from django.shortcuts import redirect
from rest_framework import permissions
from rest_framework.decorators import api_view, permission_classes
from rest_framework.generics import get_object_or_404
from rest_framework.permissions import IsAuthenticated
from rest_framework.response import Response

from vbv_lernwelt.core.serializers import UserSerializer
from vbv_lernwelt.course.models import CourseSession, CourseSessionUser
from vbv_lernwelt.iam.permissions import is_course_session_member
from vbv_lernwelt.learning_mentor.content.praxis_assignment import (
    get_praxis_assignments,
)
from vbv_lernwelt.learning_mentor.models import LearningMentor, MentorInvitation
from vbv_lernwelt.learning_mentor.serializers import PraxisAssignmentStatusSerializer
from vbv_lernwelt.learnpath.models import Circle


@api_view(["GET"])
@permission_classes([IsAuthenticated])
def mentor_summary(request, course_session_id: int):
    course_session = CourseSession.objects.get(id=course_session_id)

    mentor = get_object_or_404(
        LearningMentor, mentor=request.user, course=course_session.course
    )

    participants = mentor.participants.filter(course_session=course_session)
    users = [p.user for p in participants]

    praxis_assignments, circle_ids = get_praxis_assignments(course_session, users)

    circles = Circle.objects.filter(id__in=circle_ids).values("id", "title")

    return Response(
        {
            "participants": [UserSerializer(user).data for user in users],
            "circles": list(circles),
            "praxis_assignments": PraxisAssignmentStatusSerializer(
                praxis_assignments, many=True
            ).data,
        }
    )


class CourseSessionMember(permissions.BasePermission):
    def has_permission(self, request, view):
        return is_course_session_member(
            request.user, view.kwargs.get("course_session_id")
        )


@api_view(["GET"])
@permission_classes([IsAuthenticated])
def list_invitations(request, course_session_id: int):
    pass


@api_view(["POST"])
@permission_classes([IsAuthenticated, CourseSessionMember])
def create_invitation(request, course_session_id: int):
    course_session = get_object_or_404(CourseSession, id=course_session_id)
    course_session_user = get_object_or_404(
        CourseSessionUser, user=request.user, course_session=course_session
    )

    email = request.data.get("email")
    if not email:
        return Response({"error": "email is required"}, status=400)

    invitation = MentorInvitation.objects.get_or_create(
        email=email,
        participant=course_session_user,
    )

    return Response({})


@api_view(["GET"])
def accept_invitation(request, course_session_id: int):
    if not request.user.is_authenticated:
        return redirect(f"/onboarding/vv/account/create?next={request.path}")

    # Validate invitation