efaults to the result of wp_allowed_protocols().
 * @param array           $block_context     Optional. The block the attribute belongs to, in parsed block array format.
 * @return string[]|string The filtered and sanitized result.
 */
function filter_block_kses_value( $value, $allowed_html, $allowed_protocols = array(), $block_context = null ) {
	if ( is_array( $value ) ) {
		foreach ( $value as $key => $inner_value ) {
			$filtered_key   = filter_block_kses_value( $key, $allowed_html, $allowed_protocols, $block_context );
			$filtered_value = filter_block_kses_value( $inner_value, $allowed_html, $allowed_protocols, $block_context );

			if ( isset( $block_context['blockName'] ) && 'core/template-part' === $block_context['blockName'] ) {
				$filtered_value = filter_block_core_template_part_attributes( $filtered_value, $filtered_key, $allowed_html );
			}

			if ( $filtered_key !== $key ) {
				unset( $value[ $key ] );
			}

			$value[ $filtered_key ] = $filtered_value;
		}
	} elseif ( is_string( $value ) ) {
		return wp_kses( $value, $allowed_html, $allowed_protocols );
	}

	return $value;
}

/**
 * Sanitizes the value of the Template Part block's `tagName` attribute.
 *
 * @since 6.5.5
 *
 * @param string          $attribute_value   The attribute value to filter.
 * @param string          $attribute_name    The attribute name.
 * @param array[]|string  $allowed_html      An array of allowed HTML elements and attributes,
 *                                           or a context name such as 'post'. See wp_kses_allowed_html()
 *                                           for the list of accepted context names.
 * @return string The sanitized attribute value.
 */
function filter_block_core_template_part_attributes( $attribute_value, $attribute_name, $allowed_html ) {
	if ( empty( $attribute_value ) || 'tagName' !== $attribute_name ) {
		return $attribute_value;
	}
	if ( ! is_array( $allowed_html ) ) {
		$allowed_html = wp_kses_allowed_html( $allowed_html );
	}
	return isset( $allowed_html[ $attribute_value ] ) ? $attribute_value : '';
}

/**
 * Parses blocks out of a content string, and renders those appropriate for the excerpt.
 *
 * As the excerpt should be a small string of text relevant to the full post content,
 * this function renders the blocks that are most likely to contain such text.
 *
 * @since 5.0.0
 *
 * @param string $content The content to parse.
 * @return string The parsed and filtered content.
 */
function excerpt_remove_blocks( $content ) {
	if ( ! has_blocks( $content ) ) {
		return $content;
	}

	$allowed_inner_blocks = array(
		// Classic blocks have their blockName set to null.
		null,
		'core/freeform',
		'core/heading',
		'core/html',
		'core/list',
		'core/media-text',
		'core/paragraph',
		'core/preformatted',
		'core/pullquote',
		'core/quote',
		'core/table',
		'core/verse',
	);

	$allowed_wrapper_blocks = array(
		'core/columns',
		'core/column',
		'core/group',
	);

	/**
	 * Filters the list of blocks that can be used as wrapper blocks, allowing
	 * excerpts to be generated from the `innerBlocks` of these wrappers.
	 *
	 * @since 5.8.0
	 *
	 * @param string[] $allowed_wrapper_blocks The list of names of allowed wrapper blocks.
	 */
	$allowed_wrapper_blocks = apply_filters( 'excerpt_allowed_wrapper_blocks', $allowed_wrapper_blocks );

	$allowed_blocks = array_merge( $allowed_inner_blocks, $allowed_wrapper_blocks );

	/**
	 * Filters the list of blocks that can contribute to the excerpt.
	 *
	 * If a dynamic block is added to this list, it must not generate another
	 * excerpt, as this will cause an infinite loop to occur.
	 *
	 * @since 5.0.0
	 *
	 * @param string[] $allowed_blocks The list of names of allowed blocks.
	 */
	$allowed_blocks = apply_filters( 'excerpt_allowed_blocks', $allowed_blocks );
	$blocks         = parse_blocks( $content );
	$output         = '';

	foreach ( $blocks as $block ) {
		if ( in_array( $block['blockName'], $allowed_blocks, true ) ) {
			if ( ! empty( $block['innerBlocks'] ) ) {
				if ( in_array( $block['blockName'], $allowed_wrapper_blocks, true ) ) {
					$output .= _excerpt_render_inner_blocks( $block, $allowed_blocks );
					continue;
				}

