<?php
/**
 * PSR-4 style autoloader for ReactWoo\Atomic.
 *
 * @package ReactWoo\Atomic
 */

namespace ReactWoo\Atomic\Runtime;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

if ( class_exists( __NAMESPACE__ . '\\Autoloader', false ) ) {
	return;
}

/**
 * Maps ReactWoo\Atomic\* namespaces to directories under the plugin root.
 */
final class Autoloader {

	/**
	 * @var string
	 */
	private static $root = '';

	/**
	 * Longest-prefix map: namespace after ReactWoo\Atomic\ => relative dir.
	 *
	 * @var array<string, string>
	 */
	private static $map = array();

	/**
	 * @param string                $root Plugin root path with trailing slash.
	 * @param array<string, string> $map  Namespace relative to ReactWoo\Atomic\ => directory.
	 * @return void
	 */
	public static function register( $root, array $map ) {
		self::$root = trailingslashit( (string) $root );
		uksort(
			$map,
			static function ( $a, $b ) {
				return strlen( (string) $b ) - strlen( (string) $a );
			}
		);
		self::$map = $map;
		spl_autoload_register( array( __CLASS__, 'load' ) );
	}

	/**
	 * @param string $class Fully-qualified class name.
	 * @return void
	 */
	public static function load( $class ) {
		$prefix = 'ReactWoo\\Atomic\\';
		if ( 0 !== strpos( $class, $prefix ) ) {
			return;
		}

		$relative = substr( $class, strlen( $prefix ) );

		foreach ( self::$map as $ns => $dir ) {
			$ns = (string) $ns;
			if ( '' === $ns ) {
				continue;
			}
			if ( $relative !== $ns && 0 !== strpos( $relative, $ns . '\\' ) ) {
				continue;
			}
			$rest = trim( substr( $relative, strlen( $ns ) ), '\\' );
			if ( '' === $rest ) {
				return;
			}
			$file = self::$root . trailingslashit( str_replace( '\\', '/', (string) $dir ) ) . str_replace( '\\', '/', $rest ) . '.php';
			if ( is_readable( $file ) ) {
				require_once $file;
			}
			return;
		}
	}
}