"""get_thresholds / set_thresholds: the cutoffs host readings are graded by,
read and changed as Settings → Thresholds does."""
from __future__ import annotations

from contextlib import asynccontextmanager
from types import SimpleNamespace as NS

import pytest

from steward.mcp.tools import thresholds
from steward.models.users import UserRole


@pytest.fixture
def store(monkeypatch):
    """The settings table, the app and the audit log, in memory."""
    saved: dict = {"thresholds.temp_crit": 85}
    app = NS(config={})
    audited: list = []

    class _Db:
        @asynccontextmanager
        async def begin(self):
            yield

    @asynccontextmanager
    async def db_session():
        yield _Db()

    async def get_all_settings(_db):
        return dict(saved)

    async def set_setting(_db, key, value):
        saved[key] = value

    async def audit_mcp(*args):
        audited.append(args)

    monkeypatch.setattr(thresholds, "db_session", db_session)
    monkeypatch.setattr(thresholds, "get_all_settings", get_all_settings)
    monkeypatch.setattr(thresholds, "set_setting", set_setting)
    monkeypatch.setattr(thresholds, "mcp_app", lambda: app)
    monkeypatch.setattr(thresholds, "audit_mcp", audit_mcp)
    return NS(saved=saved, app=app, audited=audited)


async def test_the_cutoffs_read_with_their_units_and_defaults(store):
    got = await thresholds.get_thresholds()
    assert set(got) == {"cpu", "mem", "disk", "load", "temp"}
    assert got["temp"] == {"warn": 70, "crit": 85, "unit": "°C", "measures": "hottest real thermometer",
                           "default": {"warn": 70, "crit": 85}}


async def test_raising_one_cutoff_keeps_the_other_and_grades_by_it_at_once(store):
    got = await thresholds.set_thresholds({"temp": {"crit": 90}})
    assert got["temp"]["crit"] == 90 and got["temp"]["warn"] == 70
    assert store.saved == {"thresholds.temp_crit": 90}               # warn isn't written
    assert store.app.config["THRESHOLDS"]["temp"]["crit"] == 90
    (_action, _kind, _id, detail), = store.audited
    assert detail["changes"] == {"thresholds.temp_crit": {"from": 85, "to": 90}}


@pytest.mark.parametrize("cutoffs, refusal", [
    ({}, "Nothing to change"),
    ({"fan": {"crit": 1}}, "No reading named fan"),
    ({"temp": {"high": 90}}, "warn and/or crit"),
    ({"temp": {}}, "warn and/or crit"),
    ({"temp": {"crit": "hot"}}, "must be a number"),
    ({"temp": {"crit": 0}}, "more than 0"),
    ({"temp": {"crit": 60}}, r"warn \(70\) must be below its crit \(60\)"),
])
async def test_refusals_change_nothing(store, cutoffs, refusal):
    with pytest.raises(ValueError, match=refusal):
        await thresholds.set_thresholds(cutoffs)
    assert store.saved == {"thresholds.temp_crit": 85} and not store.audited


def test_the_tools_are_registered_with_their_roles(app):
    mcp = app.mcp_server
    for name, role, read_only in (("get_thresholds", UserRole.viewer, True),
                                  ("set_thresholds", UserRole.admin, False)):
        assert mcp.tool_roles[name] is role, name
        assert mcp._tool_manager.get_tool(name).annotations.read_only_hint is read_only, name