web/packages/common/dt/utils/hasOverlappingDates.ts

import { dt } from "../dt"

import type { Dayjs } from "../dt"

export function hasOverlappingDates(
  dateRangeItem: {
    startDate: Date | Dayjs | string | undefined | null
    endDate: Date | Dayjs | string | undefined | null
  },
  fromDate: Date | Dayjs,
  toDate: Date | Dayjs
) {
  const startDate = dt.utc(fromDate)
  const endDate = dt.utc(toDate)

  if (dateRangeItem.endDate && dateRangeItem.startDate) {
    const itemStartDate = dt(dateRangeItem.startDate)
    const itemEndDate = dt(dateRangeItem.endDate)

    const fromDateIsBetweenItemDates = startDate.isBetween(
      itemStartDate,
      itemEndDate,
      "date",
      "[]"
    )
    const toDateIsBetweenItemDates = endDate.isBetween(
      itemStartDate,
      itemEndDate,
      "date",
      "[]"
    )

    const itemFullyContained =
      startDate.isSameOrBefore(itemStartDate, "date") &&
      endDate.isSameOrAfter(itemEndDate, "date")

    return (
      fromDateIsBetweenItemDates ||
      toDateIsBetweenItemDates ||
      itemFullyContained
    )
  }
  return true
}