				// Skip the block if it has disallowed or nested inner blocks.
				foreach ( $block['innerBlocks'] as $inner_block ) {
					if (
						! in_array( $inner_block['blockName'], $allowed_inner_blocks, true ) ||
						! empty( $inner_block['innerBlocks'] )
					) {
						continue 2;
					}
				}
			}

			$output .= render_block( $block );
		}
	}

	return $output;
}

/**
 * Parses footnotes markup out of a content string,
 * and renders those appropriate for the excerpt.
 *
 * @since 6.3.0
 *
 * @param string $content The content to parse.
 * @return string The parsed and filtered content.
 */
function excerpt_remove_footnotes( $content ) {
	if ( ! str_contains( $content, 'data-fn=' ) ) {
		return $content;
	}

	return preg_replace(
		'_<sup data-fn="[^"]+" class="[^"]+">\s*<a href="[^"]+" id="[^"]+">\d+</a>\s*</sup>_',
		'',
		$content
	);
}

/**
 * Renders inner blocks from the allowed wrapper blocks
 * for generating an excerpt.
 *
 * @since 5.8.0
 * @access private
 *
 * @param array $parsed_block   The parsed block.
 * @param array $allowed_blocks The list of allowed inner blocks.
 * @return string The rendered inner blocks.
 */
function _excerpt_render_inner_blocks( $parsed_block, $allowed_blocks ) {
	$output = '';

	foreach ( $parsed_block['innerBlocks'] as $inner_block ) {
		if ( ! in_array( $inner_block['blockName'], $allowed_blocks, true ) ) {
			continue;
		}

		if ( empty( $inner_block['innerBlocks'] ) ) {
			$output .= render_block( $inner_block );
		} else {
			$output .= _excerpt_render_inner_blocks( $inner_block, $allowed_blocks );
		}
	}

	return $output;
}

/**
 * Renders a single block into a HTML string.
 *
 * @since 5.0.0
 *
 * @global WP_Post $post The post to edit.
 *
 * @param array $parsed_block A single parsed block object.
 * @return string String of rendered HTML.
 */
function render_block( $parsed_block ) {
	global $post;
	$parent_block = null;

	/**
	 * Allows render_block() to be short-circuited, by returning a non-null value.
	 *
	 * @since 5.1.0
	 * @since 5.9.0 The `$parent_block` parameter was added.
	 *
	 * @param string|null   $pre_render   The pre-rendered content. Default null.
	 * @param array         $parsed_block The block being rendered.
	 * @param WP_Block|null $parent_block If this is a nested block, a reference to the parent block.
	 */
	$pre_render = apply_filters( 'pre_render_block', null, $parsed_block, $parent_block );
	if ( ! is_null( $pre_render ) ) {
		return $pre_render;
	}

	$source_block = $parsed_block;

	/**
	 * Filters the block being rendered in render_block(), before it's processed.
	 *
	 * @since 5.1.0
	 * @since 5.9.0 The `$parent_block` parameter was added.
	 *
	 * @param array         $parsed_block The block being rendered.
	 * @param array         $source_block An un-modified copy of $parsed_block, as it appeared in the source content.
	 * @param WP_Block|null $parent_block If this is a nested block, a reference to the parent block.
	 */
	$parsed_block = apply_filters( 'render_block_data', $parsed_block, $source_block, $parent_block );

	$context = array();

	if ( $post instanceof WP_Post ) {
		$context['postId'] = $post->ID;

		/*
		 * The `postType` context is largely unnecessary server-side, since the ID
		 * is usually sufficient on its own. That being said, since a block's
		 * manifest is expected to be shared between the server and the client,
		 * it should be included to consistently fulfill the expectation.
		 */
		$context['postType'] = $post->post_type;
	}

