from rest_framework import viewsets,filters
from rest_framework.permissions import BasePermission, AllowAny
from . import models as m
from . import views

from seminar.permissions import AllowWrite 

class PermissionMixin(object):
	""" Redefines get_permissions so that only organizers can make changes. """

	def get_permissions(self):
		permission_classes = []
		print("get_permissions have been called.")
		if self.action in ["create", "update", "partial_update", "destroy"]:
			permission_classes = [AllowWrite] # speciální permission na zápis - orgové
		else:
			permission_classes = [AllowAny] 
		# návštěvník nemusí být zalogován, aby si prohlížel obsah
		return [permission() for permission in permission_classes]

class ReadWriteSerializerMixin(object):
	"""
	Overrides get_serializer_class to choose the read serializer
	for GET requests and the write serializer for POST requests.

	Set read_serializer_class and write_serializer_class attributes on a
	viewset. 
	"""

	read_serializer_class = None
	create_serializer_class = None
	write_serializer_class = None

	def get_serializer_class(self):		
		if self.action == "create":
			return self.get_create_serializer_class()
		if self.action in ["update", "partial_update", "destroy"]:
			return self.get_write_serializer_class()
		return self.get_read_serializer_class()

	def get_read_serializer_class(self):
		assert self.read_serializer_class is not None, (
			"'%s' should either include a `read_serializer_class` attribute,"
			"or override the `get_read_serializer_class()` method."
			% self.__class__.__name__
		)
		return self.read_serializer_class

	def get_write_serializer_class(self):
		assert self.write_serializer_class is not None, (
			"'%s' should either include a `write_serializer_class` attribute,"
			"or override the `get_write_serializer_class()` method."
			% self.__class__.__name__
		)
		return self.write_serializer_class

	def get_create_serializer_class(self):
		assert self.create_serializer_class is not None, (
			"'%s' should either include a `create_serializer_class` attribute,"
			"or override the `get_create_serializer_class()` method."
			% self.__class__.__name__
		)
		return self.create_serializer_class

class UlohaVzorakNodeViewSet(PermissionMixin, viewsets.ModelViewSet):
	queryset = m.UlohaVzorakNode.objects.all()
	serializer_class = views.UlohaVzorakNodeSerializer

class TextViewSet(PermissionMixin, viewsets.ModelViewSet):
	queryset = m.Text.objects.all()
	serializer_class = views.TextSerializer

class TextNodeViewSet(PermissionMixin, ReadWriteSerializerMixin,viewsets.ModelViewSet):
	queryset = m.TextNode.objects.all()
	read_serializer_class = views.TextNodeSerializer
	write_serializer_class = views.TextNodeWriteSerializer
	create_serializer_class = views.TextNodeCreateSerializer

class CastNodeViewSet(PermissionMixin, ReadWriteSerializerMixin,viewsets.ModelViewSet):
	queryset = m.CastNode.objects.all()
	read_serializer_class = views.CastNodeSerializer
	write_serializer_class = views.CastNodeSerializer
	create_serializer_class = views.CastNodeCreateSerializer

class UlohaVzorakNodeViewSet(PermissionMixin, viewsets.ModelViewSet):
	serializer_class = views.UlohaVzorakNodeSerializer

	def get_queryset(self):
		queryset = m.UlohaVzorakNode.objects.all()
		nazev = self.request.query_params.get('nazev',None)
		if nazev is not None:
			queryset = queryset.filter(nazev__contains=nazev)
		if self.request.user.has_perm('auth.org'):
			return queryset
		else: # pro neorgy jen zveřejněné vzoráky
			return queryset.filter(uloha__cislo_reseni__verejne_db=True)