mister-webdev / movie-app

import { useMemo } from 'react'

import { IPagination } from './types'

const DOTS = 0

const range = (start: number, end: number) => {

  const length = end - start + 1

  return Array.from({ length }, (_, idx) => idx + start)

}

const usePagination = ({

  totalPages,

  siblingCount = 1,

  currentPage,

}: IPagination) => {

  const paginationRange = useMemo(() => {

    const totalPageNumbers = siblingCount + 5

    if (totalPageNumbers >= totalPages) {

      return range(1, totalPages)

    }

    const leftSiblingIndex = Math.max(currentPage - siblingCount, 1)

    const rightSiblingIndex = Math.min(currentPage + siblingCount, totalPages)

    const showLeftDots = leftSiblingIndex > 2

    const showRightDots = rightSiblingIndex < totalPages - 2

    const firstPageIndex = 1

    const lastPageIndex = totalPages

    if (!showLeftDots && showRightDots) {

      const leftItemCount = 3 + 2 * siblingCount

      const leftRange = range(1, leftItemCount)

      return [...leftRange, DOTS, totalPages]

    }

    if (showLeftDots && !showRightDots) {

      const rightItemCount = 3 + 2 * siblingCount

      const rightRange = range(totalPages - rightItemCount + 1, totalPages)

      return [firstPageIndex, DOTS, ...rightRange]

    }

    if (showLeftDots && showRightDots) {

      return [firstPageIndex, DOTS, ...middleRange, DOTS, lastPageIndex]

    }

  }, [currentPage, totalPages, siblingCount])

  return paginationRange

}

export { usePagination, DOTS }