n
	 *                                         recurses to lower depths. Default empty.
	 * @return string[]|false Array of files, keyed by the path to the file relative to the `$path` directory prepended
	 *                        with `$relative_path`, with the values being absolute paths. False otherwise.
	 */
	private static function scandir( $path, $extensions = null, $depth = 0, $relative_path = '' ) {
		if ( ! is_dir( $path ) ) {
			return false;
		}

		if ( $extensions ) {
			$extensions  = (array) $extensions;
			$_extensions = implode( '|', $extensions );
		}

		$relative_path = trailingslashit( $relative_path );
		if ( '/' === $relative_path ) {
			$relative_path = '';
		}

		$results = scandir( $path );
		$files   = array();

		/**
		 * Filters the array of excluded directories and files while scanning theme folder.
		 *
		 * @since 4.7.4
		 *
		 * @param string[] $exclusions Array of excluded directories and files.
		 */
		$exclusions = (array) apply_filters( 'theme_scandir_exclusions', array( 'CVS', 'node_modules', 'vendor', 'bower_components' ) );

		foreach ( $results as $result ) {
			if ( '.' === $result[0] || in_array( $result, $exclusions, true ) ) {
				continue;
			}
			if ( is_dir( $path . '/' . $result ) ) {
				if ( ! $depth ) {
					continue;
				}
				$found = self::scandir( $path . '/' . $result, $extensions, $depth - 1, $relative_path . $result );
				$files = array_merge_recursive( $files, $found );
			} elseif ( ! $extensions || preg_match( '~\.(' . $_extensions . ')$~', $result ) ) {
				$files[ $relative_path . $result ] = $path . '/' . $result;
			}
		}

		return $files;
	}

	/**
	 * Loads the theme's textdomain.
	 *
	 * Translation files are not inherited from the parent theme. TODO: If this fails for the
	 * child theme, it should probably try to load the parent theme's translations.
	 *
	 * @since 3.4.0
	 *
	 * @return bool True if the textdomain was successfully loaded or has already been loaded.
	 *  False if no textdomain was specified in the file headers, or if the domain could not be loaded.
	 */
	public function load_textdomain() {
		if ( isset( $this->textdomain_loaded ) ) {
			return $this->textdomain_loaded;
		}

		$textdomain = $this->get( 'TextDomain' );
		if ( ! $textdomain ) {
			$this->textdomain_loaded = false;
			return false;
		}

		if ( is_textdomain_loaded( $textdomain ) ) {
			$this->textdomain_loaded = true;
			return true;
		}

		$path       = $this->get_stylesheet_directory();
		$domainpath = $this->get( 'DomainPath' );
		if ( $domainpath ) {
			$path .= $domainpath;
		} else {
			$path .= '/languages';
		}

		$this->textdomain_loaded = load_theme_textdomain( $textdomain, $path );
		return $this->textdomain_loaded;
	}

	/**
	 * Determines whether the theme is allowed (multisite only).
	 *
	 * @since 3.4.0
	 *
	 * @param string $check   Optional. Whether to check only the 'network'-wide settings, the 'site'
	 *                        settings, or 'both'. Defaults to 'both'.
	 * @param int    $blog_id Optional. Ignored if only network-wide settings are checked. Defaults to current site.
	 * @return bool Whether the theme is allowed for the network. Returns true in single-site.
	 */
	public function is_allowed( $check = 'both', $blog_id = null ) {
		if ( ! is_multisite() ) {
			return true;
		}

		if ( 'both' === $check || 'network' === $check ) {
			$allowed = self::get_allowed_on_network();
			if ( ! empty( $allowed[ $this->get_stylesheet() ] ) ) {
				return true;
			}
		}

		if ( 'both' === $check || 'site' === $check ) {
			$allowed = self::get_allowed_on_site( $blog_id );
			if ( ! empty( $allowed[ $this->get_stylesheet() ] ) ) {
				return true;
			}
		}

		return false;
	}

	/**
	 * Returns whether this theme is a block-based theme or not.
	 *
	 * @since 5.9.0
	 *
	 * @return bool
	 */
	public function is_block_theme() {
		if ( isset( $this->block_theme ) ) {
			return $this->block_theme;
		}

		$paths_to_index_block_template = array(
			$this->get_file_path( '/templates/index.html' ),
			$this->get_file_path( '/block-templates/index.html' ),
		);

