from django.conf import settings
from django.core.paginator import Paginator


class FilteredQuerysetMixin:
    queryset = None
    filter_class = None

    def get_filter_class(self):
        return self.filter_class

    def get_queryset(self):
        filter_cls = self.get_filter_class()
        filter_obj = filter_cls(self.request.GET)
        filter_obj.is_valid()
        qs = filter_obj.filter_queryset(self.queryset)
        return qs


class PaginatedQuerysetMixin:
    objects_per_page = settings.ITEMS_PER_PAGE or 20

    def get_paginated_queryset(self, qs):
        paginator = Paginator(qs, self.objects_per_page)
        page = self.request.GET.get('page', 1)
        qs = paginator.get_page(page)
        return qs


class StylingMixin:
    placeholder_for_field = {}
    styled_fields = []
    classes = {'input w-full'}

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.style_fields()

    def style_fields(self):
        for field_name in self.styled_fields:
            field = self.fields[field_name]
            field.required = True
            field.widget.attrs.update({'class': ' '.join(self.classes)})

            if self.placeholder_for_field.get(field_name):
                field.widget.attrs.update({
                    'placeholder': self.placeholder_for_field.get(field_name),
                })