"""
Tests use cases related to LMS Entrance Exam behavior, such as gated content access (TOC)
"""
from mock import patch, Mock

from django.core.urlresolvers import reverse
from django.test.client import RequestFactory
from nose.plugins.attrib import attr

from capa.tests.response_xml_factory import MultipleChoiceResponseXMLFactory
from courseware.model_data import FieldDataCache
from courseware.module_render import toc_for_course, get_module, handle_xblock_callback
from courseware.tests.factories import UserFactory, InstructorFactory, StaffFactory
from courseware.tests.helpers import (
    LoginEnrollmentTestCase,
    get_request_for_user
)
from courseware.entrance_exams import (
    course_has_entrance_exam,
    get_entrance_exam_content,
    get_entrance_exam_score,
    user_can_skip_entrance_exam,
    user_has_passed_entrance_exam,
)
from student.models import CourseEnrollment
from student.tests.factories import CourseEnrollmentFactory, AnonymousUserFactory
from util.milestones_helpers import (
    add_milestone,
    add_course_milestone,
    get_namespace_choices,
    generate_milestone_namespace,
    add_course_content_milestone,
    get_milestone_relationship_types,
)
from milestones.tests.utils import MilestonesTestCaseMixin
from xmodule.modulestore.django import modulestore
from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
from xmodule.modulestore.tests.factories import CourseFactory, ItemFactory


@attr('shard_2')
@patch.dict('django.conf.settings.FEATURES', {'ENTRANCE_EXAMS': True, 'MILESTONES_APP': True})
class EntranceExamTestCases(LoginEnrollmentTestCase, ModuleStoreTestCase, MilestonesTestCaseMixin):
    """
    Check that content is properly gated.

    Creates a test course from scratch. The tests below are designed to execute
    workflows regardless of the feature flag settings.
    """
    @patch.dict('django.conf.settings.FEATURES', {'ENTRANCE_EXAMS': True, 'MILESTONES_APP': True})
    def setUp(self):
        """
        Test case scaffolding
        """
        super(EntranceExamTestCases, self).setUp()
        self.course = CourseFactory.create(
            metadata={
                'entrance_exam_enabled': True,
            }
        )
        self.chapter = ItemFactory.create(
            parent=self.course,
            display_name='Overview'
        )
        self.welcome = ItemFactory.create(
            parent=self.chapter,
            display_name='Welcome'
        )
        ItemFactory.create(
            parent=self.course,
            category='chapter',
            display_name="Week 1"
        )
        self.chapter_subsection = ItemFactory.create(
            parent=self.chapter,
            category='sequential',
            display_name="Lesson 1"
        )
        chapter_vertical = ItemFactory.create(
            parent=self.chapter_subsection,
            category='vertical',
            display_name='Lesson 1 Vertical - Unit 1'
        )
        ItemFactory.create(
            parent=chapter_vertical,
            category="problem",
            display_name="Problem - Unit 1 Problem 1"
        )
        ItemFactory.create(
            parent=chapter_vertical,
            category="problem",
            display_name="Problem - Unit 1 Problem 2"
        )

        ItemFactory.create(
            category="instructor",
            parent=self.course,
            data="Instructor Tab",
            display_name="Instructor"
        )
        self.entrance_exam = ItemFactory.create(
            parent=self.course,
            category="chapter",
            display_name="Entrance Exam Section - Chapter 1",
            is_entrance_exam=True,
            in_entrance_exam=True
        )
        self.exam_1 = ItemFactory.create(
            parent=self.entrance_exam,
            category='sequential',
            display_name="Exam Sequential - Subsection 1",
            graded=True,
            in_entrance_exam=True
        )
        subsection = ItemFactory.create(
            parent=self.exam_1,
            category='vertical',
            display_name='Exam Vertical - Unit 1'
        )
        problem_xml = MultipleChoiceResponseXMLFactory().build_xml(
            question_text='The correct answer is Choice 3',
            choices=[False, False, True, False],
            choice_names=['choice_0', 'choice_1', 'choice_2', 'choice_3']
        )
        self.problem_1 = ItemFactory.create(
            parent=subsection,
            category="problem",
            display_name="Exam Problem - Problem 1",
            data=problem_xml
        )
        self.problem_2 = ItemFactory.create(
            parent=subsection,
            category="problem",
            display_name="Exam Problem - Problem 2"
        )

        add_entrance_exam_milestone(self.course, self.entrance_exam)

        self.course.entrance_exam_enabled = True
        self.course.entrance_exam_minimum_score_pct = 0.50
        self.course.entrance_exam_id = unicode(self.entrance_exam.scope_ids.usage_id)

