export const format = (d: Date) =>
  `${d.getDate()} ${d.toLocaleString("default", { month: "short" })}`;

export const startOfDay = (d: Date) => {
  const x = new Date(d);
  x.setHours(0, 0, 0, 0);
  return x;
};

export const endOfDay = (d: Date) => {
  const x = new Date(d);
  x.setHours(23, 59, 59, 999);
  return x;
};

export const getStartOfWeek = (d: Date) => {
  const date = new Date(d);
  const day = date.getDay() || 7;
  if (day !== 1) date.setDate(date.getDate() - (day - 1));
  return startOfDay(date);
};

export const shiftDate = (d: Date, days: number) =>
  new Date(d.getTime() + days * 86400000);

export const getWeekIndex = (date: Date) => {
  const firstDay = new Date(date.getFullYear(), date.getMonth(), 1);
  const firstWeekStart = getStartOfWeek(firstDay);
  return Math.floor(
    (startOfDay(date).getTime() - firstWeekStart.getTime()) /
      (7 * 86400000)
  );
};