->pagination_base );

				// Adds rules for the uppercase encoded URIs.
				$category_nicename_filtered = $this->convert_encoded_to_upper( $category_nicename );

				if ( $category_nicename_filtered !== $category_nicename ) {
					$category_rewrite = $this->add_category_rewrites( $category_rewrite, $category_nicename_filtered, $blog_prefix, $wp_rewrite->pagination_base );
				}
			}
			unset( $categories, $category, $category_nicename, $category_nicename_filtered );
		}

		// Redirect support from Old Category Base.
		$old_base                            = $wp_rewrite->get_category_permastruct();
		$old_base                            = str_replace( '%category%', '(.+)', $old_base );
		$old_base                            = trim( $old_base, '/' );
		$category_rewrite[ $old_base . '$' ] = 'index.php?wpseo_category_redirect=$matches[1]';

		return $category_rewrite;
	}

	/**
	 * Adds required category rewrites rules.
	 *
	 * @param array  $rewrites        The current set of rules.
	 * @param string $category_name   Category nicename.
	 * @param string $blog_prefix     Multisite blog prefix.
	 * @param string $pagination_base WP_Query pagination base.
	 *
	 * @return array The added set of rules.
	 */
	protected function add_category_rewrites( $rewrites, $category_name, $blog_prefix, $pagination_base ) {
		$rewrite_name = $blog_prefix . '(' . $category_name . ')';

		$rewrites[ $rewrite_name . '/(?:feed/)?(feed|rdf|rss|rss2|atom)/?$' ]    = 'index.php?category_name=$matches[1]&feed=$matches[2]';
		$rewrites[ $rewrite_name . '/' . $pagination_base . '/?([0-9]{1,})/?$' ] = 'index.php?category_name=$matches[1]&paged=$matches[2]';
		$rewrites[ $rewrite_name . '/?$' ]                                       = 'index.php?category_name=$matches[1]';

		return $rewrites;
	}

	/**
	 * Walks through category nicename and convert encoded parts
	 * into uppercase using $this->encode_to_upper().
	 *
	 * @param string $name The encoded category URI string.
	 *
	 * @return string The convered URI string.
	 */
	protected function convert_encoded_to_upper( $name ) {
		// Checks if name has any encoding in it.
		if ( strpos( $name, '%' ) === false ) {
			return $name;
		}

		$names = explode( '/', $name );
		$names = array_map( [ $this, 'encode_to_upper' ], $names );

		return implode( '/', $names );
	}

	/**
	 * Converts the encoded URI string to uppercase.
	 *
	 * @param string $encoded The encoded string.
	 *
	 * @return string The uppercased string.
	 */
	public function encode_to_upper( $encoded ) {
		if ( strpos( $encoded, '%' ) === false ) {
			return $encoded;
		}

		return strtoupper( $encoded );
	}

	/**
	 * Redirect the "old" category URL to the new one.
	 *
	 * @codeCoverageIgnore
	 *
	 * @param string $category_redirect The category page to redirect to.
	 * @return void
	 */
	protected function redirect( $category_redirect ) {
		$catlink = trailingslashit( get_option( 'home' ) ) . user_trailingslashit( $category_redirect, 'category' );

		wp_safe_redirect( $catlink, 301, 'Yoast SEO' );
		exit;
	}
}