Sorry, i was thinking you already have a line for global $COURSE. No problem here is a complete snippet again
use core_completion\progress;
global $COURSE;
$course = $COURSE;
$completion = new \completion_info($course);
// if user having edit access then ignore it
$coursecontext = context_course::instance($course->id);
if (has_capability('moodle/course:update', $coursecontext)) {
continue;
}
// First, let's make sure completion is enabled.
if (!$completion->is_enabled()) {
continue;
}
$percentage = progress::get_course_progress_percentage($course);
if (!is_null($percentage)) {
$percentage = floor($percentage);
}