# Copyright 2010 United States Government as represented by the
# Administrator of the National Aeronautics and Space Administration.
# Copyright 2011 Justin Santa Barbara
# 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.

"""Utilities and helper functions."""


import abc
import contextlib
import datetime
import functools
import hashlib
import inspect
import logging as py_logging
import os
import pyclbr
import random
import re
import shutil
import socket
import stat
import sys
import tempfile
import time
import types
from xml.dom import minidom
from xml.parsers import expat
from xml import sax
from xml.sax import expatreader
from xml.sax import saxutils

from os_brick.initiator import connector
from oslo_concurrency import lockutils
from oslo_concurrency import processutils
from oslo_config import cfg
from oslo_log import log as logging
from oslo_utils import encodeutils
from oslo_utils import importutils
from oslo_utils import strutils
from oslo_utils import timeutils
import retrying
import six

from cinder import exception
from cinder.i18n import _, _LE, _LW


CONF = cfg.CONF
LOG = logging.getLogger(__name__)
ISO_TIME_FORMAT = "%Y-%m-%dT%H:%M:%S"
PERFECT_TIME_FORMAT = "%Y-%m-%dT%H:%M:%S.%f"
VALID_TRACE_FLAGS = {'method', 'api'}
TRACE_METHOD = False
TRACE_API = False

synchronized = lockutils.synchronized_with_prefix('cinder-')


def find_config(config_path):
    """Find a configuration file using the given hint.

    :param config_path: Full or relative path to the config.
    :returns: Full path of the config, if it exists.
    :raises: `cinder.exception.ConfigNotFound`

    """
    possible_locations = [
        config_path,
        os.path.join(CONF.state_path, "etc", "cinder", config_path),
        os.path.join(CONF.state_path, "etc", config_path),
        os.path.join(CONF.state_path, config_path),
        "/etc/cinder/%s" % config_path,
    ]

    for path in possible_locations:
        if os.path.exists(path):
            return os.path.abspath(path)

    raise exception.ConfigNotFound(path=os.path.abspath(config_path))


def as_int(obj, quiet=True):
    # Try "2" -> 2
    try:
        return int(obj)
    except (ValueError, TypeError):
        pass
    # Try "2.5" -> 2
    try:
        return int(float(obj))
    except (ValueError, TypeError):
        pass
    # Eck, not sure what this is the
n.
    if not quiet:
        raise TypeError(_("Can not translate %
s to integer.") % (obj))
    return obj


def is_int_like(val):
    """Check if a value looks like an int."""
    try:
        return str(int(val)) == str(val)
    except Exception:
        return False


def check_exclusive_options(**kwargs):
    """Checks that only one of the provided options is actually not-none.

    Iterates over all the kwargs passed in and checks that only one of said
    arguments is not-none, if more than one is not-none then an exception will
    be raised with the names of those arguments who were not-none.
    """

    if not kwargs:
        return

    pretty_keys = kwargs.pop("pretty_keys", True)
    exclusive_options = {}
    for (k, v) in kwargs.items():
        if v is not None:
            exclusive_options[k] = True

    if len(exclusive_options) > 1:
        # Change the format of the names from pythonic to
        # something that is more readable.
        #
        # Ex: 'the_key' -> 'the key'
        if pretty_keys:
            names = [k.replace('_', ' ') for k in kwargs.keys()]
        else:
            names = kwargs.keys()
        names = ", ".join(sorted(names))
        msg = (_("May specify only one of %s") % (names))
        raise exception.InvalidInput(reason=msg)


def execute(*cmd, **kwargs):
    """Convenience wrapper around oslo's execute() method."""
    if 'run_as_root' in kwargs and 'root_helper' not in kwargs:
        kwargs['root_helper'] = get_root_helper()
    return processutils.execute(*cmd, **kwargs)


def check_ssh_injection(cmd_list):
    ssh_injection_pattern = ['`', '$', '|', '||', ';', '&', '&&', '>', '>>',
                             '<']

    # Check whether injection attacks exist
    for arg in cmd_list:
        arg = arg.strip()

        # Check for matching quotes on the ends
        is_quoted = re.match('^(?P<quote>[\'"])(?P<quoted>.*)(?P=quote)$', arg)
        if is_quoted:
            # Check for unescaped quotes within the quoted argument
            quoted = is_quoted.group('quoted')
            if quoted:
                if (re.match('[\'"]', quoted) or
                        re.search('[^\\\\][\'"]', quoted)):
                    raise exception.SSHInjectionThreat(command=cmd_list)
        else:
            # We only allow spaces within quoted arguments, and that
            # is the only special character allowed within quotes
            if len(arg.split()) > 1:
                raise exception.SSHInjectionThreat(command=cmd_list)

        # Second, check whether danger character in command. So the shell
        # special operator must be a single argument.
        for c in ssh_injection_pattern:
            if c not in arg:
                continue

            result = arg.find(c)
            if not result == -1:
                if result == 0 or not arg[result - 1] == '\\':
                    raise exception.SSHInjectionThreat(command=cmd_list)


def create_channel(client, width, height):
    """Invoke an interactive shell session on server."""
    channel = client.invoke_shell()
    channel.resize_pty(width, height)
    return channel


def cinderdir():
    import cinder
    return os.path.abspath(cinder.__file__).split('cinder/__init__.py')[0]


def last_completed_audit_period(unit=None):
    """This method gives you the most recently *completed* audit period.

    arguments:
            units: string, one of 'hour', 'day', 'month', 'year'
                    Periods normally begin at the beginning (UTC) of the
                    period unit (So a 'day' period begins at midnight UTC,
                    a 'month' unit on the 1st, a 'year' on Jan, 1)
                    unit string may be appended with an optional offset
                    like so:  'day@18'  This will begin the period at 18:00
                    UTC.  'month@15' starts a monthly period on the 15th,
                    and year@3 begins a yearly one on March 1st.


    returns:  2 tuple of datetimes (begin, end)
              The begin timestamp of this audit period is the same as the
              end of the previous.
    """
    if not unit:
        unit = CONF.volume_usage_audit_period

    offset = 0
    if '@' in unit:
        unit, offset = unit.split("@", 1)
        offset = int(offset)

    rightnow = timeutils.utcnow()
    if unit not in ('month', 'day', 'year', 'hour'):
        raise ValueError('Time period must be hour, day, month or year')
    if unit == 'month':
        if offset == 0:
            offset = 1
        end = datetime.datetime(day=offset,
                                month=rightnow.month,
                                year=rightnow.year)
        if end >= rightnow:
            year = rightnow.year
            if 1 >= rightnow.month:
                year -= 1
                month = 12 + (rightnow.month - 1)
            else:
                month = rightnow.month - 1
            end = datetime.datetime(day=offset,
                                    month=month,
                                    year=year)
        year = end.year
        if 1 >= end.month:
            year -= 1
            month = 12 + (end.month - 1)
        else:
            month = end.month - 1
        begin = datetime.datetime(day=offset, month=month, year=year)

 