# models ********************

class Section(models.Model):
	"""
	A section has a begin and end valid date
	which represents : 'Where can we interact with all related/children objects ?'
	"""
	title = models.CharField(_(u"Title"), max_length=200)
	begin = models.DateField(_(u"Date début"))
	end = models.DateField(_(u"Date fin"))


class Article(models.Model):
	"""
	Simple object 
	"""
	title = models.CharField(_(u"Title"), max_length=200)
	section = models.ForeignKey(Section, blank=True)


class Item(models.Model):
	"""
	This item is related to an article
	It has to know when it is valid, 
	a date between its section begin/end 
	"""
	title = models.CharField(_(u"Title"), max_length=200)
	date = models.DateField()



# forms ********************

class ItemForm(forms.ModelForm):
	"""
	The date has to be a list of choices
	from self.article.section.begin / end
	"""
	date = ChoiceField(choices={})

	def __init__(self, section, *args, **kwargs):
		super(ItemForm, self).__init__(*args, **kwargs)
		begin = date(2009, 06, 16) #section.begin
		end = date(2009, 06, 18) #section.end 
		daterange = end-begin
		choices = [('','-----')]
		for i in range(daterange.days):
			date_in = (begin + timedelta(i))
			verbose_date = "%s %s %s" % (date_in.day, month_name(date_in.month), date_in.year)
			choices.append((date_in, verbose_date))
		self.fields['date'].choices=choices

	class Meta:
		model = Item


class ArticleForm(ModelForm):
	class Meta:
		model = Article



# views ********************

def items_form(request, section_id, article_id=None):
	"""
	Create/Update an article and its related items
	"""
	section = get_object_or_404(Section, id=section_id)

	try:
		article = Article.objects.get(id=article_id)
	except Article.DoesNotExist:
		article = Article()

	ItemFormSet = inlineformset_factory(Article, Item, form=ItemForm, extra=2, can_delete=True)

	if request.method == "POST":
		form = ArticleForm(data=request.POST, instance=article)
		formset = ItemFormSet(request.POST, instance=article, **kwargs)
	
		if form.is_valid() and sessionformset.is_valid():
			object = form.save(commit=False)
			object.section=section
			object.save()
			sessionformset.save()
		
			# do something ...
		
	else:
		form = ArticleForm(instance=article)
		formset = ItemFormSet(instance=article, **kwargs)

	# render template ...