import type { DeviceLogsBackend, HistoryOpts, InternalDeviceLog, LogContext, OutputDeviceLog, Subscription } from '../struct.js';
import type { Result } from 'ioredis';
declare module 'ioredis' {
    interface RedisCommander<Context> {
        publishLogs(logsKey: string, bytesWrittenKey: string, subscribersKey: string, ...args: [...logs: string[], bytesWritten: number, limit: number]): Result<void, Context>;
        incrSubscribers(subscribersKey: string): Result<void, Context>;
        decrSubscribers(subscribersKey: string): Result<number, Context>;
    }
}
export declare class RedisBackend implements DeviceLogsBackend {
    private subscriptions;
    private subscriptionHeartbeats;
    constructor();
    history(ctx: LogContext, { count, start }: HistoryOpts): Promise<OutputDeviceLog[]>;
    get available(): boolean;
    publish(ctx: LogContext, logs: InternalDeviceLog[]): Promise<void>;
    subscribe(ctx: LogContext, subscription: Subscription): void;
    unsubscribe(ctx: LogContext, subscription: Subscription): void;
    private get connected();
    private getKey;
    private handleMessage;
    private fromRedisLog;
    private toRedisLog;
}