import base64
from datetime import datetime, timedelta
import pickle
import shutil
import tempfile

from django.conf import settings
from django.contrib.sessions.backends.db import SessionStore as DatabaseSession
from django.contrib.sessions.backends.cache import SessionStore as CacheSession
from django.contrib.sessions.backends.cached_db import SessionStore as CacheDBSession
from django.contrib.sessions.backends.file import SessionStore as FileSession
from django.contrib.sessions.backends.base import SessionBase
from django.contrib.sessions.models import Session
from django.core.exceptions import ImproperlyConfigured
from django.test import TestCase
from django.utils import unittest
from django.utils.hashcompat import md5_constructor


class SessionTestsMixin(object):
    # This does not inherit from TestCase to avoid any tests being run with this
    # class, which wouldn't work, and to allow different TestCase subclasses to
    # be used.

    backend = None # subclasses must specify

    def setUp(self):
        self.session = self.backend()

    def tearDown(self):
        # NB: be careful to delete any sessions created; stale sessions fill up
        # the /tmp (with some backends) and eventually overwhelm it after lots
        # of runs (think buildbots)
        self.session.delete()

    def test_new_session(self):
        self.assertFalse(self.session.modified)
        self.assertFalse(self.session.accessed)

    def test_get_empty(self):
        self.assertEqual(self.session.get('cat'), None)

    def test_store(self):
        self.session['cat'] = "dog"
        self.assertTrue(self.session.modified)
        self.assertEqual(self.session.pop('cat'), 'dog')

    def test_pop(self):
        self.session['some key'] = 'exists'
        # Need to reset these to pretend we haven't accessed it:
        self.accessed = False
        self.modified = False

        self.assertEqual(self.session.pop('some key'), 'exists')
        self.assertTrue(self.session.accessed)
        self.assertTrue(self.session.modified)
        self.assertEqual(self.session.get('some key'), None)

    def test_pop_default(self):
        self.assertEqual(self.session.pop('some key', 'does not exist'),
                         'does not exist')
        self.assertTrue(self.session.accessed)
        self.assertFalse(self.session.modified)

    def test_setdefault(self):
        self.assertEqual(self.session.setdefault('foo', 'bar'), 'bar')
        self.assertEqual(self.session.setdefault('foo', 'baz'), 'bar')
        self.assertTrue(self.session.accessed)
        self.assertTrue(self.session.modified)

    def test_update(self):
        self.session.update({'update key': 1})
        self.assertTrue(self.session.accessed)
        self.assertTrue(self.session.modified)
        self.assertEqual(self.session.get('update key', None), 1)

    def test_has_key(self):
        self.session['some key'] = 1
        self.session.modified = False
        self.session.accessed = False
        self.assertTrue(self.session.has_key('some key'))
        self.assertTrue(self.session.accessed)
        self.assertFalse(self.session.modified)

    def test_values(self):
        self.assertEqual(self.session.values(), [])
        self.assertTrue(self.session.accessed)
        self.session['some key'] = 1
        self.assertEqual(self.session.values(), [1])

    def test_iterkeys(self):
        self.session['x'] = 1
        self.session.modified = False
        self.session.accessed = False
        i = self.session.iterkeys()
        self.assertTrue(hasattr(i, '__iter__'))
        self.assertTrue(self.session.accessed)
        self.assertFalse(self.session.modified)
        self.assertEqual(list(i), ['x'])

    def test_iterkeys(self):
        self.session['x'] = 1
        self.session.modified = False
        self.session.accessed = False
        i = self.session.itervalues()
        self.assertTrue(hasattr(i, '__iter__'))
        self.assertTrue(self.session.accessed)
        self.assertFalse(self.session.modified)
        self.assertEqual(list(i), [1])

    def test_iteritems(self):
        self.session['x'] = 1
        self.session.modified = False
        self.session.accessed = False
        i = self.session.iteritems()
        self.assertTrue(hasattr(i, '__iter__'))
        self.assertTrue(self.session.accessed)
        self.assertFalse(self.session.modified)
        self.assertEqual(list(i), [('x',1)])

    def test_clear(self):
        self.session['x'] = 1
        self.session.modified = False
        self.session.accessed = False
        self.assertEqual(self.session.items(), [('x',1)])
        self.session.clear()
        self.assertEqual(self.session.items(), [])
        self.assertTrue(self.session.accessed)
        self.assertTrue(self.session.modified)

    def test_save(self):
        self.session.save()
        self.assertTrue(self.session.exists(self.session.session_key))

    def test_delete(self):
        self.session.delete(self.session.session_key)
        self.assertFalse(self.session.exists(self.session.session_key))

    def test_flush(self):
        self.session['foo'] = 'bar'
        self.session.save()
        prev_key = self.session.session_key
        self.session.flush()
        self.assertFalse(self.session.exists(prev_key))
        self.assertNotEqual(self.session.session_key, prev_key)
        self.assertTrue(self.session.modified)
        self.assertTrue(self.session.accessed)

    def test_cycle(self):
        self.session['a'], self.session['b'] = 'c', 'd'
        self.session.save()
        prev_key = self.session.session_key
        prev_data = self.session.items()
        self.session.cycle_key()
        self.assertNotEqual(self.session.session_key, prev_key)
        self.assertEqual(self.session.items(), prev_data)

    def test_invalid_key(self):
        # Submitting an invalid session key (either by guessing, or if the db has
        # removed the key) results in a new key being generated.
        session = self.backend('1')
        session.save()
        self.assertNotEqual(session.session_key, '1')
        self.assertEqual(session.get('cat'), None)
        session.delete()

