"""
Main views and method related to the Programs.
"""

import logging

from openedx.core.djangoapps.util.helpers import get_id_token
from openedx.core.djangoapps.programs.models import ProgramsApiConfig
from openedx.core.djangoapps.programs.utils import (
    programs_api_client,
    is_student_dashboard_programs_enabled,
    is_cache_enabled_for_programs,
    get_cached_programs_response,
    set_cached_programs_response,
)


log = logging.getLogger(__name__)
# OAuth2 Client name for programs
CLIENT_NAME = "programs"


def get_course_programs_for_dashboard(user, course_keys):   # pylint: disable=invalid-name
    """ Return all programs related to a user.

    Given a user and an iterable of course keys, find all
    the programs relevant to the user's dashboard and return them in a
    dictionary keyed by the course_key.

    Arguments:
        user (user object): Currently logged-in User for which we need to get
            JWT ID-Token
        course_keys (list): List of course keys in which user is enrolled

    Returns:
        Dictionary response containing programs or None
    """
    course_programs = {}
    if not is_student_dashboard_programs_enabled():
        log.warning("Programs service for student dashboard is disabled.")
        return course_programs

    # unicode-ify the course keys for efficient lookup
    course_keys = map(unicode, course_keys)

    # If cache config is enabled then get the response from cache first.
    if is_cache_enabled_for_programs():
        cached_programs = get_cached_programs_response()
        if cached_programs is not None:
            return _get_user_course_programs(cached_programs, course_keys)

    # get programs slumber-based client 'EdxRestApiClient'
    try:
        api_client = programs_api_client(ProgramsApiConfig.current().internal_api_url, get_id_token(user, CLIENT_NAME))
    except Exception:   # pylint: disable=broad-except
        log.exception('Failed to initialize the Programs API client.')
        return course_programs

    # get programs from api client
    try:
        response = api_client.programs.get()
    except Exception:  # pylint: disable=broad-except
        log.exception('Failed to retrieve programs from the Programs API.')
        return course_programs

    programs = response.get('results', [])
    if not programs:
        log.warning("No programs found for the user '%s'.", user.id)
        return course_programs

    # If cache config is enabled than set the cache.
    if is_cache_enabled_for_programs():
        set_cached_programs_response(programs)

    return _get_user_course_programs(programs, course_keys)


def _get_user_course_programs(programs, users_enrolled_course_keys):  # pylint: disable=invalid-name
    """ Parse the raw programs according to the users enrolled courses and
    return the matched course runs.

    Arguments:
        programs (list): List containing the programs data.
        users_enrolled_course_keys (list) : List of course keys in which the user is enrolled.
    """

    # reindex the result from pgm -> course code -> course run
    # to
    # course run -> program, ignoring course runs not present in the dashboard enrollments
    course_programs = {}
    for program in programs:
        try:
            for course_code in program['course_codes']:
                for run in course_code['run_modes']:
                    if run['course_key'] in users_enrolled_course_keys:
                        course_programs[run['course_key']] = program
        except KeyError:
            log.exception('Unable to parse Programs API response: %r', program)

    return course_programs