"""Grader/特征门测试（T-G5）：门×概率×mode 决策表 + fallback + /v1/route 契约。"""
import asyncio
import json

import pytest

pytest.importorskip("fastapi")

from gateway.sense.config import build_sense_config
from gateway.sense.errors import EmbedderDown
from gateway.sense.features import gate
from gateway.sense.grader import Grader
from gateway.sense.store import SenseStore


@pytest.fixture()
def env(tmp_path, monkeypatch):
    cfg = build_sense_config({"sense": {
        "enabled": True, "mode": "shadow",
        "db_path": str(tmp_path / "s.sqlite3"),
        "models_dir": str(tmp_path / "models")}})
    store = SenseStore.init_db(cfg.db_path)
    reset = getattr(__import__("gateway.sense.observer",
                              fromlist=["reset_observer"]), "reset_observer")
    reset()
    observer = __import__("gateway.sense.observer",
                          fromlist=["Observer"]).Observer(store)
    g = Grader(cfg, store, observer)
    yield {"cfg": cfg, "store": store, "grader": g, "observer": observer,
           "tmp": tmp_path}
    reset()


def _embed_ok(monkeypatch, dim=8):
    import gateway.sense.embedder as em
    orig = em.embed

    async def fake(text, c):
        return [1, 2, 3]

    monkeypatch.setattr("gateway.sense.grader.embed", fake)
    return orig


def _head_ok(tmp_path, monkeypatch, p1=0.95, p3=0.02):
    """注册一个 active head 工件，predict 可控。"""
    import gateway.sense.grader as gr

    class FakeHead:
        version = "test-head"

        def __init__(self, p1, p3):
            self._p = (p1, 1 - p1 - p3, p3)

        def predict(self, vec):
            p1, p2, p3 = self._p
            return {"t1": p1, "t2": p2, "t3": p3}

    head = FakeHead(p1, p3)
    monkeypatch.setattr(Grader, "_load_head",
                        lambda self: head if not self._head_loaded else None)
    return head


def test_gate_features_matrix(env):
    """特征门全表：单轮/多轮/长度/黑名单/仓库信号。"""
    cfg = env["cfg"]
    short_ok = gate("什么是递归？", "pipeline", cfg)
    assert short_ok.t1_hard_ok is True and short_ok.turns == 1
    long_text = "x" * (cfg.t1_max_tokens * 3 + 10)
    assert gate(long_text, "pipeline", cfg).t1_hard_ok is False
    multi = [{"role": "user", "content": "a"}, {"role": "assistant", "content": "b"},
             {"role": "user", "content": "c"}]
    f2 = gate(multi, "pipeline", cfg)
    assert f2.turns == 3 and f2.t1_hard_ok is False
    for word in ("重构", "脚手架", "迁移", "实现", "多文件", "项目"):
        f = gate(f"帮我{word}这个模块", "pipeline", cfg)
        assert f.intent_blocked is True and f.t1_hard_ok is False
    repo = gate("这个仓库要跨模块改造", "pipeline", cfg)
    assert repo.repo_signals is True and repo.t1_hard_ok is False


def test_grader_shadow_does_not_change_flow(env, monkeypatch):
    """shadow：decided 照算，executed=规则门现行为，观察必写（flush 后落库）。"""
    _embed_ok(monkeypatch)
    _head_ok(env["tmp"], monkeypatch, p1=0.95, p3=0.02)
    d = asyncio_run(env["grader"].decide("什么是递归？", "pipeline"))
    assert d.tier == "T1" and d.mode == "shadow" and d.fallback is False
    assert d.executed_tier == "T1"                     # 规则门现行为同为 T1
    asyncio_run(env["observer"].flush_once())
    obs_rows = env["store"].all_observations()
    assert len(obs_rows) == 1
    assert obs_rows[0]["decided_tier"] == "T1"
    assert json.loads(obs_rows[0]["features"])["t1_hard_ok"] is True


def test_grader_live_tier_is_decision(env, monkeypatch):
    """live：决策即执行档。"""
    env["cfg"].mode = "live"
    _embed_ok(monkeypatch)
    _head_ok(env["tmp"], monkeypatch, p1=0.3, p3=0.9)
    d = asyncio_run(env["grader"].decide("多文件大改造任务", "proxy"))
    assert d.tier == "T3"
    assert d.mode == "live"


def test_grader_fallback_embedder_down(env, monkeypatch):
    """Embedder 挂 -> fallback=True 规则门退化（D-G4）。"""
    def boom(text, c):
        raise EmbedderDown("挂了")
    monkeypatch.setattr("gateway.sense.grader.embed", boom)
    d = asyncio_run(env["grader"].decide("什么是递归？", "pipeline"))
    assert d.fallback is True
    assert d.tier == "T1"                              # 规则门：短文本可 T1
    assert d.probs == {}


def test_grader_conservative_thresholds(env, monkeypatch):
    """无工件 -> 保守阈值 0.9：p1=0.5 不判 T1。"""
    _embed_ok(monkeypatch)
    _head_ok(env["tmp"], monkeypatch, p1=0.5, p3=0.05)
    d = asyncio_run(env["grader"].decide("什么是递归？", "pipeline"))
    assert d.tier == "T2"                              # 置信不足默认 T2
    assert d.thresholds_version == "conservative"


def asyncio_run(coro):
    return asyncio.run(coro)