"""Kernel 不可插拔不变量（lingtai-runtime.md §1 硬核例外）。

M0 落地其中两条的可执行断言：
- "模型可见即可重建"：投影中的每条模型可见消息必须能在事件日志（llm.requested）中找到；
- 流一致性：llm.delta 事件重组文本必须与进入接纳检查的文本一致。

镜树不变量（重生成不覆盖/未归真不入忆/归真不回滚）随 M2 镜树域落地时进入本模块；
禁域裁决点随 M5 司命落地。断言失败即抛 ``InvariantViolation``：Kernel 视其为缺陷
而非业务错误，Run 进入 interrupted 并带 HJ-9000 段错误码。
"""

from __future__ import annotations

from app.modules.runtime.events import Event
from app.shenshi_client.types import ShenshiChatRequest


class InvariantViolation(Exception):
    """Kernel 不变量被违反：缺陷信号，必须中断并留痕。"""

    def __init__(self, invariant: str, detail: str) -> None:
        super().__init__(f"[{invariant}] {detail}")
        self.invariant = invariant
        self.detail = detail


def assert_model_visible_logged(
    request: ShenshiChatRequest, events: list[Event]
) -> None:
    """投影消息 ⊆ 已记录的 llm.requested 消息（"模型可见即可重建"）。"""
    requested = next((e for e in events if e.type == "llm.requested"), None)
    if requested is None:
        raise InvariantViolation(
            "model-visible-means-logged", "存在模型请求但事件日志缺少 llm.requested"
        )
    logged = requested.payload.get("request", {}).get("messages", [])
    if logged != [m.model_dump() for m in request.messages]:
        raise InvariantViolation(
            "model-visible-means-logged", "llm.requested 事件与实际发送的 IR 消息不一致"
        )


def assert_stream_reconstruction(events: list[Event], accepted_text: str) -> None:
    """llm.delta 重组文本 == 进入接纳的文本（流不丢帧、不重帧）。"""
    reconstructed = "".join(
        e.payload.get("delta", "") for e in events if e.type == "llm.delta"
    )
    if reconstructed != accepted_text:
        raise InvariantViolation(
            "stream-reconstruction",
            f"事件重组文本与接纳文本不一致：{len(reconstructed)} != {len(accepted_text)} 字符",
        )