"""管理员查看客服转人工队列的只读服务。

本模块只暴露工单中已经二次脱敏的最小必要字段；它不读取原始会话、账户、画像或
联系方式，也不提供接单、分配、解决或关闭工单的能力。
"""

from datetime import date, datetime
from decimal import Decimal
from typing import Any

from sqlalchemy import select

from app.core.contracts import RequestContext
from app.core.conversation_privacy import sanitize_customer_service_message
from app.core.cursor import parse_cursor
from app.core.errors import GenericResourceNotFoundError
from app.infrastructure.db import SessionFactory
from app.model.platform import HandoverTicket
from app.service.authorization_service import AuthorizationService


class CustomerServiceHandoverAdminService:
    """面向管理员的待处理客服转人工工单只读边界。"""

    permission = "handover:read"

    async def list_tickets(
        self, context: RequestContext, *, limit: int = 20, cursor: str | None = None
    ) -> dict[str, Any]:
        """按工单 ID 倒序返回一页已脱敏的转人工队列。"""
        await AuthorizationService.require(context, self.permission, admin=True)
        before = parse_cursor(cursor)
        async with SessionFactory() as session:
            statement = select(HandoverTicket).order_by(HandoverTicket.id.desc()).limit(limit)
            if before is not None:
                statement = statement.where(HandoverTicket.id < before)
            tickets = list(await session.scalars(statement))
        return {
            "data": [self._list_item(ticket) for ticket in tickets],
            "meta": {"trace_id": context.trace_id},
        }

    async def get_ticket(self, ticket_no: str, context: RequestContext) -> dict[str, Any]:
        """返回一个工单的脱敏摘要，不回读或拼接原始会话。"""
        await AuthorizationService.require(context, self.permission, admin=True)
        async with SessionFactory() as session:
            ticket = await session.scalar(
                select(HandoverTicket).where(HandoverTicket.ticket_no == ticket_no)
            )
        if ticket is None:
            raise GenericResourceNotFoundError("转人工工单不存在")
        return {"data": self._detail_item(ticket), "meta": {"trace_id": context.trace_id}}

    @classmethod
    def _list_item(cls, ticket: HandoverTicket) -> dict[str, Any]:
        """列表只提供队列识别、路由与状态字段，避免正文在列表页批量扩散。"""
        return {
            "ticket_id": str(ticket.id),
            "ticket_no": ticket.ticket_no,
            "session_id": ticket.session_id,
            "source_agent": ticket.source_agent,
            "priority": ticket.priority,
            "reason_code": ticket.reason_code,
            "status": ticket.status,
            "created_at": cls._public_value(ticket.created_at),
            "updated_at": cls._public_value(ticket.updated_at),
        }

    @classmethod
    def _detail_item(cls, ticket: HandoverTicket) -> dict[str, Any]:
        """详情只追加已脱敏摘要与受控来源，仍不返回客户标识或原始消息。"""
        return {
            **cls._list_item(ticket),
            "intent": ticket.intent,
            "confidence": cls._public_value(ticket.confidence),
            "reason_detail": cls._safe_text(ticket.reason_detail),
            "conversation_summary": cls._safe_text(ticket.conversation_summary),
            "source_references": cls._safe_source_references(ticket.source_references),
        }

    @staticmethod
    def _safe_text(value: str | None) -> str | None:
        """兼容历史工单：读取时再次隐藏旧记录中可能存在的敏感凭据。"""
        return sanitize_customer_service_message(value) if value is not None else None

    @staticmethod
    def _safe_source_references(value: list[dict[str, Any]] | None) -> list[dict[str, Any]]:
        """来源只透出检索引用协议字段，拒绝未来扩展字段意外进入管理面。"""
        allowed = {"source_type", "source_id", "title", "score"}
        return [
            {key: item[key] for key in allowed if key in item}
            for item in (value or [])
            if isinstance(item, dict)
        ]

    @staticmethod
    def _public_value(value: Any) -> Any:
        """统一序列化 ORM 的日期、数值和内部整数主键。"""
        if isinstance(value, datetime):
            return value.isoformat() + ("Z" if value.tzinfo is None else "")
        if isinstance(value, (date, Decimal)):
            return str(value)
        if isinstance(value, int):
            return str(value)
        return value