export function timeFromHHMM(hhmm: string): Date {
  const [h, m] = hhmm.split(':').map(Number);
  return new Date(1970, 0, 1, h, m, 0, 0); 
}

export function toDateOnly(ymd: string): Date {
  const y = Number(ymd.slice(0, 4));
  const m = Number(ymd.slice(5, 7)) - 1;
  const d = Number(ymd.slice(8, 10));
  return new Date(y, m, d, 0, 0, 0, 0); 
}

export function weekStartSunday(date_local: Date): Date {
  const start = new Date(Date.UTC(date_local.getFullYear(), date_local.getMonth(), date_local.getDate()));
  const dow = start.getDay(); // 0 = dimanche
  start.setDate(start.getDate() - dow);
  start.setHours(0, 0, 0, 0);
  return start;
}

export function formatHHmm(t: Date): string {
  const hh = String(t.getHours()).padStart(2, '0');
  const mm = String(t.getMinutes()).padStart(2, '0');
  return `${hh}:${mm}`;
}