"""
Tests for views/tools.py.
"""


import datetime
import json
import unittest
from unittest import mock

import pytest
from django.contrib.auth.models import User  # lint-amnesty, pylint: disable=imported-auth-user
from django.core.exceptions import MultipleObjectsReturned
from django.test import TestCase
from edx_when.api import set_dates_for_course
from edx_when.field_data import DateLookupFieldData
from opaque_keys.edx.keys import CourseKey
from pytz import UTC

from common.djangoapps.student.tests.factories import CourseEnrollmentFactory, UserFactory
from openedx.core.djangoapps.course_date_signals import handlers
from xmodule.fields import Date
from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase, SharedModuleStoreTestCase
from xmodule.modulestore.tests.factories import CourseFactory, ItemFactory

from ..views import tools

DATE_FIELD = Date()


class TestDashboardError(unittest.TestCase):
    """
    Test DashboardError exceptions.
    """
    def test_response(self):
        error = tools.DashboardError('Oh noes!')
        response = json.loads(error.response().content.decode('utf-8'))
        assert response == {'error': 'Oh noes!'}


class TestHandleDashboardError(unittest.TestCase):
    """
    Test handle_dashboard_error decorator.
    """
    def test_error(self):
        @tools.handle_dashboard_error
        def view(request, course_id):
            """
            Raises DashboardError.
            """
            raise tools.DashboardError("Oh noes!")

        response = json.loads(view(None, None).content.decode('utf-8'))
        assert response == {'error': 'Oh noes!'}

    def test_no_error(self):
        @tools.handle_dashboard_error
        def view(request, course_id):  # lint-amnesty, pylint: disable=unused-argument
            """
            Returns "Oh yes!"
            """
            return "Oh yes!"

        assert view(None, None) == 'Oh yes!'


class TestRequireStudentIdentifier(TestCase):
    """
    Test require_student_from_identifier()
    """
    def setUp(self):
        """
        Fixtures
        """
        super().setUp()
        self.student = UserFactory.create()

    def test_valid_student_id(self):
        assert self.student == tools.require_student_from_identifier(self.student.username)

    def test_invalid_student_id(self):
        with pytest.raises(tools.DashboardError):
            tools.require_student_from_identifier("invalid")


class TestParseDatetime(unittest.TestCase):
    """
    Test date parsing.
    """
    def test_parse_no_error(self):
        assert tools.parse_datetime('5/12/2010 2:42') == datetime.datetime(2010, 5, 12, 2, 42, tzinfo=UTC)

    def test_parse_error(self):
        with pytest.raises(tools.DashboardError):
            tools.parse_datetime('foo')


class TestFindUnit(SharedModuleStoreTestCase):
    """
    Test the find_unit function.
    """
    @classmethod
    def setUpClass(cls):
        super().setUpClass()
        cls.course = CourseFactory.create()
        with cls.store.bulk_operations(cls.course.id, emit_signals=False):
            week1 = ItemFactory.create(parent=cls.course)
            cls.homework = ItemFactory.create(parent=week1)

    def test_find_unit_success(self):
        """
        Test finding a nested unit.
        """
        url = str(self.homework.location)
        found_unit = tools.find_unit(self.course, url)
        assert found_unit.location == self.homework.location

    def test_find_unit_notfound(self):
        """
        Test attempt to find a unit that does not exist.
        """
        url = "i4x://MITx/999/chapter/notfound"
        with pytest.raises(tools.DashboardError):
            tools.find_unit(self.course, url)


class TestGetUnitsWithDueDate(ModuleStoreTestCase):
    """
    Test the get_units_with_due_date function.
    """
    def setUp(self):
        """
        Fixtures.
        """
        super().setUp()

        course = CourseFactory.create()
        week1 = ItemFactory.create(parent=course)
        week2 = ItemFactory.create(parent=course)
        child = ItemFactory.create(parent=week1)

        due = datetime.datetime(2010, 5, 12, 2, 42, tzinfo=UTC)
        set_dates_for_course(course.id, [
            (week1.location, {'due': due}),
            (week2.location, {'due': due}),
            (child.location, {'due': due}),
        ])

        self.course = course
        self.week1 = week1
        self.week2 = week2

    def test_it(self):

        def urls(seq):
            """
            URLs for sequence of nodes.
            """
            return sorted(str(i.location) for i in seq)

        assert urls(tools.get_units_with_due_date(self.course)) == urls((self.week1, self.week2))


class TestTitleOrUrl(unittest.TestCase):
    """
    Test the title_or_url funciton.
    """
    def test_title(self):
        unit = mock.Mock(display_name='hello')
        assert tools.title_or_url(unit) == 'hello'

