"""
Course Goals Python API
"""


from django.conf import settings
from opaque_keys.edx.keys import CourseKey
from rest_framework.reverse import reverse

from common.djangoapps.course_modes.models import CourseMode
from lms.djangoapps.course_goals.models import CourseGoal, GOAL_KEY_CHOICES
from openedx.features.course_experience import ENABLE_COURSE_GOALS


def add_course_goal(user, course_id, goal_key):
    """
    Add a new course goal for the provided user and course. If the goal
    already exists, simply update and save the goal.

    Arguments:
        user: The user that is setting the goal
        course_id (string): The id for the course the goal refers to
        goal_key (string): The goal key for the new goal.
    """
    course_key = CourseKey.from_string(str(course_id))
    CourseGoal.objects.update_or_create(
        user=user, course_key=course_key, defaults={'goal_key': goal_key}
    )


def get_course_goal(user, course_key):
    """
    Given a user and a course_key, return their course goal.

    If the user is anonymous or a course goal does not exist, returns None.
    """
    if user.is_anonymous:
        return None

    return CourseGoal.objects.filter(user=user, course_key=course_key).first()


def get_goal_api_url(request):
    """
    Returns the endpoint for accessing REST API.
    """
    return reverse('course_goals_api:v0:course_goal-list', request=request)


def has_course_goal_permission(request, course_id, user_access):
    """
    Returns whether the user can access the course goal functionality.

    Only authenticated users that are enrolled in a verifiable course
    can use this feature.
    """
    course_key = CourseKey.from_string(course_id)
    has_verified_mode = CourseMode.has_verified_mode(CourseMode.modes_for_course_dict(course_key))
    return user_access['is_enrolled'] and has_verified_mode and ENABLE_COURSE_GOALS.is_enabled(course_key) \
        and settings.FEATURES.get('ENABLE_COURSE_GOALS')


def get_course_goal_options():
    """
    Returns the valid options for goal keys, mapped to their translated
    strings, as defined by theCourseGoal model.
    """
    return {goal_key: goal_text for goal_key, goal_text in GOAL_KEY_CHOICES}  # lint-amnesty, pylint: disable=unnecessary-comprehension


def get_course_goal_text(goal_key):
    """
    Returns the translated string for the given goal key
    """
    goal_options = get_course_goal_options()
    return goal_options[goal_key]


def valid_course_goals_ordered(include_unsure=False):
    """
    Returns a list of the valid options for goal keys ordered by the level of commitment.
    Each option is represented as a tuple, with (goal_key, goal_string).

    This list does not return the unsure option by default since it does not have a relevant commitment level.
    """
    goal_options = get_course_goal_options()

    ordered_goal_options = []
    ordered_goal_options.append((GOAL_KEY_CHOICES.certify, goal_options[GOAL_KEY_CHOICES.certify]))
    ordered_goal_options.append((GOAL_KEY_CHOICES.complete, goal_options[GOAL_KEY_CHOICES.complete]))
    ordered_goal_options.append((GOAL_KEY_CHOICES.explore, goal_options[GOAL_KEY_CHOICES.explore]))

    if include_unsure:
        ordered_goal_options.append((GOAL_KEY_CHOICES.unsure, goal_options[GOAL_KEY_CHOICES.unsure]))

    return ordered_goal_options