<?php

/**

 * Server-side rendering of the `core/button` block.

 *

 * @package WordPress

 */

/**

 * Renders the `core/button` block on the server,

 *

 * @since 6.6.0

 *

 * @param array    $attributes The block attributes.

 * @param string   $content    The block content.

 * @param WP_Block $block      The block object.

 *

 * @return string The block content.

 */

function render_block_core_button( $attributes, $content ) {

	$p = new WP_HTML_Tag_Processor( $content );

	/*

	 * The button block can render an `<a>` or `<button>` and also has a

	 * `<div>` wrapper. Find the a or button tag.

	 */

	$tag = null;

	while ( $p->next_tag() ) {

		$tag = $p->get_tag();

		if ( 'A' === $tag || 'BUTTON' === $tag ) {

			break;

		}

	}

	/*

	 * If this happens, the likelihood is there's no block content,

	 * or the block has been modified by a plugin.

	 */

	if ( null === $tag ) {

		return $content;

	}

	// If the next token is the closing tag, the button is empty.

	$is_empty = true;

	while ( $p->next_token() && $tag !== $p->get_token_name() && $is_empty ) {

		if ( '#comment' !== $p->get_token_type() ) {

			/**

			 * Anything else implies this is not empty.

			 * This might include any text content (including a space),

			 * inline images or other HTML.

			 */

			$is_empty = false;

		}

	}

	/*

	 * When there's no text, render nothing for the block.

	 * See https://github.com/WordPress/gutenberg/issues/17221 for the

	 * reasoning behind this.

	 */

	if ( $is_empty ) {

		return '';

	}

	return $content;

}

/**

 * Registers the `core/button` block on server.

 *

 * @since 6.6.0

 */

function register_block_core_button() {

	register_block_type_from_metadata(

		__DIR__ . '/button',

		array(

			'render_callback' => 'render_block_core_button',

		)

	);

}

add_action( 'init', 'register_block_core_button' );