# Copyright (c) 2013 NEC Corporation
# 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.

import importlib
import os
import platform
import random
import string
import sys
import time
import warnings

import fixtures
import mock
import netaddr
import six

import neutron
from neutron.api.v2 import attributes
from neutron.common import constants


class AttributeMapMemento(fixtures.Fixture):
    """Create a copy of the resource attribute map so it can be restored during
    test cleanup.

    There are a few reasons why this is not included in a class derived
    from BaseTestCase:

        - Test cases may need more control about when the backup is
        made, especially if they are not direct descendants of
        BaseTestCase.

        - Inheritance is a bit of overkill for this facility and it's a
        stretch to rationalize the "is a" criteria.
    """

    def _setUp(self):
        # Shallow copy is not a proper choice for keeping a backup copy as
        # the RESOURCE_ATTRIBUTE_MAP map is modified in place through the
        # 0th level keys. Ideally deepcopy() would be used but this seems
        # to result in test failures. A compromise is to copy one level
        # deeper than a shallow copy.
        self.contents_backup = {}
        for res, attrs in six.iteritems(attributes.RESOURCE_ATTRIBUTE_MAP):
            self.contents_backup[res] = attrs.copy()
        self.addCleanup(self.restore)

    def restore(self):
        attributes.RESOURCE_ATTRIBUTE_MAP = self.contents_backup


class WarningsFixture(fixtures.Fixture):
    """Filters out warnings during test runs."""

    warning_types = (
        DeprecationWarning, PendingDeprecationWarning, ImportWarning
    )

    def _setUp(self):
        self.addCleanup(warnings.resetwarnings)
        for wtype in self.warning_types:
            warnings.filterwarnings(
                "always", category=wtype, module='^neutron\\.')


class OpenFixture(fixtures.Fixture):
    """Mock access to a specific file while preserving open for others."""

    def __init__(self, filepath, contents=''):
        self.path = filepath
        self.contents = contents

    def _setUp(self):
        self.mock_open = mock.mock_open(read_data=self.contents)
        self._orig_open = open

        def replacement_open(name, *args, **kwargs):
            if name == self.path:
                return self.mock_open(name, *args, **kwargs)
            return self._orig_open(name, *args, **kwargs)

        self._patch = mock.patch('six.moves.builtins.open',
                                 new=replacement_open)
        self._patch.start()
        self.addCleanup(self._patch.stop)


class SafeCleanupFixture(fixtures.Fixture):
    """Catch errors in daughter fixture cleanup."""

    def __init__(self, fixture):
        self.fixture = fixture

    def _setUp(self):

        def cleanUp():
            try:
                self.fixture.cleanUp()
            except Exception:
                pass

        self.fixture.setUp()
        self.addCleanup(cleanUp)


import unittest

from neutron.common import utils


def setup_mock_calls(mocked_call, expected_calls_and_values):
    """A convenient method to setup a sequence of mock calls.

    expected_calls_and_values is a list of (expected_call, return_value):

        expected_calls_and_values = [
            (mock.call(["ovs-vsctl", self.TO, '--', "--may-exist", "add-port",
                        self.BR_NAME, pname]),
             None),
            (mock.call(["ovs-vsctl", self.TO, "set", "Interface",
                        pname, "type=gre"]),
             None),
            ....
        ]

    * expected_call should be mock.call(expected_arg, ....)
    * return_value is passed to side_effect of a mocked call.
      A return value or an exception can be specified.
    """
    return_values = [call[1] for call in expected_calls_and_values]
    mocked_call.side_effect = return_values


def verify_mock_calls(mocked_call, expected_calls_and_values,
                      any_order=False):
    """A convenient method to setup a sequence of mock calls.

    expected_calls_and_values is a list of (expected_call, return_value):

        expected_calls_and_values = [
            (mock.call(["ovs-vsctl", self.TO, '--', "--may-exist", "add-port",
                        self.BR_NAME, pname]),
             None),
            (mock.call(["ovs-vsctl", self.TO, "set", "Interface",
                        pname, "type=gre"]),
             None),
            ....
        ]

    * expected_call should be mock.call(expected_arg, ....)
    * return_value is passed to side_effect of a mocked call.
      A return value or an exception can be specified.
    """
    expected_calls = [call[0] for call in expected_calls_and_values]
    mocked_call.assert_has_calls(expected_calls, any_order=any_order)


def fail(msg=None):
    """Fail immediately, with the given message.

    This method is equivalent to TestCase.fail without requiring a
    testcase instance (usefully for reducing coupling).
    """
    raise unittest.TestCase.failureException(msg)


class UnorderedList(list):
    """A list that is equals to any permutation of itself."""

    def __eq__(self, other):
        if not isinstance(other, list):
            return False
        return (sorted(self, key=utils.safe_sort_key) ==
                sorted(other, key=utils.safe_sort_key))

    def __neq__(self, other):
        return not self == other


def import_modules_recursively(topdir):
    '''Import and return all modules below the topdir directory.'''
    modules = []
    for root, dirs, files in os.walk(topdir):
        for file_ in files:
            if file_[-3:] != '.py':
                continue

            module = file_[:-3]
            if module == '__init__':
                continue

            import_base = root.replace('/', '.')

            # NOTE(ihrachys): in Python3, or when we are not located in the
            # directory containing neutron code, __file__ is absolute, so we
            # should truncate it to exclude PYTHONPATH prefix
            prefixlen = len(os.path.dirname(neutron.__file__))
            import_base = 'neutron' + import_base[prefixlen:]

            module = '.'.join([import_base, module])
            if module not in sys.modules:
                importlib.import_module(module)
            modules.append(module)

        for dir_ in dirs:
            modules.extend(import_modules_recursively(dir_))
    return modules


def get_random_string(n=10):
    return ''.join(random.choice(string.ascii_lowercase) for _ in range(n))


def get_random_boolean():
    return bool(random.getrandbits(1))


def get_random_integer(range_begin=0, range_end=1000):
    return random.randint(range_begin, range_end)


def get_random_prefixlen(version=4):
    maxlen = constants.IPV4_MAX_PREFIXLEN
    if version == 6:
        maxlen = constants.IPV6_MAX_PREFIXLEN
    return random.randint(0, maxlen)


def get_random_ip_version():
    return random.choice(constants.IP_ALLOWED_VERSIONS)


def get_random_cidr(version=4):
    if version == 4:
        return '10.%d.%d.0/%d' % (random.randint(3, 254),
                                  random.randint(3, 254),
                                  24)
    return '2001:db8:%x::/&d' % (random.getrandbits(16), 64)


def get_random_mac():
    """Generate a random mac address starting with fe:16:3e"""
    mac = [0xfe, 0x16, 0x3e,
        random.randint(0x00, 0xff),
        random.randint(0x00, 0xff),
        random.randint(0x00, 0xff)]
    return ':'.join(map(lambda x: "%02x" % x, mac))


def get_random_EUI():
    return netaddr.EUI(get_random_mac())


def get_random_ip_network(version=4):
    return netaddr.IPNetwork(get_random_cidr(version=version))


def is_bsd():
    """Return True on BSD-based systems."""

    system = platform.system()
    if system == 'Darwin':
        return True
    if 'bsd' in system.lower():
        return True
    return False


def reset_random_seed():
    # reset random seed to make sure other processes extracting values from RNG
    # don't get the same results (useful especially when you then use the
    # random values to allocate system resources from global pool, like ports
    # to listen). Use both current time and pid to make sure no tests started
    # at the same time get the same values from RNG
    seed = time.time() + os.getpid()
    random.seed(seed)
