<?php

/**

 * Server-side rendering of the `core/gallery` block.

 *

 * @package WordPress

 */

/**

 * Handles backwards compatibility for Gallery Blocks,

 * whose images feature a `data-id` attribute.

 *

 * Now that the Gallery Block contains inner Image Blocks,

 * we add a custom `data-id` attribute before rendering the gallery

 * so that the Image Block can pick it up in its render_callback.

 *

 * @param array $parsed_block The block being rendered.

 * @return array The migrated block object.

 */

function block_core_gallery_data_id_backcompatibility( $parsed_block ) {

	if ( 'core/gallery' === $parsed_block['blockName'] ) {

		foreach ( $parsed_block['innerBlocks'] as $key => $inner_block ) {

			if ( 'core/image' === $inner_block['blockName'] ) {

				if ( ! isset( $parsed_block['innerBlocks'][ $key ]['attrs']['data-id'] ) && isset( $inner_block['attrs']['id'] ) ) {

					$parsed_block['innerBlocks'][ $key ]['attrs']['data-id'] = esc_attr( $inner_block['attrs']['id'] );

				}

			}

		}

	}

	return $parsed_block;

}

add_filter( 'render_block_data', 'block_core_gallery_data_id_backcompatibility' );

/**

 * Adds a style tag for the --wp--style--unstable-gallery-gap var.

 *

 * The Gallery block needs to recalculate Image block width based on

 * the current gap setting in order to maintain the number of flex columns

 * so a css var is added to allow this.

 *

 * @param array  $attributes Attributes of the block being rendered.

 * @param string $content Content of the block being rendered.

 * @return string The content of the block being rendered.

 */

function block_core_gallery_render( $attributes, $content ) {

	$gap = _wp_array_get( $attributes, array( 'style', 'spacing', 'blockGap' ) );

	// Skip if gap value contains unsupported characters.

	// Regex for CSS value borrowed from `safecss_filter_attr`, and used here

	// because we only want to match against the value, not the CSS attribute.

	if ( is_array( $gap ) ) {

		foreach ( $gap as $key => $value ) {

			$gap[ $key ] = $value && preg_match( '%[\\\(&=}]|/\*%', $value ) ? null : $value;

		}

	} else {

		$gap = $gap && preg_match( '%[\\\(&=}]|/\*%', $gap ) ? null : $gap;

	}

	$class   = wp_unique_id( 'wp-block-gallery-' );

	$content = preg_replace(

		'/' . preg_quote( 'class="', '/' ) . '/',

		'class="' . $class . ' ',

		$content,

		1

	);

	// --gallery-block--gutter-size is deprecated. --wp--style--gallery-gap-default should be used by themes that want to set a default

	// gap on the gallery.

	$fallback_gap = 'var( --wp--style--gallery-gap-default, var( --gallery-block--gutter-size, var( --wp--style--block-gap, 0.5em ) ) )';

	$gap_value    = $gap ? $gap : $fallback_gap;

	$gap_column   = $gap_value;

	if ( is_array( $gap_value ) ) {

		$gap_row    = isset( $gap_value['top'] ) ? $gap_value['top'] : $fallback_gap;

		$gap_column = isset( $gap_value['left'] ) ? $gap_value['left'] : $fallback_gap;

		$gap_value  = $gap_row === $gap_column ? $gap_row : $gap_row . ' ' . $gap_column;

	}

	// Set the CSS variable to the column value, and the `gap` property to the combined gap value.

	$style = '.' . $class . '{ --wp--style--unstable-gallery-gap: ' . $gap_column . '; gap: ' . $gap_value . '}';

	// Ideally styles should be loaded in the head, but blocks may be parsed

	// after that, so loading in the footer for now.

	// See https://core.trac.wordpress.org/ticket/53494.

	add_action(

		'wp_footer',

		function () use ( $style ) {

			echo '<style> ' . $style . '</style>';

		},

		11

	);

	return $content;

}

/**

 * Registers the `core/gallery` block on server.

 */

function register_block_core_gallery() {

	register_block_type_from_metadata(

		__DIR__ . '/gallery',

		array(

			'render_callback' => 'block_core_gallery_render',

		)

	);

}

add_action( 'init', 'register_block_core_gallery' );