	/**
	 * Filters the default context provided to a rendered block.
	 *
	 * @since 5.5.0
	 * @since 5.9.0 The `$parent_block` parameter was added.
	 *
	 * @param array         $context      Default context.
	 * @param array         $parsed_block Block being rendered, filtered by `render_block_data`.
	 * @param WP_Block|null $parent_block If this is a nested block, a reference to the parent block.
	 */
	$context = apply_filters( 'render_block_context', $context, $parsed_block, $parent_block );

	$block = new WP_Block( $parsed_block, $context );

	return $block->render();
}

/**
 * Parses blocks out of a content string.
 *
 * @since 5.0.0
 *
 * @param string $content Post content.
 * @return array[] Array of parsed block objects.
 */
function parse_blocks( $content ) {
	/**
	 * Filter to allow plugins to replace the server-side block parser.
	 *
	 * @since 5.0.0
	 *
	 * @param string $parser_class Name of block parser class.
	 */
	$parser_class = apply_filters( 'block_parser_class', 'WP_Block_Parser' );

	$parser = new $parser_class();
	return $parser->parse( $content );
}

/**
 * Parses dynamic blocks out of `post_content` and re-renders them.
 *
 * @since 5.0.0
 *
 * @param string $content Post content.
 * @return string Updated post content.
 */
function do_blocks( $content ) {
	$blocks = parse_blocks( $content );
	$output = '';

	foreach ( $blocks as $block ) {
		$output .= render_block( $block );
	}

	// If there are blocks in this content, we shouldn't run wpautop() on it later.
	$priority = has_filter( 'the_content', 'wpautop' );
	if ( false !== $priority && doing_filter( 'the_content' ) && has_blocks( $content ) ) {
		remove_filter( 'the_content', 'wpautop', $priority );
		add_filter( 'the_content', '_restore_wpautop_hook', $priority + 1 );
	}

	return $output;
}

/**
 * If do_blocks() needs to remove wpautop() from the `the_content` filter, this re-adds it afterwards,
 * for subsequent `the_content` usage.
 *
 * @since 5.0.0
 * @access private
 *
 * @param string $content The post content running through this filter.
 * @return string The unmodified content.
 */
function _restore_wpautop_hook( $content ) {
	$current_priority = has_filter( 'the_content', '_restore_wpautop_hook' );

	add_filter( 'the_content', 'wpautop', $current_priority - 1 );
	remove_filter( 'the_content', '_restore_wpautop_hook', $current_priority );

	return $content;
}

/**
 * Returns the current version of the block format that the content string is using.
 *
 * If the string doesn't contain blocks, it returns 0.
 *
 * @since 5.0.0
 *
 * @param string $content Content to test.
 * @return int The block format version is 1 if the content contains one or more blocks, 0 otherwise.
 */
function block_version( $content ) {
	return has_blocks( $content ) ? 1 : 0;
}

/**
 * Registers a new block style.
 *
 * @since 5.3.0
 *
 * @link https://developer.wordpress.org/block-editor/reference-guides/block-api/block-styles/
 *
 * @param string $block_name       Block type name including namespace.
 * @param array  $style_properties Array containing the properties of the style name, label,
 *                                 style_handle (name of the stylesheet to be enqueued),
 *                                 inline_style (string containing the CSS to be added).
 * @return bool True if the block style was registered with success and false otherwise.
 */
function register_block_style( $block_name, $style_properties ) {
	return WP_Block_Styles_Registry::get_instance()->register( $block_name, $style_properties );
}

/**
 * Unregisters a block style.
 *
 * @since 5.3.0
 *
 * @param string $block_name       Block type name including namespace.
 * @param string $block_style_name Block style name.
 * @return bool True if the block style was unregistered with success and false otherwise.
 */
function unregister_block_style( $block_name, $block_style_name ) {
	return WP_Block_Styles_Registry::get_instance()->unregister( $block_name, $block_style_name );
}

