"""
State API ViewSet
"""
from rest_framework import viewsets, filters
from rest_framework.pagination import LimitOffsetPagination
from django_filters.rest_framework import DjangoFilterBackend
from stateflow import models
from stateflow.serializers import (
    StateListSerializer,
    StateDetailSerializer,
    StateCreateUpdateSerializer,
)


class StateViewSet(viewsets.ModelViewSet):
    """
    状态节点 CRUD 接口
    
    list: 获取状态列表
    retrieve: 获取状态详情（包含参数）
    create: 创建状态
    update: 更新状态
    partial_update: 部分更新状态
    destroy: 删除状态
    
    查询参数:
    - name: 按名称模糊查询
    - search: 全文搜索（名称和描述）
    - ordering: 排序字段，支持 id, name, created_at, updated_at
    """
    queryset = models.State.objects.all()
    pagination_class = LimitOffsetPagination
    filter_backends = [DjangoFilterBackend, filters.SearchFilter, filters.OrderingFilter]
    filterset_fields = ['name']
    search_fields = ['name', 'description']
    ordering_fields = ['id', 'name', 'created_at', 'updated_at']
    ordering = ['-created_at']
    
    def get_serializer_class(self):
        """根据动作选择序列化器"""
        if self.action == 'list':
            return StateListSerializer
        elif self.action in ['create', 'update', 'partial_update']:
            return StateCreateUpdateSerializer
        else:  # retrieve
            return StateDetailSerializer
    
    def get_queryset(self):
        """优化查询，retrieve 时预加载参数"""
        queryset = super().get_queryset()
        if self.action == 'retrieve':
            queryset = queryset.prefetch_related('parameters')
        return queryset