# Authors:
#   Jason Gerard DeRose <jderose@redhat.com>
#
# Copyright (C) 2008  Red Hat
# see file 'COPYING' for use and warranty information
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation; version 2 only
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

"""
Various utility functions.
"""

import os
from os import path
import imp
import optparse
import logging
import time
import krbV


def xmlrpc_marshal(*args, **kw):
    """
    Marshal (args, kw) into ((kw,) + args).
    """
    return ((kw,) + args)


def xmlrpc_unmarshal(*params):
    """
    Unmarshal (params) into (args, kw).
    """
    if len(params) > 0:
        kw = params[0]
        if type(kw) is not dict:
            raise TypeError('first xmlrpc argument must be dict')
    else:
        kw = {}
    return (params[1:], kw)


def get_current_principal():
    try:
        return krbV.default_context().default_ccache().principal().name
    except krbV.Krb5Error:
        #TODO: do a kinit
        print "Unable to get kerberos principal"
        return None


# FIXME: This function has no unit test
def find_modules_in_dir(src_dir):
    """
    Iterate through module names found in ``src_dir``.
    """
    if not (path.abspath(src_dir) == src_dir and path.isdir(src_dir)):
        return
    if path.islink(src_dir):
        return
    suffix = '.py'
    for name in sorted(os.listdir(src_dir)):
        if not name.endswith(suffix):
            continue
        py_file = path.join(src_dir, name)
        if path.islink(py_file) or not path.isfile(py_file):
            continue
        module = name[:-len(suffix)]
        if module == '__init__':
            continue
        yield module


# FIXME: This function has no unit test
def load_plugins_in_dir(src_dir):
    """
    Import each Python module found in ``src_dir``.
    """
    for module in find_modules_in_dir(src_dir):
        imp.load_module(module, *imp.find_module(module, [src_dir]))


# FIXME: This function has no unit test
def import_plugins_subpackage(name):
    """
    Import everythig in ``plugins`` sub-package of package named ``name``.
    """
    try:
        plugins = __import__(name + '.plugins').plugins
    except ImportError:
        return
    src_dir = path.dirname(path.abspath(plugins.__file__))
    for name in find_modules_in_dir(src_dir):
        full_name = '%s.%s' % (plugins.__name__, name)
        __import__(full_name)


def add_global_options(parser=None):
    """
    Add global options to an optparse.OptionParser instance.
    """
    if parser is None:
        parser = optparse.OptionParser()
    parser.add_option('-e', dest='env', metavar='KEY=VAL', action='append',
        help='Set environment variable KEY to VAL',
    )
    parser.add_option('-c', dest='conf', metavar='FILE',
        help='Load configuration from FILE',
    )
    parser.add_option('-d', '--debug', action='store_true',
        help='Produce full debuging output',
    )
    parser.add_option('-v', '--verbose', action='store_true',
        help='Produce more verbose output',
    )
    return parser


class LogFormatter(logging.Formatter):
    """
    Log formatter that uses UTC for all timestamps.
    """
    converter = time.gmtime