        self.anonymous_user = AnonymousUserFactory()
        self.request = get_request_for_user(UserFactory())
        modulestore().update_item(self.course, self.request.user.id)  # pylint: disable=no-member

        self.client.login(username=self.request.user.username, password="test")
        CourseEnrollment.enroll(self.request.user, self.course.id)

        self.expected_locked_toc = (
            [
                {
                    'active': True,
                    'sections': [
                        {
                            'url_name': u'Exam_Sequential_-_Subsection_1',
                            'display_name': u'Exam Sequential - Subsection 1',
                            'graded': True,
                            'format': '',
                            'due': None,
                            'active': True
                        }
                    ],
                    'url_name': u'Entrance_Exam_Section_-_Chapter_1',
                    'display_name': u'Entrance Exam Section - Chapter 1',
                    'display_id': u'entrance-exam-section-chapter-1',
                }
            ]
        )
        self.expected_unlocked_toc = (
            [
                {
                    'active': False,
                    'sections': [
                        {
                            'url_name': u'Welcome',
                            'display_name': u'Welcome',
                            'graded': False,
                            'format': '',
                            'due': None,
                            'active': False
                        },
                        {
                            'url_name': u'Lesson_1',
                            'display_name': u'Lesson 1',
                            'graded': False,
                            'format': '',
                            'due': None,
                            'active': False
                        }
                    ],
                    'url_name': u'Overview',
                    'display_name': u'Overview',
                    'display_id': u'overview'
                },
                {
                    'active': False,
                    'sections': [],
                    'url_name': u'Week_1',
                    'display_name': u'Week 1',
                    'display_id': u'week-1'
                },
                {
                    'active': False,
                    'sections': [],
                    'url_name': u'Instructor',
                    'display_name': u'Instructor',
                    'display_id': u'instructor'
                },
                {
                    'active': True,
                    'sections': [
                        {
                            'url_name': u'Exam_Sequential_-_Subsection_1',
                            'display_name': u'Exam Sequential - Subsection 1',
                            'graded': True,
                            'format': '',
                            'due': None,
                            'active': True
                        }
                    ],
                    'url_name': u'Entrance_Exam_Section_-_Chapter_1',
                    'display_name': u'Entrance Exam Section - Chapter 1',
                    'display_id': u'entrance-exam-section-chapter-1'
                }
            ]
        )

    def test_view_redirect_if_entrance_exam_required(self):
        """
        Unit Test: if entrance exam is required. Should return a redirect.
        """
        url = reverse('courseware', kwargs={'course_id': unicode(self.course.id)})
        expected_url = reverse('courseware_section',
                               kwargs={
                                   'course_id': unicode(self.course.id),
                                   'chapter': self.entrance_exam.location.name,
                                   'section': self.exam_1.location.name
                               })
        resp = self.client.get(url)
        self.assertRedirects(resp, expected_url, status_code=302, target_status_code=200)

    @patch.dict('django.conf.settings.FEATURES', {'ENTRANCE_EXAMS': False})
    def test_entrance_exam_content_absence(self):
        """
        Unit Test: If entrance exam is not enabled then page should be redirected with chapter contents.
        """
        url = reverse('courseware', kwargs={'course_id': unicode(self.course.id)})
        expected_url = reverse('courseware_section',
                               kwargs={
                                   'course_id': unicode(self.course.id),
                                   'chapter': self.chapter.location.name,
                                   'section': self.welcome.location.name
                               })
        resp = self.client.get(url)
        self.assertRedirects(resp, expected_url, status_code=302, target_status_code=200)
        resp = self.client.get(expected_url)
        self.assertNotIn('Exam Vertical - Unit 1', resp.content)

    def test_entrance_exam_content_presence(self):
        """
        Unit Test: If entrance exam is enabled then its content e.g. problems should be loaded and redirection will
        occur with entrance exam contents.
        """
        url = reverse('courseware', kwargs={'course_id': unicode(self.course.id)})
        expected_url = reverse('courseware_section',
                               kwargs={
                                   'course_id': unicode(self.course.id),
                                   'chapter': self.entrance_exam.location.name,
                                   'section': self.exam_1.location.name
                               })
        resp = self.client.get(url)
        self.assertRedirects(resp, expected_url, status_code=302, target_status_code=200)
        resp = self.client.get(expected_url)
        self.assertIn('Exam Vertical - Unit 1', resp.content)

