# -*- coding: utf-8 -*-

# Copyright (C) 2012-2017 RhodeCode GmbH
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License, version 3
# (only), as published by the Free Software Foundation.
#
# 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 Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
# This program is dual-licensed. If you wish to learn more about the
# RhodeCode Enterprise Edition, including its added features, Support services,
# and proprietary license terms, please see https://rhodecode.com/licenses/

import logging

from pyramid.exceptions import ConfigurationError
from zope.interface import implementer

from rhodecode.authentication.interface import IAuthnPluginRegistry
from rhodecode.lib.utils2 import safe_str
from rhodecode.model.settings import SettingsModel

log = logging.getLogger(__name__)


@implementer(IAuthnPluginRegistry)
class AuthenticationPluginRegistry(object):

    # INI settings key to set a fallback authentication plugin.
    fallback_plugin_key = 'rhodecode.auth_plugin_fallback'

    def __init__(self, settings):
        self._plugins = {}
        self._fallback_plugin = settings.get(self.fallback_plugin_key, None)

    def add_authn_plugin(self, config, plugin):
        plugin_id = plugin.get_id()
        if plugin_id in self._plugins.keys():
            raise ConfigurationError(
                'Cannot register authentication plugin twice: "%s"', plugin_id)
        else:
            log.debug('Register authentication plugin: "%s"', plugin_id)
            self._plugins[plugin_id] = plugin

    def get_plugins(self):
        def sort_key(plugin):
            return str.lower(safe_str(plugin.get_display_name()))

        return sorted(self._plugins.values(), key=sort_key)

    def get_plugin(self, plugin_id):
        return self._plugins.get(plugin_id, None)

    def get_plugins_for_authentication(self):
        """
        Returns a list of plugins which should be consulted when authenticating
        a user. It only returns plugins which are enabled and active.
        Additionally it includes the fallback plugin from the INI file, if
        `rhodecode.auth_plugin_fallback` is set to a plugin ID.
        """
        plugins = []

        # Add all enabled and active plugins to the list. We iterate over the
        # auth_plugins setting from DB beacuse it also represents the ordering.
        enabled_plugins = SettingsModel().get_auth_plugins()
        for plugin_id in enabled_plugins:
            plugin = self.get_plugin(plugin_id)
            if plugin is not None and plugin.is_active():
                plugins.append(plugin)

        # Add the fallback plugin from ini file.
        if self._fallback_plugin:
            log.warn(
                'Using fallback authentication plugin from INI file: "%s"',
                self._fallback_plugin)
            plugin = self.get_plugin(self._fallback_plugin)
            if plugin is not None and plugin not in plugins:
                plugins.append(plugin)

        return plugins