<?php
/**
 * Akeeba Engine
 *
 * @package   akeebaengine
 * @copyright Copyright (c)2006-2022 Nicholas K. Dionysopoulos / Akeeba Ltd
 * @license   GNU General Public License version 3, or later
 */

namespace Akeeba\Engine;

defined('AKEEBAENGINE') || die();

/**
 * The main class autoloader for AkeebaEngine
 */
class Autoloader
{
	/**
	 * An instance of this autoloader
	 *
	 * @var   Autoloader
	 */
	public static $autoloader = null;

	/**
	 * The path to the Akeeba Engine root directory
	 *
	 * @var   string
	 */
	public static $enginePath = null;

	/**
	 * The directories where Akeeba Engine platforms are stored
	 *
	 * @var      array
	 */
	public static $platformDirs = null;

	/**
	 * Public constructor. Registers the autoloader with PHP.
	 */
	public function __construct()
	{
		self::$enginePath = __DIR__;

		spl_autoload_register([$this, 'autoload_akeeba_engine']);
	}

	/**
	 * Initialise this autoloader
	 *
	 * @return  Autoloader
	 */
	public static function init()
	{
		if (self::$autoloader == null)
		{
			self::$autoloader = new self;
		}

		return self::$autoloader;
	}

	/**
	 * The actual autoloader
	 *
	 * @param   string  $className  The name of the class to load
	 *
	 * @return  void
	 */
	public function autoload_akeeba_engine($className)
	{
		// Trim the trailing backslash
		$className = ltrim($className, '\\');

		// Make sure the class has an Akeeba\Engine prefix
		if (substr($className, 0, 13) != 'Akeeba\\Engine')
		{
			return;
		}

		// Remove the prefix and explode on backslashes
		$className = substr($className, 14);
		$class     = explode('\\', $className);

		// Do we have a list of platform directories?
		if (is_null(self::$platformDirs) && class_exists('\\Akeeba\\Engine\\Platform', false))
		{
			self::$platformDirs = Platform::getPlatformDirectories();

			if (!is_array(self::$platformDirs))
			{
				self::$platformDirs = [];
			}
		}

		$rootPaths = [self::$enginePath];

		if (is_array(self::$platformDirs))
		{
			$rootPaths = array_merge(
				self::$platformDirs, [self::$enginePath]
			);
		}

		foreach ($rootPaths as $rootPath)
		{
			// First try finding in structured directory format (preferred)
			$path = $rootPath . '/' . implode('/', $class) . '.php';

			if (@file_exists($path))
			{
				include_once $path;
			}

			// Then try the duplicate last name structured directory format (not recommended)
			if (!class_exists($className, false))
			{
				reset($class);
				$lastPart = end($class);
				$path     = $rootPath . '/' . implode('/', $class) . '/' . $lastPart . '.php';

				if (@file_exists($path))
				{
					include_once $path;
				}
			}
		}
	}
}

// Register the Akeeba Engine autoloader
Autoloader::init();