    def test_get_entrance_exam_content(self):
        """
        test get entrance exam content method
        """
        exam_chapter = get_entrance_exam_content(self.request.user, self.course)
        self.assertEqual(exam_chapter.url_name, self.entrance_exam.url_name)
        self.assertFalse(user_has_passed_entrance_exam(self.request, self.course))

        answer_entrance_exam_problem(self.course, self.request, self.problem_1)
        answer_entrance_exam_problem(self.course, self.request, self.problem_2)

        exam_chapter = get_entrance_exam_content(self.request.user, self.course)
        self.assertEqual(exam_chapter, None)
        self.assertTrue(user_has_passed_entrance_exam(self.request, self.course))

    def test_entrance_exam_score(self):
        """
        test entrance exam score. we will hit the method get_entrance_exam_score to verify exam score.
        """
        with self.assertNumQueries(1):
            exam_score = get_entrance_exam_score(self.request, self.course)
        self.assertEqual(exam_score, 0)

        answer_entrance_exam_problem(self.course, self.request, self.problem_1)
        answer_entrance_exam_problem(self.course, self.request, self.problem_2)

        with self.assertNumQueries(1):
            exam_score = get_entrance_exam_score(self.request, self.course)
        # 50 percent exam score should be achieved.
        self.assertGreater(exam_score * 100, 50)

    def test_entrance_exam_requirement_message(self):
        """
        Unit Test: entrance exam requirement message should be present in response
        """
        url = reverse(
            'courseware_section',
            kwargs={
                'course_id': unicode(self.course.id),
                'chapter': self.entrance_exam.location.name,
                'section': self.exam_1.location.name,
            }
        )
        resp = self.client.get(url)
        self.assertEqual(resp.status_code, 200)
        self.assertIn('To access course materials, you must score', resp.content)

    def test_entrance_exam_requirement_message_with_correct_percentage(self):
        """
        Unit Test: entrance exam requirement message should be present in response
        and percentage of required score should be rounded as expected
        """
        minimum_score_pct = 29
        self.course.entrance_exam_minimum_score_pct = float(minimum_score_pct) / 100
        modulestore().update_item(self.course, self.request.user.id)  # pylint: disable=no-member
        url = reverse(
            'courseware_section',
            kwargs={
                'course_id': unicode(self.course.id),
                'chapter': self.entrance_exam.location.name,
                'section': self.exam_1.location.name
            }
        )
        resp = self.client.get(url)
        self.assertEqual(resp.status_code, 200)
        self.assertIn('To access course materials, you must score {required_score}% or higher'.format(
            required_score=minimum_score_pct
        ), resp.content)

    def test_entrance_exam_requirement_message_hidden(self):
        """
        Unit Test: entrance exam message should not be present outside the context of entrance exam subsection.
        """
        # Login as staff to avoid redirect to entrance exam
        self.client.logout()
        staff_user = StaffFactory(course_key=self.course.id)
        self.client.login(username=staff_user.username, password='test')
        CourseEnrollment.enroll(staff_user, self.course.id)

        url = reverse(
            'courseware_section',
            kwargs={
                'course_id': unicode(self.course.id),
                'chapter': self.chapter.location.name,
                'section': self.chapter_subsection.location.name
            }
        )
        resp = self.client.get(url)
        self.assertEqual(resp.status_code, 200)
        self.assertNotIn('To access course materials, you must score', resp.content)
        self.assertNotIn('You have passed the entrance exam.', resp.content)

    def test_entrance_exam_passed_message_and_course_content(self):
        """
        Unit Test: exam passing message and rest of the course section should be present
        when user achieves the entrance exam milestone/pass the exam.
        """
        url = reverse(
            'courseware_section',
            kwargs={
                'course_id': unicode(self.course.id),
                'chapter': self.entrance_exam.location.name,
                'section': self.exam_1.location.name
            }
        )

        answer_entrance_exam_problem(self.course, self.request, self.problem_1)
        answer_entrance_exam_problem(self.course, self.request, self.problem_2)

        resp = self.client.get(url)
        self.assertNotIn('To access course materials, you must score', resp.content)
        self.assertIn('You have passed the entrance exam.', resp.content)
        self.assertIn('Lesson 1', resp.content)

    def test_entrance_exam_gating(self):
        """
        Unit Test: test_entrance_exam_gating
        """
        # This user helps to cover a discovered bug in the milestone fulfillment logic
        chaos_user = UserFactory()
        locked_toc = self._return_table_of_contents()
        for toc_section in self.expected_locked_toc:
            self.assertIn(toc_section, locked_toc)

