"""What a rule's Send test carries (#5466): the rule's own name and
condition, marked TEST, on its resource at the latest reading; a rule
covering hosts tests on its first host."""
from types import SimpleNamespace

from steward.alerts import service as alert_svc
from steward.models.alerts import AlertOperator


def _rule(**kw):
    base = dict(id="r1", name="Hot", source_module="host_agent", resource_name="web01",
                metric_name="cpu_pct", operator=AlertOperator.gt, threshold=90.0,
                covers="resource", cover_group=None, parent_id=None)
    return SimpleNamespace(**{**base, **kw})


class _Db:
    """Answers the one query test_alert makes: a covering rule's first host's rule."""

    def __init__(self, child):
        self.child = child

    async def execute(self, stmt):
        return SimpleNamespace(scalar_one_or_none=lambda: self.child)


def _readings(monkeypatch, values):
    async def latest(db, rule):
        return values.get(rule.resource_name)
    monkeypatch.setattr(alert_svc, "latest_value", latest)


async def test_a_rule_tests_on_its_own_resource_at_its_latest_reading(monkeypatch):
    _readings(monkeypatch, {"web01": 42.0})
    got = await alert_svc.test_alert(_Db(None), _rule())
    assert {k: got[k] for k in ("rule_name", "state", "resource", "value", "operator", "threshold")} == {
        "rule_name": "Hot", "state": "TEST", "resource": "web01", "value": 42.0,
        "operator": ">", "threshold": 90.0}


async def test_a_covering_rule_tests_on_its_first_host(monkeypatch):
    _readings(monkeypatch, {"db01": 12.0})
    parent = _rule(resource_name="", covers="group", cover_group="web")
    got = await alert_svc.test_alert(_Db(_rule(id="c1", name="Hot: db01", resource_name="db01",
                                               parent_id="r1")), parent)
    assert (got["rule_name"], got["resource"], got["value"]) == ("Hot", "db01", 12.0)


async def test_a_covering_rule_with_no_hosts_yet_says_what_it_covers(monkeypatch):
    _readings(monkeypatch, {})
    got = await alert_svc.test_alert(_Db(None), _rule(resource_name="", covers="all_hosts"))
    assert (got["resource"], got["value"]) == ("every host", None)