"""Which temperature sensors are thermometers, judged from how each moves
against the host's CPU (#5783). VDNT-Util01's SYSTIN ran at r = −0.81
against its CPU package over a week; CPUTIN beside it at +0.83 (#5782)."""

import math
from datetime import datetime, timedelta, timezone

from plugins.host_agent import sensors as s

T0 = datetime(2026, 10, 8, tzinfo=timezone.utc)


def _hours(n, f):
    """{hour: f(i)} for n hourly buckets."""
    return {T0 + timedelta(hours=i): f(i) for i in range(n)}


def cpu(i):                                  # a CPU that swings 50-80 °C through the day
    return 65 + 15 * math.sin(i / 24 * 2 * math.pi)


def test_a_sensor_that_falls_as_the_cpu_warms_is_not_a_thermometer():
    ref = _hours(96, cpu)
    systin = _hours(96, lambda i: 114 - 0.1 * (cpu(i) - 65))       # Util01's shape
    why = s.judge(ref, systin)
    assert why.startswith("falls as the CPU warms (r -1.00 over 96 h")


def test_a_sensor_that_holds_still_is_not_a_thermometer():
    why = s.judge(_hours(96, cpu), _hours(96, lambda i: 110.0 + (0.1 if i % 2 else 0.0)))
    assert why == "holds at 110 °C while the CPU moved 50–80 °C"


def test_a_wired_sensor_is_left_alone_even_when_it_barely_follows_the_cpu():
    ref = _hours(96, cpu)
    assert s.judge(ref, _hours(96, lambda i: 40 + 0.3 * (cpu(i) - 65))) is None     # a board sensor
    assert s.judge(ref, _hours(96, lambda i: 45 + 3 * math.sin(i))) is None          # a drive, its own rhythm


def test_nothing_is_judged_without_enough_history_or_a_cpu_that_moved():
    falls = lambda i: 114 - 0.1 * (cpu(i) - 65)                                      # noqa: E731
    assert s.judge(_hours(48, cpu), _hours(48, falls)) is None                      # 48 h < MIN_HOURS
    idle = _hours(96, lambda i: 50 + (i % 3))                                       # moved 2 °C
    assert s.judge(idle, _hours(96, lambda i: 110 - (i % 3))) is None


def test_the_cpu_reference_is_found_by_its_driver_names():
    assert s.reference_label(["SYSTIN", "Core 0", "Package id 1", "Package id 0"]) == "Package id 0"
    assert s.reference_label(["Tccd1", "Tctl", "Composite"]) == "Tctl"
    assert s.reference_label(["PECI Agent 0", "SYSTIN"]) == "PECI Agent 0"
    assert s.reference_label(["Composite", "temp1"]) is None


def test_hosts_are_judged_from_hourly_rows_and_a_host_without_a_cpu_reading_is_skipped():
    rows = []
    for i in range(96):
        h = T0 + timedelta(hours=i)
        rows += [("util:temp:Package id 0", h, cpu(i)),
                 ("util:temp:SYSTIN", h, 114 - 0.1 * (cpu(i) - 65)),
                 ("util:temp:CPUTIN", h, 40 + 0.3 * (cpu(i) - 65)),
                 ("nas:temp:temp1", h, 110 - 0.1 * (cpu(i) - 65)),
                 ("util", h, 1.0)]                                                   # not a sensor row
    got = s.judge_hosts(rows)
    assert list(got) == ["util"] and list(got["util"]) == ["SYSTIN"]


def test_a_judged_sensor_is_left_out_of_the_host_temperature_and_listed_with_why(monkeypatch):
    from plugins.host_agent.routes import is_thermometer, split_temps
    monkeypatch.setattr(s, "_unwired", {"util": {"temp3": "falls as the CPU warms (r -0.81 over 168 h)"}})
    assert not is_thermometer("util", "temp3", 62.0)       # a plausible value, still not a thermometer
    assert is_thermometer("other", "temp3", 62.0)
    real, unwired = split_temps("util", {"temp3": 62.0, "Package id 0": 55.0})
    assert list(real) == ["Package id 0"]
    assert unwired == {"temp3": (62.0, "falls as the CPU warms (r -0.81 over 168 h)")}


def test_a_later_read_replaces_the_hour_that_was_filling_and_old_hours_drop():
    hours = {"h:temp:a": {T0: 50.0, T0 + timedelta(hours=1): 51.0}}
    s.merge_hours(hours, [("h:temp:a", T0 + timedelta(hours=1), 55.0),     # the hour, read whole
                          ("h:temp:a", T0 + timedelta(hours=2), 56.0),
                          ("h:temp:b", T0 + timedelta(hours=2), None)], since=T0 + timedelta(hours=1))
    assert hours == {"h:temp:a": {T0 + timedelta(hours=1): 55.0, T0 + timedelta(hours=2): 56.0}}
    s.merge_hours(hours, [], since=T0 + timedelta(hours=9))                # a sensor gone quiet
    assert hours == {}