import type { HealthcareService, Location } from 'fhir/r4';

/**
 * WHERE A SERVICE IS OFFERED, in the words a front desk uses.
 *
 * It exists to separate two catalogue rows that read the same. MEASURED at Great River: the visit-service
 * picker lists **Consultation twice**, and the two are not equivalent - one is scoped to West Burlington
 * Hospital and Southeast Iowa Regional Medical Center, the other is scoped to nothing at all, and
 * choosing the second is answered with *"Nobody at this practice currently offers Consultation"*. Same
 * name, same type coding; the location scope is the whole difference between a booking and a dead end.
 *
 * A SERVICE THAT NAMES NO LOCATION IS NOT A SERVICE OFFERED EVERYWHERE, and saying so would be the more
 * useful-sounding lie. It is a service nobody has tied to a place, which is exactly the state the
 * unbookable row is in - so the phrase points at the real condition rather than promising availability
 * this list cannot check.
 *
 * RETURNS UNDEFINED WHEN THE NAMES CANNOT BE RESOLVED, never a reference or an id. A row reading
 * "Consultation - Location/cfd68bc5" is worse than an undistinguished one: it is noise that looks like
 * information, and `distinguishDuplicateOptions` treats undefined as "I have no fact to offer" and
 * leaves the plain label alone.
 */
export const NO_LOCATION_SUMMARY = 'Not tied to a location';

export const serviceLocationSummary = (
    service: HealthcareService | undefined,
    locations: Location[] | undefined,
): string | undefined => {
    const references = service?.location ?? [];
    if (references.length === 0) return NO_LOCATION_SUMMARY;

    const names = references
        .map((reference) => reference.reference?.split('/').pop())
        .map((id) => (id ? locations?.find((location) => location.id === id)?.name?.trim() : undefined))
        .filter((name): name is string => Boolean(name));

    return names.length > 0 ? names.join(', ') : undefined;
};