		$this->block_theme = false;

		foreach ( $paths_to_index_block_template as $path_to_index_block_template ) {
			if ( is_file( $path_to_index_block_template ) && is_readable( $path_to_index_block_template ) ) {
				$this->block_theme = true;
				break;
			}
		}

		return $this->block_theme;
	}

	/**
	 * Retrieves the path of a file in the theme.
	 *
	 * Searches in the stylesheet directory before the template directory so themes
	 * which inherit from a parent theme can just override one file.
	 *
	 * @since 5.9.0
	 *
	 * @param string $file Optional. File to search for in the stylesheet directory.
	 * @return string The path of the file.
	 */
	public function get_file_path( $file = '' ) {
		$file = ltrim( $file, '/' );

		$stylesheet_directory = $this->get_stylesheet_directory();
		$template_directory   = $this->get_template_directory();

		if ( empty( $file ) ) {
			$path = $stylesheet_directory;
		} elseif ( $stylesheet_directory !== $template_directory && file_exists( $stylesheet_directory . '/' . $file ) ) {
			$path = $stylesheet_directory . '/' . $file;
		} else {
			$path = $template_directory . '/' . $file;
		}

		/** This filter is documented in wp-includes/link-template.php */
		return apply_filters( 'theme_file_path', $path, $file );
	}

	/**
	 * Determines the latest WordPress default theme that is installed.
	 *
	 * This hits the filesystem.
	 *
	 * @since 4.4.0
	 *
	 * @return WP_Theme|false Object, or false if no theme is installed, which would be bad.
	 */
	public static function get_core_default_theme() {
		foreach ( array_reverse( self::$default_themes ) as $slug => $name ) {
			$theme = wp_get_theme( $slug );
			if ( $theme->exists() ) {
				return $theme;
			}
		}
		return false;
	}

	/**
	 * Returns array of stylesheet names of themes allowed on the site or network.
	 *
	 * @since 3.4.0
	 *
	 * @param int $blog_id Optional. ID of the site. Defaults to the current site.
	 * @return string[] Array of stylesheet names.
	 */
	public static function get_allowed( $blog_id = null ) {
		/**
		 * Filters the array of themes allowed on the network.
		 *
		 * Site is provided as context so that a list of network allowed themes can
		 * be filtered further.
		 *
		 * @since 4.5.0
		 *
		 * @param string[] $allowed_themes An array of theme stylesheet names.
		 * @param int      $blog_id        ID of the site.
		 */
		$network = (array) apply_filters( 'network_allowed_themes', self::get_allowed_on_network(), $blog_id );
		return $network + self::get_allowed_on_site( $blog_id );
	}

	/**
	 * Returns array of stylesheet names of themes allowed on the network.
	 *
	 * @since 3.4.0
	 *
	 * @return string[] Array of stylesheet names.
	 */
	public static function get_allowed_on_network() {
		static $allowed_themes;
		if ( ! isset( $allowed_themes ) ) {
			$allowed_themes = (array) get_site_option( 'allowedthemes' );
		}

		/**
		 * Filters the array of themes allowed on the network.
		 *
		 * @since MU (3.0.0)
		 *
		 * @param string[] $allowed_themes An array of theme stylesheet names.
		 */
		$allowed_themes = apply_filters( 'allowed_themes', $allowed_themes );

		return $allowed_themes;
	}

	/**
	 * Returns array of stylesheet names of themes allowed on the site.
	 *
	 * @since 3.4.0
	 *
	 * @param int $blog_id Optional. ID of the site. Defaults to the current site.
	 * @return string[] Array of stylesheet names.
	 */
	public static function get_allowed_on_site( $blog_id = null ) {
		static $allowed_themes = array();

		if ( ! $blog_id || ! is_multisite() ) {
			$blog_id = get_current_blog_id();
		}

		if ( isset( $allowed_themes[ $blog_id ] ) ) {
			/**
			 * Filters the array of themes allowed on the site.
			 *
			 * @since 4.5.0
			 *
			 * @param string[] $allowed_themes An array of theme stylesheet names.
			 * @param int      $blog_id        ID of the site. Defaults to current site.
			 */
			return (array) apply_filters( 'site_allowed_themes', $allowed_themes[ $blog_id ], $blog_id );
		}

		$current = get_current_blog_id() === $blog_id;

		if ( $current ) {
			$allowed_themes[ $blog_id ] = get_option( 'allowedthemes' );
		} else {
			switch_to_blog( $blog_id );
			$allowed_themes[ $blog_id ] = get_option( 'allowedthemes' );
			restore_current_blog();
		}

