from django.shortcuts import get_object_or_404
from rest_framework.decorators import api_view, permission_classes
from rest_framework.exceptions import PermissionDenied
from rest_framework.permissions import IsAuthenticated
from rest_framework.response import Response

from vbv_lernwelt.core.models import User
from vbv_lernwelt.course.models import CourseCompletion
from vbv_lernwelt.learning_mentor.models import LearningMentor
from vbv_lernwelt.learnpath.models import LearningUnit
from vbv_lernwelt.self_evaluation_feedback.models import (
    CourseCompletionFeedback,
    SelfEvaluationFeedback,
)
from vbv_lernwelt.self_evaluation_feedback.serializers import (
    SelfEvaluationFeedbackSerializer,
)


@api_view(["POST"])
@permission_classes([IsAuthenticated])
def start_self_evaluation_feedback(request, learning_unit_id):
    feedback_provider_user_id = request.data.get("feedback_provider_user_id")

    learning_unit = get_object_or_404(LearningUnit, id=learning_unit_id)
    feedback_provider_user = get_object_or_404(User, id=feedback_provider_user_id)

    if not LearningMentor.objects.filter(
        course=learning_unit.get_course(),
        mentor=feedback_provider_user,
        participants__user=request.user,
    ).exists():
        raise PermissionDenied()

    # calling start multiple times shall be a no-op
    _, created = SelfEvaluationFeedback.objects.get_or_create(
        feedback_requester_user=request.user,
        feedback_provider_user=feedback_provider_user,
        learning_unit=learning_unit,
    )

    if created:
        # TODO: Create notification for feedback_provider_user
        ...

    return Response({"success": True})


@api_view(["PUT"])
@permission_classes([IsAuthenticated])
def submit_provider_self_evaluation_feedback(request, feedback_id):
    feedback = get_object_or_404(
        SelfEvaluationFeedback, id=feedback_id, feedback_provider_user=request.user
    )

    feedback.feedback_submitted = True
    feedback.save()

    return Response({"success": True})


@api_view(["GET"])
@permission_classes([IsAuthenticated])
def get_self_evaluation_feedback_as_provider(request, learning_unit_id):
    feedback = get_object_or_404(
        SelfEvaluationFeedback,
        learning_unit_id=learning_unit_id,
        feedback_provider_user=request.user,
    )

    return Response(SelfEvaluationFeedbackSerializer(feedback).data)


@api_view(["GET"])
@permission_classes([IsAuthenticated])
def get_self_evaluation_feedback_as_requester(request, learning_unit_id):
    learning_unit = get_object_or_404(LearningUnit, id=learning_unit_id)

    feedback = get_object_or_404(
        SelfEvaluationFeedback,
        learning_unit=learning_unit,
        feedback_requester_user=request.user,
    )

    return Response(SelfEvaluationFeedbackSerializer(feedback).data)


@api_view(["PUT"])
@permission_classes([IsAuthenticated])
def add_provider_self_evaluation_feedback(request, feedback_id):
    feedback_assessment = request.data.get("feedback_assessment")

    feedback = get_object_or_404(
        SelfEvaluationFeedback, id=feedback_id, feedback_provider_user=request.user
    )

    course_completion = get_object_or_404(
        CourseCompletion,
        id=request.data.get("course_completion_id"),
        user=feedback.feedback_requester_user,
    )

    (
        course_completion_feedback,
        created,
    ) = CourseCompletionFeedback.objects.get_or_create(
        feedback=feedback,
        course_completion=course_completion,
        defaults={"feedback_assessment": feedback_assessment},
    )

    if not created:
        course_completion_feedback.feedback_assessment = feedback_assessment
        course_completion_feedback.save()

    return Response({"success": True})