<?php
/**
 * Block theme integration.
 *
 * @package HeadFoot
 */

namespace HeadFoot\Compat;

use HeadFoot\Kses;

defined( 'ABSPATH' ) || exit;

/**
 * Replaces the header and footer template parts of a block theme.
 *
 * The sections print next to the template parts, whether or not a plugin
 * header or footer replaces the part.
 *
 * Block themes do not call get_header(). They render a core/template-part
 * block with the slug header or footer. The filter matches on the slug,
 * because the area attribute is not always present.
 */
class Block_Theme {

	/**
	 * Adds the hooks.
	 */
	public function __construct() {
		add_filter( 'render_block_core/template-part', [ $this, 'replace_part' ], 10, 2 );
	}

	/**
	 * Returns the map from template part slug to location.
	 *
	 * @return array slug => header or footer
	 */
	public static function get_slug_map() {
		/**
		 * Filters the map from template part slugs to locations.
		 *
		 * @param array $map slug => header or footer.
		 */
		$map = apply_filters(
			'headfoot_block_template_part_slugs',
			[
				'header' => 'header',
				'footer' => 'footer',
			]
		);

		return is_array( $map ) ? $map : [];
	}

	/**
	 * Swaps a template part for the plugin template that matches the request.
	 *
	 * @param string $html  Rendered block.
	 * @param array  $block Parsed block.
	 * @return string
	 */
	public function replace_part( $html, $block ) {
		$slug = isset( $block['attrs']['slug'] ) ? (string) $block['attrs']['slug'] : '';

		if ( '' === $slug ) {
			return $html;
		}

		$map = self::get_slug_map();

		if ( ! isset( $map[ $slug ] ) ) {
			return $html;
		}

		if ( 'header' === $map[ $slug ] ) {
			// The header area carries the below header section.
			return headfoot_header_enabled() ? Kses::filter( headfoot_get_header_html() ) : $html . Kses::filter( headfoot_get_below_header_html() );
		}

		if ( 'footer' === $map[ $slug ] ) {
			// The footer area carries the above footer section.
			return headfoot_footer_enabled() ? Kses::filter( headfoot_get_footer_html() ) : Kses::filter( headfoot_get_above_footer_html() ) . $html;
		}

		return $html;
	}
}