"""Generates common contexts"""


import logging

from opaque_keys import InvalidKeyError
from opaque_keys.edx.keys import CourseKey, LearningContextKey
from six import text_type

from openedx.core.lib.request_utils import COURSE_REGEX

log = logging.getLogger(__name__)


def course_context_from_url(url):
    """
    Extracts the course_context from the given `url` and passes it on to
    `course_context_from_course_id()`.
    """
    url = url or ''

    match = COURSE_REGEX.match(url)
    course_id = None
    if match:
        course_id_string = match.group('course_id')
        try:
            course_id = CourseKey.from_string(course_id_string)
        except InvalidKeyError:
            log.warning(
                'unable to parse course_id "{course_id}"'.format(
                    course_id=course_id_string
                ),
                exc_info=True
            )

    return course_context_from_course_id(course_id)


def course_context_from_course_id(course_id):
    """
    Creates a course context from a `course_id`.

    For newer parts of the system (i.e. Blockstore-based libraries/courses/etc.)
    use context_dict_for_learning_context instead of this method.

    Example Returned Context::

        {
            'course_id': 'org/course/run',
            'org_id': 'org'
        }
    """
    context_dict = context_dict_for_learning_context(course_id)
    # Remove the newer 'context_id' field for now in this method so we're not
    # adding a new field to the course tracking logs
    del context_dict['context_id']
    return context_dict


def context_dict_for_learning_context(context_key):
    """
    Creates a tracking log context dictionary for the given learning context
    key, which may be None, a CourseKey, a content library key, or any other
    type of LearningContextKey.

    Example Returned Context Dict::

        {
            'context_id': 'course-v1:org+course+run',
            'course_id': 'course-v1:org+course+run',
            'org_id': 'org'
        }

    Example 2::

        {
            'context_id': 'lib:edX:a-content-library',
            'course_id': '',
            'org_id': 'edX'
        }

    """
    context_dict = {
        'context_id': text_type(context_key) if context_key else '',
        'course_id': '',
        'org_id': '',
    }
    if context_key is not None:
        assert isinstance(context_key, LearningContextKey)
        if context_key.is_course:
            context_dict['course_id'] = text_type(context_key)
        if hasattr(context_key, 'org'):
            context_dict['org_id'] = context_key.org
    return context_dict