import type { DB } from '../db/client.js';
export interface PreferenceStoreOptions {
    db: DB;
}
export interface SetOptions {
    /** If provided, reject the call when `value` is not in this list. */
    allowed?: readonly string[];
}
export declare class PreferenceStore {
    readonly db: DB;
    constructor({ db }: PreferenceStoreOptions);
    /**
     * Read a preference. Returns `defaultValue` if the user has no row for `key`.
     */
    get(whatsapp: string, key: string, defaultValue?: string | null): Promise<string | null>;
    /**
     * Upsert a preference. If `allowed` is supplied, rejects values not in it
     * (returns false without writing).
     */
    set(whatsapp: string, key: string, value: string, { allowed }?: SetOptions): Promise<boolean>;
    clear(whatsapp: string, key: string): Promise<void>;
    /**
     * Fetch all preferences for one user as a key→value map.
     * Missing keys are simply absent — supply your own defaults.
     */
    getAll(whatsapp: string): Promise<Record<string, string>>;
}
/**
 * Define a typed preference for ergonomic call sites.
 *
 *   const deliveryMode = definePreference('delivery_mode', 'both', ['text', 'audio', 'both'] as const);
 *   await deliveryMode.get(prefs, '5551');           // 'both' (default)
 *   await deliveryMode.set(prefs, '5551', 'audio');  // validates
 */
export declare function definePreference<T extends string>(key: string, defaultValue: T, allowed?: readonly T[]): {
    key: string;
    defaultValue: T;
    allowed: readonly T[] | undefined;
    get(store: PreferenceStore, whatsapp: string): Promise<T>;
    set(store: PreferenceStore, whatsapp: string, value: T): Promise<boolean>;
};
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