import markdown

from django import forms
from django.http import HttpResponse
from django.shortcuts import get_object_or_404, redirect
from django.template.defaultfilters import slugify
from django.views.decorators.http import require_POST
from django.views.generic import (DetailView, ListView,
        CreateView, UpdateView, DeleteView)

from .models import News


def find_unique_slug(newsitem):
    '''Attempt to find a unique slug for this news item.'''
    existing = list(News.objects.values_list(
        'slug', flat=True).order_by().distinct())

    suffixed = slug = slugify(newsitem.title)
    suffix = 0
    while suffixed in existing:
        suffix += 1
        suffixed = "%s-%d" % (slug, suffix)

    return suffixed


class NewsForm(forms.ModelForm):
    class Meta:
        model = News
        exclude = ('id', 'slug', 'author', 'postdate')


class NewsDetailView(DetailView):
    model = News
    template_name = "news/view.html"


class NewsListView(ListView):
    queryset = News.objects.all().select_related('author').defer('content')
    template_name = "news/list.html"
    paginate_by = 50


class NewsCreateView(CreateView):
    model = News
    form_class = NewsForm
    template_name = "news/add.html"

    def form_valid(self, form):
        # special logic, we auto-fill the author and slug fields
        newsitem = form.save(commit=False)
        newsitem.author = self.request.user
        newsitem.slug = find_unique_slug(newsitem)
        newsitem.save()
        return super(NewsCreateView, self).form_valid(form)


class NewsEditView(UpdateView):
    model = News
    form_class = NewsForm
    template_name = "news/add.html"


class NewsDeleteView(DeleteView):
    model = News
    template_name = "news/delete.html"
    success_url = "/news/"


def view_redirect(request, object_id):
    newsitem = get_object_or_404(News, pk=object_id)
    return redirect(newsitem, permanent=True)


@require_POST
def preview(request):
    data = request.POST.get('data', '')
    markup = markdown.markdown(data, safe_mode=True, enable_attributes=False)
    return HttpResponse(markup)

# vim: set ts=4 sw=4 et: