager $extension_manager)
	{
		$this->extension_manager = $extension_manager;
	}

	/**
	* Finds items using the extension manager.
	*
	* @return array     List of task names
	*/
	abstract protected function find();

	/**
	* Retrieve an iterator over all items
	*
	* @return \ArrayIterator An iterator for the array of template paths
	*/
	public function getIterator(): \ArrayIterator
	{
		if ($this->items === null)
		{
			$this->items = $this->find();
		}

		return new \ArrayIterator($this->items);
	}
}
