import { HealthcareService } from 'fhir/r4';

// Appointment duration model (design: docs/appointments/appointment-durations-and-breaks-design.md).
// Effective duration = per-service override org default the 1-hour fallback. All values are integer MINUTES on
// a 15-minute grid; storage is uncapped (a hospital stay can run overnight or days).

// Per-service override. FHIR HealthcareService has no native appointment-duration field, so this Akashic
// extension carries it - byte-identical URL across plugin + infra.
export const SERVICE_DEFAULT_DURATION_EXTENSION_URL =
    'https://akashichealthrecords.com/fhir/StructureDefinition/service-default-duration';

// The fallback when neither the service nor the org sets a default. Ships at 1 hour.
export const DEFAULT_APPOINTMENT_DURATION_MINUTES = 60;

// 15-minute-grid quick-picks for the duration controls. Uncapped in storage - a "Custom" entry handles anything
// longer than these (overnight / multi-day stays).
export const DURATION_QUICK_PICK_MINUTES = [15, 30, 45, 60, 90, 120, 180, 240];

// The per-service override in minutes, if set (and positive).
export const getServiceDefaultDurationMinutes = (service?: HealthcareService): number | undefined => {
    const value = (service?.extension ?? []).find(
        (e) => e.url === SERVICE_DEFAULT_DURATION_EXTENSION_URL,
    )?.valueInteger;
    return typeof value === 'number' && value > 0 ? value : undefined;
};

// Effective appointment duration: per-service override org default 1-hour fallback.
export const resolveAppointmentDurationMinutes = (
    service: HealthcareService | undefined,
    orgDefaultMinutes: number | undefined,
): number =>
    getServiceDefaultDurationMinutes(service)
    ?? (orgDefaultMinutes && orgDefaultMinutes > 0 ? orgDefaultMinutes : DEFAULT_APPOINTMENT_DURATION_MINUTES);

// Human label for a minute count: 30 "30m", 90 "1h 30m", 240 "4h".
export const formatDurationLabel = (minutes: number): string => {
    const hours = Math.floor(minutes / 60);
    const mins = minutes % 60;
    if (hours === 0) return `${mins}m`;
    if (mins === 0) return `${hours}h`;
    return `${hours}h ${mins}m`;
};