public function add_cdn_url( $url, $original_url = '' ) {
		if ( ! empty( $original_url ) ) {
			if ( $this->cdn->is_excluded( $original_url ) ) {
				return $url;
			}
		}

		return $this->cdn->rewrite_url( $url );
	}

	/**
	 * Replace CDN URL with site URL on the provided asset URL.
	 *
	 * @since 3.5.3
	 *
	 * @param string $url   URL of the asset.
	 * @param array  $zones Array of corresponding zones for the asset.
	 *
	 * @return string
	 */
	public function maybe_replace_url( $url, array $zones = [ 'all' ] ) {
		if ( ! $this->is_allowed() ) {
			return $url;
		}

		$url_parts = get_rocket_parse_url( $url );

		if ( empty( $url_parts['host'] ) ) {
			return $url;
		}

		$site_url_parts = get_rocket_parse_url( site_url() );

		if ( empty( $site_url_parts['host'] ) ) {
			return $url;
		}

		if ( $url_parts['host'] === $site_url_parts['host'] ) {
			return $url;
		}

		$cdn_urls = $this->cdn->get_cdn_urls( $zones );

		if ( empty( $cdn_urls ) ) {
			return $url;
		}

		$cdn_urls = array_map( 'rocket_add_url_protocol', $cdn_urls );

		$site_url = $site_url_parts['scheme'] . '://' . $site_url_parts['host'];

		foreach ( $cdn_urls as $cdn_url ) {
			if ( false === strpos( $url, $cdn_url ) ) {
				continue;
			}

			return str_replace( $cdn_url, $site_url, $url );
		}

		return $url;
	}

	/**
	 * Add a preconnect tag for the CDN.
	 *
	 * @since 3.8.3
	 *
	 * @param array  $urls          The initial array of wp_resource_hint urls.
	 * @param string $relation_type The relation type for the hint: eg., 'preconnect', 'prerender', etc.
	 *
	 * @return array The filtered urls.
	 */
	public function add_preconnect_cdn( array $urls, string $relation_type ): array {
		if (
			'preconnect' !== $relation_type
			||
			rocket_bypass()
			||
			! $this->is_allowed()
			||
			! $this->is_cdn_enabled()
		) {
			return $urls;
		}

		$cdn_urls = $this->cdn->get_cdn_urls( [ 'all', 'images', 'css_and_js', 'css', 'js' ] );

		if ( empty( $cdn_urls ) ) {
			return $urls;
		}

		foreach ( $cdn_urls as $url ) {
			$url_parts = get_rocket_parse_url( $url );

			if ( empty( $url_parts['scheme'] ) ) {
				if ( preg_match( '/^(?![\/])(?=[^\.]+\/).+/i', $url ) ) {
					continue;
				}

				$url       = '//' . $url;
				$url_parts = get_rocket_parse_url( $url );
			}

			$domain = empty( $url_parts['scheme'] )
				? '//' . $url_parts['host']
				: $url_parts['scheme'] . '://' . $url_parts['host'];

			// Note: As of 22 Feb, 2021 we cannot add more than one instance of a domain url
			// on the wp_resource_hint() hook -- wp_resource_hint() will
			// only actually print the first one.
			// Ideally, we want both because CSS resources will use the crossorigin version,
			// But JS resources will not.
			// Jonathan has submitted a ticket to change this behavior:
			// @see https://core.trac.wordpress.org/ticket/52465
			// Until then, we order these to prefer/print the non-crossorigin version.
			$urls[] = [ 'href' => $domain ];
			$urls[] = [
				'href'        => $domain,
				'crossorigin' => 'anonymous',
			];
		}

		return $urls;
	}

	/**
	 * Checks if CDN can be applied
	 *
	 * @since 3.4
	 *
	 * @return boolean
	 */
	private function is_allowed() {
		if ( rocket_get_constant( 'DONOTROCKETOPTIMIZE' ) ) {
			return false;
		}

		if ( ! $this->is_cdn_enabled() ) {
			return false;
		}

		if ( is_rocket_post_excluded_option( 'cdn' ) ) {
			return false;
		}

		return true;
	}

	/**
	 * Checks if the CDN option is enabled
	 *
	 * @since 3.5.5
	 *
	 * @return bool
	 */
	private function is_cdn_enabled() {
		return (bool) $this->options->get( 'cdn', 0 );
	}
}