/**
 * Checks whether the current block type supports the feature requested.
 *
 * @since 5.8.0
 * @since 6.4.0 The `$feature` parameter now supports a string.
 *
 * @param WP_Block_Type $block_type    Block type to check for support.
 * @param string|array  $feature       Feature slug, or path to a specific feature to check support for.
 * @param mixed         $default_value Optional. Fallback value for feature support. Default false.
 * @return bool Whether the feature is supported.
 */
function block_has_support( $block_type, $feature, $default_value = false ) {
	$block_support = $default_value;
	if ( $block_type instanceof WP_Block_Type ) {
		if ( is_array( $feature ) && count( $feature ) === 1 ) {
			$feature = $feature[0];
		}

		if ( is_array( $feature ) ) {
			$block_support = _wp_array_get( $block_type->supports, $feature, $default_value );
		} elseif ( isset( $block_type->supports[ $feature ] ) ) {
			$block_support = $block_type->supports[ $feature ];
		}
	}

	return true === $block_support || is_array( $block_support );
}

/**
 * Converts typography keys declared under `supports.*` to `supports.typography.*`.
 *
 * Displays a `_doing_it_wrong()` notice when a block using the older format is detected.
 *
 * @since 5.8.0
 *
 * @param array $metadata Metadata for registering a block type.
 * @return array Filtered metadata for registering a block type.
 */
function wp_migrate_old_typography_shape( $metadata ) {
	if ( ! isset( $metadata['supports'] ) ) {
		return $metadata;
	}

	$typography_keys = array(
		'__experimentalFontFamily',
		'__experimentalFontStyle',
		'__experimentalFontWeight',
		'__experimentalLetterSpacing',
		'__experimentalTextDecoration',
		'__experimentalTextTransform',
		'fontSize',
		'lineHeight',
	);

	foreach ( $typography_keys as $typography_key ) {
		$support_for_key = isset( $metadata['supports'][ $typography_key ] ) ? $metadata['supports'][ $typography_key ] : null;

		if ( null !== $support_for_key ) {
			_doing_it_wrong(
				'register_block_type_from_metadata()',
				sprintf(
					/* translators: 1: Block type, 2: Typography supports key, e.g: fontSize, lineHeight, etc. 3: block.json, 4: Old metadata key, 5: New metadata key. */
					__( 'Block "%1$s" is declaring %2$s support in %3$s file under %4$s. %2$s support is now declared under %5$s.' ),
					$metadata['name'],
					"<code>$typography_key</code>",
					'<code>block.json</code>',
					"<code>supports.$typography_key</code>",
					"<code>supports.typography.$typography_key</code>"
				),
				'5.8.0'
			);

			_wp_array_set( $metadata['supports'], array( 'typography', $typography_key ), $support_for_key );
			unset( $metadata['supports'][ $typography_key ] );
		}
	}

	return $metadata;
}

/**
 * Helper function that constructs a WP_Query args array from
 * a `Query` block properties.
 *
 * It's used in Query Loop, Query Pagination Numbers and Query Pagination Next blocks.
 *
 * @since 5.8.0
 * @since 6.1.0 Added `query_loop_block_query_vars` filter and `parents` support in query.
 *
 * @param WP_Block $block Block instance.
 * @param int      $page  Current query's page.
 *
 * @return array Returns the constructed WP_Query arguments.
 */
function build_query_vars_from_query_block( $block, $page ) {
	$query = array(
		'post_type'    => 'post',
		'order'        => 'DESC',
		'orderby'      => 'date',
		'post__not_in' => array(),
	);

	if ( isset( $block->context['query'] ) ) {
		if ( ! empty( $block->context['query']['postType'] ) ) {
			$post_type_param = $block->context['query']['postType'];
			if ( is_post_type_viewable( $post_type_param ) ) {
				$query['post_type'] = $post_type_param;
			}
		}
		if ( isset( $block->context['query']['sticky'] ) && ! empty( $block->context['query']['sticky'] ) ) {
			$sticky = get_option( 'sticky_posts' );
			if ( 'only' === $block->context['query']['sticky'] ) {
				/*
				 * Passing an empty array to post__in will return have_posts() as true (and all posts will be returned).
				 * Logic should be used before hand to determine if WP_Query should be used in the event that the array
				 * being passed to post__in is empty.
				 *
				 * @see https://core.trac.wordpress.org/ticket/28099
				 */
				$query['post__in']            = ! empty( $sticky ) ? $sticky : array( 0 );
				$query['ignore_sticky_posts'] = 1;
			} else {
				$query['post__not_in'] = array_merge( $query['post__not_in'], $sticky );
			}
		}
		if ( ! empty( $block->context['query']['exclude'] ) ) {
			$excluded_post_ids     = array_map( 'intval', $block->context['query']['exclude'] );
			$excluded_post_ids     = array_filter( $excluded_post_ids );
			$query['post__not_in'] = array_merge( $query['post__not_in'], $excluded_post_ids );
		}
		if (
			isset( $block->context['query']['perPage'] ) &&
			is_numeric( $block->context['query']['perPage'] )
		) {
			$per_page = absint( $block->context['query']['perPage'] );
			$offset   = 0;

