export type PaginationPageControlMode = 'select' | 'display'

interface PaginationDisplayStateArgs {
  pageIndex: number
  pageSize?: number
  totalCount?: number
  currentPageCount?: number
}

interface PaginationControlsStateArgs {
  pageIndex: number
  pageSize?: number
  totalCount?: number
  canNextPage?: boolean
  pageControlMode?: PaginationPageControlMode
}

export function getPaginationDisplayState({
  pageIndex,
  pageSize,
  totalCount,
  currentPageCount,
}: PaginationDisplayStateArgs) {
  if (pageSize === undefined) {
    return {
      hasTotalCount: totalCount !== undefined,
      canRenderDisplay: false,
      start: 0,
      end: 0,
    }
  }

  const hasTotalCount = totalCount !== undefined
  const effectiveCurrentPageCount = hasTotalCount
    ? Math.max(0, Math.min(pageSize, (totalCount ?? 0) - pageIndex * pageSize))
    : Math.max(0, currentPageCount ?? 0)
  const hasRows = effectiveCurrentPageCount > 0
  const start = hasRows ? pageIndex * pageSize + 1 : 0
  const end = hasTotalCount
    ? Math.min((pageIndex + 1) * pageSize, totalCount)
    : hasRows
      ? start + effectiveCurrentPageCount - 1
      : 0

  return {
    hasTotalCount,
    canRenderDisplay: hasRows,
    start,
    end,
  }
}

export function getPaginationControlsState({
  pageIndex,
  pageSize,
  totalCount,
  canNextPage: canNextPageProp,
  pageControlMode = 'select',
}: PaginationControlsStateArgs) {
  const pageCount =
    totalCount !== undefined && pageSize !== undefined
      ? Math.ceil(totalCount / pageSize)
      : undefined

  const effectivePageControlMode =
    pageControlMode === 'select' && pageCount !== undefined
      ? 'select'
      : 'display'

  const canPreviousPage = pageIndex > 0
  const canNextPage =
    canNextPageProp ??
    (pageCount !== undefined ? pageIndex < pageCount - 1 : false)

  return {
    currentPage: pageIndex + 1,
    pageCount,
    effectivePageControlMode,
    canPreviousPage,
    canNextPage,
    canRenderControls: canPreviousPage || canNextPage,
  }
}