# This file is part of k4ever, a point-of-sale system
#   Contact............  <k4ever@lists.someserver.de>
#   Website............  http://k4ever.someserver.de/
#   Bug tracker........  http://k4ever.someserver.de/report
#
# Licensed under GNU Affero General Public License v3 or later

from django.conf import settings
from django.contrib.auth import REDIRECT_FIELD_NAME
from django.http import HttpResponse, HttpResponseRedirect
from django.utils.http import urlquote


class DjangoAuthentication(object):
	"""
	Authenticate against djangos own authentication backend
	"""

	def is_authenticated(self, request):
		""" Check, if user is already authenticated.
		
		From piston docs:
		`is_authenticated`: Will be called when checking for
		authentication. Receives a `request` object, please
		set your `User` object on `request.user`, otherwise
		return False (or something that evaluates to False.)
		"""
		self.request = request
		return request.user.is_authenticated()

	def challenge(self):
		""" Redirect unauthenticated requests to login form

		From piston docs
		`challenge`: In cases where `is_authenticated` returns
		False, the result of this method will be returned.
		This will usually be a `HttpResponse` object with
		some kind of challenge headers and 401 code on it.
		"""

		loginPage = "%s?%s=%s" % (
			settings.LOGIN_URL,
			REDIRECT_FIELD_NAME,
			urlquote(self.request.get_full_path()),
		)
		return HttpResponseRedirect(loginPage)


class MultiAuthentication(object):
	"""  """
	def __init__(self, authenticators):
		if len(authenticators) ==0:
			raise ValueError("MultiAuthentication needs at least one authenticator in list")
		self.authenticators = authenticators
		self.currentAuthenticator = self.authenticators[0]

	def is_authenticated(self, request):
		""" Try to authenticate against all given authenticators. """
		for authenticator in self.authenticators:
			if authenticator.is_authenticated(request):
				# success!
				self.currentAuthenticator = authenticator
				return True
		return False

	def challenge(self):
		""" Return challenge for current or default authenticator. """
		return self.currentAuthenticator.challenge()