			if (
				isset( $block->context['query']['offset'] ) &&
				is_numeric( $block->context['query']['offset'] )
			) {
				$offset = absint( $block->context['query']['offset'] );
			}

			$query['offset']         = ( $per_page * ( $page - 1 ) ) + $offset;
			$query['posts_per_page'] = $per_page;
		}
		// Migrate `categoryIds` and `tagIds` to `tax_query` for backwards compatibility.
		if ( ! empty( $block->context['query']['categoryIds'] ) || ! empty( $block->context['query']['tagIds'] ) ) {
			$tax_query = array();
			if ( ! empty( $block->context['query']['categoryIds'] ) ) {
				$tax_query[] = array(
					'taxonomy'         => 'category',
					'terms'            => array_filter( array_map( 'intval', $block->context['query']['categoryIds'] ) ),
					'include_children' => false,
				);
			}
			if ( ! empty( $block->context['query']['tagIds'] ) ) {
				$tax_query[] = array(
					'taxonomy'         => 'post_tag',
					'terms'            => array_filter( array_map( 'intval', $block->context['query']['tagIds'] ) ),
					'include_children' => false,
				);
			}
			$query['tax_query'] = $tax_query;
		}
		if ( ! empty( $block->context['query']['taxQuery'] ) ) {
			$query['tax_query'] = array();
			foreach ( $block->context['query']['taxQuery'] as $taxonomy => $terms ) {
				if ( is_taxonomy_viewable( $taxonomy ) && ! empty( $terms ) ) {
					$query['tax_query'][] = array(
						'taxonomy'         => $taxonomy,
						'terms'            => array_filter( array_map( 'intval', $terms ) ),
						'include_children' => false,
					);
				}
			}
		}
		if (
			isset( $block->context['query']['order'] ) &&
				in_array( strtoupper( $block->context['query']['order'] ), array( 'ASC', 'DESC' ), true )
		) {
			$query['order'] = strtoupper( $block->context['query']['order'] );
		}
		if ( isset( $block->context['query']['orderBy'] ) ) {
			$query['orderby'] = $block->context['query']['orderBy'];
		}
		if (
			isset( $block->context['query']['author'] )
		) {
			if ( is_array( $block->context['query']['author'] ) ) {
				$query['author__in'] = array_filter( array_map( 'intval', $block->context['query']['author'] ) );
			} elseif ( is_string( $block->context['query']['author'] ) ) {
				$query['author__in'] = array_filter( array_map( 'intval', explode( ',', $block->context['query']['author'] ) ) );
			} elseif ( is_int( $block->context['query']['author'] ) && $block->context['query']['author'] > 0 ) {
				$query['author'] = $block->context['query']['author'];
			}
		}
		if ( ! empty( $block->context['query']['search'] ) ) {
			$query['s'] = $block->context['query']['search'];
		}
		if ( ! empty( $block->context['query']['parents'] ) && is_post_type_hierarchical( $query['post_type'] ) ) {
			$query['post_parent__in'] = array_filter( array_map( 'intval', $block->context['query']['parents'] ) );
		}
	}

	/**
	 * Filters the arguments which will be passed to `WP_Query` for the Query Loop Block.
	 *
	 * Anything to this filter should be compatible with the `WP_Query` API to form
	 * the query context which will be passed down to the Query Loop Block's children.
	 * This can help, for example, to include additional settings or meta queries not
	 * directly supported by the core Query Loop Block, and extend its capabilities.
	 *
	 * Please note that this will only influence the query that will be rendered on the
	 * front-end. The editor preview is not affected by this filter. Also, worth noting
	 * that the editor preview uses the REST API, so, ideally, one should aim to provide
	 * attributes which are also compatible with the REST API, in order to be able to
	 * implement identical queries on both sides.
	 *
	 * @since 6.1.0
	 *
	 * @param array    $query Array containing parameters for `WP_Query` as parsed by the block context.
	 * @param WP_Block $block Block instance.
	 * @param int      $page  Current query's page.
	 */
	return apply_filters( 'query_loop_block_query_vars', $query, $block, $page );
}

