"""验证遥测口径、有界内存和请求关联，防止监控干扰业务及泄漏原始地址。"""

from datetime import datetime, timedelta

from fastapi import FastAPI
from fastapi.testclient import TestClient

from app.core.monitoring import REQUEST_ID, MonitorMiddleware, Recorder, merge_metrics


def test_合并直方图计算P95且四百不计系统错误():
    recorder = Recorder()
    at = datetime(2026, 11, 2, 10)
    for status, elapsed in [(200, 10), (400, 100), (403, 200), (500, 750)]:
        recorder.record("GET", "/items/{id}", status, elapsed, "r", at=at)
    result = merge_metrics(recorder.metrics()[at].values())
    assert (result["count"], result["errors_4xx"], result["errors_5xx"]) == (4, 2, 1)
    assert result["error_rate"] == 25
    assert result["p95_ms"] == 750
    assert merge_metrics([])["p95_ms"] is None


def test_中间件生成编号使用模板排除自身且不读取正文():
    app, recorder = FastAPI(), Recorder()
    app.add_middleware(MonitorMiddleware, recorder=recorder)

    @app.get("/items/{id}")
    def item(id: str):
        return {"request_id": REQUEST_ID.get()}

    @app.get("/api/v1/system/monitor/overview")
    def monitor():
        return {}

    client = TestClient(app)
    response = client.get("/items/private-id?token=never-record")
    assert response.headers["x-request-id"] == response.json()["request_id"]
    client.get("/api/v1/system/monitor/overview")
    client.get("/private-route")
    values = next(iter(recorder.metrics().values()))
    assert set(values) == {("GET", "/items/{id}"), ("GET", "/__unmatched__")}
    assert "private" not in str(recorder.metrics())
    assert REQUEST_ID.get() == "-"


def test_内存分钟路由和事件队列均有界():
    recorder = Recorder()
    at = datetime(2026, 11, 2, 10)
    for i in range(2100):
        recorder.record("GET", f"/route/{i}", 500, 1, str(i), at=at)
    assert len(recorder.events) == 2000 and recorder.dropped_events == 100
    assert len(recorder.metrics()[at]) == 201
    for i in range(11):
        recorder.record("GET", "/ok", 200, 1, "r", at=at + timedelta(minutes=i))
    assert len(recorder.metrics()) == 10


def test_遥测内部失败不改变业务响应(monkeypatch):
    app, recorder = FastAPI(), Recorder()
    app.add_middleware(MonitorMiddleware, recorder=recorder)

    @app.get("/ok")
    def ok():
        return {"ok": True}

    def broken(*args, **kwargs):
        raise RuntimeError("synthetic-recorder-failure")

    monkeypatch.setattr(recorder, "record", broken)
    response = TestClient(app).get("/ok")
    assert response.status_code == 200 and response.json() == {"ok": True}