import { BadRequestException } from "@nestjs/common";

export const hhmmFromLocal = (d: Date) =>
  `${String(d.getHours()).padStart(2,'0')}:${String(d.getMinutes()).padStart(2,'0')}`;

export const toDateOnly = (s: string): Date => {
  if (/^\d{4}-\d{2}-\d{2}$/.test(s)) {
    const y = Number(s.slice(0,4));
    const m = Number(s.slice(5,7)) - 1;
    const d = Number(s.slice(8,10));
    return new Date(y, m, d, 0, 0, 0, 0); 
  }
  const dt = new Date(s);
  if (Number.isNaN(dt.getTime())) throw new BadRequestException(`Invalid date: ${s}`);
  return new Date(dt.getFullYear(), dt.getMonth(), dt.getDate(), 0,0,0,0);
};

// export const toStringFromDate = (d: Date) =>
//   `${d.getFullYear()}-${String(d.getMonth()+1).padStart(2,'0')}-${String(d.getDate()).padStart(2,'0')}`;


export const toISOtoDateOnly = (iso: string): Date => {
    const date = new Date(iso);
    if (Number.isNaN(date.getTime())) {
        throw new BadRequestException(`Invalid date: ${iso}`);
    }
    date.setHours(0, 0, 0, 0);
    return date;
};

export const toISODateKey = (date: Date): string => date.toISOString().slice(0, 10);

export const normalizeDates = (dates: string[]): string[] =>
    Array.from(new Set(dates.map((iso) => toISODateKey(toISOtoDateOnly(iso)))));