from django.core.paginator import Paginator, InvalidPage


DEFAULT_PER_PAGE = 10
DEFAULT_ORPHANS = 5

DEFAULT_PAGE_VAR = 'page'


def pagination(request, object_list):
    paginator = Paginator(object_list, DEFAULT_PER_PAGE, DEFAULT_ORPHANS)

    try:
        page_number = int(request.GET.get(DEFAULT_PAGE_VAR) or 1)
        page_obj = paginator.page(page_number)
    except (ValueError, InvalidPage) as e:
        page_obj = paginator.page(page_number)  # show first page on error

    request_GET = request.GET.copy()
    if DEFAULT_PAGE_VAR in request_GET:
        del request_GET[DEFAULT_PAGE_VAR]

    if len(request_GET.keys()) > 0:
        getvars = '&%s' % request_GET.urlencode()
    else:
        getvars = ''

    return paginator, page_obj, getvars