URL Rewrite Question

Not sure this is where to put this, but I have a question. What I’m trying to do is the following… When someone hits https://example.com/foo/bar/ on my site, they should see the word “bar” and nothing more.. I’m simplifying all of this of course. Here’s my code. This doesn’t seem to be working.

add_filter( 'query_vars', 'analytics_rewrite_add_var' ); 

function analytics_rewrite_add_var( $vars )
{
	array_push( $vars, 'foo' );
	return $vars;
} 

function add_analytic_rewrite_rule($rules){
	add_rewrite_tag( '%foo%', '([^&]+)' );
	add_rewrite_rule(
		'^foo/([^/]*)/?',
		'index.php?foo=$matches[1]',
		'top'
	);
}
add_action('rewrite_rules_array', 'add_analytic_rewrite_rule');
add_action( 'template_redirect', 'analytics_rewrite_catch' ); 

function analytics_rewrite_catch()
{
	global $wp_query; 

	if ( array_key_exists( 'foo', $wp_query->query_vars ) ) { 

	echo $_GET['foo'];
		exit; 

	}
}

function the_unique_rewrite_flush(){
	global $wp_rewrite;
   	$wp_rewrite->flush_rules();
}
add_action('init','the_unique_rewrite_flush');