import { Observation, Reference } from 'fhir/r4';

/**
 * Who performed an observation, in words, beside the kind of performer the list already shows: the name it was recorded
 * with, the patient it is about, or that no name was recorded. Never the stored reference, and never a lookup of a
 * record the viewer was not already shown.
 */
export const performerLabel = (ref: Reference, observation: Pick<Observation, 'subject'>): string => {
    if (ref.display?.trim()) return ref.display.trim();
    if (ref.reference && ref.reference === observation.subject?.reference) return 'This patient';
    return 'Name not recorded';
};

/** The performers with a readable display, so the shared reference list shows names rather than stored references. */
export const namedPerformers = (observation: Pick<Observation, 'performer' | 'subject'>): Reference[] | undefined =>
    observation.performer?.map((ref) => ({ ...ref, display: performerLabel(ref, observation) }));