"""
This is a copy of django.contrib.auth.mixins module, shipped with django-rules
for compatibility with Django versions before 1.9. Used under permission by
the Django Software Foundation.

Copyright (c) Django Software Foundation and individual contributors.
All rights reserved.

Redistribution and use in source and binary forms, with or without modification,
are permitted provided that the following conditions are met:

    1. Redistributions of source code must retain the above copyright notice,
       this list of conditions and the following disclaimer.

    2. Redistributions in binary form must reproduce the above copyright
       notice, this list of conditions and the following disclaimer in the
       documentation and/or other materials provided with the distribution.

    3. Neither the name of Django nor the names of its contributors may be used
       to endorse or promote products derived from this software without
       specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
"""

from django.conf import settings
from django.contrib.auth import REDIRECT_FIELD_NAME
from django.contrib.auth.views import redirect_to_login
from django.core.exceptions import ImproperlyConfigured, PermissionDenied
from django.utils import six
from django.utils.encoding import force_text


class AccessMixin(object):
    """
    Abstract CBV mixin that gives access mixins the same customizable
    functionality.
    """
    login_url = None
    permission_denied_message = ''
    raise_exception = False
    redirect_field_name = REDIRECT_FIELD_NAME

    def get_login_url(self):
        """
        Override this method to override the login_url attribute.
        """
        login_url = self.login_url or settings.LOGIN_URL
        if not login_url:
            raise ImproperlyConfigured(
                '{0} is missing the login_url attribute. Define {0}.login_url, settings.LOGIN_URL, or override '
                '{0}.get_login_url().'.format(self.__class__.__name__)
            )
        return force_text(login_url)

    def get_permission_denied_message(self):
        """
        Override this method to override the permission_denied_message attribute.
        """
        return self.permission_denied_message

    def get_redirect_field_name(self):
        """
        Override this method to override the redirect_field_name attribute.
        """
        return self.redirect_field_name

    def handle_no_permission(self):
        if self.raise_exception:
            raise PermissionDenied(self.get_permission_denied_message())
        return redirect_to_login(self.request.get_full_path(), self.get_login_url(), self.get_redirect_field_name())


class LoginRequiredMixin(AccessMixin):
    """
    CBV mixin which verifies that the current user is authenticated.
    """
    def dispatch(self, request, *args, **kwargs):
        if not request.user.is_authenticated():
            return self.handle_no_permission()
        return super(LoginRequiredMixin, self).dispatch(request, *args, **kwargs)


class PermissionRequiredMixin(AccessMixin):
    """
    CBV mixin which verifies that the current user has all specified
    permissions.
    """
    permission_required = None

    def get_permission_required(self):
        """
        Override this method to override the permission_required attribute.
        Must return an iterable.
        """
        if self.permission_required is None:
            raise ImproperlyConfigured(
                '{0} is missing the permission_required attribute. Define {0}.permission_required, or override '
                '{0}.get_permission_required().'.format(self.__class__.__name__)
            )
        if isinstance(self.permission_required, six.string_types):
            perms = (self.permission_required, )
        else:
            perms = self.permission_required
        return perms

    def has_permission(self):
        """
        Override this method to customize the way permissions are checked.
        """
        perms = self.get_permission_required()
        return self.request.user.has_perms(perms)

    def dispatch(self, request, *args, **kwargs):
        if not self.has_permission():
            return self.handle_no_permission()
        return super(PermissionRequiredMixin, self).dispatch(request, *args, **kwargs)


class UserPassesTestMixin(AccessMixin):
    """
    CBV Mixin that allows you to define a test function which must return True
    if the current user can access the view.
    """

    def test_func(self):
        raise NotImplementedError(
            '{0} is missing the implementation of the test_func() method.'.format(self.__class__.__name__)
        )

    def get_test_func(self):
        """
        Override this method to use a different test_func method.
        """
        return self.test_func

    def dispatch(self, request, *args, **kwargs):
        user_test_result = self.get_test_func()()
        if not user_test_result:
            return self.handle_no_permission()
        return super(UserPassesTestMixin, self).dispatch(request, *args, **kwargs)
