import type { Extension, HealthcareService } from 'fhir/r4';
import { fromFhirMoney, toFhirMoney } from '../utils/money';

// Per-service price. FHIR HealthcareService has no native price field, so this Akashic extension carries it -
// byte-identical URL across plugin + infra. Stored as FHIR Money (decimal); read/written in integer cents.
export const SERVICE_PRICE_EXTENSION_URL =
    'https://akashichealthrecords.com/fhir/StructureDefinition/service-price';

// The service's price in integer cents, if set (and non-negative). Undefined = unpriced.
export const getServicePriceCents = (service?: HealthcareService | null): number | undefined => {
    const money = (service?.extension ?? []).find(
        (e) => e.url === SERVICE_PRICE_EXTENSION_URL,
    )?.valueMoney;
    if (!money || typeof money.value !== 'number') {
        return undefined;
    }
    const cents = fromFhirMoney(money);
    return cents >= 0 ? cents : undefined;
};

// Strip-then-append the price extension (mirrors AddServiceModal's inline extension writes). Passing
// `undefined` removes the price.
//
// - KEEP THE EMPTY ARRAY. It used to collapse an empty result to `extension: undefined`, which
// made "I curated the extensions and there are none left" byte-identical to the bare
// transformToFhirHealthcareService output ("I never considered extensions"). The server's
// preserveHealthcareServiceFeatureExtensions carries the stored extensions forward on the second case,
// so collapsing here meant clearing the LAST extension silently resurrected it on the next save.
// An explicit `[]` is the signal that the omission was deliberate; the server normalizes it away before
// writing, since HealthLake rejects empty arrays.
export const applyServicePrice = (
    service: HealthcareService,
    cents: number | undefined,
): HealthcareService => {
    const others: Extension[] = (service.extension ?? []).filter(
        (e) => e.url !== SERVICE_PRICE_EXTENSION_URL,
    );
    const next: Extension[] =
        cents === undefined
            ? others
            : [...others, { url: SERVICE_PRICE_EXTENSION_URL, valueMoney: toFhirMoney(cents) }];
    return { ...service, extension: next };
};