<?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' );

/**
 * Adds a unique ID to the gallery block context.
 *
 * @since 7.0.0
 *
 * @param array $context      Default context.
 * @param array $parsed_block Block being rendered, filtered by render_block_data.
 * @return array Filtered context.
 */
function block_core_gallery_render_context( $context, $parsed_block ) {
    if ( 'core/gallery' === $parsed_block['blockName'] ) {
        $context['galleryId'] = uniqid();
    }
    return $context;
}

add_filter( 'render_block_context', 'block_core_gallery_render_context', 10, 2 );

/**
 * 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.
 * @param array  $block      The block instance being rendered.
 * @return string The content of the block being rendered.
 */
function block_core_gallery_render( $attributes, $content, $block ) {
    // 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    = $gap_value['top'] ?? $fallback_gap;
        $gap_column = $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'] ) ) {
        // 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>/s';

        preg_match_all( $pattern, $updated_content, $matches );
        if ( $matches ) {
            $image_blocks = $matches[0];
            shuffle( $image_blocks );

            $i               = 0;
            $updated_content = preg_replace_callback(
                $pattern,
                static function () use ( $image_blocks, &$i ) {
                    return $image_blocks[ $i++ ];
                },
                $updated_content
            );
        }
    }

    // Gets all image IDs from the state that match this gallery's ID.
    $state      = wp_interactivity_state( 'core/image' );
    $gallery_id = $block->context['galleryId'] ?? null;
    $image_ids  = array();

    // Extracts image IDs from state metadata that match the current gallery ID.
    if ( isset( $gallery_id ) && isset( $state['metadata'] ) ) {
        foreach ( $state['metadata'] as $image_id => $metadata ) {
            if ( isset( $metadata['galleryId'] ) && $metadata['galleryId'] === $gallery_id ) {
                $image_ids[] = $image_id;
            }
        }
    }

    // If there are image IDs associated with this gallery, set interactivity
    // attributes and order metadata for lightbox navigation.
    if ( ! empty( $image_ids ) ) {
        $total          = count( $image_ids );
        $lightbox_index = 0;
        $processor      = new WP_HTML_Tag_Processor( $updated_content );
        $processor->next_tag();
        $processor->set_attribute( 'data-wp-interactive', 'core/gallery' );
        $processor->set_attribute(
            'data-wp-context',
            wp_json_encode(
                array( 'galleryId' => $gallery_id ),
                JSON_HEX_TAG | JSON_HEX_APOS | JSON_HEX_QUOT | JSON_HEX_AMP
            )
        );
        while ( $processor->next_tag( 'figure' ) ) {
            $wp_key = $processor->get_attribute( 'data-wp-key' );
            if ( $wp_key && isset( $state['metadata'][ $wp_key ] ) ) {
                $alt = $state['metadata'][ $wp_key ]['alt'];
                wp_interactivity_state(
                    'core/image',
                    array(
                        'metadata' => array(
                            $wp_key => array(
                                'customAriaLabel'        => empty( $alt )
                                    /* translators: %1$s: current image index, %2$s: total number of images */
                                    ? sprintf( __( 'Enlarged image %1$s of %2$s' ), $lightbox_index + 1, $total )
                                    /* translators: %1$s: current image index, %2$s: total number of images, %3$s: Image alt text */
                                    : sprintf( __( 'Enlarged image %1$s of %2$s: %3$s' ), $lightbox_index + 1, $total, $alt ),
                                /* translators: %1$s: current image index, %2$s: total number of images */
                                'triggerButtonAriaLabel' => sprintf( __( 'Enlarge %1$s of %2$s' ), $lightbox_index + 1, $total ),
                                'order'                  => $lightbox_index,
                            ),
                        ),
                    )
                );
                ++$lightbox_index;
            }
        }
        return $processor->get_updated_html();
    }

    return $updated_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' );