"""打印中心 async ViewSets。

- PrintTemplateViewSet：模板 CRUD
- PrintSettingsViewSet：抬头读取/更新（单例）
- render_document_view：渲染整页打印 HTML（前端 axios 取回后 window.print()）
"""

from asgiref.sync import sync_to_async
from adrf.decorators import api_view
from rest_framework import status
from rest_framework.response import Response
from rest_framework.exceptions import ValidationError, NotFound

from apps.core.viewset import BaseTenantViewSet
from .models import PrintSettings, PrintTemplate
from .serializers import PrintSettingsSerializer, PrintTemplateSerializer
from . import services as printing_services


class PrintTemplateViewSet(BaseTenantViewSet):
    model = PrintTemplate
    serializer_class = PrintTemplateSerializer
    search_fields = ["code", "name", "doc_type"]


@api_view(["GET", "PUT", "PATCH"])
async def print_settings_detail(request):
    """打印抬头：租户单例。GET 读取 / PUT(整更) / PATCH(部分更)。"""
    from apps.core.viewset import resolve_tenant

    def _resolve():
        return resolve_tenant(request.META.get("HTTP_X_TENANT_ID", ""))

    tenant = await sync_to_async(_resolve)()
    if tenant is None:
        raise ValidationError({"tenant": "无法识别租户"})
    obj = await sync_to_async(printing_services.ensure_settings)(tenant)

    if request.method == "GET":
        serializer = PrintSettingsSerializer(obj)
        data = await serializer.adata if hasattr(serializer, "adata") else serializer.data
        return Response(serializer.data)

    partial = request.method == "PATCH"
    serializer = PrintSettingsSerializer(obj, data=request.data, partial=partial)
    await sync_to_async(serializer.is_valid)(raise_exception=True)
    await sync_to_async(serializer.save)(
        updated_by=request.user if request.user.is_authenticated else None
    )
    return Response(serializer.data)


@api_view(["GET"])
async def render_document_view(request, doc_type, document_id):
    """GET /api/v1/printing/render/<doc_type>/<id>/?template=code&autoprint=0

    返回整页 HTML（Content-Type: text/html）。鉴权走 JWT + 租户中间件。
    """
    from django.http import HttpResponse

    from apps.core.viewset import resolve_tenant

    if doc_type not in printing_services.DOC_CONTEXT_BUILDERS:
        raise ValidationError({"doc_type": f"不支持的文档类型 {doc_type}"})

    def _resolve():
        code = request.META.get("HTTP_X_TENANT_ID", "")
        return resolve_tenant(code)

    tenant = await sync_to_async(_resolve)()
    if tenant is None:
        raise ValidationError({"tenant": "无法识别租户"})

    module_name, model_name, _ = printing_services.DOC_CONTEXT_BUILDERS[doc_type]
    model = getattr(__import__(module_name, fromlist=[model_name]), model_name)

    def _load_doc():
        qs = model.objects.filter(tenant=tenant, pk=document_id)
        if doc_type == "sales_bill":
            return qs.select_related(
                "customer", "warehouse",
            ).prefetch_related(
                "lines__product__base_unit", "lines__source_unit",
            ).first()
        return qs.select_related(
            "supplier", "warehouse",
        ).prefetch_related(
            "lines__product__base_unit", "lines__source_unit",
        ).first()

    document = await sync_to_async(_load_doc)()
    if document is None:
        raise NotFound("document not found")

    template_code = request.GET.get("template", "") or ""
    autoprint = request.GET.get("autoprint", "1") not in ("0", "false", "False")
    html_out = await sync_to_async(printing_services.render_document)(
        tenant=tenant, doc_type=doc_type, document=document,
        template_code=template_code, autoprint=autoprint,
    )
    return HttpResponse(html_out, content_type="text/html; charset=utf-8")