// Real-time clock accumulator and in-game calendar helpers.

export function createClock() {
  return { acc: 0 };
}

// Feed it the real elapsed ms; it returns how many in-game days are due.
// dt is capped so a background tab doesn't fast-forward the game on return, and
// floored at 0: the first animation frame can carry a timestamp slightly before
// the one the caller recorded, and a negative step would pre-load a whole day.
export function consumeClock(clock, dtMs, msPerDay, speed) {
  clock.acc += Math.max(0, Math.min(dtMs, 1000)) * speed;
  const days = Math.floor(clock.acc / msPerDay);
  clock.acc -= days * msPerDay;
  return days;
}

export function dateOfDay(startDate, day) {
  const [y, m, d] = startDate.split("-").map(Number);
  const date = new Date(Date.UTC(y, m - 1, d + day));
  return {
    year: date.getUTCFullYear(),
    month: date.getUTCMonth() + 1,
    day: date.getUTCDate(),
    weekday: date.getUTCDay(), // 0 = Sunday
    iso: date.toISOString().slice(0, 10),
  };
}

export const weekOfDay = (day, bal) => Math.floor(day / bal.time.daysPerWeek);
export const quarterOfDay = (day, bal) => Math.floor(day / bal.time.daysPerQuarter);