"""
Tests for StaticContentServer
"""
import copy

import datetime
import ddt
import logging
import unittest
from uuid import uuid4

from django.conf import settings
from django.test.client import Client
from django.test.utils import override_settings
from mock import patch

from xmodule.contentstore.django import contentstore
from xmodule.modulestore.django import modulestore
from xmodule.modulestore.tests.django_utils import SharedModuleStoreTestCase
from xmodule.modulestore import ModuleStoreEnum
from xmodule.modulestore.xml_importer import import_course_from_xml

from contentserver.middleware import parse_range_header, HTTP_DATE_FORMAT, StaticContentServer
from student.models import CourseEnrollment
from student.tests.factories import UserFactory, AdminFactory

log = logging.getLogger(__name__)

TEST_DATA_CONTENTSTORE = copy.deepcopy(settings.CONTENTSTORE)
TEST_DATA_CONTENTSTORE['DOC_STORE_CONFIG']['db'] = 'test_xcontent_%s' % uuid4().hex

TEST_DATA_DIR = settings.COMMON_TEST_DATA_ROOT


@ddt.ddt
@override_settings(CONTENTSTORE=TEST_DATA_CONTENTSTORE)
class ContentStoreToyCourseTest(SharedModuleStoreTestCase):
    """
    Tests that use the toy course.
    """

    @classmethod
    def setUpClass(cls):
        super(ContentStoreToyCourseTest, cls).setUpClass()

        cls.contentstore = contentstore()
        cls.modulestore = modulestore()

        cls.course_key = cls.modulestore.make_course_key('edX', 'toy', '2012_Fall')

        import_course_from_xml(
            cls.modulestore, 1, TEST_DATA_DIR, ['toy'],
            static_content_store=cls.contentstore, verbose=True
        )

        # A locked asset
        cls.locked_asset = cls.course_key.make_asset_key('asset', 'sample_static.txt')
        cls.url_locked = unicode(cls.locked_asset)
        cls.contentstore.set_attr(cls.locked_asset, 'locked', True)

        # An unlocked asset
        cls.unlocked_asset = cls.course_key.make_asset_key('asset', 'another_static.txt')
        cls.url_unlocked = unicode(cls.unlocked_asset)
        cls.length_unlocked = cls.contentstore.get_attr(cls.unlocked_asset, 'length')

    def setUp(self):
        """
        Create user and login.
        """
        super(ContentStoreToyCourseTest, self).setUp()
        self.staff_usr = AdminFactory.create()
        self.non_staff_usr = UserFactory.create()

        self.client = Client()

    def test_unlocked_asset(self):
        """
        Test that unlocked assets are being served.
        """
        self.client.logout()
        resp = self.client.get(self.url_unlocked)
        self.assertEqual(resp.status_code, 200)

    def test_locked_asset_not_logged_in(self):
        """
        Test that locked assets behave appropriately in case the user is not
        logged in.
        """
        self.client.logout()
        resp = self.client.get(self.url_locked)
        self.assertEqual(resp.status_code, 403)

    def test_locked_asset_not_registered(self):
        """
        Test that locked assets behave appropriately in case user is logged in
        in but not registered for the course.
        """
        self.client.login(username=self.non_staff_usr, password='test')
        resp = self.client.get(self.url_locked)
        self.assertEqual(resp.status_code, 403)

    def test_locked_asset_registered(self):
        """
        Test that locked assets behave appropriately in case user is logged in
        and registered for the course.
        """
        CourseEnrollment.enroll(self.non_staff_usr, self.course_key)
        self.assertTrue(CourseEnrollment.is_enrolled(self.non_staff_usr, self.course_key))

        self.client.login(username=self.non_staff_usr, password='test')
        resp = self.client.get(self.url_locked)
        self.assertEqual(resp.status_code, 200)

    def test_locked_asset_staff(self):
        """
        Test that locked assets behave appropriately in case user is staff.
        """
        self.client.login(username=self.staff_usr, password='test')
        resp = self.client.get(self.url_locked)
        self.assertEqual(resp.status_code, 200)

    def test_range_request_full_file(self):
        """
        Test that a range request from byte 0 to last,
        outputs partial content status code and valid Content-Range and Content-Length.
        """
        resp = self.client.get(self.url_unlocked, HTTP_RANGE='bytes=0-')

