<?php 

/**
 * Helper function to detect changed fields
 * 
 * Compares current data with previous data to identify which fields changed
 * 
 * @param mixed $data Current data
 * @param mixed $beforeData Previous data (null for new records)
 * @return array Array of changed field names
 */
function detectChangedFields($data, $beforeData): array
{
    if (is_null($beforeData)) {
        // New record - all fields are "changed"
        return array_keys((array) $data);
    }

    $changedFields = [];
    $dataArray = (array) $data;
    $beforeDataArray = (array) $beforeData;

    foreach ($dataArray as $key => $value) {
        $oldValue = $beforeDataArray[$key] ?? null;
        
        // Compare values - consider both strict and loose equality for type changes
        if ($oldValue !== $value) {
            $changedFields[] = $key;
        }
    }

    return $changedFields;
}

?>