# 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 inspect
import logging
import os
import re
import signal
import socket
import time
import urllib2
import uuid

from autotest_lib.client.common_lib import base_utils
from autotest_lib.client.common_lib import error
from autotest_lib.client.common_lib import global_config
from autotest_lib.client.common_lib import lsbrelease_utils
from autotest_lib.client.cros import constants


# Keep checking if the pid is alive every second until the timeout (in seconds)
CHECK_PID_IS_ALIVE_TIMEOUT = 6

_LOCAL_HOST_LIST = ('localhost', '127.0.0.1')

# The default address of a vm gateway.
DEFAULT_VM_GATEWAY = '10.0.2.2'

# Google Storage bucket URI to store results in.
DEFAULT_OFFLOAD_GSURI = global_config.global_config.get_config_value(
        'CROS', 'results_storage_server', default=None)

# Default Moblab Ethernet Interface.
MOBLAB_ETH = 'eth0'

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 host: the host to ping.
    @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 CLIENT.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('CLIENT', '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_chrome_version(job_views):
    """
    Retrieves the version of the chrome binary associated with a job.

    When a test runs we query the chrome binary for it's version and drop
    that value into a client keyval. To retrieve the chrome version we get all
    the views associated with a test from the db, including those of the
    server and client jobs, and parse the version out of the first test view
    that has it. If we never ran a single test in the suite the job_views
    dictionary will not contain a chrome version.

    This method cannot retrieve the chrome version from a dictionary that
    does not conform to the structure of an autotest tko view.

    @param job_views: a list of a job's result views, as returned by
                      the get_detailed_test_views method in rpc_interface.
    @return: The chrome version string, or None if one can't be found.
    """

    # Aborted jobs have no views.
    if not job_views:
        return None

    for view in job_views:
        if (view.get('attributes')
            and constants.CHROME_VERSION in view['attributes'].keys()):

            return view['attributes'].get(constants.CHROME_VERSION)

    logging.warning('Could not find chrome version for failure.')
    return None


def get_interface_mac_address(interface):
    """Return the MAC address of a given interface.

    @param interface: Interface to look up the MAC address of.
    """
    interface_link = base_utils.run(
            'ip addr show %s | grep link/ether' % interface).stdout
    # The output will be in the format of:
    # 'link/ether <mac> brd ff:ff:ff:ff:ff:ff'
    return interface_link.split()[1]


def get_offload_gsuri():
    """Return the GSURI to offload test results to.

    For the normal use case this is the results_storage_server in the
    global_config.

    However partners using Moblab will be offloading their results to a
    subdirectory of their image storage buckets. The subdirectory is
    determined by the MAC Address of the Moblab device.

    @returns gsuri to offload test results to.
    """
    if not lsbrelease_utils.is_moblab():
        return DEFAULT_OFFLOAD_GSURI
    moblab_id_filepath = '/home/moblab/.moblab_id'
    if os.path.exists(moblab_id_filepath):
        with open(moblab_id_filepath, 'r') as moblab_id_file:
            random_id = moblab_id_file.read()
    else:
        random_id = uuid.uuid1()
        with open(moblab_id_filepath, 'w') as moblab_id_file:
            moblab_id_file.write('%s' % random_id)
    return '%sresults/%s/%s/' % (
            global_config.global_config.get_config_value(
                    'CROS', 'image_storage_server'),
            get_interface_mac_address(MOBLAB_ETH), random_id)


# TODO(petermayo): crosbug.com/31826 Share this with _GsUpload in
# //chromite.git/buildbot/prebuilt.py somewhere/somehow
def gs_upload(local_file, remote_file, acl, result_dir=None,
              transfer_timeout=300, acl_timeout=300):
    """Upload to GS bucket.

    @param local_file: Local file to upload
    @param remote_file: Remote location to upload the local_file to.
    @param acl: name or file used for controlling access to the uploaded
                file.
    @param result_dir: Result directory if you want to add tracing to the
                       upload.
    @param transfer_timeout: Timeout for this upload call.
    @param acl_timeout: Timeout for the acl call needed to confirm that
                        the uploader has permissions to execute the upload.

    @raise CmdError: the exit code of the gsutil call was not 0.

    @returns True/False - depending on if the upload succeeded or failed.
    """
    # https://developers.google.com/storage/docs/accesscontrol#extension
    CANNED_ACLS = ['project-private', 'private', 'public-read',
                   'public-read-write', 'authenticated-read',
                   'bucket-owner-read', 'bucket-owner-full-control']
    _GSUTIL_BIN = 'gsutil'
    acl_cmd = None
    if acl in CANNED_ACLS:
        cmd = '%s cp -a %s %s %s' % (_GSUTIL_BIN, acl, local_file, remote_file)
    else:
        # For private uploads we assume that the overlay board is set up
        # properly and a googlestore_acl.xml is present, if not this script
        # errors
        cmd = '%s cp -a private %s %s' % (_GSUTIL_BIN, local_file, remote_file)
        if not os.path.exists(acl):
            logging.error('Unable to find ACL File %s.', acl)
            return False
        acl_cmd = '%s setacl %s %s' % (_GSUTIL_BIN, acl, remote_file)
    if not result_dir:
        base_utils.run(cmd, timeout=transfer_timeout, verbose=True)
        if acl_cmd:
            base_utils.run(acl_cmd, timeout=acl_timeout, verbose=True)
        return True
    with open(os.path.join(result_dir, 'tracing'), 'w') as ftrace:
        ftrace.write('Preamble\n')
        base_utils.run(cmd, timeout=transfer_timeout, verbose=True,
                       stdout_tee=ftrace, stderr_tee=ftrace)
        if acl_cmd:
            ftrace.write('\nACL setting\n')
            # Apply the passed in ACL xml file to the uploaded object.
            base_utils.run(acl_cmd, timeout=acl_timeout, verbose=True,
                           stdout_tee=ftrace, stderr_tee=ftrace)
        ftrace.write('Postamble\n')
        return True


def gs_ls(uri_pattern):
    """Returns a list of URIs that match a given pattern.