		/*
		 * This is all super old MU back compat joy.
		 * 'allowedthemes' keys things by stylesheet. 'allowed_themes' keyed things by name.
		 */
		if ( false === $allowed_themes[ $blog_id ] ) {
			if ( $current ) {
				$allowed_themes[ $blog_id ] = get_option( 'allowed_themes' );
			} else {
				switch_to_blog( $blog_id );
				$allowed_themes[ $blog_id ] = get_option( 'allowed_themes' );
				restore_current_blog();
			}

			if ( ! is_array( $allowed_themes[ $blog_id ] ) || empty( $allowed_themes[ $blog_id ] ) ) {
				$allowed_themes[ $blog_id ] = array();
			} else {
				$converted = array();
				$themes    = wp_get_themes();
				foreach ( $themes as $stylesheet => $theme_data ) {
					if ( isset( $allowed_themes[ $blog_id ][ $theme_data->get( 'Name' ) ] ) ) {
						$converted[ $stylesheet ] = true;
					}
				}
				$allowed_themes[ $blog_id ] = $converted;
			}
			// Set the option so we never have to go through this pain again.
			if ( is_admin() && $allowed_themes[ $blog_id ] ) {
				if ( $current ) {
					update_option( 'allowedthemes', $allowed_themes[ $blog_id ], false );
					delete_option( 'allowed_themes' );
				} else {
					switch_to_blog( $blog_id );
					update_option( 'allowedthemes', $allowed_themes[ $blog_id ], false );
					delete_option( 'allowed_themes' );
					restore_current_blog();
				}
			}
		}

		/** This filter is documented in wp-includes/class-wp-theme.php */
		return (array) apply_filters( 'site_allowed_themes', $allowed_themes[ $blog_id ], $blog_id );
	}

	/**
	 * Returns the folder names of the block template directories.
	 *
	 * @since 6.4.0
	 *
	 * @return string[] {
	 *     Folder names used by block themes.
	 *
	 *     @type string $wp_template      Theme-relative directory name for block templates.
	 *     @type string $wp_template_part Theme-relative directory name for block template parts.
	 * }
	 */
	public function get_block_template_folders() {
		// Return set/cached value if available.
		if ( isset( $this->block_template_folders ) ) {
			return $this->block_template_folders;
		}

		$this->block_template_folders = $this->default_template_folders;

		$stylesheet_directory = $this->get_stylesheet_directory();
		// If the theme uses deprecated block template folders.
		if ( file_exists( $stylesheet_directory . '/block-templates' ) || file_exists( $stylesheet_directory . '/block-template-parts' ) ) {
			$this->block_template_folders = array(
				'wp_template'      => 'block-templates',
				'wp_template_part' => 'block-template-parts',
			);
		}
		return $this->block_template_folders;
	}

	/**
	 * Gets block pattern data for a specified theme.
	 * Each pattern is defined as a PHP file and defines
	 * its metadata using plugin-style headers. The minimum required definition is:
	 *
	 *     /**
	 *      * Title: My Pattern
	 *      * Slug: my-theme/my-pattern
	 *      *
	 *
	 * The output of the PHP source corresponds to the content of the pattern, e.g.:
	 *
	 *     <main><p>Hello</p></main>
	 *
	 * If applicable, this will collect from both parent and child theme.
	 *
	 * Other settable fields include:
	 *
	 *     - Description
	 *     - Viewport Width
	 *     - Inserter         (yes/no)
	 *     - Categories       (comma-separated values)
	 *     - Keywords         (comma-separated values)
	 *     - Block Types      (comma-separated values)
	 *     - Post Types       (comma-separated values)
	 *     - Template Types   (comma-separated values)
	 *
	 * @since 6.4.0
	 *
	 * @return array Block pattern data.
	 */
	public function get_block_patterns() {
		$can_use_cached = ! wp_is_development_mode( 'theme' );

		$pattern_data = $this->get_pattern_cache();
		if ( is_array( $pattern_data ) ) {
			if ( $can_use_cached ) {
				return $pattern_data;
			}
			// If in development mode, clear pattern cache.
			$this->delete_pattern_cache();
		}

		$dirpath      = $this->get_stylesheet_directory() . '/patterns/';
		$pattern_data = array();

		if ( ! file_exists( $dirpath ) ) {
			if ( $can_use_cached ) {
				$this->set_pattern_cache( $pattern_data );
			}
			return $pattern_data;
		}
		$files = glob( $dirpath . '*.php' );
		if ( ! $files ) {
			if ( $can_use_cached ) {
				$this->set_pattern_cache( $pattern_data );
			}
			return $pattern_data;
		}

