"""报表中心 ViewSets：
1. ReportDefinitionViewSet: 报表元数据 CRUD + run 执行报表 + init_system 预置报表
2. DashboardViewSet: 经营大盘总览指标、销售排行、库存透视
"""

from rest_framework import status
from rest_framework.decorators import action
from rest_framework.response import Response
from rest_framework.exceptions import ValidationError
from asgiref.sync import sync_to_async
from adrf.viewsets import ViewSet

from apps.core.viewset import BaseTenantViewSet
from .models import ReportDefinition
from .serializers import ReportDefinitionSerializer
from . import services as report_services


class ReportDefinitionViewSet(BaseTenantViewSet):
    model = ReportDefinition
    serializer_class = ReportDefinitionSerializer
    search_fields = ["code", "name", "description"]

    @action(detail=False, methods=["post"], url_path="init-system")
    async def init_system(self, request):
        """一键初始化系统预置标准报表。"""
        tenant = await self.get_tenant()
        if not tenant:
            raise ValidationError({"tenant": "无法识别租户"})
        n = await sync_to_async(report_services.init_system_reports)(tenant)
        return Response({"ok": True, "created_count": n, "message": f"成功初始化 {n} 个系统报表定义"})

    @action(detail=True, methods=["post", "get"], url_path="run")
    async def run_report(self, request, pk=None):
        """执行指定报表定义并返回数据。"""
        tenant = await self.get_tenant()
        try:
            report_def = await sync_to_async(self.model.objects.get)(tenant=tenant, pk=pk)
        except self.model.DoesNotExist:
            return Response({"detail": "报表不存在"}, status=status.HTTP_404_NOT_FOUND)

        data = await sync_to_async(report_services.execute_report_definition)(tenant, report_def)
        return Response(data)


class DashboardViewSet(ViewSet):
    """进销存与财务经营大盘。"""

    async def get_tenant(self):
        from apps.core.viewset import resolve_tenant
        from django.conf import settings
        code = self.request.META.get("HTTP_X_TENANT_ID", settings.TENANT_DEFAULT)
        return await sync_to_async(resolve_tenant)(code)

    @action(detail=False, methods=["get"], url_path="summary")
    async def summary(self, request):
        """获取本月经营总览指标（销售额、采购额、库存估值、应收应付总额）。"""
        tenant = await self.get_tenant()
        if not tenant:
            raise ValidationError({"tenant": "无法识别租户"})
        data = await sync_to_async(report_services.get_dashboard_summary)(tenant)
        return Response(data)

    @action(detail=False, methods=["get"], url_path="sales-rank")
    async def sales_rank(self, request):
        """销售排行：参数 rank_by=product/customer，top_n=10。"""
        tenant = await self.get_tenant()
        if not tenant:
            raise ValidationError({"tenant": "无法识别租户"})
        rank_by = request.query_params.get("rank_by", "product")
        try:
            top_n = int(request.query_params.get("top_n", 10))
        except ValueError:
            top_n = 10
        data = await sync_to_async(report_services.get_sales_rank)(tenant, rank_by=rank_by, top_n=top_n)
        return Response({"rank_by": rank_by, "results": data})

    @action(detail=False, methods=["get"], url_path="inventory-status")
    async def inventory_status(self, request):
        """各仓库库存分布与资产估值。"""
        tenant = await self.get_tenant()
        if not tenant:
            raise ValidationError({"tenant": "无法识别租户"})
        data = await sync_to_async(report_services.get_inventory_status_report)(tenant)
        return Response(data)