<?php
/**
 * Block level presets support.
 *
 * @package WordPress
 * @since 6.2.0
 */

/**
 * Get the class name used on block level presets.
 *
 * @internal
 *
 * @since 6.2.0
 * @access private
 *
 * @param array $block Block object.
 * @return string      The unique class name.
 */
function _wp_get_presets_class_name( $block ) {
    return 'wp-settings-' . md5( serialize( $block ) );
}

/**
 * Update the block content with block level presets class name.
 *
 * @internal
 *
 * @since 6.2.0
 * @access private
 *
 * @param  string $block_content Rendered block content.
 * @param  array  $block         Block object.
 * @return string                Filtered block content.
 */
function _wp_add_block_level_presets_class( $block_content, $block ) {
    if ( ! $block_content ) {
        return $block_content;
    }

    // return early if the block doesn't have support for settings.
    $block_type = WP_Block_Type_Registry::get_instance()->get_registered( $block['blockName'] );
    if ( ! block_has_support( $block_type, '__experimentalSettings', false ) ) {
        return $block_content;
    }

    // return early if no settings are found on the block attributes.
    $block_settings = $block['attrs']['settings'] ?? null;
    if ( empty( $block_settings ) ) {
        return $block_content;
    }

    // Like the layout hook this assumes the hook only applies to blocks with a single wrapper.
    // Add the class name to the first element, presuming it's the wrapper, if it exists.
    $tags = new WP_HTML_Tag_Processor( $block_content );
    if ( $tags->next_tag() ) {
        $tags->add_class( _wp_get_presets_class_name( $block ) );
    }

    return $tags->get_updated_html();
}

/**
 * Render the block level presets stylesheet.
 *
 * @internal
 *
 * @since 6.2.0
 * @since 6.3.0 Updated preset styles to use Selectors API.
 * @access private
 *
 * @param string|null $pre_render   The pre-rendered content. Default null.
 * @param array       $block The block being rendered.
 *
 * @return null
 */
function _wp_add_block_level_preset_styles( $pre_render, $block ) {
    // Return early if the block has not support for descendent block styles.
    $block_type = WP_Block_Type_Registry::get_instance()->get_registered( $block['blockName'] );
    if ( ! block_has_support( $block_type, '__experimentalSettings', false ) ) {
        return null;
    }

    // return early if no settings are found on the block attributes.
    $block_settings = $block['attrs']['settings'] ?? null;
    if ( empty( $block_settings ) ) {
        return null;
    }

    $class_name = '.' . _wp_get_presets_class_name( $block );

    // the root selector for preset variables needs to target every possible block selector
    // in order for the general setting to override any bock specific setting of a parent block or
    // the site root.
    $variables_root_selector = '*,[class*="wp-block"]';
    $registry                = WP_Block_Type_Registry::get_instance();
    $blocks                  = $registry->get_all_registered();
    foreach ( $blocks as $block_type ) {
        /*
         * We only want to append selectors for blocks using custom selectors
         * i.e. not `wp-block-<name>`.
         */
        $has_custom_selector =
            ( isset( $block_type->supports['__experimentalSelector'] ) && is_string( $block_type->supports['__experimentalSelector'] ) ) ||
            ( isset( $block_type->selectors['root'] ) && is_string( $block_type->selectors['root'] ) );

        if ( $has_custom_selector ) {
            $variables_root_selector .= ',' . wp_get_block_css_selector( $block_type );
        }
    }
    $variables_root_selector = WP_Theme_JSON::scope_selector( $class_name, $variables_root_selector );

    // Remove any potentially unsafe styles.
    $theme_json_shape  = WP_Theme_JSON::remove_insecure_properties(
        array(
            'version'  => WP_Theme_JSON::LATEST_SCHEMA,
            'settings' => $block_settings,
        )
    );
    $theme_json_object = new WP_Theme_JSON( $theme_json_shape );

    $styles = '';

    // include preset css variables declaration on the stylesheet.
    $styles .= $theme_json_object->get_stylesheet(
        array( 'variables' ),
        null,
        array(
            'root_selector' => $variables_root_selector,
            'scope'         => $class_name,
        )
    );

    // include preset css classes on the the stylesheet.
    $styles .= $theme_json_object->get_stylesheet(
        array( 'presets' ),
        null,
        array(
            'root_selector' => $class_name . ',' . $class_name . ' *',
            'scope'         => $class_name,
        )
    );

    if ( ! empty( $styles ) ) {
        wp_enqueue_block_support_styles( $styles );
    }

    return null;
}

add_filter( 'render_block', '_wp_add_block_level_presets_class', 10, 2 );
add_filter( 'pre_render_block', '_wp_add_block_level_preset_styles', 10, 2 );