    def test_url(self):
        # pylint: disable=unused-argument
        def mock_location_text(self):
            """
            Mock implementation of __unicode__ or __str__ for the unit's location.
            """
            return 'test:hello'

        unit = mock.Mock(display_name=None)
        unit.location.__str__ = mock_location_text
        assert tools.title_or_url(unit) == 'test:hello'


def inject_field_data(blocks, course, user):
    use_cached = False
    for block in blocks:
        block._field_data = DateLookupFieldData(block._field_data, course.id, user, use_cached=use_cached)   # pylint: disable=protected-access
        use_cached = True


class TestSetDueDateExtension(ModuleStoreTestCase):
    """
    Test the set_due_date_extensions function.
    """
    def setUp(self):
        """
        Fixtures.
        """
        super().setUp()

        self.due = due = datetime.datetime(2010, 5, 12, 2, 42, tzinfo=UTC)
        course = CourseFactory.create()
        week1 = ItemFactory.create(due=due, parent=course)
        week2 = ItemFactory.create(due=due, parent=course)
        week3 = ItemFactory.create(parent=course)
        homework = ItemFactory.create(parent=week1)
        assignment = ItemFactory.create(parent=homework, due=due)
        handlers.extract_dates(None, course.id)

        user = UserFactory.create()

        self.course = course
        self.week1 = week1
        self.homework = homework
        self.assignment = assignment
        self.week2 = week2
        self.week3 = week3
        self.user = user

        CourseEnrollmentFactory.create(user=self.user, course_id=self.course.id)

        inject_field_data((course, week1, week2, week3, homework, assignment), course, user)

    def _clear_field_data_cache(self):
        """
        Clear field data cache for xblocks under test. Normally this would be
        done by virtue of the fact that xblocks are reloaded on subsequent
        requests.
        """
        for block in (self.week1, self.week2, self.week3,
                      self.homework, self.assignment):
            block._field_data._load_dates(self.course.id, self.user, use_cached=False)  # pylint: disable=protected-access
            block.fields['due']._del_cached_value(block)  # pylint: disable=protected-access

    def test_set_due_date_extension(self):
        # First, extend the leaf assignment date
        extended_hw = datetime.datetime(2013, 10, 25, 0, 0, tzinfo=UTC)
        tools.set_due_date_extension(self.course, self.assignment, self.user, extended_hw)
        self._clear_field_data_cache()
        assert self.week1.due == self.due
        assert self.homework.due == self.due
        assert self.assignment.due == extended_hw

        # Now, extend the whole section that the assignment was in. Both it and all under it should change
        extended_week = datetime.datetime(2013, 12, 25, 0, 0, tzinfo=UTC)
        tools.set_due_date_extension(self.course, self.week1, self.user, extended_week)
        self._clear_field_data_cache()
        assert self.week1.due == extended_week
        assert self.homework.due == extended_week
        assert self.assignment.due == extended_week

    def test_set_due_date_extension_invalid_date(self):
        extended = datetime.datetime(2009, 1, 1, 0, 0, tzinfo=UTC)
        with pytest.raises(tools.DashboardError):
            tools.set_due_date_extension(self.course, self.week1, self.user, extended)

    def test_set_due_date_extension_no_date(self):
        extended = datetime.datetime(2013, 12, 25, 0, 0, tzinfo=UTC)
        with pytest.raises(tools.DashboardError):
            tools.set_due_date_extension(self.course, self.week3, self.user, extended)

    def test_reset_due_date_extension(self):
        extended = datetime.datetime(2013, 12, 25, 0, 0, tzinfo=UTC)
        tools.set_due_date_extension(self.course, self.week1, self.user, extended)
        tools.set_due_date_extension(self.course, self.week1, self.user, None)
        assert self.week1.due == self.due

    def test_reset_due_date_extension_with_no_enrollment(self):
        """
        Tests that DashboardError is raised when trying to extend due date
        for a block given the user is not enrolled in the course.
        """
        user = UserFactory.create()
        extended = datetime.datetime(2013, 12, 25, 0, 0, tzinfo=UTC)
        with pytest.raises(tools.DashboardError):
            tools.set_due_date_extension(self.course, self.week3, user, extended)


class TestDataDumps(ModuleStoreTestCase):
    """
    Test data dumps for reporting.
    """

    def setUp(self):
        """
        Fixtures.
        """
        super().setUp()