/**
 * Helper function that returns the proper pagination arrow HTML for
 * `QueryPaginationNext` and `QueryPaginationPrevious` blocks based
 * on the provided `paginationArrow` from `QueryPagination` context.
 *
 * It's used in QueryPaginationNext and QueryPaginationPrevious blocks.
 *
 * @since 5.9.0
 *
 * @param WP_Block $block   Block instance.
 * @param bool     $is_next Flag for handling `next/previous` blocks.
 * @return string|null The pagination arrow HTML or null if there is none.
 */
function get_query_pagination_arrow( $block, $is_next ) {
	$arrow_map = array(
		'none'    => '',
		'arrow'   => array(
			'next'     => '→',
			'previous' => '←',
		),
		'chevron' => array(
			'next'     => '»',
			'previous' => '«',
		),
	);
	if ( ! empty( $block->context['paginationArrow'] ) && array_key_exists( $block->context['paginationArrow'], $arrow_map ) && ! empty( $arrow_map[ $block->context['paginationArrow'] ] ) ) {
		$pagination_type = $is_next ? 'next' : 'previous';
		$arrow_attribute = $block->context['paginationArrow'];
		$arrow           = $arrow_map[ $block->context['paginationArrow'] ][ $pagination_type ];
		$arrow_classes   = "wp-block-query-pagination-$pagination_type-arrow is-arrow-$arrow_attribute";
		return "<span class='$arrow_classes' aria-hidden='true'>$arrow</span>";
	}
	return null;
}

/**
 * Helper function that constructs a comment query vars array from the passed
 * block properties.
 *
 * It's used with the Comment Query Loop inner blocks.
 *
 * @since 6.0.0
 *
 * @param WP_Block $block Block instance.
 * @return array Returns the comment query parameters to use with the
 *               WP_Comment_Query constructor.
 */
function build_comment_query_vars_from_block( $block ) {

	$comment_args = array(
		'orderby'       => 'comment_date_gmt',
		'order'         => 'ASC',
		'status'        => 'approve',
		'no_found_rows' => false,
	);

	if ( is_user_logged_in() ) {
		$comment_args['include_unapproved'] = array( get_current_user_id() );
	} else {
		$unapproved_email = wp_get_unapproved_comment_author_email();

		if ( $unapproved_email ) {
			$comment_args['include_unapproved'] = array( $unapproved_email );
		}
	}

	if ( ! empty( $block->context['postId'] ) ) {
		$comment_args['post_id'] = (int) $block->context['postId'];
	}

	if ( get_option( 'thread_comments' ) ) {
		$comment_args['hierarchical'] = 'threaded';
	} else {
		$comment_args['hierarchical'] = false;
	}

	if ( get_option( 'page_comments' ) === '1' || get_option( 'page_comments' ) === true ) {
		$per_page     = get_option( 'comments_per_page' );
		$default_page = get_option( 'default_comments_page' );
		if ( $per_page > 0 ) {
			$comment_args['number'] = $per_page;

			$page = (int) get_query_var( 'cpage' );
			if ( $page ) {
				$comment_args['paged'] = $page;
			} elseif ( 'oldest' === $default_page ) {
				$comment_args['paged'] = 1;
			} elseif ( 'newest' === $default_page ) {
				$max_num_pages = (int) ( new WP_Comment_Query( $comment_args ) )->max_num_pages;
				if ( 0 !== $max_num_pages ) {
					$comment_args['paged'] = $max_num_pages;
				}
			}
			// Set the `cpage` query var to ensure the previous and next pagination links are correct
			// when inheriting the Discussion Settings.
			if ( 0 === $page && isset( $comment_args['paged'] ) && $comment_args['paged'] > 0 ) {
				set_query_var( 'cpage', $comment_args['paged'] );
			}
		}
	}

