if ( empty( $resources ) ) {
			return;
		}

		foreach ( $resources as $resource ) {

			if ( 'css' === $type && ! $this->is_valid_stylesheet( $resource[0] ) ) {
				continue;
			}

			if ( 'js' === $type && ! $this->is_valid_script( $resource[0] ) ) {
				continue;
			}

			$external_url = $this->is_external_file( $resource['url'] );
			$path         = $this->get_url_path( $resource['url'], $external_url );

			$this->resources[ $path ] = [
				'url'      => $this->normalize_fullurl( $resource['url'], false ),
				'type'     => $type,
				'path'     => $path,
				'external' => $external_url,
			];

			if ( 'css' === $type ) {
				$this->resources[ $path ]['media'] = $this->get_stylesheet_media( $resource[0] );
			}
		}

	}

	/**
	 * Check that a link element is a stylesheet.
	 *
	 * @since 3.9
	 *
	 * @param string $link The link element to check.
	 *
	 * @return bool True for stylesheet; false for anything else.
	 */
	private function is_valid_stylesheet( string $link ) : bool {
		$valid_rel = $this->find( '(?:rel=[\'"]stylesheet[\'"])', $link, 'is' );
		if ( empty( $valid_rel ) ) {
			return false;
		}

		$exclusions = '';
		foreach ( $this->excluded_stylesheets as $excluded_item ) {
			$exclusions .= preg_quote( $excluded_item, '/' ) . '|';
		}

		$excluded = $this->find( rtrim( $exclusions, '|' ), $link );
		if ( ! empty( $excluded ) ) {
			return false;
		}

		return true;

	}

	/**
	 * Check if script is valid.
	 *
	 * @since 3.9
	 *
	 * @param string $script Script tag to be validated.
	 *
	 * @return bool
	 */
	private function is_valid_script( string $script ) : bool {
		return ! preg_match( '/(application\/ld\+json)|(application\/json)/i', $script );
	}

	/**
	 * Get media attribute from stylesheet.
	 *
	 * @param string $link Link HTML tag.
	 *
	 * @return string
	 */
	private function get_stylesheet_media( string $link ) : string {
		if (
			! preg_match( '/media\s*=\s*[\'"](?<media>.*)[\'"]/iUs', $link, $media_matches )
			||
			! isset( $media_matches['media'] )
		) {
			return 'all';
		}

		return $media_matches['media'];
	}

	/**
	 * Get url file path.
	 *
	 * @param string $url File url.
	 * @param bool   $external_url Is external url (true) or internal (false).
	 *
	 * @return string
	 */
	private function get_url_path( $url, bool $external_url ) : string {
		$file_path = $external_url ? $this->local_cache->get_filepath( $url ) : $this->get_file_path( $url );

		if ( empty( $file_path ) ) {
			Logger::error(
				'Couldn’t get the file path from the URL.',
				[
					'RUCSS warmup process',
					'url' => $url,
				]
			);

			return md5( uniqid() );
		}

		return $file_path;
	}

	/**
	 * Gets the CDN zones.
	 *
	 * @return array
	 */
	public function get_zones() : array {
		return [ 'all', 'css_and_js' ];
	}

	/**
	 * Compress the HTML data before sending it to the resources fetcher
	 *
	 * @since 3.9.2
	 *
	 * @param string $data HTML data.
	 *
	 * @return string
	 */
	public function compress( string $data ): string {
		if ( ! function_exists( 'gzencode' ) ) {
			return $data;
		}

		if ( empty( $data ) ) {
			return '';
		}

		$compressed = gzencode( $data, apply_filters( 'rocket_gzencode_level_compression', 6 ) );

		if ( false === $compressed ) {
			return $data;
		}

		return $compressed;
	}

	/**
	 * Decompress the HTML data received by the resources fetcher
	 *
	 * @since 3.9.2
	 *
	 * @param string $data Compressed HTML data.
	 *
	 * @return string
	 */
	private function decompress( string $data ): string {
		if ( ! function_exists( 'gzdecode' ) ) {
			return $data;
		}

		if ( empty( $data ) ) {
			return '';
		}

		$decompressed = @gzdecode( $data ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged

		if ( false === $decompressed ) {
			return $data;
		}

		return $decompressed;
	}

	/**
	 * Cancel resource fetcher process
	 *
	 * @since 3.10
	 *
	 * @return void
	 */
	public function cancel_resource_fetcher_process() {
		$this->process->cancel_process();
	}
}