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

/**
* Renders the `core/comments` block on the server.
*
* This render callback is mainly for rendering a dynamic, legacy version of
* this block (the old `core/post-comments`). It uses the `comments_template()`
* function to generate the output, in the same way as classic PHP themes.
*
* As this callback will always run during SSR, first we need to check whether
* the block is in legacy mode. If not, the HTML generated in the editor is
* returned instead.
*
* @since 6.1.0
*
* @global WP_Post $post Global post object.
*
* @param array $attributes Block attributes.
* @param string $content Block default content.
* @param WP_Block $block Block instance.
* @return string Returns the filtered post comments for the current post wrapped inside "p" tags.
*/
function render_block_core_comments( $attributes, $content, $block ) {
global $post;

$post_id = $block->context['postId'];
if ( ! isset( $post_id ) ) {
return '';
}

// Return early if there are no comments and comments are closed.
if ( ! comments_open( $post_id ) && (int) get_comments_number( $post_id ) === 0 ) {
return '';
}

// If this isn't the legacy block, we need to render the static version of this block.
$is_legacy = 'core/post-comments' === $block->name || ! empty( $attributes['legacy'] );
if ( ! $is_legacy ) {
return $block->render( array( 'dynamic' => false ) );
}

$post_before = $post;
$post = get_post( $post_id );
setup_postdata( $post );

ob_start();

/*
* There's a deprecation warning generated by WP Core.
* Ideally this deprecation is removed from Core.
* In the meantime, this removes it from the output.
*/
add_filter( 'deprecated_file_trigger_error', '__return_false' );
comments_template();
remove_filter( 'deprecated_file_trigger_error', '__return_false' );

$output = ob_get_clean();
$post = $post_before;

$classnames = array();
// Adds the old class name for styles' backwards compatibility.
if ( isset( $attributes['legacy'] ) ) {
$classnames[] = 'wp-block-post-comments';
}
if ( isset( $attributes['textAlign'] ) ) {
$classnames[] = 'has-text-align-' . $attributes['textAlign'];
}

$wrapper_attributes = get_block_wrapper_attributes(
array( 'class' => implode( ' ', $classnames ) )
);

/*
* Enqueues scripts and styles required only for the legacy version. That is
* why they are not defined in `block.json`.
*/
wp_enqueue_script( 'comment-reply' );
enqueue_legacy_post_comments_block_styles( $block->name );

return sprintf( '<div %1$s>%2$s</div>', $wrapper_attributes, $output );
}

/**
* Registers the `core/comments` block on the server.
*
* @since 6.1.0
*/
function register_block_core_comments() {
register_block_type_from_metadata(
__DIR__ . '/comments',
array(
'render_callback' => 'render_block_core_comments',
'skip_inner_blocks' => true,
)
);
}
add_action( 'init', 'register_block_core_comments' );

/**
* Use the button block classes for the form-submit button.
*
* @since 6.1.0
*
* @param array $fields The default comment form arguments.
*
* @return array Returns the modified fields.
*/
function comments_block_form_defaults( $fields ) {
if ( wp_is_block_theme() ) {
$fields['submit_button'] = '<input name="%1$s" type="submit" id="%2$s" class="%3$s wp-block-button__link ' . wp_theme_get_element_class_name( 'button' ) . '" value="%4$s" />';
$fields['submit_field'] = '<p class="form-submit wp-block-button">%1$s %2$s</p>';
}

return $fields;
}
add_filter( 'comment_form_defaults', 'comments_block_form_defaults' );

/**
* Enqueues styles from the legacy `core/post-comments` block. These styles are
* required only by the block's fallback.
*
* @since 6.1.0
*
* @param string $block_name Name of the new block type.
*/
function enqueue_legacy_post_comments_block_styles( $block_name ) {
static $are_styles_enqueued = false;

if ( ! $are_styles_enqueued ) {
$handles = array(
'wp-block-post-comments',
'wp-block-buttons',
'wp-block-button',
);
foreach ( $handles as $handle ) {
wp_enqueue_block_style( $block_name, array( 'handle' => $handle ) );
}
$are_styles_enqueued = true;
}
}

/**
* Ensures backwards compatibility for any users running the Gutenberg plugin
* who have used Post Comments before it was merged into Comments Query Loop.
*
* The same approach was followed when core/query-loop was renamed to
* core/post-template.
*
* @since 6.1.0
*
* @see https://github.com/WordPress/gutenberg/pull/41807
* @see https://github.com/WordPress/gutenberg/pull/32514
*/
function register_legacy_post_comments_block() {
$registry = WP_Block_Type_Registry::get_instance();

/*
* Remove the old `post-comments` block if it was already registered, as it
* is about to be replaced by the type defined below.
*/
if ( $registry->is_registered( 'core/post-comments' ) ) {
unregister_block_type( 'core/post-comments' );
}

// Recreate the legacy block metadata.
$metadata = array(
'name' => 'core/post-comments',
'category' => 'theme',
'attributes' => array(
'textAlign' => array(
'type' => 'string',
),
),
'uses_context' => array(
'postId',
'postType',
),
'supports' => array(
'html' => false,
'align' => array( 'wide', 'full' ),
'typography' => array(
'fontSize' => true,
'lineHeight' => true,
'__experimentalFontStyle' => true,
'__experimentalFontWeight' => true,
'__experimentalLetterSpacing' => true,
'__experimentalTextTransform' => true,
'__experimentalDefaultControls' => array(
'fontSize' => true,
),
),
'color' => array(
'gradients' => true,
'link' => true,
'__experimentalDefaultControls' => array(
'background' => true,
'text' => true,
),
),
'inserter' => false,
),
'style' => array(
'wp-block-post-comments',
'wp-block-buttons',
'wp-block-button',
),
'render_callback' => 'render_block_core_comments',
'skip_inner_blocks' => true,
);

/*
* Filters the metadata object, the same way it's done inside
* `register_block_type_from_metadata()`. This applies some default filters,
* like `_wp_multiple_block_styles`, which is required in this case because
* the block has multiple styles.
*/
/** This filter is documented in wp-includes/blocks.php */
$metadata = apply_filters( 'block_type_metadata', $metadata );

register_block_type( 'core/post-comments', $metadata );
}
add_action( 'init', 'register_legacy_post_comments_block', 21 );