from django.conf import settings
from django.core.paginator import Paginator
from django import forms
from django.db import models
from django.views.generic import TemplateView
from django.shortcuts import get_object_or_404, render


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 = []

    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": "my-2 bg-gray-50 border border-gray-300 text-gray-900 sm:text-sm rounded-lg "
                    "focus:ring-primary-600 focus:border-primary-600 block w-full p-2.5 dark:bg-gray-700 "
                    "dark:border-gray-600 dark:placeholder-gray-400 dark:text-white dark:focus:ring-primary-500 "
                    "dark:focus:border-primary-500"
                }
            )

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


class ReadUpdateView(TemplateView):
    model: models.Model = None
    form_class: forms.ModelForm = None
    template_name: str = ""
    ok_template_name: str = ""
    error_template_name: str = ""

    def get_model(self):
        return self.model

    def get_object(self):
        pk = self.kwargs.get('pk')
        cls = self.get_model()
        return get_object_or_404(cls, pk=pk)

    def get_initial_values(self, instance):
        return {}

    def get_context_data(self, **kwargs):
        instance = self.get_object()
        form = self.form_class(initial=self.get_initial_values(instance))

        return {
            "form": form,
        }

    def post(self, request, *args, **kwargs):
        form = self.form_class(request.POST)

        if form.is_valid():
            instance = form.save()
            return render(request, self.ok_template_name, {
                "form": form,
                "instance": instance,
            })

        return render(request, self.error_template_name, {
            "form": form,
        })