<?php
/**
 * Server-side rendering of the `core/comment-template` block.
 *
 * @package WordPress
 */

/**
 * Function that recursively renders a list of nested comments.
 *
 * @since 6.3.0 Changed render_block_context priority to `1`.
 *
 * @global int $comment_depth
 *
 * @param WP_Comment[] $comments        The array of comments.
 * @param WP_Block     $block           Block instance.
 * @return string
 */
function block_core_comment_template_render_comments( $comments, $block ) {
    global $comment_depth;
    $thread_comments       = get_option( 'thread_comments' );
    $thread_comments_depth = get_option( 'thread_comments_depth' );

    if ( empty( $comment_depth ) ) {
        $comment_depth = 1;
    }

    $content = '';
    foreach ( $comments as $comment ) {
        $comment_id           = $comment->comment_ID;
        $filter_block_context = static function ( $context ) use ( $comment_id ) {
            $context['commentId'] = $comment_id;
            return $context;
        };

        /*
         * We set commentId context through the `render_block_context` filter so
         * that dynamically inserted blocks (at `render_block` filter stage)
         * will also receive that context.
         *
         * Use an early priority to so that other 'render_block_context' filters
         * have access to the values.
         */
        add_filter( 'render_block_context', $filter_block_context, 1 );

        /*
         * We construct a new WP_Block instance from the parsed block so that
         * it'll receive any changes made by the `render_block_data` filter.
         */
        $block_content = ( new WP_Block( $block->parsed_block ) )->render( array( 'dynamic' => false ) );

        remove_filter( 'render_block_context', $filter_block_context, 1 );

        $children = $comment->get_children();

        /*
         * We need to create the CSS classes BEFORE recursing into the children.
         * This is because comment_class() uses globals like `$comment_alt`
         * and `$comment_thread_alt` which are order-sensitive.
         *
         * The `false` parameter at the end means that we do NOT want the function
         * to `echo` the output but to return a string.
         * See https://developer.wordpress.org/reference/functions/comment_class/#parameters.
         */
        $comment_classes = comment_class( '', $comment->comment_ID, $comment->comment_post_ID, false );

        // If the comment has children, recurse to create the HTML for the nested
        // comments.
        if ( ! empty( $children ) && ! empty( $thread_comments ) ) {
            if ( $comment_depth < $thread_comments_depth ) {
                ++$comment_depth;
                $inner_content  = block_core_comment_template_render_comments(
                    $children,
                    $block
                );
                $block_content .= sprintf( '<ol>%1$s</ol>', $inner_content );
                --$comment_depth;
            } else {
                $block_content .= block_core_comment_template_render_comments(
                    $children,
                    $block
                );
            }
        }

        $content .= sprintf( '<li id="comment-%1$s" %2$s>%3$s</li>', $comment->comment_ID, $comment_classes, $block_content );
    }

    return $content;
}

/**
 * Renders the `core/comment-template` block on the server.
 *
 * @since 6.0.0
 *
 * @param array    $attributes Block attributes.
 * @param string   $content    Block default content.
 * @param WP_Block $block      Block instance.
 *
 * @return string Returns the HTML representing the comments using the layout
 * defined by the block's inner blocks.
 */
function render_block_core_comment_template( $attributes, $content, $block ) {
    // Bail out early if the post ID is not set for some reason.
    if ( empty( $block->context['postId'] ) ) {
        return '';
    }

    if ( post_password_required( $block->context['postId'] ) ) {
        return;
    }

    $comment_query = new WP_Comment_Query(
        build_comment_query_vars_from_block( $block )
    );

    // Get an array of comments for the current post.
    $comments = $comment_query->get_comments();
    if ( count( $comments ) === 0 ) {
        return '';
    }

    $comment_order = get_option( 'comment_order' );

    if ( 'desc' === $comment_order ) {
        $comments = array_reverse( $comments );
    }

    $wrapper_attributes = get_block_wrapper_attributes();

    return sprintf(
        '<ol %1$s>%2$s</ol>',
        $wrapper_attributes,
        block_core_comment_template_render_comments( $comments, $block )
    );
}

/**
 * Registers the `core/comment-template` block on the server.
 *
 * @since 6.0.0
 */
function register_block_core_comment_template() {
    register_block_type_from_metadata(
        __DIR__ . '/comment-template',
        array(
            'render_callback'   => 'render_block_core_comment_template',
            'skip_inner_blocks' => true,
        )
    );
}
add_action( 'init', 'register_block_core_comment_template' );