        self.assertEqual(resp.status_code, 206)  # HTTP_206_PARTIAL_CONTENT
        self.assertEqual(
            resp['Content-Range'],
            'bytes {first}-{last}/{length}'.format(
                first=0, last=self.length_unlocked - 1,
                length=self.length_unlocked
            )
        )
        self.assertEqual(resp['Content-Length'], str(self.length_unlocked))

    def test_range_request_partial_file(self):
        """
        Test that a range request for a partial file,
        outputs partial content status code and valid Content-Range and Content-Length.
        first_byte and last_byte are chosen to be simple but non trivial values.
        """
        first_byte = self.length_unlocked / 4
        last_byte = self.length_unlocked / 2
        resp = self.client.get(self.url_unlocked, HTTP_RANGE='bytes={first}-{last}'.format(
            first=first_byte, last=last_byte))

        self.assertEqual(resp.status_code, 206)  # HTTP_206_PARTIAL_CONTENT
        self.assertEqual(resp['Content-Range'], 'bytes {first}-{last}/{length}'.format(
            first=first_byte, last=last_byte, length=self.length_unlocked))
        self.assertEqual(resp['Content-Length'], str(last_byte - first_byte + 1))

    def test_range_request_multiple_ranges(self):
        """
        Test that multiple ranges in request outputs the full content.
        """
        first_byte = self.length_unlocked / 4
        last_byte = self.length_unlocked / 2
        resp = self.client.get(self.url_unlocked, HTTP_RANGE='bytes={first}-{last}, -100'.format(
            first=first_byte, last=last_byte))

        self.assertEqual(resp.status_code, 200)
        self.assertNotIn('Content-Range', resp)
        self.assertEqual(resp['Content-Length'], str(self.length_unlocked))

    @ddt.data(
        'bytes 0-',
        'bits=0-',
        'bytes=0',
        'bytes=one-',
    )
    def test_syntax_errors_in_range(self, header_value):
        """
        Test that syntactically invalid Range values result in a 200 OK full content response.
        """
        resp = self.client.get(self.url_unlocked, HTTP_RANGE=header_value)
        self.assertEqual(resp.status_code, 200)
        self.assertNotIn('Content-Range', resp)

    def test_range_request_malformed_invalid_range(self):
        """
        Test that a range request with malformed Range (first_byte > last_byte) outputs
        416 Requested Range Not Satisfiable.
        """
        resp = self.client.get(self.url_unlocked, HTTP_RANGE='bytes={first}-{last}'.format(
            first=(self.length_unlocked / 2), last=(self.length_unlocked / 4)))
        self.assertEqual(resp.status_code, 416)

    def test_range_request_malformed_out_of_bounds(self):
        """
        Test that a range request with malformed Range (first_byte, last_byte == totalLength, offset by 1 error)
        outputs 416 Requested Range Not Satisfiable.
        """
        resp = self.client.get(self.url_unlocked, HTTP_RANGE='bytes={first}-{last}'.format(
            first=(self.length_unlocked), last=(self.length_unlocked)))
        self.assertEqual(resp.status_code, 416)

    def test_vary_header_sent(self):
        """
        Tests that we're properly setting the Vary header to ensure browser requests don't get
        cached in a way that breaks XHR requests to the same asset.
        """
        resp = self.client.get(self.url_unlocked)
        self.assertEqual(resp.status_code, 200)
        self.assertEquals('Origin', resp['Vary'])

    @patch('contentserver.models.CourseAssetCacheTtlConfig.get_cache_ttl')
    def test_cache_headers_with_ttl_unlocked(self, mock_get_cache_ttl):
        """
        Tests that when a cache TTL is set, an unlocked asset will be sent back with
        the correct cache control/expires headers.
        """
        mock_get_cache_ttl.return_value = 10

        resp = self.client.get(self.url_unlocked)
        self.assertEqual(resp.status_code, 200)
        self.assertIn('Expires', resp)
        self.assertEquals('public, max-age=10, s-maxage=10', resp['Cache-Control'])

    @patch('contentserver.models.CourseAssetCacheTtlConfig.get_cache_ttl')
    def test_cache_headers_with_ttl_locked(self, mock_get_cache_ttl):
        """
        Tests that when a cache TTL is set, a locked asset will be sent back without
        any cache control/expires headers.
        """
        mock_get_cache_ttl.return_value = 10