        # Set up the chaos user
        answer_entrance_exam_problem(self.course, self.request, self.problem_1, chaos_user)
        answer_entrance_exam_problem(self.course, self.request, self.problem_1)
        answer_entrance_exam_problem(self.course, self.request, self.problem_2)

        unlocked_toc = self._return_table_of_contents()

        for toc_section in self.expected_unlocked_toc:
            self.assertIn(toc_section, unlocked_toc)

    def test_skip_entrance_exam_gating(self):
        """
        Tests gating is disabled if skip entrance exam is set for a user.
        """
        # make sure toc is locked before allowing user to skip entrance exam
        locked_toc = self._return_table_of_contents()
        for toc_section in self.expected_locked_toc:
            self.assertIn(toc_section, locked_toc)

        # hit skip entrance exam api in instructor app
        instructor = InstructorFactory(course_key=self.course.id)
        self.client.login(username=instructor.username, password='test')
        url = reverse('mark_student_can_skip_entrance_exam', kwargs={'course_id': unicode(self.course.id)})
        response = self.client.post(url, {
            'unique_student_identifier': self.request.user.email,
        })
        self.assertEqual(response.status_code, 200)

        unlocked_toc = self._return_table_of_contents()
        for toc_section in self.expected_unlocked_toc:
            self.assertIn(toc_section, unlocked_toc)

    def test_entrance_exam_gating_for_staff(self):
        """
        Tests gating is disabled if user is member of staff.
        """

        # Login as member of staff
        self.client.logout()
        staff_user = StaffFactory(course_key=self.course.id)
        staff_user.is_staff = True
        self.client.login(username=staff_user.username, password='test')

        # assert staff has access to all toc
        self.request.user = staff_user
        unlocked_toc = self._return_table_of_contents()
        for toc_section in self.expected_unlocked_toc:
            self.assertIn(toc_section, unlocked_toc)

    @patch('courseware.entrance_exams.user_has_passed_entrance_exam', Mock(return_value=False))
    def test_courseware_page_access_without_passing_entrance_exam(self):
        """
        Test courseware access page without passing entrance exam
        """
        url = reverse(
            'courseware_chapter',
            kwargs={'course_id': unicode(self.course.id), 'chapter': self.chapter.url_name}
        )
        response = self.client.get(url)
        expected_url = reverse('courseware_section',
                               kwargs={
                                   'course_id': unicode(self.course.id),
                                   'chapter': self.entrance_exam.location.name,
                                   'section': self.exam_1.location.name
                               })
        self.assertRedirects(response, expected_url, status_code=302, target_status_code=200)

    @patch('courseware.entrance_exams.user_has_passed_entrance_exam', Mock(return_value=False))
    def test_courseinfo_page_access_without_passing_entrance_exam(self):
        """
        Test courseware access page without passing entrance exam
        """
        url = reverse('info', args=[unicode(self.course.id)])
        response = self.client.get(url)
        redirect_url = reverse('courseware', args=[unicode(self.course.id)])
        self.assertRedirects(response, redirect_url, status_code=302, target_status_code=302)
        response = self.client.get(redirect_url)
        exam_url = response.get('Location')
        self.assertRedirects(response, exam_url)

    @patch('courseware.entrance_exams.user_has_passed_entrance_exam', Mock(return_value=True))
    def test_courseware_page_access_after_passing_entrance_exam(self):
        """
        Test courseware access page after passing entrance exam
        """
        # Mocking get_required_content with empty list to assume user has passed entrance exam
        self._assert_chapter_loaded(self.course, self.chapter)

    @patch('util.milestones_helpers.get_required_content', Mock(return_value=['a value']))
    def test_courseware_page_access_with_staff_user_without_passing_entrance_exam(self):
        """
        Test courseware access page without passing entrance exam but with staff user
        """
        self.logout()
        staff_user = StaffFactory.create(course_key=self.course.id)
        self.login(staff_user.email, 'test')
        CourseEnrollmentFactory(user=staff_user, course_id=self.course.id)
        self._assert_chapter_loaded(self.course, self.chapter)

    def test_courseware_page_access_with_staff_user_after_passing_entrance_exam(self):
        """
        Test courseware access page after passing entrance exam but with staff user
        """
        self.logout()
        staff_user = StaffFactory.create(course_key=self.course.id)
        self.login(staff_user.email, 'test')
        CourseEnrollmentFactory(user=staff_user, course_id=self.course.id)
        self._assert_chapter_loaded(self.course, self.chapter)