		$default_headers = array(
			'title'         => 'Title',
			'slug'          => 'Slug',
			'description'   => 'Description',
			'viewportWidth' => 'Viewport Width',
			'inserter'      => 'Inserter',
			'categories'    => 'Categories',
			'keywords'      => 'Keywords',
			'blockTypes'    => 'Block Types',
			'postTypes'     => 'Post Types',
			'templateTypes' => 'Template Types',
		);

		$properties_to_parse = array(
			'categories',
			'keywords',
			'blockTypes',
			'postTypes',
			'templateTypes',
		);

		foreach ( $files as $file ) {
			$pattern = get_file_data( $file, $default_headers );

			if ( empty( $pattern['slug'] ) ) {
				_doing_it_wrong(
					__FUNCTION__,
					sprintf(
						/* translators: 1: file name. */
						__( 'Could not register file "%s" as a block pattern ("Slug" field missing)' ),
						$file
					),
					'6.0.0'
				);
				continue;
			}

			if ( ! preg_match( '/^[A-z0-9\/_-]+$/', $pattern['slug'] ) ) {
				_doing_it_wrong(
					__FUNCTION__,
					sprintf(
						/* translators: 1: file name; 2: slug value found. */
						__( 'Could not register file "%1$s" as a block pattern (invalid slug "%2$s")' ),
						$file,
						$pattern['slug']
					),
					'6.0.0'
				);
			}

			// Title is a required property.
			if ( ! $pattern['title'] ) {
				_doing_it_wrong(
					__FUNCTION__,
					sprintf(
						/* translators: 1: file name. */
						__( 'Could not register file "%s" as a block pattern ("Title" field missing)' ),
						$file
					),
					'6.0.0'
				);
				continue;
			}

			// For properties of type array, parse data as comma-separated.
			foreach ( $properties_to_parse as $property ) {
				if ( ! empty( $pattern[ $property ] ) ) {
					$pattern[ $property ] = array_filter( wp_parse_list( (string) $pattern[ $property ] ) );
				} else {
					unset( $pattern[ $property ] );
				}
			}

			// Parse properties of type int.
			$property = 'viewportWidth';
			if ( ! empty( $pattern[ $property ] ) ) {
				$pattern[ $property ] = (int) $pattern[ $property ];
			} else {
				unset( $pattern[ $property ] );
			}

			// Parse properties of type bool.
			$property = 'inserter';
			if ( ! empty( $pattern[ $property ] ) ) {
				$pattern[ $property ] = in_array(
					strtolower( $pattern[ $property ] ),
					array( 'yes', 'true' ),
					true
				);
			} else {
				unset( $pattern[ $property ] );
			}

			$key = str_replace( $dirpath, '', $file );

			$pattern_data[ $key ] = $pattern;
		}

		if ( $can_use_cached ) {
			$this->set_pattern_cache( $pattern_data );
		}

		return $pattern_data;
	}

	/**
	 * Gets block pattern cache.
	 *
	 * @since 6.4.0
	 * @since 6.6.0 Uses transients to cache regardless of site environment.
	 *
	 * @return array|false Returns an array of patterns if cache is found, otherwise false.
	 */
	private function get_pattern_cache() {
		if ( ! $this->exists() ) {
			return false;
		}

		$pattern_data = get_site_transient( 'wp_theme_files_patterns-' . $this->cache_hash );

		if ( is_array( $pattern_data ) && $pattern_data['version'] === $this->get( 'Version' ) ) {
			return $pattern_data['patterns'];
		}
		return false;
	}

	/**
	 * Sets block pattern cache.
	 *
	 * @since 6.4.0
	 * @since 6.6.0 Uses transients to cache regardless of site environment.
	 *
	 * @param array $patterns Block patterns data to set in cache.
	 */
	private function set_pattern_cache( array $patterns ) {
		$pattern_data = array(
			'version'  => $this->get( 'Version' ),
			'patterns' => $patterns,
		);

		/**
		 * Filters the cache expiration time for theme files.
		 *
		 * @since 6.6.0
		 *
		 * @param int    $cache_expiration Cache expiration time in seconds.
		 * @param string $cache_type       Type of cache being set.
		 */
		$cache_expiration = (int) apply_filters( 'wp_theme_files_cache_ttl', self::$cache_expiration, 'theme_block_patterns' );