	return $comment_args;
}

/**
 * Helper function that returns the proper pagination arrow HTML for
 * `CommentsPaginationNext` and `CommentsPaginationPrevious` blocks based on the
 * provided `paginationArrow` from `CommentsPagination` context.
 *
 * It's used in CommentsPaginationNext and CommentsPaginationPrevious blocks.
 *
 * @since 6.0.0
 *
 * @param WP_Block $block           Block instance.
 * @param string   $pagination_type Optional. Type of the arrow we will be rendering.
 *                                  Accepts 'next' or 'previous'. Default 'next'.
 * @return string|null The pagination arrow HTML or null if there is none.
 */
function get_comments_pagination_arrow( $block, $pagination_type = 'next' ) {
	$arrow_map = array(
		'none'    => '',
		'arrow'   => array(
			'next'     => '→',
			'previous' => '←',
		),
		'chevron' => array(
			'next'     => '»',
			'previous' => '«',
		),
	);
	if ( ! empty( $block->context['comments/paginationArrow'] ) && ! empty( $arrow_map[ $block->context['comments/paginationArrow'] ][ $pagination_type ] ) ) {
		$arrow_attribute = $block->context['comments/paginationArrow'];
		$arrow           = $arrow_map[ $block->context['comments/paginationArrow'] ][ $pagination_type ];
		$arrow_classes   = "wp-block-comments-pagination-$pagination_type-arrow is-arrow-$arrow_attribute";
		return "<span class='$arrow_classes' aria-hidden='true'>$arrow</span>";
	}
	return null;
}

/**
 * Strips all HTML from the content of footnotes, and sanitizes the ID.
 * This function expects slashed data on the footnotes content.
 *
 * @access private
 * @since 6.3.2
 *
 * @param string $footnotes JSON encoded string of an array containing the content and ID of each footnote.
 * @return string Filtered content without any HTML on the footnote content and with the sanitized id.
 */
function _wp_filter_post_meta_footnotes( $footnotes ) {
	$footnotes_decoded   = json_decode( $footnotes, true );
	if ( ! is_array( $footnotes_decoded ) ) {
		return '';
	}
	$footnotes_sanitized = array();
	foreach ( $footnotes_decoded as $footnote ) {
		if ( ! empty( $footnote['content'] ) && ! empty( $footnote['id'] ) ) {
			$footnotes_sanitized[] = array(
				'id'      => sanitize_key( $footnote['id'] ),
				'content' => wp_unslash( wp_filter_post_kses( wp_slash( $footnote['content'] ) ) ),
			);
		}
	}
	return wp_json_encode( $footnotes_sanitized );
}

/**
 * Adds the filters to filter footnotes meta field.
 *
 * @access private
 * @since 6.3.2
 */
function _wp_footnotes_kses_init_filters() {
	add_filter( 'sanitize_post_meta_footnotes', '_wp_filter_post_meta_footnotes' );
}

/**
 * Removes the filters that filter footnotes meta field.
 *
 * @access private
 * @since 6.3.2
 */
function _wp_footnotes_remove_filters() {
	remove_filter( 'sanitize_post_meta_footnotes', '_wp_filter_post_meta_footnotes' );
}

/**
 * Registers the filter of footnotes meta field if the user does not have unfiltered_html capability.
 *
 * @access private
 * @since 6.3.2
 */
function _wp_footnotes_kses_init() {
	_wp_footnotes_remove_filters();
	if ( ! current_user_can( 'unfiltered_html' ) ) {
		_wp_footnotes_kses_init_filters();
	}
}

/**
 * Initializes footnotes meta field filters when imported data should be filtered.
 *
 * This filter is the last being executed on force_filtered_html_on_import.
 * If the input of the filter is true it means we are in an import situation and should
 * enable kses, independently of the user capabilities.
 * So in that case we call _wp_footnotes_kses_init_filters;
 *
 * @access private
 * @since 6.3.2
 *
 * @param string $arg Input argument of the filter.
 * @return string Input argument of the filter.
 */
function _wp_footnotes_force_filtered_html_on_import_filter( $arg ) {
	// force_filtered_html_on_import is true we need to init the global styles kses filters.
	if ( $arg ) {
		_wp_footnotes_kses_init_filters();
	}
	return $arg;
}