import pytest

from hermes_thermal.policy import LEVELS, SCALE, ThermalPolicy, scaled


def run(p, temps, t0=0.0, dt=1.0):
    t, out = t0, []
    for temp in temps:
        t += dt
        out.append(p.update(temp, t))
    return out, t


def test_cool_stays_ok():
    out, _ = run(ThermalPolicy(), [55, 60, 65, 71.9])
    assert set(out) == {'ok'}


def test_heating_escalates_at_once_even_several_levels():
    p = ThermalPolicy()
    assert p.update(73, 1.0) == 'warm'
    assert p.update(78, 2.0) == 'hot'
    assert p.update(90, 3.0) == 'critical'         # straight to the top if it asks for it
    assert ThermalPolicy().update(84, 1.0) == 'critical'


def test_cooling_needs_the_margin_and_the_dwell_and_goes_one_step_at_a_time():
    p = ThermalPolicy(dwell_s=20.0, margin_c=3.0)
    p.update(84, 0.0)                              # critical
    assert p.update(75, 5.0) == 'critical'         # cooler, but inside the dwell
    assert p.update(75, 25.0) == 'hot'             # dwell over, 75 < 82-3: one step down
    assert p.update(75, 26.0) == 'hot'             # not another step at once
    assert p.update(73, 46.0) == 'warm'            # 73 < 77-3
    assert p.update(70, 47.0) == 'warm'
    assert p.update(68, 67.0) == 'ok'              # 68 < 72-3


def test_a_temperature_hovering_at_a_threshold_does_not_flap():
    p = ThermalPolicy(dwell_s=20.0, margin_c=3.0)
    out, _ = run(p, [72.5, 71.5, 72.2, 71.0, 72.1, 70.0, 72.3] * 6, dt=1.0)
    assert out[0] == 'warm' and set(out) == {'warm'}     # never drops back to ok while it stays within the margin


def test_a_reheat_during_recovery_escalates_again():
    p = ThermalPolicy(dwell_s=10.0)
    p.update(84, 0.0)
    assert p.update(70, 20.0) == 'hot'
    assert p.update(83, 21.0) == 'critical'


def test_scaling_respects_floors_and_never_exceeds_normal():
    assert scaled(15.0, 'ok', 2.0) == 15.0
    assert scaled(15.0, 'hot', 2.0) == pytest.approx(15 * 0.45)
    assert scaled(15.0, 'critical', 4.0) == 4.0            # the floor wins over 15*0.2 = 3
    assert scaled(1.0, 'critical', 2.0) == 1.0             # a floor above normal must not raise the rate
    assert [scaled(30.0, lv, 8.0) for lv in LEVELS] == sorted([scaled(30.0, lv, 8.0) for lv in LEVELS], reverse=True)
    assert SCALE['ok'] == 1.0