<?php
/**
 * Joomla! Content Management System
 *
 * @copyright  (C) 2019 Open Source Matters, Inc. <https://www.joomla.org>
 * @license    GNU General Public License version 2 or later; see LICENSE
 */

namespace Joomla\CMS\MVC\Model;

\defined('JPATH_PLATFORM') or die;

use Joomla\CMS\Object\CMSObject;

/**
 * Trait which supports state behavior
 *
 * @since  4.0.0
 */
trait StateBehaviorTrait
{
	/**
	 * Indicates if the internal state has been set
	 *
	 * @var    boolean
	 * @since  4.0.0
	 */
	protected $__state_set = null;

	/**
	 * A state object
	 *
	 * @var    CMSObject
	 * @since  4.0.0
	 */
	protected $state = null;

	/**
	 * Method to get state variables.
	 *
	 * @param   string  $property  Optional parameter name
	 * @param   mixed   $default   Optional default value
	 *
	 * @return  mixed  The property where specified, the state object where omitted
	 *
	 * @since   4.0.0
	 */
	public function getState($property = null, $default = null)
	{
		if ($this->state === null)
		{
			$this->state = new CMSObject;
		}

		if (!$this->__state_set)
		{
			// Protected method to auto-populate the state
			$this->populateState();

			// Set the state set flag to true.
			$this->__state_set = true;
		}

		return $property === null ? $this->state : $this->state->get($property, $default);
	}

	/**
	 * Method to set state variables.
	 *
	 * @param   string  $property  The name of the property
	 * @param   mixed   $value     The value of the property to set or null
	 *
	 * @return  mixed  The previous value of the property or null if not set
	 *
	 * @since   4.0.0
	 */
	public function setState($property, $value = null)
	{
		if ($this->state === null)
		{
			$this->state = new CMSObject;
		}

		return $this->state->set($property, $value);
	}

	/**
	 * Method to auto-populate the state.
	 *
	 * This method should only be called once per instantiation and is designed
	 * to be called on the first call to the getState() method unless the
	 * configuration flag to ignore the request is set.
	 *
	 * @return  void
	 *
	 * @note    Calling getState in this method will result in recursion.
	 * @since   4.0.0
	 */
	protected function populateState()
	{
	}
}
