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

const dayFormatter = new Intl.DateTimeFormat('en-CA', {
  timeZone: 'Asia/Shanghai',
  year: 'numeric',
  month: '2-digit',
  day: '2-digit',
});
export const todayKey = (now = new Date()) => dayFormatter.format(now);
export const databaseDay = (key: string) => new Date(`${key}T00:00:00.000Z`);
export const startOfDay = (key: string) => new Date(`${key}T00:00:00+08:00`);
export const addDays = (key: string, days: number) =>
  new Date(databaseDay(key).getTime() + days * 86_400_000).toISOString().slice(0, 10);
export function analyticsDate(value?: string, now = new Date()) {
  const key = value || todayKey(now);
  if (
    !/^\d{4}-\d{2}-\d{2}$/.test(key) ||
    !Number.isFinite(databaseDay(key).getTime()) ||
    databaseDay(key).toISOString().slice(0, 10) !== key ||
    key > todayKey(now)
  ) {
    throw new BadRequestException('统计日期必须为有效的北京时间日期，不能晚于今天');
  }
  return key;
}
export function analyticsPage(page = 1, pageSize = 25) {
  if (!Number.isInteger(page) || page < 1 || ![10, 25, 50, 100].includes(pageSize))
    throw new BadRequestException('分页参数无效');
  return { page, pageSize };
}
export const mutableDay = (day: string, now = new Date()) => day < todayKey(now) && day >= addDays(todayKey(now), -3);