import type { UsageCounter } from '../usage/usage_counter.js';
import type { QuietHours } from '../util/quiet_hours.js';
export interface RateCappedDispatcherOptions {
    counter: UsageCounter;
    /**
     * Feature key — partitions the `feature_usage` table. Pick something
     * unique per channel ('reactive_ad', 'tip', 'upsell_nudge').
     */
    feature: string;
    /** Maximum impressions per calendar day. */
    dailyMax: number;
    /**
     * Minimum gap (seconds) between two dispatches to the same user. Set 0
     * to disable. Defaults to 0.
     */
    minGapSeconds?: number;
    /** Optional quiet-hours guard. Skips dispatch entirely when inside. */
    quietHours?: QuietHours | null;
}
export type DispatchReason = 'sent' | 'quiet_hours' | 'min_gap' | 'daily_cap' | 'send_failed' | 'no_whatsapp';
export interface DispatchResult {
    sent: boolean;
    reason: DispatchReason;
}
export type SendFn = () => Promise<boolean | void> | boolean | void;
export declare class RateCappedDispatcher {
    readonly counter: UsageCounter;
    readonly feature: string;
    readonly dailyMax: number;
    readonly minGapSeconds: number;
    readonly quietHours: QuietHours | null;
    constructor({ counter, feature, dailyMax, minGapSeconds, quietHours }: RateCappedDispatcherOptions);
    /**
     * Check the gap + cap, run `send`, record an impression on success.
     * Never throws — failures surface in the `reason` field.
     *
     * `send` returns truthy to mean "delivered". A void return is treated as
     * delivered. A thrown error is caught and treated as `send_failed` (no
     * impression recorded, no propagation to the caller).
     */
    tryDispatch(whatsapp: string, send: SendFn, key?: string | null): Promise<DispatchResult>;
    /** ms-since-epoch of the last dispatch for this user, or null. */
    lastDispatchedAt(whatsapp: string): Promise<number | null>;
}
//# sourceMappingURL=rate_capped_dispatcher.d.ts.map