        due = datetime.datetime(2010, 5, 12, 2, 42, tzinfo=UTC)
        course = CourseFactory.create()
        week1 = ItemFactory.create(due=due, parent=course)
        week2 = ItemFactory.create(due=due, parent=course)

        homework = ItemFactory.create(
            parent=week1,
            due=due
        )

        user1 = UserFactory.create()
        user2 = UserFactory.create()
        self.course = course
        self.week1 = week1
        self.homework = homework
        self.week2 = week2
        self.user1 = user1
        self.user2 = user2
        CourseEnrollmentFactory.create(user=self.user1, course_id=self.course.id)
        CourseEnrollmentFactory.create(user=self.user2, course_id=self.course.id)
        handlers.extract_dates(None, course.id)

    def test_dump_module_extensions(self):
        extended = datetime.datetime(2013, 12, 25, 0, 0, tzinfo=UTC)
        tools.set_due_date_extension(self.course, self.week1, self.user1,
                                     extended)
        tools.set_due_date_extension(self.course, self.week1, self.user2,
                                     extended)
        report = tools.dump_module_extensions(self.course, self.week1)
        assert (
            report['title'] == 'Users with due date extensions for ' +
            self.week1.display_name)
        assert (
            report['header'] == ["Username", "Full Name", "Extended Due Date"])
        self.assertCountEqual(
            report['data'],
            [
                {
                    "Username": self.user1.username,
                    "Full Name": self.user1.profile.name,
                    "Extended Due Date": "2013-12-25 00:00"
                }, {
                    "Username": self.user2.username,
                    "Full Name": self.user2.profile.name,
                    "Extended Due Date": "2013-12-25 00:00"
                }
            ]
        )

    def test_dump_student_extensions(self):
        extended = datetime.datetime(2013, 12, 25, 0, 0, tzinfo=UTC)
        tools.set_due_date_extension(self.course, self.week1, self.user1,
                                     extended)
        tools.set_due_date_extension(self.course, self.week2, self.user1,
                                     extended)
        report = tools.dump_student_extensions(self.course, self.user1)
        assert (
            report['title'] == 'Due date extensions for %s (%s)' %
            (self.user1.profile.name, self.user1.username))
        assert (
            report['header'] == ["Unit", "Extended Due Date"])
        assert (report['data'] == [
            {"Unit": self.week1.display_name,
             "Extended Due Date": "2013-12-25 00:00"},
            {"Unit": self.week2.display_name,
             "Extended Due Date": "2013-12-25 00:00"}])


def msk_from_problem_urlname(course_id, urlname, block_type='problem'):
    """
    Convert a 'problem urlname' to a module state key (db field)
    """
    if not isinstance(course_id, CourseKey):
        raise ValueError
    if urlname.endswith(".xml"):
        urlname = urlname[:-4]

    return course_id.make_usage_key(block_type, urlname)


class TestStudentFromIdentifier(TestCase):
    """
    Test get_student_from_identifier()
    """
    @classmethod
    def setUpClass(cls):
        super().setUpClass()
        cls.valid_student = UserFactory.create(username='baz@touchstone')
        cls.student_conflicting_email = UserFactory.create(email='foo@touchstone.com')
        cls.student_conflicting_username = UserFactory.create(username='foo@touchstone.com')

    def test_valid_student_id(self):
        """Test with valid username"""
        assert self.valid_student == tools.get_student_from_identifier(self.valid_student.username)

    def test_valid_student_email(self):
        """Test with valid email"""
        assert self.valid_student == tools.get_student_from_identifier(self.valid_student.email)

    def test_student_username_has_conflict_with_others_email(self):
        """
        An edge case where there is a user A with username example: foo@touchstone.com and
        there is user B with email example: foo@touchstone.com
        """
        with pytest.raises(MultipleObjectsReturned):
            tools.get_student_from_identifier(self.student_conflicting_username.username)

        # can get student with alternative identifier, in this case email.
        assert self.student_conflicting_username == tools.get_student_from_identifier(
            self.student_conflicting_username.email
        )

    def test_student_email_has_conflict_with_others_username(self):
        """
        An edge case where there is a user A with email example: foo@touchstone.com and
        there is user B with username example: foo@touchstone.com
        """
        with pytest.raises(MultipleObjectsReturned):
            tools.get_student_from_identifier(self.student_conflicting_email.email)

        # can get student with alternative identifier, in this case username.
        assert self.student_conflicting_email == tools.get_student_from_identifier(
            self.student_conflicting_email.username
        )

    def test_invalid_student_id(self):
        """Test with invalid identifier"""
        with pytest.raises(User.DoesNotExist):
            assert tools.get_student_from_identifier("invalid")