# 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
import imp
import optparse
import logging
import time
import krbV
import socket
from ipalib import errors


def get_current_principal():
    try:
        return unicode(krbV.default_context().default_ccache().principal().name)
    except krbV.Krb5Error:
        #TODO: do a kinit?
        raise errors.CCacheError()

def get_fqdn():
    fqdn = ""
    try:
        fqdn = socket.getfqdn()
    except:
        try:
            fqdn = socket.gethostname()
        except:
            fqdn = ""
    return fqdn

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


# 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 = os.path.dirname(os.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.disable_interspersed_args()
    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


def make_repr(name, *args, **kw):
    """
    Construct a standard representation of a class instance.
    """
    args = [repr(a) for a in args]
    kw = ['%s=%r' % (k, kw[k]) for k in sorted(kw)]
    return '%s(%s)' % (name, ', '.join(args + kw))

def realm_to_suffix(realm_name):
    s = realm_name.split(".")
    terms = ["dc=" + x.lower() for x in s]
    return ",".join(terms)