export declare function normalizeReferralCode(value: unknown): string | null;
/** Stable, unguessable share code. The unique user constraint handles concurrent creation. */
export declare function createReferralCode(ownerId: number, database?: ReferralDatabase): Promise<string>;
/**
 * First attribution wins. Call only from trusted new-account creation, never a
 * public claim endpoint. Pass the registration transaction to commit together.
 * Invalid, unknown, repeated, and self referrals do not disrupt registration.
 */
export declare function attributeReferral(newUserId: number, input: unknown, database?: ReferralDatabase): Promise<boolean>;
/** Server-only conversion hook. Replays preserve the first qualification time. */
export declare function qualifyReferral(referredUserId: number, database?: ReferralDatabase): Promise<void>;
/** Aggregate only: a referrer never receives another account's email or profile. */
export declare function referralSummary(ownerId: number, database?: ReferralDatabase): Promise<ReferralSummary>;
/** Minimal database contract, also accepted by transaction-scoped connections. */
export declare interface ReferralDatabase {
  unsafe: (sql: string, bindings?: unknown[]) => { execute: () => Promise<unknown> }
}
export declare interface ReferralCode {
  code: string
  user_id: number
}
export declare interface ReferralSummary {
  code: string | null
  referred: number
  qualified: number
}