"""司命裁决器：行动前的四维裁决与禁域否决（mandate-and-capability-model.md §3/§4）。

裁决顺序（后者不可被前者越过）：
1. **禁域**：代码常量，无任何配置/Profile/插件写入路径——Prompt、人物、模型、扩展、
   普通管理员与自托管配置均不能关闭（专项测试钉死）；
2. **能力与授契**：能力未注册/停用/未授契 → 拒绝并留痕（HJ-1303）；
3. **行契条件**：预算耗尽/过期/超范围 → 降级为请命或拒绝；
4. **请命**：consent_mode=ask 或裁决为高风险 → 登记请命，用户当次同意前不执行，
   超时视为拒绝（HJ-1302）。

四维（能力/数据/后果/情境）取能力注册表的风险标注与调用上下文综合，亲密或
"过去允许过"不构成授权。
"""

from __future__ import annotations

import re
from dataclasses import dataclass
from datetime import UTC, datetime, timedelta

from sqlalchemy import select

from app.core.errors import AppError
from app.core.time import utc_now
from app.db.session import AsyncSessionLocal
from app.domains.baigong.models import Capability, Mandate, RISK_DIMENSIONS

# ── 禁域：不可覆盖的核心边界 ──────────────────────────────
# 形态：对能力输入的硬否决规则。模块级常量，无运行时写入口；
# 任何 Profile/插件/DB 配置在裁决顺序上位于其后，无法绕过。

_FORBIDDEN_SHELL = re.compile(
    r"rm\s+-[rfRF]+\s+/(?:\s|$)"  # rm -rf / 递归删除根
    r"|mkfs(\.\w+)?\s"
    r"|dd\s+.*of=/dev/(?:sd|disk|nvme)"
    r"|:\(\)\{.*\};\s*:",  # fork 炸弹
)
_FORBIDDEN_URL = re.compile(r"^file://", re.IGNORECASE)
# 密钥与身份材料不得经任何能力外发
_SENSITIVE_KEY = re.compile(r"sk-[a-zA-Z0-9]{16,}|-----BEGIN [A-Z ]*PRIVATE KEY-----")


class ForbiddenViolation(AppError):
    """禁域违规：HJ-1301，不可申诉绕过。"""

    def __init__(self, rule: str) -> None:
        super().__init__("HJ-1301", f"禁域裁决拒绝：{rule}", status_code=403)
        self.rule = rule


def check_forbidden(capability: Capability, params: dict) -> None:
    """禁域检查：任何能力、任何参数形态都先过这里。抛 ForbiddenViolation。"""
    text = " ".join(str(v) for v in params.values())
    if capability.executor_type == "qiankun" and _FORBIDDEN_SHELL.search(text):
        raise ForbiddenViolation("禁止递归删除根文件系统/格式化/写裸设备/炸弹进程")
    if _FORBIDDEN_URL.search(text):
        raise ForbiddenViolation("禁止经能力访问本机文件协议")
    if _SENSITIVE_KEY.search(text):
        raise ForbiddenViolation("禁止将密钥材料作为能力参数外发")


# ── 裁决结果 ──────────────────────────────

@dataclass
class Ruling:
    """一次司命裁决的结论。"""

    decision: str  # allow / ask / denied
    mandate: Mandate | None = None
    risk_level: str = "L1"
    reason: str = ""


def _risk_level(dims: dict) -> str:
    """四维取最高档：L0 < L1 < L2 < L3 < L4。"""
    order = ["L0", "L1", "L2", "L3", "L4"]
    level = "L0"
    for dim in RISK_DIMENSIONS:
        v = str(dims.get(dim, "L1"))
        if v in order and order.index(v) > order.index(level):
            level = v
    return level


async def _active_mandate(
    capability: Capability,
    *,
    owner_scope: str,
    character_id: str | None,
    now: datetime,
) -> Mandate | None:
    """查命中且仍有效的授契/行契：用户全局或本人物；未过期、未撤销、预算未尽。"""
    async with AsyncSessionLocal() as session:
        result = await session.execute(
            select(Mandate).where(
                Mandate.capability_id == capability.id,
                Mandate.owner_scope == owner_scope,
                Mandate.status == "active",
                (Mandate.character_id.is_(None))
                | (Mandate.character_id == (character_id or "")),
                (Mandate.expires_at.is_(None)) | (Mandate.expires_at > now),
                (Mandate.budget_total == 0) | (Mandate.budget_used < Mandate.budget_total),
            )
        )
        mandate = result.scalars().first()
        if mandate is not None:
            session.expunge(mandate)
        return mandate


async def rule(
    capability: Capability,
    params: dict,
    *,
    owner_scope: str,
    character_id: str | None,
    confirmed: bool = False,
) -> Ruling:
    """四维裁决入口。禁域在调用方（service.invoke）最先执行，这里做授契与请命裁决。"""
    now = datetime.now(UTC)
    if not capability.enabled:
        return Ruling(decision="denied", reason=f"能力已停用：{capability.name}")

    mandate = await _active_mandate(
        capability, owner_scope=owner_scope, character_id=character_id, now=now
    )
    risk = _risk_level(_load_dims(capability))

    if mandate is None:
        return Ruling(
            decision="denied",
            risk_level=risk,
            reason=f"未授契能力被拒：{capability.name}（HJ-1303）",
        )

    # 行契维度：高数据/后果风险即便授契也要请命（一次确认不得自动扩大为无限行契）
    needs_ask = capability.consent_mode == "ask" or risk in ("L3", "L4")
    if needs_ask and not confirmed:
        return Ruling(decision="ask", mandate=mandate, risk_level=risk, reason="高风险动作需当次请命")

    return Ruling(decision="allow", mandate=mandate, risk_level=risk)


def _load_dims(capability: Capability) -> dict:
    import json

    try:
        return dict(json.loads(capability.risk_dims_json or "{}"))
    except ValueError:
        return {}


# ── 请命超时 ──────────────────────────────

PETITION_TTL = timedelta(minutes=10)


def petition_deadline() -> datetime:
    """请命截止时刻：超时即视为拒绝（不执行，HJ-1302）。"""
    return utc_now() + PETITION_TTL