import type { MetricsClient } from './connection';
import { type MetricsKeys } from './keys';
export interface Retention {
    /** Days of minute-level detail. Doubles as the recorder's catch-up window. */
    minutes: number;
    /** Days of hourly rollup. */
    hours: number;
    /** Days of daily totals, which is what the shipped charts read. */
    days: number;
}
export declare class HistoryStore {
    private readonly redis;
    private readonly keys;
    readonly retention: Retention;
    constructor(opts: {
        redis: MetricsClient;
        keys: MetricsKeys;
        retention: Retention;
    });
    upsertMinute(queue: string, metric: string, minute: number, value: number): Promise<void>;
    /**
     * Raw HMGET of the totals hash: `null` means the day was never recorded, a present
     * string (including `'0'`) means it was. Distinguishing "missing" from "stored zero"
     * matters for callers deciding between empty history vs. a zero-backfilled series.
     */
    readDailyTotalsRaw(queue: string, metric: string, days: string[]): Promise<(string | null)[]>;
    readDayMinutes(queue: string, metric: string, day: string): Promise<Record<string, number>>;
    /**
     * Hourly buckets for one day, keyed by absolute hour index.
     *
     * Falls back to folding the minute hash when the hourly rollup is absent, which covers
     * days recorded before the rollup existed. Once those minute hashes age out, the days
     * they cover are already outside the minute window anyway.
     */
    readDayHours(queue: string, metric: string, day: string): Promise<Record<string, number>>;
    private readNumericHash;
}