# =============================================================================
# 企微IT智能服务台 — 阶段5 自动化 审批单服务
# =============================================================================
# 说明：管理高危动作 / 员工二次确认对应的审批单（ApprovalTicket）。
#   1. ensure_ticket：动作首次需要审批时创建（幂等，避免重复提单）
#   2. decide：坐席审批或员工 H5 确认后更新状态
#   3. get_pending_for_action：查询动作当前待决审批单
# =============================================================================

from __future__ import annotations

import logging
from datetime import datetime, timezone
from typing import Any, Optional

from sqlalchemy import select

from app.models.automation import ApprovalTicket

logger = logging.getLogger(__name__)


class ApprovalService:
    """审批单服务。"""

    def __init__(self, db: Any):
        self.db = db

    async def ensure_ticket(
        self, action: Any, channel: str, reason: Optional[str] = None
    ) -> ApprovalTicket:
        """确保动作存在一张待决审批单（幂等）。"""
        stmt = select(ApprovalTicket).where(
            ApprovalTicket.action_id == action.id,
            ApprovalTicket.status == "pending",
        )
        existing = (await self.db.execute(stmt)).scalar_one_or_none()
        if existing is not None:
            return existing

        ticket = ApprovalTicket(
            action_id=action.id,
            session_id=action.session_id,
            channel=channel,
            status="pending",
            reason=reason,
        )
        self.db.add(ticket)
        await self.db.flush()
        return ticket

    async def get_pending_for_action(self, action_id: str) -> Optional[ApprovalTicket]:
        """查询动作当前待决审批单。"""
        stmt = select(ApprovalTicket).where(
            ApprovalTicket.action_id == action_id,
            ApprovalTicket.status == "pending",
        )
        return (await self.db.execute(stmt)).scalar_one_or_none()

    async def decide(
        self,
        ticket_id: str,
        decision: str,
        note: Optional[str],
        approver_id: Optional[str],
    ) -> ApprovalTicket:
        """更新审批单决策。

        Args:
            decision: approve / reject
            note: 审批意见
            approver_id: 审批人（坐席或员工）

        Returns:
            ApprovalTicket: 更新后的审批单

        Raises:
            ValueError: 审批单不存在或已决
        """
        stmt = select(ApprovalTicket).where(ApprovalTicket.id == ticket_id)
        ticket = (await self.db.execute(stmt)).scalar_one_or_none()
        if ticket is None:
            raise ValueError(f"审批单不存在: {ticket_id}")
        if ticket.status != "pending":
            return ticket

        ticket.status = "approved" if decision == "approve" else "rejected"
        ticket.decision_note = note
        ticket.approver_id = approver_id
        ticket.decided_at = datetime.now(timezone.utc)
        await self.db.flush()
        return ticket