import type { AuditEvent, Bundle } from 'fhir/r4';

const CONDITION_REF = /^Condition\/([A-Za-z0-9._-]+)$/;

/** Condition ids from DELETE AuditEvents (`entity.what.reference` = Condition/{id}).
 * FHIR DELETE drops SEARCH; Provenance search requires `target`. */
export function conditionIdsDeletedInAudit(bundle: Bundle<AuditEvent> | undefined): string[] {
    const ids = new Set<string>();
    for (const entry of bundle?.entry ?? []) {
        const event = entry.resource;
        if (!event || event.resourceType !== 'AuditEvent') continue;
        if (event.action && event.action !== 'D') continue;
        for (const entity of event.entity ?? []) {
            const match = CONDITION_REF.exec(entity.what?.reference ?? '');
            if (match) ids.add(match[1]);
        }
    }
    return [...ids];
}