rsvpmaker-block-theme-template

<?php
/*
* Adds variation on a block theme's single template for custom post type
* called on plugin activation or after_theme_switch action
*/

register_activation_hook( __FILE__, 'rsvpmaker_single_block_template' );
add_action('after_switch_theme','rsvpmaker_single_block_template');

function rsvpmaker_single_block_template() {
	global $rsvp_template_done;
	if(!function_exists('get_block_templates') || $rsvp_template_done)
		return;
	$rsvp_template_done = true; // don't do twice
	$templates = get_block_templates();
	foreach($templates as $template) {
		if($template->slug == 'single') {
			$rsvpmaker_content = $template->content;
			$theme = $template->theme;
		}
		if($template->slug == 'single-rsvpmaker') {
			return; // if already exists, don't add
		}
	}

	if(!empty($rsvpmaker_content)) // found existing template, not stopped by existing rsvpmaker template
	{
		$rsvpmaker_content = preg_replace('/<[^a-z]+wp:post-(date|author)[^>]+>/','',$rsvpmaker_content);
		$new['post_name'] = 'single-rsvpmaker';
		$new['post_type'] = 'wp_template';
		$new['post_status'] = 'publish';
		$new['post_excerpt'] = 'Single event from RSVPMaker';
		$new['post_title'] = 'RSVPMaker Single';
		$new['post_content'] = $rsvpmaker_content;
		$post_id = wp_insert_post($new);
		wp_add_object_terms($post_id,$theme,'wp_theme');
	}
}