import type { PhpArrayLike, PhpRuntimeValue } from '../_helpers/_phpTypes.ts'

type RandomValue = PhpRuntimeValue

export function array_rand<TValue extends RandomValue>(array: PhpArrayLike<TValue>): string | null
export function array_rand<TValue extends RandomValue>(
  array: PhpArrayLike<TValue>,
  num: null | undefined,
): string | null
export function array_rand<TValue extends RandomValue>(array: PhpArrayLike<TValue>, num: 1): string | null
export function array_rand<TValue extends RandomValue>(
  array: PhpArrayLike<TValue>,
  num: number,
): string | string[] | null
export function array_rand<TValue extends RandomValue>(
  array: PhpArrayLike<TValue>,
  num?: number | null,
): string | string[] | null {
  //       discuss at: https://locutus.io/php/array_rand/
  //      original by: Waldo Malqui Silva (https://waldo.malqui.info)
  // reimplemented by: Rafał Kukawski
  //        example 1: array_rand( ['Kevin'], 1 )
  //        returns 1: '0'

  // By using Object.keys we support both, arrays and objects
  // which phpjs wants to support
  const keys = Object.keys(array)

  if (typeof num === 'undefined' || num === null) {
    num = 1
  } else {
    num = +num
  }

  if (isNaN(num) || num < 1 || num > keys.length) {
    return null
  }

  // shuffle the array of keys
  for (let i = keys.length - 1; i > 0; i--) {
    const j = Math.floor(Math.random() * (i + 1)) // 0 ≤ j ≤ i

    const tmp = keys[j]
    const current = keys[i]
    if (tmp === undefined || current === undefined) {
      return null
    }
    keys[j] = current
    keys[i] = tmp
  }

  return num === 1 ? (keys[0] ?? null) : keys.slice(0, num)
}