# combo - content management system
# Copyright (C) 2015  Entr'ouvert
#
# This program is free software: you can redistribute it and/or modify it
# under the terms of the GNU Affero General Public License as published
# by the Free Software Foundation, either version 3 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 Affero 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/>.

from pkg_resources import iter_entry_points
import logging

from django.apps import apps
from django.conf.urls import patterns, include, url

logger = logging.getLogger(__name__)

PLUGIN_GROUP_NAME = 'combo.plugin'

class PluginError(Exception):
    pass


def get_plugins(*args, **kwargs):
    plugins = []
    for entrypoint in iter_entry_points(PLUGIN_GROUP_NAME):
        try:
            plugin = entrypoint.load()
        except Exception, e:
            logger.exception('failed to load entrypoint %s', entrypoint)
            raise PluginError('failed to load entrypoint %s' % entrypoint, e)
        plugins.append(plugin(*args, **kwargs))
    return plugins

def register_plugins_urls(urlpatterns):
    pre_urls = []
    post_urls = []
    for plugin in apps.get_app_configs():
        if hasattr(plugin, 'get_before_urls'):
            urls = plugin.get_before_urls()
            if urls:
                pre_urls.append(url('^', include(urls)))
        if hasattr(plugin, 'get_after_urls'):
            urls = plugin.get_after_urls()
            if urls:
                post_urls.append(url('^', include(urls)))
    pre_patterns = patterns('', *pre_urls)
    post_patterns = patterns('', *post_urls)
    return pre_patterns + urlpatterns + post_patterns

def register_plugins_manager_urls(urlpatterns):
    pre_urls = []
    post_urls = []
    for plugin in apps.get_app_configs():
        if hasattr(plugin, 'get_before_manager_urls'):
            urls = plugin.get_before_manager_urls()
            if urls:
                pre_urls.append(url('^', include(urls)))
        if hasattr(plugin, 'get_after_manager_urls'):
            urls = plugin.get_after_manager_urls()
            if urls:
                post_urls.append(url('^', include(urls)))
    pre_patterns = patterns('', *pre_urls)
    post_patterns = patterns('', *post_urls)
    return pre_patterns + urlpatterns + post_patterns

def register_plugins_apps(installed_apps):
    installed_apps = tuple(installed_apps)
    for plugin in get_plugins():
        if hasattr(plugin, 'get_apps'):
            installed_apps += tuple(app for app in plugin.get_apps()
                    if app not in installed_apps)
    return installed_apps

def get_extra_manager_actions():
    '''This iterates over all appconfigs and returns a list of dictionaries,
       with href and text keys.'''
    actions = []
    for plugin in apps.get_app_configs():
        if hasattr(plugin, 'get_extra_manager_actions'):
            actions.extend(plugin.get_extra_manager_actions())
    return actions