/* eslint-disable eslint-comments/no-unlimited-disable */
/* eslint-disable */
// @ts-nocheck

import { normalizeDates } from '../_lib/normalizeDates/index.ts';
import { addDays } from '../addDays/index.ts';
import { differenceInCalendarDays } from '../differenceInCalendarDays/index.ts';
import { isSameDay } from '../isSameDay/index.ts';
import { isValid } from '../isValid/index.ts';
import { isWeekend } from '../isWeekend/index.ts';
import type { ContextOptions, DateArg } from '../types.ts';

/**
 * The {@link differenceInBusinessDays} function options.
 */
export interface DifferenceInBusinessDaysOptions extends ContextOptions<Date> {}

/**
 * @name differenceInBusinessDays
 * @category Day Helpers
 * @summary Get the number of business days between the given dates.
 *
 * @description
 * Get the number of business day periods between the given dates.
 * Business days being days that aren't in the weekend.
 * Like `differenceInCalendarDays`, the function removes the times from
 * the dates before calculating the difference.
 *
 * @param laterDate - The later date
 * @param earlierDate - The earlier date
 * @param options - An object with options
 *
 * @returns The number of business days
 *
 * @example
 * // How many business days are between
 * // 10 January 2014 and 20 July 2014?
 * const result = differenceInBusinessDays(
 *   new Date(2014, 6, 20),
 *   new Date(2014, 0, 10)
 * )
 * //=> 136
 *
 * // How many business days are between
 * // 30 November 2021 and 1 November 2021?
 * const result = differenceInBusinessDays(
 *   new Date(2021, 10, 30),
 *   new Date(2021, 10, 1)
 * )
 * //=> 21
 *
 * // How many business days are between
 * // 1 November 2021 and 1 December 2021?
 * const result = differenceInBusinessDays(
 *   new Date(2021, 10, 1),
 *   new Date(2021, 11, 1)
 * )
 * //=> -22
 *
 * // How many business days are between
 * // 1 November 2021 and 1 November 2021 ?
 * const result = differenceInBusinessDays(
 *   new Date(2021, 10, 1),
 *   new Date(2021, 10, 1)
 * )
 * //=> 0
 */
export function differenceInBusinessDays(
  laterDate: DateArg<Date> & {},
  earlierDate: DateArg<Date> & {},
  options?: DifferenceInBusinessDaysOptions | undefined,
): number {
  const [laterDate_, earlierDate_] = normalizeDates(options?.in, laterDate, earlierDate);

  if (!isValid(laterDate_) || !isValid(earlierDate_)) return NaN;

  const diff = differenceInCalendarDays(laterDate_, earlierDate_);
  const sign = diff < 0 ? -1 : 1;
  const weeks = Math.trunc(diff / 7);

  let result = weeks * 5;
  let movingDate = addDays(earlierDate_, weeks * 7);

  // the loop below will run at most 6 times to account for the remaining days that don't makeup a full week
  while (!isSameDay(laterDate_, movingDate)) {
    // sign is used to account for both negative and positive differences
    result += isWeekend(movingDate, options) ? 0 : sign;
    movingDate = addDays(movingDate, sign);
  }

  // Prevent negative zero
  return result === 0 ? 0 : result;
}

/* eslint-enable */