from __future__ import annotations

import pytest

from smokescreen.models import ProbeReading
from smokescreen.router import ProbeRouter


def reading(probe_id: str, tip_c: float = 60.0) -> ProbeReading:
    return ProbeReading(probe_id=probe_id, tip_c=tip_c, source="test")


def test_pinned_probe_drives_its_jack():
    router = ProbeRouter(jacks=[1, 2], pinned={2: "meater:aa"})
    assert router.observe(reading("meater:aa")) == 2


def test_auto_assignment_fills_free_jacks_in_order():
    router = ProbeRouter(jacks=[1, 2])
    assert router.observe(reading("probe:a")) == 1
    assert router.observe(reading("probe:b")) == 2


def test_auto_assignment_skips_pinned_jacks():
    router = ProbeRouter(jacks=[1, 2], pinned={1: "meater:aa"})
    assert router.observe(reading("probe:b")) == 2


def test_binding_is_sticky_across_a_dropout():
    """A probe that reconnects must not land on a different jack mid-cook."""
    router = ProbeRouter(jacks=[1, 2])
    assert router.observe(reading("probe:a")) == 1
    assert router.observe(reading("probe:b")) == 2
    assert router.observe(reading("probe:a", 70.0)) == 1


def test_extra_probes_have_nowhere_to_go():
    router = ProbeRouter(jacks=[1, 2])
    router.observe(reading("probe:a"))
    router.observe(reading("probe:b"))
    assert router.observe(reading("probe:c")) is None
    assert [r.probe_id for r in router.unassigned()] == ["probe:c"]


def test_reading_for_returns_latest_sample():
    router = ProbeRouter(jacks=[1])
    router.observe(reading("probe:a", 50.0))
    router.observe(reading("probe:a", 75.0))
    assert router.reading_for(1).tip_c == 75.0


def test_reading_for_unbound_jack_is_none():
    assert ProbeRouter(jacks=[1, 2]).reading_for(2) is None


def test_pin_to_unknown_jack_is_rejected():
    with pytest.raises(ValueError, match="unknown jacks"):
        ProbeRouter(jacks=[1, 2], pinned={3: "probe:a"})


def test_probe_pinned_twice_is_rejected():
    with pytest.raises(ValueError, match="more than one jack"):
        ProbeRouter(jacks=[1, 2], pinned={1: "probe:a", 2: "probe:a"})