How to implement the functionality of an alarm clock in a chat bot?

Question

Software design

Hello! I set myself a slightly strange goal to implement the functionality of an alarm clock in a chat bot. In general, the user sets a certain time, and when this time comes, he receives a certain message. In general, now I see it like this: I take the user's time and remember it in the database, then I create a script that will run every 5 seconds, it will run all the times of all users from the database and if the time matches or is equal to the current time + -5sec ( + - a couple of seconds for the duration of the script), then we send a message. Does this solution look adequate or is there some more elegant alternative? I have never used cron and I have vague doubts that running a task every 5 seconds is not comme il faut. Thank you all in advance!

Answer 1

The question is the following. How often will "alarm clocks" be added? Why choose PHP? Are there plans to further expand the system? Is it possible to run a script from the console with no runtime restrictions?

class Delay {

  private static $alarms = [];

  public static function addInterval($seconds, $userId) {
    self::$alarms[time() + $seconds][$userId] = $seconds;
  }

  public static function loop() {
    while (true) {
      $dttm = time();

      if (isset(self::$alarms[$dttm])) {
        foreach (self::$alarms[$dttm] as $userId => $seconds) {
          self::$alarms[$dttm + $seconds][$userId] = $seconds;
          echo "User #{$userId} прождал {$seconds} cек\n ";
        }

        unset(self::$alarms[$dttm]);
      }

      sleep(1);
    }
  }
}

Delay::addInterval(5, 1);
Delay::addInterval(10, 2);
Delay::loop();