from rest_framework.decorators import api_view
from rest_framework.response import Response
from rest_framework import status
from django.shortcuts import get_object_or_404
from .models import Metric
from .serializers import MetricSerializer, MetricListSerializer


@api_view(['GET', 'POST'])
def metric_list(request):
    user = request.user

    if request.method == 'GET':
        metrics = Metric.objects.all()
        serializer = MetricListSerializer(metrics, many=True)
        return Response(serializer.data)

    elif request.method == 'POST':
        if Metric.objects.filter(user=user).exists():
            return Response({'detail': 'Metric already exists for this user.'}, status=status.HTTP_400_BAD_REQUEST)
        serializer = MetricSerializer(data=request.data)
        if serializer.is_valid():
            serializer.save(user=user)
            return Response(serializer.data, status=status.HTTP_201_CREATED)
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)


@api_view(['GET', 'PUT', 'DELETE'])
def metric_detail(request):
    user = request.user

    if request.method == 'GET':
        metric = get_object_or_404(Metric, user=user)
        serializer = MetricSerializer(metric)
        return Response(serializer.data)

    elif request.method == 'PUT':
        metric = get_object_or_404(Metric, user=user)
        serializer = MetricSerializer(metric, data=request.data)
        if serializer.is_valid():
            serializer.save()
            return Response(serializer.data)
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

    elif request.method == 'DELETE':
        metric = get_object_or_404(Metric, user=user)
        metric.delete()
        return Response({'detail': 'Metric deleted successfully.'}, status=status.HTTP_204_NO_CONTENT)