# vim: tabstop=4 shiftwidth=4 softtabstop=4

# Copyright 2011 OpenStack, LLC
# All Rights Reserved.
#
#    Licensed under the Apache License, Version 2.0 (the "License"); you may
#    not use this file except in compliance with the License. You may obtain
#    a copy of the License at
#
#         http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
#    License for the specific language governing permissions and limitations
#    under the License.

from contextlib import contextmanager
import os
import random
import shutil
import StringIO
import unittest

import stubout

from glance import image_cache
from glance.common import utils
from glance.openstack.common import cfg
from glance.tests import utils as test_utils
from glance.tests.utils import skip_if_disabled, xattr_writes_supported

FIXTURE_LENGTH = 1024
FIXTURE_DATA = '*' * FIXTURE_LENGTH


class ImageCacheTestCase(object):

    def _setup_fixture_file(self):
        FIXTURE_FILE = StringIO.StringIO(FIXTURE_DATA)

        self.assertFalse(self.cache.is_cached(1))

        self.assertTrue(self.cache.cache_image_file(1, FIXTURE_FILE))

        self.assertTrue(self.cache.is_cached(1))

    @skip_if_disabled
    def test_is_cached(self):
        """
        Verify is_cached(1) returns 0, then add something to the cache
        and verify is_cached(1) returns 1.
        """
        self._setup_fixture_file()

    @skip_if_disabled
    def test_read(self):
        """
        Verify is_cached(1) returns 0, then add something to the cache
        and verify after a subsequent read from the cache that
        is_cached(1) returns 1.
        """
        self._setup_fixture_file()

        buff = StringIO.StringIO()
        with self.cache.open_for_read(1) as cache_file:
            for chunk in cache_file:
                buff.write(chunk)

        self.assertEqual(FIXTURE_DATA, buff.getvalue())

    @skip_if_disabled
    def test_open_for_read(self):
        """
        Test convenience wrapper for opening a cache file via
        its image identifier.
        """
        self._setup_fixture_file()

        buff = StringIO.StringIO()
        with self.cache.open_for_read(1) as cache_file:
            for chunk in cache_file:
                buff.write(chunk)

        self.assertEqual(FIXTURE_DATA, buff.getvalue())

    @skip_if_disabled
    def test_get_image_size(self):
        """
        Test convenience wrapper for querying cache file size via
        its image identifier.
        """
        self._setup_fixture_file()

        size = self.cache.get_image_size(1)

        self.assertEqual(FIXTURE_LENGTH, size)

    @skip_if_disabled
    def test_delete(self):
        """
        Test delete method that removes an image from the cache
        """
        self._setup_fixture_file()

        self.cache.delete_cached_image(1)

        self.assertFalse(self.cache.is_cached(1))

    @skip_if_disabled
    def test_delete_all(self):
        """
        Test delete method that removes an image from the cache
        """
        for image_id in (1, 2):
            self.assertFalse(self.cache.is_cached(image_id))

        for image_id in (1, 2):
            FIXTURE_FILE = StringIO.StringIO(FIXTURE_DATA)
            self.assertTrue(self.cache.cache_image_file(image_id,
                                                        FIXTURE_FILE))

        for image_id in (1, 2):
            self.assertTrue(self.cache.is_cached(image_id))

        self.cache.delete_all_cached_images()

        for image_id in (1, 2):
            self.assertFalse(self.cache.is_cached(image_id))

    @skip_if_disabled
    def test_clean_stalled(self):
        """
        Test the clean method removes expected images
        """
        incomplete_file_path = os.path.join(self.cache_dir, 'incomplete', '1')
        incomplete_file = open(incomplete_file_path, 'w')
        incomplete_file.write(FIXTURE_DATA)
        incomplete_file.close()

        self.assertTrue(os.path.exists(incomplete_file_path))

        self.cache.clean(stall_time=0)

        self.assertFalse(os.path.exists(incomplete_file_path))

    @skip_if_disabled
    def test_prune(self):
        """
        Test that pruning the cache works as expected...
        """
        self.assertEqual(0, self.cache.get_cache_size())

        # Add a bunch of images to the cache. The max cache
        # size for the cache is set to 5KB and each image is
        # 1K. We add 10 images to the cache and then we'll
        # prune it. We should see only 5 images left after
        # pruning, and the images that are least recently accessed
        # should be the ones pruned...
        for x in xrange(0, 10):
            FIXTURE_FILE = StringIO.StringIO(FIXTURE_DATA)
            self.assertTrue(self.cache.cache_image_file(x,
                                                        FIXTURE_FILE))

        self.assertEqual(10 * 1024, self.cache.get_cache_size())

        # OK, hit the images that are now cached...
        for x in xrange(0, 10):
            buff = StringIO.StringIO()
            with self.cache.open_for_read(x) as cache_file:
                for chunk in cache_file:
                    buff.write(chunk)

        self.cache.prune()

        self.assertEqual(5 * 1024, self.cache.get_cache_size())

        for x in xrange(0, 5):
            self.assertFalse(self.cache.is_cached(x),
                             "Image %s was cached!" % x)

        for x in xrange(5, 10):
            self.assertTrue(self.cache.is_cached(x),
                            "Image %s was not cached!" % x)

