import {
  Pagination,
  PaginationContent,
  PaginationEllipsis,
  PaginationItem,
  PaginationLink,
  PaginationNext,
  PaginationPrevious,
} from "@/components/ui/pagination";

interface Props {
  page: number;
  totalPages: number;
  buildHref: (page: number) => string;
}

function pageNumbers(
  page: number,
  totalPages: number
): (number | "ellipsis")[] {
  if (totalPages <= 7) {
    return Array.from({ length: totalPages }, (_, i) => i + 1);
  }

  const pages: (number | "ellipsis")[] = [1];

  if (page > 3) pages.push("ellipsis");

  const start = Math.max(2, page - 1);
  const end = Math.min(totalPages - 1, page + 1);
  for (let i = start; i <= end; i++) pages.push(i);

  if (page < totalPages - 2) pages.push("ellipsis");

  pages.push(totalPages);

  return pages;
}

export function PaginationNav({ page, totalPages, buildHref }: Props) {
  if (totalPages <= 1) return null;

  return (
    <Pagination className="mt-8">
      <PaginationContent>
        <PaginationItem>
          <PaginationPrevious
            href={page > 1 ? buildHref(page - 1) : "#"}
            aria-disabled={page <= 1}
          />
        </PaginationItem>

        {pageNumbers(page, totalPages).map((p, i) =>
          p === "ellipsis" ? (
            <PaginationItem key={`ellipsis-${i}`}>
              <PaginationEllipsis />
            </PaginationItem>
          ) : (
            <PaginationItem key={p}>
              <PaginationLink href={buildHref(p)} isActive={p === page}>
                {p}
              </PaginationLink>
            </PaginationItem>
          )
        )}

        <PaginationItem>
          <PaginationNext
            href={page < totalPages ? buildHref(page + 1) : "#"}
            aria-disabled={page >= totalPages}
          />
        </PaginationItem>
      </PaginationContent>
    </Pagination>
  );
}