"""
tests for the models
"""
import json
from datetime import datetime, timedelta

import ddt
from nose.plugins.attrib import attr
from pytz import utc

from student.roles import CourseCcxCoachRole
from student.tests.factories import AdminFactory
from xmodule.modulestore.tests.django_utils import TEST_DATA_SPLIT_MODULESTORE, ModuleStoreTestCase
from xmodule.modulestore.tests.factories import CourseFactory, check_mongo_calls

from ..overrides import override_field_for_ccx
from .factories import CcxFactory


@ddt.ddt
@attr(shard=1)
class TestCCX(ModuleStoreTestCase):
    """Unit tests for the CustomCourseForEdX model
    """

    MODULESTORE = TEST_DATA_SPLIT_MODULESTORE

    def setUp(self):
        """common setup for all tests"""
        super(TestCCX, self).setUp()
        self.course = CourseFactory.create()
        self.coach = AdminFactory.create()
        role = CourseCcxCoachRole(self.course.id)
        role.add_users(self.coach)
        self.ccx = CcxFactory(course_id=self.course.id, coach=self.coach)

    def set_ccx_override(self, field, value):
        """Create a field override for the test CCX on <field> with <value>"""
        override_field_for_ccx(self.ccx, self.course, field, value)

    def test_ccx_course_is_correct_course(self):
        """verify that the course property of a ccx returns the right course"""
        expected = self.course
        actual = self.ccx.course
        self.assertEqual(expected, actual)

    def test_ccx_course_caching(self):
        """verify that caching the propery works to limit queries"""
        with check_mongo_calls(3):
            # these statements are used entirely to demonstrate the
            # instance-level caching of these values on CCX objects. The
            # check_mongo_calls context is the point here.
            self.ccx.course  # pylint: disable=pointless-statement
        with check_mongo_calls(0):
            self.ccx.course  # pylint: disable=pointless-statement

    def test_ccx_start_is_correct(self):
        """verify that the start datetime for a ccx is correctly retrieved

        Note that after setting the start field override microseconds are
        truncated, so we can't do a direct comparison between before and after.
        For this reason we test the difference between and make sure it is less
        than one second.
        """
        expected = datetime.now(utc)
        self.set_ccx_override('start', expected)
        actual = self.ccx.start  # pylint: disable=no-member
        diff = expected - actual
        self.assertLess(abs(diff.total_seconds()), 1)

    def test_ccx_start_caching(self):
        """verify that caching the start property works to limit queries"""
        now = datetime.now(utc)
        self.set_ccx_override('start', now)
        with check_mongo_calls(3):
            # these statements are used entirely to demonstrate the
            # instance-level caching of these values on CCX objects. The
            # check_mongo_calls context is the point here.
            self.ccx.start  # pylint: disable=pointless-statement, no-member
        with check_mongo_calls(0):
            self.ccx.start  # pylint: disable=pointless-statement, no-member

    def test_ccx_due_without_override(self):
        """verify that due returns None when the field has not been set"""
        actual = self.ccx.due  # pylint: disable=no-member
        self.assertIsNone(actual)

    def test_ccx_due_is_correct(self):
        """verify that the due datetime for a ccx is correctly retrieved"""
        expected = datetime.now(utc)
        self.set_ccx_override('due', expected)
        actual = self.ccx.due  # pylint: disable=no-member
        diff = expected - actual
        self.assertLess(abs(diff.total_seconds()), 1)

    def test_ccx_due_caching(self):
        """verify that caching the due property works to limit queries"""
        expected = datetime.now(utc)
        self.set_ccx_override('due', expected)
        with check_mongo_calls(3):
            # these statements are used entirely to demonstrate the
            # instance-level caching of these values on CCX objects. The
            # check_mongo_calls context is the point here.
            self.ccx.due  # pylint: disable=pointless-statement, no-member
        with check_mongo_calls(0):
            self.ccx.due  # pylint: disable=pointless-statement, no-member

    def test_ccx_has_started(self):
        """verify that a ccx marked as starting yesterday has started"""
        now = datetime.now(utc)
        delta = timedelta(1)
        then = now - delta
        self.set_ccx_override('start', then)
        self.assertTrue(self.ccx.has_started())  # pylint: disable=no-member

    def test_ccx_has_not_started(self):
        """verify that a ccx marked as starting tomorrow has not started"""
        now = datetime.now(utc)
        delta = timedelta(1)
        then = now + delta
        self.set_ccx_override('start', then)
        self.assertFalse(self.ccx.has_started())  # pylint: disable=no-member

    def test_ccx_has_ended(self):
        """verify that a ccx that has a due date in the past has ended"""
        now = datetime.now(utc)
        delta = timedelta(1)
        then = now - delta
        self.set_ccx_override('due', then)
        self.assertTrue(self.ccx.has_ended())  # pylint: disable=no-member

    def test_ccx_has_not_ended(self):
        """verify that a ccx that has a due date in the future has not eneded
        """
        now = datetime.now(utc)
        delta = timedelta(1)
        then = now + delta
        self.set_ccx_override('due', then)
        self.assertFalse(self.ccx.has_ended())  # pylint: disable=no-member

    def test_ccx_without_due_date_has_not_ended(self):
        """verify that a ccx without a due date has not ended"""
        self.assertFalse(self.ccx.has_ended())  # pylint: disable=no-member

    def test_ccx_max_student_enrollment_correct(self):
        """
        Verify the override value for max_student_enrollments_allowed
        """
        expected = 200
        self.set_ccx_override('max_student_enrollments_allowed', expected)
        actual = self.ccx.max_student_enrollments_allowed  # pylint: disable=no-member
        self.assertEqual(expected, actual)

    def test_structure_json_default_empty(self):
        """
        By default structure_json does not contain anything
        """
        self.assertEqual(self.ccx.structure_json, None)  # pylint: disable=no-member
        self.assertEqual(self.ccx.structure, None)  # pylint: disable=no-member

    def test_structure_json(self):
        """
        Test a json stored in the structure_json
        """
        dummy_struct = [
            "block-v1:Organization+CN101+CR-FALL15+type@chapter+block@Unit_4",
            "block-v1:Organization+CN101+CR-FALL15+type@chapter+block@Unit_5",
            "block-v1:Organization+CN101+CR-FALL15+type@chapter+block@Unit_11"
        ]
        json_struct = json.dumps(dummy_struct)
        ccx = CcxFactory(
            course_id=self.course.id,
            coach=self.coach,
            structure_json=json_struct
        )
        self.assertEqual(ccx.structure_json, json_struct)  # pylint: disable=no-member
        self.assertEqual(ccx.structure, dummy_struct)  # pylint: disable=no-member

    def test_locator_property(self):
        """
        Verify that the locator helper property returns a correct CCXLocator
        """
        locator = self.ccx.locator  # pylint: disable=no-member
        self.assertEqual(self.ccx.id, long(locator.ccx))