from importlib import import_module

from django.conf import settings
from django.urls import path, include
from django.core.exceptions import ImproperlyConfigured


class LectureManager:

    install_lectures = {}

    def __init__(self, *args, **kwargs):
        self.install_lectures = {}
        self.install_lectures_urls = []
        self._setup()

    def _setup(self):
        # import Lecture from settings.INSTALLED_LECTURES
        # raise exception if `.lecture.Lectrue` is not found
        # keep silent if `.urls` is not found
        for l_type, l_app in settings.INSTALLED_LECTURES.items():
            try:
                lecture_adapter = getattr(
                    import_module('{}.lecture'.format(l_app)),
                    'lecture_adapter'
                )
                self.install_lectures[l_type] = lecture_adapter
            except ImportError:
                raise ImproperlyConfigured(
                    'Did not found `lecture.Lecture` in {}'.format(l_app))

            try:
                import_module('{}.urls'.format(l_app))
                self.install_lectures_urls.append(
                    path('{}/'.format(l_type), include('{}.urls'.format(l_app))))
            except ImportError:
                pass

    @property
    def urls(self):
        urlpatterns = self.install_lectures_urls
        return urlpatterns, 'lecture', 'lecture'


lecture_manager = LectureManager()