    @patch.dict("django.conf.settings.FEATURES", {'ENTRANCE_EXAMS': False})
    def test_courseware_page_access_when_entrance_exams_disabled(self):
        """
        Test courseware page access when ENTRANCE_EXAMS feature is disabled
        """
        self._assert_chapter_loaded(self.course, self.chapter)

    def test_can_skip_entrance_exam_with_anonymous_user(self):
        """
        Test can_skip_entrance_exam method with anonymous user
        """
        self.assertFalse(user_can_skip_entrance_exam(self.anonymous_user, self.course))

    def test_has_passed_entrance_exam_with_anonymous_user(self):
        """
        Test has_passed_entrance_exam method with anonymous user
        """
        self.request.user = self.anonymous_user
        self.assertFalse(user_has_passed_entrance_exam(self.request, self.course))

    def test_course_has_entrance_exam_missing_exam_id(self):
        course = CourseFactory.create(
            metadata={
                'entrance_exam_enabled': True,
            }
        )
        self.assertFalse(course_has_entrance_exam(course))

    def test_user_has_passed_entrance_exam_short_circuit_missing_exam(self):
        course = CourseFactory.create(
        )
        self.assertTrue(user_has_passed_entrance_exam(self.request, course))

    @patch.dict("django.conf.settings.FEATURES", {'ENABLE_MASQUERADE': False})
    def test_entrance_exam_xblock_response(self):
        """
        Tests entrance exam xblock has `entrance_exam_passed` key in json response.
        """
        request_factory = RequestFactory()
        data = {'input_{}_2_1'.format(unicode(self.problem_1.location.html_id())): 'choice_2'}
        request = request_factory.post(
            'problem_check',
            data=data
        )
        request.user = self.user
        response = handle_xblock_callback(
            request,
            unicode(self.course.id),
            unicode(self.problem_1.location),
            'xmodule_handler',
            'problem_check',
        )
        self.assertEqual(response.status_code, 200)
        self.assertIn('entrance_exam_passed', response.content)

    def _assert_chapter_loaded(self, course, chapter):
        """
        Asserts courseware chapter load successfully.
        """
        url = reverse(
            'courseware_chapter',
            kwargs={'course_id': unicode(course.id), 'chapter': chapter.url_name}
        )
        response = self.client.get(url)
        self.assertEqual(response.status_code, 200)

    def _return_table_of_contents(self):
        """
        Returns table of content for the entrance exam specific to this test

        Returns the table of contents for course self.course, for chapter
        self.entrance_exam, and for section self.exam1
        """
        self.field_data_cache = FieldDataCache.cache_for_descriptor_descendents(  # pylint: disable=attribute-defined-outside-init
            self.course.id,
            self.request.user,
            self.entrance_exam
        )
        toc = toc_for_course(
            self.request.user,
            self.request,
            self.course,
            self.entrance_exam.url_name,
            self.exam_1.url_name,
            self.field_data_cache
        )
        return toc['chapters']


def answer_entrance_exam_problem(course, request, problem, user=None):
    """
    Takes a required milestone `problem` in a `course` and fulfills it.

    Args:
        course (Course): Course object, the course the required problem is in
        request (Request): request Object
        problem (xblock): xblock object, the problem to be fulfilled
        user (User): User object in case it is different from request.user
    """
    if not user:
        user = request.user

    grade_dict = {'value': 1, 'max_value': 1, 'user_id': user.id}
    field_data_cache = FieldDataCache.cache_for_descriptor_descendents(
        course.id,
        user,
        course,
        depth=2
    )
    # pylint: disable=protected-access
    module = get_module(
        user,
        request,
        problem.scope_ids.usage_id,
        field_data_cache,
    )._xmodule
    module.system.publish(problem, 'grade', grade_dict)


def add_entrance_exam_milestone(course, entrance_exam):
    """
    Adds the milestone for given `entrance_exam` in `course`

    Args:
        course (Course): Course object in which the extrance_exam is located
        entrance_exam (xblock): the entrance exam to be added as a milestone
    """
    namespace_choices = get_namespace_choices()
    milestone_relationship_types = get_milestone_relationship_types()

    milestone_namespace = generate_milestone_namespace(
        namespace_choices.get('ENTRANCE_EXAM'),
        course.id
    )
    milestone = add_milestone(
        {
            'name': 'Test Milestone',
            'namespace': milestone_namespace,
            'description': 'Testing Courseware Entrance Exam Chapter',
        }
    )
    add_course_milestone(
        unicode(course.id),
        milestone_relationship_types['REQUIRES'],
        milestone
    )
    add_course_content_milestone(
        unicode(course.id),
        unicode(entrance_exam.location),
        milestone_relationship_types['FULFILLS'],
        milestone
    )
