import type { Identifier } from 'fhir/r4';

/**
 * THE LINK FROM A STAFF RECORD BACK TO THE HUMAN'S OWN ACCOUNT-HOME PATIENT, MODELLED AS AN IDENTIFIER.
 *
 * The server writes it at hire (`api/src/utils/homePatientIdentifier.ts`) and reads it back in at least
 * four places: guardian resolution (`isActiveGuardianOfChild`), the proxy list, pending related-person
 * invitations, and practitioner matching by personal mobile. It is infrastructure, not something a
 * person entered.
 *
 * WHY THIS CONSTANT EXISTS IN THE CLIENT AT ALL. The staff Profile's Identifiers tab renders every
 * identifier whose system is not the NPI one, as an EDITABLE, DELETABLE generic row - and the save path
 * writes `identifier` back as the whole array. So an admin who tidied up a row they did not recognise
 * would silently destroy the link the four consumers above depend on, on somebody's clinical record,
 * with no error and nothing to notice.
 *
 * It was found sitting in a real practitioner's Identifiers tab reading `Patient/36d9a6ab-...`, flagged
 * as "probably a different defect". It is not a defect in the WRITE; it is a defect in showing it.
 *
 * The value must match the server's exactly. Both sides search on `system|value`, so a client that
 * invented its own spelling would write a row that looks right and matches nothing.
 */
export const ACCOUNT_HOME_PATIENT_SYSTEM =
    'https://akashichealthrecords.com/fhir/identifier/account-home-patient';

export const isAccountHomeIdentifier = (identifier: Identifier): boolean =>
    identifier.system === ACCOUNT_HOME_PATIENT_SYSTEM;

/**
 * Split an identifier list into the ones a person may edit and the ones the system owns.
 *
 * Returned rather than filtered in place because BOTH halves are needed: the editable half feeds the
 * form, and the system half has to be re-attached on save. Dropping the second is exactly the data loss
 * this prevents, so the shape makes forgetting it awkward.
 */
export const splitSystemOwnedIdentifiers = (
    identifiers: Identifier[] | undefined,
): { editable: Identifier[]; systemOwned: Identifier[] } => {
    const all = identifiers ?? [];
    return {
        editable: all.filter((identifier) => !isAccountHomeIdentifier(identifier)),
        systemOwned: all.filter(isAccountHomeIdentifier),
    };
};