		// We don't want to cache patterns infinitely.
		if ( $cache_expiration <= 0 ) {
			_doing_it_wrong(
				__METHOD__,
				sprintf(
					/* translators: %1$s: The filter name.*/
					__( 'The %1$s filter must return an integer value greater than 0.' ),
					'<code>wp_theme_files_cache_ttl</code>'
				),
				'6.6.0'
			);

			$cache_expiration = self::$cache_expiration;
		}

		set_site_transient( 'wp_theme_files_patterns-' . $this->cache_hash, $pattern_data, $cache_expiration );
	}

	/**
	 * Clears block pattern cache.
	 *
	 * @since 6.4.0
	 * @since 6.6.0 Uses transients to cache regardless of site environment.
	 */
	public function delete_pattern_cache() {
		delete_site_transient( 'wp_theme_files_patterns-' . $this->cache_hash );
	}

	/**
	 * Enables a theme for all sites on the current network.
	 *
	 * @since 4.6.0
	 *
	 * @param string|string[] $stylesheets Stylesheet name or array of stylesheet names.
	 */
	public static function network_enable_theme( $stylesheets ) {
		if ( ! is_multisite() ) {
			return;
		}

		if ( ! is_array( $stylesheets ) ) {
			$stylesheets = array( $stylesheets );
		}

		$allowed_themes = get_site_option( 'allowedthemes' );
		foreach ( $stylesheets as $stylesheet ) {
			$allowed_themes[ $stylesheet ] = true;
		}

		update_site_option( 'allowedthemes', $allowed_themes );
	}

	/**
	 * Disables a theme for all sites on the current network.
	 *
	 * @since 4.6.0
	 *
	 * @param string|string[] $stylesheets Stylesheet name or array of stylesheet names.
	 */
	public static function network_disable_theme( $stylesheets ) {
		if ( ! is_multisite() ) {
			return;
		}

		if ( ! is_array( $stylesheets ) ) {
			$stylesheets = array( $stylesheets );
		}

		$allowed_themes = get_site_option( 'allowedthemes' );
		foreach ( $stylesheets as $stylesheet ) {
			if ( isset( $allowed_themes[ $stylesheet ] ) ) {
				unset( $allowed_themes[ $stylesheet ] );
			}
		}

		update_site_option( 'allowedthemes', $allowed_themes );
	}

	/**
	 * Sorts themes by name.
	 *
	 * @since 3.4.0
	 *
	 * @param WP_Theme[] $themes Array of theme objects to sort (passed by reference).
	 */
	public static function sort_by_name( &$themes ) {
		if ( str_starts_with( get_user_locale(), 'en_' ) ) {
			uasort( $themes, array( 'WP_Theme', '_name_sort' ) );
		} else {
			foreach ( $themes as $key => $theme ) {
				$theme->translate_header( 'Name', $theme->headers['Name'] );
			}
			uasort( $themes, array( 'WP_Theme', '_name_sort_i18n' ) );
		}
	}

	/**
	 * Callback function for usort() to naturally sort themes by name.
	 *
	 * Accesses the Name header directly from the class for maximum speed.
	 * Would choke on HTML but we don't care enough to slow it down with strip_tags().
	 *
	 * @since 3.4.0
	 *
	 * @param WP_Theme $a First theme.
	 * @param WP_Theme $b Second theme.
	 * @return int Negative if `$a` falls lower in the natural order than `$b`. Zero if they fall equally.
	 *             Greater than 0 if `$a` falls higher in the natural order than `$b`. Used with usort().
	 */
	private static function _name_sort( $a, $b ) {
		return strnatcasecmp( $a->headers['Name'], $b->headers['Name'] );
	}

	/**
	 * Callback function for usort() to naturally sort themes by translated name.
	 *
	 * @since 3.4.0
	 *
	 * @param WP_Theme $a First theme.
	 * @param WP_Theme $b Second theme.
	 * @return int Negative if `$a` falls lower in the natural order than `$b`. Zero if they fall equally.
	 *             Greater than 0 if `$a` falls higher in the natural order than `$b`. Used with usort().
	 */
	private static function _name_sort_i18n( $a, $b ) {
		return strnatcasecmp( $a->name_translated, $b->name_translated );
	}

	private static function _check_headers_property_has_correct_type( $headers ) {
		if ( ! is_array( $headers ) ) {
			return false;
		}
		foreach ( $headers as $key => $value ) {
			if ( ! is_string( $key ) || ! is_string( $value ) ) {
				return false;
			}
		}
		return true;
	}
}