Keep your Mac awake by jiggling the mouse

jiggler.js

#!/usr/bin/env osascript -l JavaScript

ObjC.import("Cocoa");
ObjC.import("CoreGraphics");

function screenSize() {
  const w = $.NSScreen.mainScreen.frame.size.width;
  const h = $.NSScreen.mainScreen.frame.size.height;
  return { w, h };
}

function mousePos() {
  const event = $.CGEventCreate(null);
  const pos = $.CGEventGetLocation(event);
  return { x: parseInt(pos.x), y: parseInt(pos.y) };
}

function mouseMove(pos) {
  const event = $.CGEventCreateMouseEvent(null, $.kCGEventMouseMoved, $.CGPointMake(pos.x, pos.y), null);
  $.CGEventPost($.kCGHIDEventTap, event);
}

function newPos(val, distance, max) {
  const jitter = Math.round(Math.random() * distance);
  let result = Math.random() < 0.5 ? val - jitter : val + jitter;
  if (val - jitter < 0) result = val + jitter;
  else if (val + jitter >= max) result = val - jitter;
  return result;
}

function print(str) {
  $.NSFileHandle.fileHandleWithStandardOutput.writeData($.NSString.alloc.initWithUTF8String(str).dataUsingEncoding($.NSUTF8StringEncoding));
}

function timeFmt(date) {
  const hh = date.getHours();
  const mm = date.getMinutes();
  return `${hh}:${mm.toString().padStart(2, "0")}`;
}

function run(argv) {
  let distance, interval, hours, minutes;
  if (argv.length === 3) {
    distance = Number(argv[0]);
    interval = Number(argv[1]);
    [hours, minutes] = argv[2].split(":").map(Number);
  }
  if (isNaN(distance) || isNaN(interval) || isNaN(hours) || isNaN(minutes)) {
    print("Usage: engaging.js <distance pixels> <interval seconds> <until HH:MM>\n");
    return;
  }

  if (interval < 1 || interval > 300) {
    print("Interval must be between 1 and 300 seconds.\n");
    return;
  }

  if (distance < 1 || distance > 200) {
    print("Distance must be between 1 and 200 pixels.\n");
    return;
  }

  if (hours < 0 || hours > 23 || minutes < 0 || minutes > 59) {
    print("Time must be in HH:MM format (24-hour clock).\n");
    return;
  }

  const until = new Date();
  until.setHours(hours, minutes, 0, 0);

  const now = new Date();
  if (now > until && now - until > 12 * 60 * 60 * 1000) {
    until.setDate(until.getDate() + 1);
  }
  if (new Date() >= until) {
    print(`The specified time ${timeFmt(until)} has already passed today.\n`);
    return;
  }

  print(`Jiggling mouse by ${distance} pixels every ${interval} sec until ${timeFmt(until)}...\n`);

  let prev_pos = { x: -1, y: -1 };
  const ss = screenSize();
  while (new Date() < until) {
    const pos = mousePos();
    if (pos.x != prev_pos.x || pos.y != prev_pos.y) {
      prev_pos = pos;
      delay(interval);
      continue;
    }
    mouseMove({ x: newPos(pos.x, distance, ss.w), y: newPos(pos.y, distance, ss.h) });
    print(".");
    delay(0.5);
    mouseMove(pos);
    delay(interval - 0.5);
  }
  print("\nFinished.\n");
}