import { JobModel } from './models/index';
import { TaskCallback, JobContext, JobScheduler, PublishableTask } from './index';
import { Properties } from './types';
export declare const isHealthy: (heartbeat: number, timeout: number) => boolean;
export declare const computeNextRuns: (interval: string, { timezone, startDate, count, }?: {
    timezone?: string | undefined;
    startDate?: string | undefined;
    count?: number | undefined;
}) => string[];
export declare const computeNextRun: (interval: string, { timezone, startDate, }?: {
    timezone?: string | undefined;
    startDate?: string | undefined;
}) => string;
/**
 * @description Call publish method on Publishable Tasks passing JobContext
 * @param task {SteveoTask}
 * @returns
 */
export declare const taskRunner: (task: PublishableTask) => (payload: Properties, context?: JobContext) => Promise<void>;
export type TimestampHelper = <T extends {
    context?: JobContext;
} = any, R = any>(job: JobModel, task: TaskCallback<T, R>) => (args: T, context: JobContext) => Promise<any>;
/**
 * @description This helper function is used to manipulate the timestamps on the job row in the DB
 * It does the following:
 * 1. Adds an accepted at timestamp (as the current timestamp) on the job to signal the job was accepted at this time
 * 2. Runs the callback (whatever the task is)
 * 3. When the callback runs successfully without any issues, it calculates the next run at for the job using its lunartick (https://www.npmjs.com/package/lunartick) rule and adds the following to the job
 * - queued: false //signalling the job is now over and ready to be picked up at the next run time
 * - nextRunAt: timestamp //time to pick up the job
 * - lastFinishedAt: timestamp //when did the job finish
 * 4. If the callback fails for some reason, it adds a failure to the job and reruns it with a backoff
 * @returns Promise<void>
 */
export declare const timestampHelperFactory: (jobScheduler: JobScheduler) => TimestampHelper;