# Copyright (C) 2007-2017 by the Free Software Foundation, Inc.
#
# This file is part of GNU Mailman.
#
# GNU Mailman 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 3 of the License, or (at your option)
# any later version.
#
# GNU Mailman 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
# GNU Mailman.  If not, see <http://www.gnu.org/licenses/>.

"""Language manager."""

from mailman.interfaces.configuration import ConfigurationUpdatedEvent
from mailman.interfaces.languages import ILanguageManager
from mailman.languages.language import Language
from public import public
from zope.component import getUtility
from zope.interface import implementer


@public
@implementer(ILanguageManager)
class LanguageManager:
    """Language manager."""

    def __init__(self):
        # Mapping from 2-letter code to Language instance.
        self._languages = {}

    def add(self, code, charset, description):
        """See `ILanguageManager`."""
        if code in self._languages:
            raise ValueError('Language code already registered: ' + code)
        language = Language(code, charset, description)
        self._languages[code] = language
        return language

    @property
    def codes(self):
        """See `ILanguageManager`."""
        return iter(self._languages)

    @property
    def languages(self):
        """See `ILanguageManager`."""
        return iter(self._languages.values())

    def get(self, code, default=None):
        """See `ILanguageManager`."""
        return self._languages.get(code, default)

    def __getitem__(self, code):
        """See `ILanguageManager`."""
        return self._languages[code]

    def __contains__(self, code):
        """See `ILanguageManager`."""
        return code in self._languages

    def clear(self):
        """See `ILanguageManager`."""
        self._languages.clear()


@public
def handle_ConfigurationUpdatedEvent(event):
    if not isinstance(event, ConfigurationUpdatedEvent):
        return
    manager = getUtility(ILanguageManager)
    for language in event.config.language_configs:
        if language.enabled:
            code = language.name.split('.')[1]
            manager.add(code, language.charset, language.description)
    # the default language must always be available.
    assert event.config.mailman.default_language in manager, (
        'system default language code not defined: {0}'.format(
            event.config.mailman.default_language))