import type { Database as DatabaseType } from "better-sqlite3";
/** Derive the 3-letter candidate for a department slug. Falls back to X-padding
 *  for short/letterless slugs instead of throwing like the company derivation. */
export declare function derivePrefixCandidate(slug: string): string;
/** Deterministic collision fallback: try the candidate, then advance the third
 *  letter A→Z, then the second, then the first. Throws only if every variant of
 *  all three positions is taken (78 tries — practically impossible). */
export declare function pickFreePrefix(candidate: string, taken: ReadonlySet<string>): string;
/** Resolve (lazily registering) the immutable ID prefix for a department slug.
 *  `reservedCompanyPrefix` is the company namespace and can never be assigned
 *  to a department. Registration races resolve via the UNIQUE constraint. */
export declare function resolveDepartmentPrefix(db: DatabaseType, slug: string, reservedCompanyPrefix: string): string;
export interface DepartmentRecord {
    slug: string;
    prefix: string;
    createdAt: string;
}
export interface DepartmentSummary extends DepartmentRecord {
    /** Live count of Todos currently IN the department (items keep their birth
     *  prefix when moved, so this counts membership, not the ID namespace). */
    todoCount: number;
}
/** The `GET /api/departments` surface: registry rows + one GROUP BY count. */
export declare function listDepartmentsWithCounts(db: DatabaseType): DepartmentSummary[];
//# sourceMappingURL=departments.d.ts.map