from django.shortcuts import render
from django.contrib.auth.mixins import (LoginRequiredMixin,
                                        PermissionRequiredMixin)

from django.contrib.admin.views.decorators import staff_member_required


from django.urls import reverse, reverse_lazy
from django.views import generic

from courses.models import Course
from courses.forms import CourseForm, CourseUnitFormset

class CreateCourse(LoginRequiredMixin,generic.CreateView):
    form_class = CourseForm
    template_name = 'courses/course_form.html'

    def get_success_url(self):
        return reverse('courses:list')

    def get_context_data(self, **kwargs):
        context = super(CreateCourse, self).get_context_data(**kwargs)
        if self.request.POST:
            context['courseunit_formset'] = CourseUnitFormset(self.request.POST)
        else:
            context['courseunit_formset'] = CourseUnitFormset()
        return context

    def form_valid(self, form):
        form.instance.user = self.request.user
        context = self.get_context_data(form=form)
        formset = context['courseunit_formset']
        if formset.is_valid():
            response = super().form_valid(form)
            formset.instance = self.object
            formset.save()
            return response
        else:
            return super().form_invalid(form)

class SingleCourse(generic.DetailView):
    model = Course

class ListCourses(generic.ListView):
    model = Course
    paginate_by = 10

class DeleteCourse(LoginRequiredMixin,generic.DeleteView):
    model = Course
    success_url = reverse_lazy('courses:list')

class UpdateCourse(LoginRequiredMixin,generic.UpdateView):
    form_class = CourseForm
    template_name = 'courses/course_form.html'
    model = Course

    def get_success_url(self):
        return reverse('courses:show', kwargs={'pk': self.kwargs['pk']})

    def get_context_data(self, **kwargs):
        context = super(UpdateCourse, self).get_context_data(**kwargs)
        if self.request.POST:
            context['courseunit_formset'] = CourseUnitFormset(self.request.POST, instance=self.object)
            context['courseunit_formset'].full_clean()
        else:
            context['courseunit_formset'] = CourseUnitFormset(instance=self.object)
        return context

    def form_valid(self, form):
        context = self.get_context_data(form=form)
        formset = context['courseunit_formset']
        if formset.is_valid():
            response = super().form_valid(form)
            formset.instance = self.object
            formset.save()
            return response
        else:
            return super().form_invalid(form)