    # Custom session expiry
    def test_default_expiry(self):
        # A normal session has a max age equal to settings
        self.assertEqual(self.session.get_expiry_age(), settings.SESSION_COOKIE_AGE)

        # So does a custom session with an idle expiration time of 0 (but it'll
        # expire at browser close)
        self.session.set_expiry(0)
        self.assertEqual(self.session.get_expiry_age(), settings.SESSION_COOKIE_AGE)

    def test_custom_expiry_seconds(self):
        # Using seconds
        self.session.set_expiry(10)
        delta = self.session.get_expiry_date() - datetime.now()
        self.assertTrue(delta.seconds in (9, 10))

        age = self.session.get_expiry_age()
        self.assertTrue(age in (9, 10))

    def test_custom_expiry_timedelta(self):
        # Using timedelta
        self.session.set_expiry(timedelta(seconds=10))
        delta = self.session.get_expiry_date() - datetime.now()
        self.assertTrue(delta.seconds in (9, 10))

        age = self.session.get_expiry_age()
        self.assertTrue(age in (9, 10))

    def test_custom_expiry_timedelta(self):
        # Using timedelta
        self.session.set_expiry(datetime.now() + timedelta(seconds=10))
        delta = self.session.get_expiry_date() - datetime.now()
        self.assertTrue(delta.seconds in (9, 10))

        age = self.session.get_expiry_age()
        self.assertTrue(age in (9, 10))

    def test_custom_expiry_reset(self):
        self.session.set_expiry(None)
        self.session.set_expiry(10)
        self.session.set_expiry(None)
        self.assertEqual(self.session.get_expiry_age(), settings.SESSION_COOKIE_AGE)

    def test_get_expire_at_browser_close(self):
        # Tests get_expire_at_browser_close with different settings and different
        # set_expiry calls
        try:
            try:
                original_expire_at_browser_close = settings.SESSION_EXPIRE_AT_BROWSER_CLOSE
                settings.SESSION_EXPIRE_AT_BROWSER_CLOSE = False

                self.session.set_expiry(10)
                self.assertFalse(self.session.get_expire_at_browser_close())

                self.session.set_expiry(0)
                self.assertTrue(self.session.get_expire_at_browser_close())

                self.session.set_expiry(None)
                self.assertFalse(self.session.get_expire_at_browser_close())

                settings.SESSION_EXPIRE_AT_BROWSER_CLOSE = True

                self.session.set_expiry(10)
                self.assertFalse(self.session.get_expire_at_browser_close())

                self.session.set_expiry(0)
                self.assertTrue(self.session.get_expire_at_browser_close())

                self.session.set_expiry(None)
                self.assertTrue(self.session.get_expire_at_browser_close())

            except:
                raise
        finally:
            settings.SESSION_EXPIRE_AT_BROWSER_CLOSE = original_expire_at_browser_close

    def test_decode(self):
        # Ensure we can decode what we encode
        data = {'a test key': 'a test value'}
        encoded = self.session.encode(data)
        self.assertEqual(self.session.decode(encoded), data)

    def test_decode_django12(self):
        # Ensure we can decode values encoded using Django 1.2
        # Hard code the Django 1.2 method here:
        def encode(session_dict):
            pickled = pickle.dumps(session_dict, pickle.HIGHEST_PROTOCOL)
            pickled_md5 = md5_constructor(pickled + settings.SECRET_KEY).hexdigest()
            return base64.encodestring(pickled + pickled_md5)

        data = {'a test key': 'a test value'}
        encoded = encode(data)
        self.assertEqual(self.session.decode(encoded), data)


class DatabaseSessionTests(SessionTestsMixin, TestCase):

    backend = DatabaseSession

    def test_session_get_decoded(self):
        """
        Test we can use Session.get_decoded to retrieve data stored
        in normal way
        """
        self.session['x'] = 1
        self.session.save()

        s = Session.objects.get(session_key=self.session.session_key)

        self.assertEqual(s.get_decoded(), {'x': 1})

    def test_sessionmanager_save(self):
        """
        Test SessionManager.save method
        """
        # Create a session
        self.session['y'] = 1
        self.session.save()

        s = Session.objects.get(session_key=self.session.session_key)
        # Change it
        Session.objects.save(s.session_key, {'y':2}, s.expire_date)
        # Clear cache, so that it will be retrieved from DB
        del self.session._session_cache
        self.assertEqual(self.session['y'], 2)


class CacheDBSessionTests(SessionTestsMixin, TestCase):

    backend = CacheDBSession

# Don't need DB flushing for these tests, so can use unittest.TestCase as base class
class FileSessionTests(SessionTestsMixin, unittest.TestCase):

    backend = FileSession

    def setUp(self):
        super(FileSessionTests, self).setUp()
        # Do file session tests in an isolated directory, and kill it after we're done.
        self.original_session_file_path = settings.SESSION_FILE_PATH
        self.temp_session_store = settings.SESSION_FILE_PATH = tempfile.mkdtemp()

    def tearDown(self):
        settings.SESSION_FILE_PATH = self.original_session_file_path
        shutil.rmtree(self.temp_session_store)
        super(FileSessionTests, self).tearDown()

    def test_configuration_check(self):
        # Make sure the file backend checks for a good storage dir
        settings.SESSION_FILE_PATH = "/if/this/directory/exists/you/have/a/weird/computer"
        self.assertRaises(ImproperlyConfigured, self.backend)


class CacheSessionTests(SessionTestsMixin, unittest.TestCase):

    backend = CacheSession