import createDebugger from "debug";
import { Agenda } from ".";
import { processJobs } from "../utils";

const debug = createDebugger("agenda:start");

/**
 * Starts processing jobs using processJobs() methods, storing an interval ID
 * This method will only resolve if a db has been set up beforehand.
 * @name Agenda#start
 * @function
 * @returns resolves if db set beforehand, returns undefined otherwise
 */
export const start = async function (this: Agenda): Promise<void | unknown> {
  if (this._processInterval) {
    debug("Agenda.start was already called, ignoring");
    return this._ready;
  }

  await this._ready;
  debug(
    "Agenda.start called, creating interval to call processJobs every [%dms]",
    this._processEvery
  );
  this._processInterval = setInterval(
    processJobs.bind(this),
    this._processEvery
  );
  process.nextTick(processJobs.bind(this));
};