export const hours: Record<number,[number,number]> = {2:[600,1080],3:[600,1080],4:[660,1140],5:[600,1080],6:[540,900]};
export function daySlots(date:string,duration:number) {
  if(!/^\d{4}-\d{2}-\d{2}$/.test(date))return [];
  const day=new Date(`${date}T12:00:00`);
  if(!Number.isFinite(day.getTime()) || day.toISOString().slice(0,10)!==date)return [];
  const today=new Date(); today.setHours(0,0,0,0);
  if(day<today || day.getTime()>today.getTime()+90*86400000)return [];
  const range=hours[day.getDay()]; if(!range)return [];
  const result:string[]=[];
  for(let minute=range[0];minute+duration<=range[1];minute+=30){
    const time=`${Math.floor(minute/60).toString().padStart(2,"0")}:${(minute%60).toString().padStart(2,"0")}`;
    if(new Date(`${date}T${time}`)>new Date())result.push(time);
  }
  return result;
}