    @skip_if_disabled
    def test_queue(self):
        """
        Test that queueing works properly
        """

        self.assertFalse(self.cache.is_cached(1))
        self.assertFalse(self.cache.is_queued(1))

        FIXTURE_FILE = StringIO.StringIO(FIXTURE_DATA)

        self.assertTrue(self.cache.queue_image(1))

        self.assertTrue(self.cache.is_queued(1))
        self.assertFalse(self.cache.is_cached(1))

        # Should not return True if the image is already
        # queued for caching...
        self.assertFalse(self.cache.queue_image(1))

        self.assertFalse(self.cache.is_cached(1))

        # Test that we return False if we try to queue
        # an image that has already been cached

        self.assertTrue(self.cache.cache_image_file(1, FIXTURE_FILE))

        self.assertFalse(self.cache.is_queued(1))
        self.assertTrue(self.cache.is_cached(1))

        self.assertFalse(self.cache.queue_image(1))

        self.cache.delete_cached_image(1)

        for x in xrange(0, 3):
            self.assertTrue(self.cache.queue_image(x))

        self.assertEqual(self.cache.get_queued_images(),
                         ['0', '1', '2'])


class TestImageCacheXattr(unittest.TestCase,
                          ImageCacheTestCase):

    """Tests image caching when xattr is used in cache"""

    def setUp(self):
        """
        Test to see if the pre-requisites for the image cache
        are working (python-xattr installed and xattr support on the
        filesystem)
        """
        if getattr(self, 'disable', False):
            return

        self.cache_dir = os.path.join("/", "tmp", "test.cache.%d" %
                                      random.randint(0, 1000000))
        utils.safe_mkdirs(self.cache_dir)

        if not getattr(self, 'inited', False):
            try:
                import xattr
            except ImportError:
                self.inited = True
                self.disabled = True
                self.disabled_message = ("python-xattr not installed.")
                return

        self.inited = True
        self.disabled = False
        self.conf = test_utils.TestConfigOpts({
                'image_cache_dir': self.cache_dir,
                'image_cache_driver': 'xattr',
                'image_cache_max_size': 1024 * 5,
                'registry_host': '0.0.0.0',
                'registry_port': 9191})
        self.cache = image_cache.ImageCache(self.conf)

        if not xattr_writes_supported(self.cache_dir):
            self.inited = True
            self.disabled = True
            self.disabled_message = ("filesystem does not support xattr")
            return

    def tearDown(self):
        if os.path.exists(self.cache_dir):
            shutil.rmtree(self.cache_dir)


class TestImageCacheSqlite(unittest.TestCase,
                           ImageCacheTestCase):

    """Tests image caching when SQLite is used in cache"""

    def setUp(self):
        """
        Test to see if the pre-requisites for the image cache
        are working (python-sqlite3 installed)
        """
        if getattr(self, 'disable', False):
            return

        if not getattr(self, 'inited', False):
            try:
                import sqlite3
            except ImportError:
                self.inited = True
                self.disabled = True
                self.disabled_message = ("python-sqlite3 not installed.")
                return

        self.inited = True
        self.disabled = False
        self.cache_dir = os.path.join("/", "tmp", "test.cache.%d" %
                                      random.randint(0, 1000000))
        self.conf = test_utils.TestConfigOpts({
                'image_cache_dir': self.cache_dir,
                'image_cache_driver': 'sqlite',
                'image_cache_max_size': 1024 * 5,
                'registry_host': '0.0.0.0',
                'registry_port': 9191})
        self.cache = image_cache.ImageCache(self.conf)

    def tearDown(self):
        if os.path.exists(self.cache_dir):
            shutil.rmtree(self.cache_dir)


class TestImageCacheNoDep(unittest.TestCase):

    def setUp(self):
        self.driver = None

        def init_driver(self2):
            self2.driver = self.driver

        self.stubs = stubout.StubOutForTesting()
        self.stubs.Set(image_cache.ImageCache, 'init_driver', init_driver)

    def tearDown(self):
        self.stubs.UnsetAll()

    def test_get_caching_iter_when_write_fails(self):

        class FailingFile(object):

            def write(self, data):
                if data == "Fail":
                    raise IOError

        class FailingFileDriver(object):

            def is_cacheable(self, *args, **kwargs):
                return True

            @contextmanager
            def open_for_write(self, *args, **kwargs):
                yield FailingFile()

        self.driver = FailingFileDriver()
        conf = cfg.ConfigOpts()
        cache = image_cache.ImageCache(conf)
        data = ['a', 'b', 'c', 'Fail', 'd', 'e', 'f']

        caching_iter = cache.get_caching_iter('dummy_id', iter(data))
        self.assertEqual(list(caching_iter), data)

    def test_get_caching_iter_when_open_fails(self):

        class OpenFailingDriver(object):

            def is_cacheable(self, *args, **kwargs):
                return True

            @contextmanager
            def open_for_write(self, *args, **kwargs):
                raise IOError

        self.driver = OpenFailingDriver()
        conf = cfg.ConfigOpts()
        cache = image_cache.ImageCache(conf)
        data = ['a', 'b', 'c', 'd', 'e', 'f']

        caching_iter = cache.get_caching_iter('dummy_id', iter(data))
        self.assertEqual(list(caching_iter), data)