    @param uri_pattern: a GS URI pattern, may contain wildcards

    @return A list of URIs matching the given pattern.

    @raise CmdError: the gsutil command failed.

    """
    gs_cmd = ' '.join(['gsutil', 'ls', uri_pattern])
    result = base_utils.system_output(gs_cmd).splitlines()
    return [path.rstrip() for path in result if path]


def nuke_pids(pid_list, signal_queue=[signal.SIGTERM, signal.SIGKILL]):
    """
    Given a list of pid's, kill them via an esclating series of signals.

    @param pid_list: List of PID's to kill.
    @param signal_queue: Queue of signals to send the PID's to terminate them.

    @return: A mapping of the signal name to the number of processes it
        was sent to.
    """
    sig_count = {}
    # Though this is slightly hacky it beats hardcoding names anyday.
    sig_names = dict((k, v) for v, k in signal.__dict__.iteritems()
                     if v.startswith('SIG'))
    for sig in signal_queue:
        logging.debug('Sending signal %s to the following pids:', sig)
        sig_count[sig_names.get(sig, 'unknown_signal')] = len(pid_list)
        for pid in pid_list:
            logging.debug('Pid %d', pid)
            try:
                os.kill(pid, sig)
            except OSError:
                # The process may have died from a previous signal before we
                # could kill it.
                pass
        if sig == signal.SIGKILL:
            return sig_count
        pid_list = [pid for pid in pid_list if base_utils.pid_is_alive(pid)]
        if not pid_list:
            break
        time.sleep(CHECK_PID_IS_ALIVE_TIMEOUT)
    failed_list = []
    for pid in pid_list:
        if base_utils.pid_is_alive(pid):
            failed_list.append('Could not kill %d for process name: %s.' % pid,
                               base_utils.get_process_name(pid))
    if failed_list:
        raise error.AutoservRunError('Following errors occured: %s' %
                                     failed_list, None)
    return sig_count


def externalize_host(host):
    """Returns an externally accessible host name.

    @param host: a host name or address (string)

    @return An externally visible host name or address

    """
    return socket.gethostname() if host in _LOCAL_HOST_LIST else host


def urlopen_socket_timeout(url, data=None, timeout=5):
    """
    Wrapper to urllib2.urlopen with a socket timeout.

    This method will convert all socket timeouts to
    TimeoutExceptions, so we can use it in conjunction
    with the rpc retry decorator and continue to handle
    other URLErrors as we see fit.

    @param url: The url to open.
    @param data: The data to send to the url (eg: the urlencoded dictionary
                 used with a POST call).
    @param timeout: The timeout for this urlopen call.

    @return: The response of the urlopen call.

    @raises: error.TimeoutException when a socket timeout occurs.
             urllib2.URLError for errors that not caused by timeout.
             urllib2.HTTPError for errors like 404 url not found.
    """
    old_timeout = socket.getdefaulttimeout()
    socket.setdefaulttimeout(timeout)
    try:
        return urllib2.urlopen(url, data=data)
    except urllib2.URLError as e:
        if type(e.reason) is socket.timeout:
            raise error.TimeoutException(str(e))
        raise
    finally:
        socket.setdefaulttimeout(old_timeout)


def parse_chrome_version(version_string):
    """
    Parse a chrome version string and return version and milestone.

    Given a chrome version of the form "W.X.Y.Z", return "W.X.Y.Z" as
    the version and "W" as the milestone.

    @param version_string: Chrome version string.
    @return: a tuple (chrome_version, milestone). If the incoming version
             string is not of the form "W.X.Y.Z", chrome_version will
             be set to the incoming "version_string" argument and the
             milestone will be set to the empty string.
    """
    match = re.search('(\d+)\.\d+\.\d+\.\d+', version_string)
    ver = match.group(0) if match else version_string
    milestone = match.group(1) if match else ''
    return ver, milestone


def is_localhost(server):
    """Check if server is equivalent to localhost.

    @param server: Name of the server to check.

    @return: True if given server is equivalent to localhost.

    @raise socket.gaierror: If server name failed to be resolved.
    """
    if server in _LOCAL_HOST_LIST:
        return True
    try:
        return (socket.gethostbyname(socket.gethostname()) ==
                socket.gethostbyname(server))
    except socket.gaierror:
        logging.error('Failed to resolve server name %s.', server)
        return False


def get_function_arg_value(func, arg_name, args, kwargs):
    """Get the value of the given argument for the function.

    @param func: Function being called with given arguments.
    @param arg_name: Name of the argument to look for value.
    @param args: arguments for function to be called.
    @param kwargs: keyword arguments for function to be called.

    @return: The value of the given argument for the function.

    @raise ValueError: If the argument is not listed function arguemnts.
    @raise KeyError: If no value is found for the given argument.
    """
    if arg_name in kwargs:
        return kwargs[arg_name]

    argspec = inspect.getargspec(func)
    index = argspec.args.index(arg_name)
    try:
        return args[index]
    except IndexError:
        try:
            # The argument can use a default value. Reverse the default value
            # so argument with default value can be counted from the last to
            # the first.
            return argspec.defaults[::-1][len(argspec.args) - index - 1]
        except IndexError:
            raise KeyError('Argument %s is not given a value. argspec: %s, '
                           'args:%s, kwargs:%s' %
                           (arg_name, argspec, args, kwargs))