import structlog
from django.db.models.signals import m2m_changed, post_delete, pre_delete, pre_save
from django.dispatch import receiver
from keycloak.exceptions import KeycloakDeleteError, KeycloakError, KeycloakPostError

from vbv_lernwelt.core.models import User
from vbv_lernwelt.course.models import CourseSessionUser
from vbv_lernwelt.course_session_group.models import CourseSessionGroup
from vbv_lernwelt.learning_mentor.models import LearningMentor
from vbv_lernwelt.sso.role_sync.services import (
    add_roles_to_user,
    remove_roles_from_user,
    update_roles_for_user,
)

logger = structlog.get_logger(__name__)


# CourseSessionUser
@receiver(post_delete, sender=CourseSessionUser, dispatch_uid="delete_sso_roles_in_cs")
def remove_sso_roles_in_cs(sender, instance, **kwargs):
    # check if the user has any other roles in the course
    if not CourseSessionUser.objects.filter(
        user=instance.user, course_session__course=instance.course_session.course
    ).exists():
        _remove_sso_role(
            instance.user, instance.course_session.course.slug, instance.role
        )


@receiver(pre_save, sender=CourseSessionUser, dispatch_uid="update_sso_roles_in_cs")
def update_sso_roles_in_cs(sender, instance: CourseSessionUser, **kwargs):
    if not instance.created_at:
        _add_sso_role(instance.user, instance.course_session.course.slug, instance.role)
    else:
        old_csu = CourseSessionUser.objects.get(pk=instance.pk)
        if (
            old_csu.role != instance.role
            or old_csu.course_session.course != instance.course_session.course
        ):
            try:
                update_roles_for_user(
                    instance.user,
                    add_course_roles=[
                        (instance.course_session.course.slug, instance.role)
                    ],
                    remove_course_roles=[
                        (old_csu.course_session.course.slug, old_csu.role)
                    ],
                )
            except KeycloakError:
                # fail silently, error object is being created in the service
                pass


# CourseSessionGroup
@receiver(pre_delete, sender=CourseSessionGroup, dispatch_uid="delete_sso_roles_in_csg")
def remove_sso_roles_in_csg(sender, instance: CourseSessionGroup, **kwargs):
    for user in instance.supervisor.all():
        _remove_sso_role(user, instance.course.slug, "SUPERVISOR")


@receiver(
    m2m_changed,
    sender=CourseSessionGroup.supervisor.through,
    dispatch_uid="update_sso_roles_in_csg",
)
def update_sso_roles_in_csg(sender, instance, action, reverse, model, pk_set, **kwargs):
    if action == "pre_add":
        added_supervisors = model.objects.filter(pk__in=pk_set)
        for user in added_supervisors:
            _add_sso_role(user, instance.course.slug, "SUPERVISOR")

    elif action == "pre_remove":
        removed_supervisors = model.objects.filter(pk__in=pk_set)
        for user in removed_supervisors:
            _remove_sso_role(user, instance.course.slug, "SUPERVISOR")


# LearningMentor
@receiver(post_delete, sender=LearningMentor, dispatch_uid="delete_sso_roles_in_lm")
def remove_sso_roles_in_lm(sender, instance: LearningMentor, **kwargs):
    if not LearningMentor.objects.filter(
        mentor=instance.mentor, course_session__course=instance.course_session.course
    ).exists():
        _remove_sso_role(
            instance.mentor, instance.course_session.course.slug, "LEARNING_MENTOR"
        )


@receiver(pre_save, sender=LearningMentor, dispatch_uid="update_sso_roles_in_lm")
def update_sso_roles_in_lm(sender, instance: LearningMentor, **kwargs):
    if not instance.pk:
        _add_sso_role(
            instance.mentor, instance.course_session.course.slug, "LEARNING_MENTOR"
        )


def _remove_sso_role(user: User, course_slug: str, role: str):
    try:
        logger.debug(
            f"Removing {role} role from user",
            user=user,
            course=course_slug,
            label="role_sync",
        )
        remove_roles_from_user(user, [(course_slug, role)])
    except KeycloakDeleteError:
        # fail silently, error object is being created in the service
        pass


def _add_sso_role(user: User, course_slug: str, role: str):
    try:
        logger.debug(
            f"Adding {role} role to user",
            user=user,
            course=course_slug,
            label="role_sync",
        )
        add_roles_to_user(user, [(course_slug, role)])
    except KeycloakPostError:
        # fail silently, error object is being created in the service
        pass