"""Opaque cursor pagination (``API-STANDARD.md`` §6)."""

from __future__ import annotations

from typing import Any

from rest_framework.pagination import CursorPagination as DRFCursorPagination
from rest_framework.response import Response

__all__ = ["CursorPagination"]


class CursorPagination(DRFCursorPagination):
    """Cursor pagination with a camelCase ``pageSize`` param and envelope meta.

    Defaults to ordering by ``-pk`` so it works on every model out of the box;
    views with a preferred ordering override the ``ordering`` attribute.
    """

    page_size = 25
    max_page_size = 100
    page_size_query_param = "pageSize"
    cursor_query_param = "cursor"
    ordering = "-pk"

    def get_paginated_response(self, data: Any) -> Response:
        return Response(
            {
                "next": self.get_next_link(),
                "previous": self.get_previous_link(),
                "page_size": self.page_size,
                "results": data,
            }
        )