<?php
/**
 * Works out the WordPress.org slug of an installed plugin.
 *
 * @package Brachmelder
 */

namespace Brachmelder\Check;

defined( 'ABSPATH' ) || exit;

/**
 * Resolves plugin slugs.
 */
final class SlugResolver {

	/**
	 * Plugins whose file name differs from their WordPress.org slug.
	 *
	 * @var array<string, string>
	 */
	const KNOWN = array(
		'hello.php' => 'hello-dolly',
	);

	/**
	 * Returns the WordPress.org slug or null if the plugin is clearly not hosted there.
	 *
	 * @param string               $plugin_file    Plugin basename, e.g. "akismet/akismet.php".
	 * @param array<string, mixed> $plugin_data    Plugin headers from get_plugins().
	 * @param object|false|null    $update_plugins Value of the update_plugins site transient.
	 * @return string|null
	 */
	public static function resolve( string $plugin_file, array $plugin_data, $update_plugins ): ?string {
		// Plugins that declare a foreign update source are not on WordPress.org.
		$update_uri = isset( $plugin_data['UpdateURI'] ) ? trim( (string) $plugin_data['UpdateURI'] ) : '';
		if ( '' !== $update_uri && ! self::is_wporg_uri( $update_uri ) ) {
			return null;
		}

		// WordPress core already knows the slug for plugins it checks for updates.
		if ( is_object( $update_plugins ) ) {
			foreach ( array( 'response', 'no_update' ) as $list ) {
				$items = isset( $update_plugins->$list ) && is_array( $update_plugins->$list ) ? $update_plugins->$list : array();
				$item  = $items[ $plugin_file ] ?? null;
				if ( is_object( $item ) && ! empty( $item->slug ) ) {
					return sanitize_key( (string) $item->slug );
				}
			}
		}

		if ( isset( self::KNOWN[ $plugin_file ] ) ) {
			return self::KNOWN[ $plugin_file ];
		}

		$dir  = dirname( $plugin_file );
		$slug = ( '.' === $dir || '' === $dir ) ? basename( $plugin_file, '.php' ) : $dir;
		$slug = sanitize_key( $slug );

		return '' === $slug ? null : $slug;
	}

	/**
	 * Whether an Update URI points to WordPress.org.
	 *
	 * @param string $uri Update URI header.
	 * @return bool
	 */
	private static function is_wporg_uri( string $uri ): bool {
		$host = wp_parse_url( $uri, PHP_URL_HOST );
		if ( ! is_string( $host ) ) {
			$host = strtok( $uri, '/' );
		}
		return in_array( strtolower( (string) $host ), array( 'wordpress.org', 'w.org' ), true );
	}
}