from django.http import JsonResponse
from adrf.views import APIView
from rest_framework.permissions import IsAuthenticated
from rest_framework.parsers import JSONParser
from asgiref.sync import sync_to_async
from ..models import Tool, ToolFavorite


class ToolFavoriteToggleView(APIView):
    permission_classes = [IsAuthenticated]
    parser_classes = [JSONParser]

    async def post(self, request, tool_id):
        # 事务段（get_or_create + delete + count）整体放入同步函数，sync_to_async 执行保证原子性
        def _toggle_in_txn():
            from django.db import transaction
            with transaction.atomic():
                try:
                    tool = Tool.objects.get(pk=tool_id, is_enabled=True)
                except Tool.DoesNotExist:
                    return None
                favorite, created = ToolFavorite.objects.get_or_create(
                    user=request.user,
                    tool=tool
                )
                if not created:
                    favorite.delete()
                    is_favorite = False
                    message = '已取消收藏'
                else:
                    is_favorite = True
                    message = '已添加收藏'
                favorite_count = ToolFavorite.objects.filter(tool=tool).count()
                return {
                    'tool_id': tool.id,
                    'is_favorite': is_favorite,
                    'favorite_count': favorite_count,
                    'message': message,
                }

        result = await sync_to_async(_toggle_in_txn)()
        if result is None:
            return JsonResponse({'success': False, 'error': '工具不存在'}, status=404)
        return JsonResponse({
            'success': True,
            'data': {
                'id': result['tool_id'],
                'is_favorite': result['is_favorite'],
                'favorite_count': result['favorite_count']
            },
            'message': result['message']
        })


class ToolFavoriteListView(APIView):
    permission_classes = [IsAuthenticated]

    async def get(self, request):
        favorites = [fav async for fav in ToolFavorite.objects.select_related(
            'tool', 'tool__category'
        ).filter(
            user=request.user,
            tool__is_enabled=True
        ).order_by('-created_at')]

        data = []
        for fav in favorites:
            favorite_count = await ToolFavorite.objects.filter(tool=fav.tool).acount()
            data.append({
                'id': fav.tool.id,
                'name': fav.tool.name,
                'description': fav.tool.description,
                'icon': fav.tool.icon,
                'url_path': fav.tool.url_path,
                'color': fav.tool.color,
                'category': fav.tool.category.id if fav.tool.category else None,
                'category_name': fav.tool.category.name if fav.tool.category else '',
                'is_favorite': True,
                'favorite_count': favorite_count,
                'created_at': fav.created_at.isoformat()
            })

        return JsonResponse({
            'success': True,
            'data': {
                'count': len(data),
                'results': data
            }
        })


class ToolFavoriteStatusView(APIView):
    permission_classes = [IsAuthenticated]

    async def get(self, request, tool_id):
        is_favorite = await ToolFavorite.objects.filter(
            user=request.user,
            tool_id=tool_id
        ).aexists()

        favorite_count = await ToolFavorite.objects.filter(tool_id=tool_id).acount()

        return JsonResponse({
            'success': True,
            'data': {
                'tool_id': tool_id,
                'is_favorite': is_favorite,
                'favorite_count': favorite_count
            }
        })