# Copyright (c) 2012 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
import re
import socket

from autotest_lib.client.common_lib import base_utils, global_config

def ping(host, deadline=None, tries=None, timeout=60):
    """Attempt to ping |host|.

    Shell out to 'ping' to try to reach |host| for |timeout| seconds.
    Returns exit code of ping.

    Per 'man ping', if you specify BOTH |deadline| and |tries|, ping only
    returns 0 if we get responses to |tries| pings within |deadline| seconds.

    Specifying |deadline| or |count| alone should return 0 as long as
    some packets receive responses.

    @param deadline: seconds within which |tries| pings must succeed.
    @param tries: number of pings to send.
    @param timeout: number of seconds after which to kill 'ping' command.
    @return exit code of ping command.
    """
    args = [host]
    if deadline:
        args.append('-w%d' % deadline)
    if tries:
        args.append('-c%d' % tries)
    return base_utils.run('ping', args=args,
                          ignore_status=True, timeout=timeout,
                          stdout_tee=base_utils.TEE_TO_LOGS,
                          stderr_tee=base_utils.TEE_TO_LOGS).exit_status


def host_is_in_lab_zone(hostname):
    """Check if the host is in the CROS.dns_zone.

    @param hostname: The hostname to check.
    @returns True if hostname.dns_zone resolves, otherwise False.
    """
    host_parts = hostname.split('.')
    dns_zone = global_config.global_config.get_config_value('CROS', 'dns_zone',
                                                            default=None)
    fqdn = '%s.%s' % (host_parts[0], dns_zone)
    try:
        socket.gethostbyname(fqdn)
        return True
    except socket.gaierror:
      return False


def get_current_board():
    """Return the current board name.

    @return current board name, e.g "lumpy", None on fail.
    """
    with open('/etc/lsb-release') as lsb_release_file:
        for line in lsb_release_file:
            m = re.match(r'^CHROMEOS_RELEASE_BOARD=(.+)$', line)
            if m:
                return m.group(1)
    return None