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

# Copyright (c) 2011 Citrix Systems, Inc.
#
#    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.

"""This modules stubs out functions in nova.utils."""

import re

from eventlet import greenthread

from nova import exception
from nova.openstack.common import log as logging
from nova import utils

LOG = logging.getLogger(__name__)

_fake_execute_repliers = []
_fake_execute_log = []


def fake_execute_get_log():
    return _fake_execute_log


def fake_execute_clear_log():
    global _fake_execute_log
    _fake_execute_log = []


def fake_execute_set_repliers(repliers):
    """Allows the client to configure replies to commands."""
    global _fake_execute_repliers
    _fake_execute_repliers = repliers


def fake_execute_default_reply_handler(*ignore_args, **ignore_kwargs):
    """A reply handler for commands that haven't been added to the reply list.

    Returns empty strings for stdout and stderr.

    """
    return '', ''


def fake_execute(*cmd_parts, **kwargs):
    """This function stubs out execute.

    It optionally executes a preconfigued function to return expected data.

    """
    global _fake_execute_repliers

    process_input = kwargs.get('process_input', None)
    check_exit_code = kwargs.get('check_exit_code', 0)
    delay_on_retry = kwargs.get('delay_on_retry', True)
    attempts = kwargs.get('attempts', 1)
    run_as_root = kwargs.get('run_as_root', False)
    cmd_str = ' '.join(str(part) for part in cmd_parts)

    LOG.debug(_("Faking execution of cmd (subprocess): %s"), cmd_str)
    _fake_execute_log.append(cmd_str)

    reply_handler = fake_execute_default_reply_handler

    for fake_replier in _fake_execute_repliers:
        if re.match(fake_replier[0], cmd_str):
            reply_handler = fake_replier[1]
            LOG.debug(_('Faked command matched %s') % fake_replier[0])
            break

    if isinstance(reply_handler, basestring):
        # If the reply handler is a string, return it as stdout
        reply = reply_handler, ''
    else:
        try:
            # Alternative is a function, so call it
            reply = reply_handler(cmd_parts,
                                  process_input=process_input,
                                  delay_on_retry=delay_on_retry,
                                  attempts=attempts,
                                  run_as_root=run_as_root,
                                  check_exit_code=check_exit_code)
        except exception.ProcessExecutionError as e:
            LOG.debug(_('Faked command raised an exception %s'), e)
            raise

    stdout = reply[0]
    stderr = reply[1]
    LOG.debug(_("Reply to faked command is stdout='%(stdout)s' "
                "stderr='%(stderr)s'") % locals())

    # Replicate the sleep call in the real function
    greenthread.sleep(0)
    return reply


def stub_out_utils_execute(stubs):
    fake_execute_set_repliers([])
    fake_execute_clear_log()
    stubs.Set(utils, 'execute', fake_execute)
