# -*- coding: utf-8 -*-
"""转园申请两级审核状态机（纯规则，无 DB）。

流程：
  pending_from（待转出园区审）
    → 转出园区 approved → pending_to（待转入园区审）
    → 转入园区 approved → approved（执行迁移）
  任一级 rejected → rejected（终态）
  operator 任意时刻可 force-approve / reject（兜底终审）。
  园区未设管理员时该级自动通过（apply 时直接跳级）。

发起人：operator / from-park carrier / to-park carrier / 企业管理员 / 用户本人。
"""
from __future__ import annotations

STAGES = ("pending_from", "pending_to", "approved", "rejected", "cancelled")
INITIATOR_ROLES = ("operator", "carrier", "enterprise", "user")
TARGET_KINDS = ("user", "company")


class TransferError(Exception):
    """转园流程违规（路由层转 400/403）。"""


def has_park_admin(tenant: dict | None) -> bool:
    """园区是否已绑定管理员（operator_user_id 或旧 admin_username）。"""
    if not tenant:
        return False
    return bool(tenant.get("operator_user_id") or tenant.get("admin_username"))


def initial_stage(from_tenant: dict | None) -> str:
    """发起时的初始阶段：转出园区无管理员 → 第一级自动通过，直接进第二级。"""
    return "pending_from" if has_park_admin(from_tenant) else "pending_to"


def review(stage: str, *, side: str, decision: str) -> dict:
    """推进一步状态机。side ∈ from|to|operator；decision ∈ approved|rejected。

    返回 {"stage": 新阶段, "from_status":…, "to_status":…}；不合法流转 raise TransferError。
    """
    if decision not in ("approved", "rejected"):
        raise TransferError("审核决定仅支持 approved/rejected")
    if stage in ("approved", "rejected", "cancelled"):
        raise TransferError("该申请已终态，无法再审核")

    if side == "operator":
        # 运营端兜底：任意未终态阶段可直接终审
        return {"stage": decision, "from_status": decision,
                "to_status": decision if stage == "pending_to" or decision == "rejected" else "pending"}

    if side == "from":
        if stage != "pending_from":
            raise TransferError("当前不在转出园区审核阶段")
        if decision == "rejected":
            return {"stage": "rejected", "from_status": "rejected", "to_status": "pending"}
        return {"stage": "pending_to", "from_status": "approved", "to_status": "pending"}

    if side == "to":
        if stage == "pending_from":
            raise TransferError("转出园区尚未审核")
        if stage != "pending_to":
            raise TransferError("该申请已终态，无法再审核")
        if decision == "rejected":
            return {"stage": "rejected", "from_status": "approved", "to_status": "rejected"}
        return {"stage": "approved", "from_status": "approved", "to_status": "approved"}

    raise TransferError("非法审核方")


def can_initiate(actor_role: str, *, from_park_id: str, to_park_id: str,
                 my_park_id: str = "", is_company_admin: bool = False,
                 target_park_id: str = "") -> bool:
    """发起资格：operator 任意；carrier 限 from/to 本园区；enterprise 限本企业 admin；user 限本人。"""
    if actor_role == "operator":
        return True
    if actor_role == "carrier":
        return bool(my_park_id) and my_park_id in (from_park_id, to_park_id)
    if actor_role == "enterprise":
        return is_company_admin
    if actor_role == "user":
        return bool(target_park_id) and target_park_id == from_park_id
    return False


def review_side(transfer: dict, my_park_id: str) -> str | None:
    """园区端审核时判定自己审哪一级：from 园区审第一级，to 园区审第二级。"""
    stage = transfer.get("stage")
    if stage == "pending_from" and transfer.get("from_park_id") == my_park_id:
        return "from"
    if stage == "pending_to" and transfer.get("to_park_id") == my_park_id:
        return "to"
    return None