import type { Invoice, PaymentReconciliation } from 'fhir/r4';

// The server stamps the practice that owns a bill (and each payment against it) as this tag on every write, and
// scopes every practice read by it. It is the one answer to "whose bill is this": never the URL, the issuer's
// display name or the practice the screen happens to have selected.
export const OWNING_PRACTICE_TAG_SYSTEM = 'https://akashichealthrecords.com/fhir/tags/organization';

/** The practice that owns a record, or undefined when it carries none or more than one. */
export const owningPracticeOf = (record: Invoice | PaymentReconciliation | undefined): string | undefined => {
    const owners = [...new Set((record?.meta?.tag ?? [])
        .filter((tag) => tag.system === OWNING_PRACTICE_TAG_SYSTEM && tag.code)
        .map((tag) => tag.code as string))];
    return owners.length === 1 ? owners[0] : undefined;
};

/** A bill read through practice `practiceId` for patient `patientId` is theirs only when it says so itself. */
export const isBillOf = (invoice: Invoice | undefined, practiceId: string, patientId: string): boolean =>
    owningPracticeOf(invoice) === practiceId && invoice?.subject?.reference === `Patient/${patientId}`;