<?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.
*
* @since 5.9.0
*
* @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' );

/**
* Renders the `core/gallery` block on the server.
*
* @since 6.0.0
*
* @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 ) {
// 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.

$gap = $attributes['style']['spacing']['blockGap'] ?? null;
// 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 ) {
// Make sure $value is a string to avoid PHP 8.1 deprecation error in preg_match() when the value is null.
$value = is_string( $value ) ? $value : '';
$value = $value && preg_match( '%[\\\(&=}]|/\*%', $value ) ? null : $value;

// Get spacing CSS variable from preset value if provided.
if ( is_string( $value ) && str_contains( $value, 'var:preset|spacing|' ) ) {
$index_to_splice = strrpos( $value, '|' ) + 1;
$slug = _wp_to_kebab_case( substr( $value, $index_to_splice ) );
$value = "var(--wp--preset--spacing--$slug)";
}

$gap[ $key ] = $value;
}
} else {
// Make sure $gap is a string to avoid PHP 8.1 deprecation error in preg_match() when the value is null.
$gap = is_string( $gap ) ? $gap : '';
$gap = $gap && preg_match( '%[\\\(&=}]|/\*%', $gap ) ? null : $gap;

// Get spacing CSS variable from preset value if provided.
if ( is_string( $gap ) && str_contains( $gap, 'var:preset|spacing|' ) ) {
$index_to_splice = strrpos( $gap, '|' ) + 1;
$slug = _wp_to_kebab_case( substr( $gap, $index_to_splice ) );
$gap = "var(--wp--preset--spacing--$slug)";
}
}

$unique_gallery_classname = wp_unique_id( 'wp-block-gallery-' );
$processed_content = new WP_HTML_Tag_Processor( $content );
$processed_content->next_tag();
$processed_content->add_class( $unique_gallery_classname );

// --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;
}

// The unstable gallery gap calculation requires a real value (such as `0px`) and not `0`.
if ( '0' === $gap_column ) {
$gap_column = '0px';
}

// Set the CSS variable to the column value, and the `gap` property to the combined gap value.
$gallery_styles = array(
array(
'selector' => ".wp-block-gallery.{$unique_gallery_classname}",
'declarations' => array(
'--wp--style--unstable-gallery-gap' => $gap_column,
'gap' => $gap_value,
),
),
);

wp_style_engine_get_stylesheet_from_css_rules(
$gallery_styles,
array(
'context' => 'block-supports',
)
);

// The WP_HTML_Tag_Processor class calls get_updated_html() internally
// when the instance is treated as a string, but here we explicitly
// convert it to a string.
$updated_content = $processed_content->get_updated_html();

/*
* Randomize the order of image blocks. Ideally we should shuffle
* the `$parsed_block['innerBlocks']` via the `render_block_data` hook.
* However, this hook doesn't apply inner block updates when blocks are
* nested.
* @todo In the future, if this hook supports updating innerBlocks in
* nested blocks, it should be refactored.
*
* @see: https://github.com/WordPress/gutenberg/pull/58733
*/
if ( empty( $attributes['randomOrder'] ) ) {
return $updated_content;
}

// This pattern matches figure elements with the `wp-block-image` class to
// avoid the gallery's wrapping `figure` element and extract images only.
$pattern = '/<figure[^>]*\bwp-block-image\b[^>]*>.*?<\/figure>/';

// Find all Image blocks.
preg_match_all( $pattern, $updated_content, $matches );
if ( ! $matches ) {
return $updated_content;
}
$image_blocks = $matches[0];

// Randomize the order of Image blocks.
shuffle( $image_blocks );
$i = 0;
$content = preg_replace_callback(
$pattern,
static function () use ( $image_blocks, &$i ) {
$new_image_block = $image_blocks[ $i ];
++$i;
return $new_image_block;
},
$updated_content
);

return $content;
}
/**
* Registers the `core/gallery` block on server.
*
* @since 5.9.0
*/
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' );