from rest_framework import viewsets, permissions, status, filters
from rest_framework.decorators import action
from rest_framework.response import Response
from .models import Comment, Rating, Like, Favorite
from .serializers import (
    CommentSerializer,
    CommentCreateSerializer,
    RatingSerializer,
    RatingCreateSerializer,
    LikeSerializer,
    FavoriteSerializer,
    FavoriteCreateSerializer
)


class CommentViewSet(viewsets.ModelViewSet):
    """ViewSet for Comment model."""

    queryset = Comment.objects.select_related('author')
    permission_classes = [permissions.IsAuthenticatedOrReadOnly]
    filter_backends = [filters.SearchFilter, filters.OrderingFilter, filters.DjangoFilterBackend]
    search_fields = ['content']
    filterset_fields = ['target_type', 'target_id', 'ai_status']
    ordering_fields = ['created_at']
    ordering = ['-created_at']

    def get_queryset(self):
        # Only show approved comments
        if not self.request.user.is_authenticated:
            return self.queryset.filter(ai_status='approved')

        # Admins see all
        if self.request.user.is_admin():
            return self.queryset

        # Regular users see approved + their own
        return self.queryset.filter(
            Q(ai_status='approved') |
            Q(author=self.request.user)
        ).distinct()

    def get_serializer_class(self):
        if self.action == 'create':
            return CommentCreateSerializer
        return CommentSerializer

    def perform_create(self, serializer):
        serializer.save()

    def perform_update(self, serializer):
        # Only allow updating own comments
        if str(serializer.instance.author.id) != str(self.request.user.id):
            from rest_framework.exceptions import PermissionDenied
            raise PermissionDenied("You can only update your own comments")
        serializer.save()

    def perform_destroy(self, instance):
        # Only allow deleting own comments or by admin
        if (not self.request.user.is_admin() and
            str(instance.author.id) != str(self.request.user.id)):
            from rest_framework.exceptions import PermissionDenied
            raise PermissionDenied("You can only delete your own comments")
        instance.delete()

    @action(detail=True, methods=['post'])
    def approve_ai(self, request, pk=None):
        """Approve comment by AI (simulated)."""
        if not request.user.is_ai_auditor():
            return Response(
                {'detail': 'Only AI auditors can approve comments'},
                status=status.HTTP_403_FORBIDDEN
            )

        comment = self.get_object()
        comment.approve_ai()
        return Response({'message': 'Comment approved by AI'})

    @action(detail=True, methods=['post'])
    def reject_ai(self, request, pk=None):
        """Reject comment by AI (simulated)."""
        if not request.user.is_ai_auditor():
            return Response(
                {'detail': 'Only AI auditors can reject comments'},
                status=status.HTTP_403_FORBIDDEN
            )

        comment = self.get_object()
        reason = request.data.get('reason', 'Content violates guidelines')
        comment.reject_ai(reason)
        return Response({'message': 'Comment rejected by AI'})


class RatingViewSet(viewsets.ModelViewSet):
    """ViewSet for Rating model."""

    queryset = Rating.objects.select_related('user')
    serializer_class = RatingSerializer
    permission_classes = [permissions.IsAuthenticatedOrReadOnly]
    filter_backends = [filters.SearchFilter, filters.OrderingFilter, filters.DjangoFilterBackend]
    filterset_fields = ['target_type', 'target_id', 'user']
    ordering_fields = ['created_at']
    ordering = ['-created_at']

    def get_queryset(self):
        # Admins see all
        if self.request.user.is_admin():
            return self.queryset

        # Regular users see their own ratings
        return self.queryset.filter(user=self.request.user)

    def get_serializer_class(self):
        if self.action == 'create':
            return RatingCreateSerializer
        return RatingSerializer

    def perform_create(self, serializer):
        serializer.save()

    def perform_destroy(self, instance):
        # Only allow deleting own ratings
        if str(instance.user.id) != str(self.request.user.id):
            from rest_framework.exceptions import PermissionDenied
            raise PermissionDenied("You can only delete your own ratings")
        instance.delete()

    @action(detail=False, methods=['get'])
    def my_ratings(self, request):
        """Get current user's ratings."""
        ratings = Rating.objects.filter(user=request.user).select_related()
        serializer = self.get_serializer(ratings, many=True)
        return Response(serializer.data)


class LikeViewSet(viewsets.ModelViewSet):
    """ViewSet for Like model."""

    queryset = Like.objects.select_related('user')
    serializer_class = LikeSerializer
    permission_classes = [permissions.IsAuthenticated]
    filter_backends = [filters.OrderingFilter, filters.DjangoFilterBackend]
    filterset_fields = ['target_type', 'target_id', 'user']
    ordering_fields = ['created_at']
    ordering = ['-created_at']

    def get_queryset(self):
        # Admins see all
        if self.request.user.is_admin():
            return self.queryset

        # Regular users see their own likes
        return self.queryset.filter(user=self.request.user)

    @action(detail=False, methods=['post'])
    def toggle(self, request):
        """Toggle like on a target."""
        target_type = request.data.get('target_type')
        target_id = request.data.get('target_id')

        if not target_type or not target_id:
            return Response(
                {'detail': 'target_type and target_id are required'},
                status=status.HTTP_400_BAD_REQUEST
            )

        like, created = Like.objects.get_or_create(
            user=request.user,
            target_type=target_type,
            target_id=target_id
        )

        if not created:
            like.delete()
            return Response({'message': 'Unliked', 'liked': False})

        return Response({'message': 'Liked', 'liked': True})

    @action(detail=False, methods=['get'])
    def my_likes(self, request):
        """Get current user's likes."""
        likes = Like.objects.filter(user=request.user).select_related()
        serializer = self.get_serializer(likes, many=True)
        return Response(serializer.data)


class FavoriteViewSet(viewsets.ModelViewSet):
    """ViewSet for Favorite model."""

    queryset = Favorite.objects.select_related('user')
    serializer_class = FavoriteSerializer
    permission_classes = [permissions.IsAuthenticated]
    filter_backends = [filters.OrderingFilter, filters.DjangoFilterBackend]
    filterset_fields = ['target_type', 'target_id', 'user']
    ordering_fields = ['created_at']
    ordering = ['-created_at']

    def get_queryset(self):
        # Admins see all
        if self.request.user.is_admin():
            return self.queryset

        # Regular users see their own favorites
        return self.queryset.filter(user=self.request.user)

    def get_serializer_class(self):
        if self.action == 'create':
            return FavoriteCreateSerializer
        return FavoriteSerializer

    @action(detail=False, methods=['post'])
    def toggle(self, request):
        """Toggle favorite on a target."""
        serializer = FavoriteCreateSerializer(data=request.data)
        if serializer.is_valid():
            result = serializer.save()
            if result is None:
                return Response({'message': 'Unfavorited', 'favorited': False})
            return Response({'message': 'Favorited', 'favorited': True})
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

    @action(detail=False, methods=['get'])
    def my_favorites(self, request):
        """Get current user's favorites."""
        favorites = Favorite.objects.filter(user=request.user).select_related()
        serializer = FavoriteSerializer(favorites, many=True)
        return Response(serializer.data)