from django.core.cache import cache
from django.db.models import Avg, Count
from django.db.models.functions import Round
from comment.models import Comment
from problem.models import Problem
from utils.api import APIView
from utils.constants import CacheKey
from account.decorators import login_required
from utils.api.api import validate_serializer
from comment.serializers import CreateCommentSerializer, CommentSerializer
from submission.models import Submission, JudgeStatus


class CommentAPI(APIView):
    @validate_serializer(CreateCommentSerializer)
    @login_required
    def post(self, request):
        data = request.data
        try:
            problem = Problem.objects.get(id=data["problem_id"], visible=True)
        except Problem.DoesNotExist:
            self.error("problem is not exists")

        try:
            submission = (
                Submission.objects.select_related("problem")
                .filter(
                    user_id=request.user.id,
                    problem_id=data["problem_id"],
                    result=JudgeStatus.ACCEPTED,
                )
                .first()
            )
        except Submission.DoesNotExist:
            self.error("submission is not exists or not accepted")

        language = submission.language
        if language == "Python3":
            language = "Python"

        Comment.objects.create(
            user=request.user,
            problem=problem,
            submission=submission,
            language=language,
            description_rating=data["description_rating"],
            difficulty_rating=data["difficulty_rating"],
            comprehensive_rating=data["comprehensive_rating"],
            content=data["content"],
        )
        cache.delete(f"{CacheKey.comment_stats}:{problem.id}")
        return self.success()

    @login_required
    def get(self, request):
        problem_id = request.GET.get("problem_id")
        comment = (
            Comment.objects.select_related("problem")
            .filter(user=request.user, problem_id=problem_id)
            .first()
        )
        if comment:
            return self.success(CommentSerializer(comment).data)
        else:
            return self.success()


class CommentStatisticsAPI(APIView):
    def get(self, request):
        problem_id = request.GET.get("problem_id")
        cache_key = f"{CacheKey.comment_stats}:{problem_id}"
        cached = cache.get(cache_key)
        if cached is not None:
            return self.success(cached)

        agg = Comment.objects.filter(problem_id=problem_id).aggregate(
            count=Count("id"),
            description=Round(Avg("description_rating"), 2),
            difficulty=Round(Avg("difficulty_rating"), 2),
            comprehensive=Round(Avg("comprehensive_rating"), 2),
        )
        if not agg["count"]:
            return self.success()

        data = {"count": agg["count"], "rating": {
            "description": agg["description"],
            "difficulty": agg["difficulty"],
            "comprehensive": agg["comprehensive"],
        }}
        cache.set(cache_key, data, 3600)
        return self.success(data)