        CourseEnrollment.enroll(self.non_staff_usr, self.course_key)
        self.assertTrue(CourseEnrollment.is_enrolled(self.non_staff_usr, self.course_key))

        self.client.login(username=self.non_staff_usr, password='test')
        resp = self.client.get(self.url_locked)
        self.assertEqual(resp.status_code, 200)
        self.assertNotIn('Expires', resp)
        self.assertEquals('private, no-cache, no-store', resp['Cache-Control'])

    @patch('contentserver.models.CourseAssetCacheTtlConfig.get_cache_ttl')
    def test_cache_headers_without_ttl_unlocked(self, mock_get_cache_ttl):
        """
        Tests that when a cache TTL is not set, an unlocked asset will be sent back without
        any cache control/expires headers.
        """
        mock_get_cache_ttl.return_value = 0

        resp = self.client.get(self.url_unlocked)
        self.assertEqual(resp.status_code, 200)
        self.assertNotIn('Expires', resp)
        self.assertNotIn('Cache-Control', resp)

    @patch('contentserver.models.CourseAssetCacheTtlConfig.get_cache_ttl')
    def test_cache_headers_without_ttl_locked(self, mock_get_cache_ttl):
        """
        Tests that when a cache TTL is not set, a locked asset will be sent back with a
        cache-control header that indicates this asset should not be cached.
        """
        mock_get_cache_ttl.return_value = 0

        CourseEnrollment.enroll(self.non_staff_usr, self.course_key)
        self.assertTrue(CourseEnrollment.is_enrolled(self.non_staff_usr, self.course_key))

        self.client.login(username=self.non_staff_usr, password='test')
        resp = self.client.get(self.url_locked)
        self.assertEqual(resp.status_code, 200)
        self.assertNotIn('Expires', resp)
        self.assertEquals('private, no-cache, no-store', resp['Cache-Control'])

    def test_get_expiration_value(self):
        start_dt = datetime.datetime.strptime("Thu, 01 Dec 1983 20:00:00 GMT", HTTP_DATE_FORMAT)
        near_expire_dt = StaticContentServer.get_expiration_value(start_dt, 55)
        self.assertEqual("Thu, 01 Dec 1983 20:00:55 GMT", near_expire_dt)


@ddt.ddt
class ParseRangeHeaderTestCase(unittest.TestCase):
    """
    Tests for the parse_range_header function.
    """

    def setUp(self):
        super(ParseRangeHeaderTestCase, self).setUp()
        self.content_length = 10000

    def test_bytes_unit(self):
        unit, __ = parse_range_header('bytes=100-', self.content_length)
        self.assertEqual(unit, 'bytes')

    @ddt.data(
        ('bytes=100-', 1, [(100, 9999)]),
        ('bytes=1000-', 1, [(1000, 9999)]),
        ('bytes=100-199, 200-', 2, [(100, 199), (200, 9999)]),
        ('bytes=100-199, 200-499', 2, [(100, 199), (200, 499)]),
        ('bytes=-100', 1, [(9900, 9999)]),
        ('bytes=-100, -200', 2, [(9900, 9999), (9800, 9999)])
    )
    @ddt.unpack
    def test_valid_syntax(self, header_value, excepted_ranges_length, expected_ranges):
        __, ranges = parse_range_header(header_value, self.content_length)
        self.assertEqual(len(ranges), excepted_ranges_length)
        self.assertEqual(ranges, expected_ranges)

    @ddt.data(
        ('bytes=one-20', ValueError, 'invalid literal for int()'),
        ('bytes=-one', ValueError, 'invalid literal for int()'),
        ('bytes=-', ValueError, 'invalid literal for int()'),
        ('bytes=--', ValueError, 'invalid literal for int()'),
        ('bytes', ValueError, 'Invalid syntax'),
        ('bytes=', ValueError, 'Invalid syntax'),
        ('bytes=0', ValueError, 'Invalid syntax'),
        ('bytes=0-10,0', ValueError, 'Invalid syntax'),
        ('bytes=0=', ValueError, 'too many values to unpack'),
    )
    @ddt.unpack
    def test_invalid_syntax(self, header_value, exception_class, exception_message_regex):
        self.assertRaisesRegexp(
            exception_class, exception_message_regex, parse_range_header, header_value, self.content_length
        )
