<?php



class WP_URL_Pattern_Prefixer {

	
	private $contexts;

	
	public function __construct( array $contexts = array() ) {
		if ( count( $contexts ) > 0 ) {
			$this->contexts = array_map(
				static function ( string $str ): string {
					return self::escape_pattern_string( trailingslashit( $str ) );
				},
				$contexts
			);
		} else {
			$this->contexts = self::get_default_contexts();
		}
	}

	
	public function prefix_path_pattern( string $path_pattern, string $context = 'home' ): string {
		// If context path does not exist, the context is invalid.
		if ( ! isset( $this->contexts[ $context ] ) ) {
			_doing_it_wrong(
				__FUNCTION__,
				esc_html(
					sprintf(
						/* translators: %s: context string */
						__( 'Invalid URL pattern context %s.' ),
						$context
					)
				),
				'6.8.0'
			);
			return $path_pattern;
		}

		/*
		 * In the event that the context path contains a :, ? or # (which can cause the URL pattern parser to switch to
		 * another state, though only the latter two should be percent encoded anyway), it additionally needs to be
		 * enclosed in grouping braces. The final forward slash (trailingslashit ensures there is one) affects the
		 * meaning of the * wildcard, so is left outside the braces.
		 */
		$context_path         = $this->contexts[ $context ];
		$escaped_context_path = $context_path;
		if ( strcspn( $context_path, ':?#' ) !== strlen( $context_path ) ) {
			$escaped_context_path = '{' . substr( $context_path, 0, -1 ) . '}/';
		}

		/*
		 * If the path already starts with the context path (including '/'), remove it first
		 * since it is about to be added back.
		 */
		if ( str_starts_with( $path_pattern, $context_path ) ) {
			$path_pattern = substr( $path_pattern, strlen( $context_path ) );
		}

		return $escaped_context_path . ltrim( $path_pattern, '/' );
	}

	
	public static function get_default_contexts(): array {
		return array(
			'home'       => self::escape_pattern_string( trailingslashit( (string) wp_parse_url( home_url( '/' ), PHP_URL_PATH ) ) ),
			'site'       => self::escape_pattern_string( trailingslashit( (string) wp_parse_url( site_url( '/' ), PHP_URL_PATH ) ) ),
			'uploads'    => self::escape_pattern_string( trailingslashit( (string) wp_parse_url( wp_upload_dir( null, false )['baseurl'], PHP_URL_PATH ) ) ),
			'content'    => self::escape_pattern_string( trailingslashit( (string) wp_parse_url( content_url(), PHP_URL_PATH ) ) ),
			'plugins'    => self::escape_pattern_string( trailingslashit( (string) wp_parse_url( plugins_url(), PHP_URL_PATH ) ) ),
			'template'   => self::escape_pattern_string( trailingslashit( (string) wp_parse_url( get_stylesheet_directory_uri(), PHP_URL_PATH ) ) ),
			'stylesheet' => self::escape_pattern_string( trailingslashit( (string) wp_parse_url( get_template_directory_uri(), PHP_URL_PATH ) ) ),
		);
	}

	
	private static function escape_pattern_string( string $str ): string {
		return addcslashes( $str, '+*?:{}()\\' );
	}
}