"""The rule form's Resource and Metric pickers read the latest-value table,
one row per series, never the raw history: a DISTINCT over plugin_metrics
reads every sample and held the rule page for up to 15 s on host_agent."""
from types import SimpleNamespace

from steward.alerts import service as alert_svc


async def _sql(fn, source) -> list[str]:
    """The SQL `fn` sends for `source`, against a session that returns no rows."""
    sent: list[str] = []

    async def execute(stmt):
        sent.append(str(stmt.compile(compile_kwargs={"literal_binds": True})))
        return []
    await fn(SimpleNamespace(execute=execute), source)
    return sent


async def test_resources_come_from_the_latest_value_table():
    (sql,) = await _sql(alert_svc.resources_for, "host_agent")
    assert "FROM plugin_metric_latest" in sql and "plugin_metrics" not in sql


async def test_a_dynamic_source_s_metrics_come_from_the_latest_value_table():
    (sql,) = await _sql(alert_svc.metrics_for, "snmp")
    assert "FROM plugin_metric_latest" in sql and "plugin_metrics" not in sql