Populate Gravity Forms form hidden field with ACF field.php

/** Populate Gravity Forms form hidden field with ACF field "resource_type" data
NOTE: In the Gravity Forms hidden field, enter "resource_type" as the dynamic population parameter. **/
// Populate GF hidden field with parameter name: resource_type
add_filter('gform_field_value_resource_type', function ($value) {
	// Bail if ACF isn't loaded
	if ( ! function_exists('get_field') ) {
		return $value;
	}

	// Get a reliable post ID even when the form is injected via hooks/Elements
	$post_id = get_the_ID();
	if ( ! $post_id ) {
		$post_id = get_queried_object_id();
	}

	$acf = get_field('resource_type', $post_id);

	// Normalize ACF output to a string
	$to_string = function($v) {
		// Taxonomy term object(s)
		if ( is_object($v) && isset($v->name) )   return (string) $v->name; // use ->slug if you prefer
		// ACF select/checkbox set to "Both (Array)"
		if ( is_array($v) && (isset($v['label']) || isset($v['value'])) ) {
			return (string) ($v['label'] ?? $v['value']);
		}
		// Mixed arrays (e.g., multiple terms / multiple selects)
		if ( is_array($v) ) {
			return implode(', ', array_map(function($item){
				if (is_object($item) && isset($item->name)) return (string) $item->name;
				if (is_array($item)) return (string) ($item['label'] ?? $item['value'] ?? reset($item));
				return (string) $item;
			}, $v));
		}
		return (string) $v;
	};

	$out = $to_string($acf);

	// Optional fallback to ACF Options page
	if ($out === '' || $out === null) {
		$opt = get_field('resource_type', 'option');
		if ($opt) $out = $to_string($opt);
	}

	return $out;
});