#! /usr/bin/env python

# Copyright (C) 2009 Sayamindu Dasgupta <sayamindu@laptop.org>
#
# 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; either version 2 of the License, or
# (at your option) any later version.
#
# 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

import libxml2

_ISO_639_XML_PATH = '/usr/share/xml/iso-codes/iso_639.xml'

def singleton(object, instantiated=[]):
    # From http://norvig.com/python-iaq.html
    "Raise an exception if an object of this class has been instantiated before."
    assert object.__class__ not in instantiated, \
        "%s is a Singleton class but is already instantiated" % object.__class__
    instantiated.append(object.__class__)

class LanguageNames(object):
    def __init__(self):
        singleton(self)
        try:
            self._xmldoc = libxml2.parseFile('/usr/share/xml/iso-codes/iso_639.xml')
        except libxml2.parserError:
            self._xmldoc = None
            return

        self._eroot = self._xmldoc.getRootElement()

    def close(self):
        if self._xmldoc is not None:
            self._xmldoc.freeDoc()

    def get_full_language_name(self, code):
        if self._xmldoc is None:
            return code

        for child in self._eroot.children:
            if child.properties is not None:
                for property in child.properties:
                    if property.get_content() == code:
                        return self._real_get_full_language_name(child)

        return code

    def _real_get_full_language_name(self, node):
        for property in node.properties:
            if property.get_name() == 'name':
                return property.get_content()