import pytest

from v1.fall_state import Evidence, FallState, FallStateMachine


def test_confirmed_event_is_emitted_once_after_persistent_evidence():
    machine = FallStateMachine(confirm_window_seconds=1.8, recovery_window_seconds=2.0)

    assert machine.update("P-0007", Evidence(True, True), now=0.0) == []
    events = machine.update("P-0007", Evidence(True, True), now=1.8)

    assert len(events) == 1
    assert events[0].track_id == "P-0007"
    assert events[0].latency_seconds == 1.8
    assert machine.update("P-0007", Evidence(True, True), now=2.0) == []
    assert machine.state_of("P-0007") is FallState.CONFIRMED


def test_brief_low_posture_returns_to_normal_without_event():
    machine = FallStateMachine(confirm_window_seconds=1.0, recovery_window_seconds=2.0)

    machine.update("P-0007", Evidence(True, True), now=0.0)
    events = machine.update("P-0007", Evidence(True, False), now=0.3)

    assert events == []
    assert machine.state_of("P-0007") is FallState.NORMAL


def test_rejected_pose_resets_suspect_and_cannot_shorten_confirmation_window():
    machine = FallStateMachine(confirm_window_seconds=1.0, recovery_window_seconds=2.0)

    machine.update("P-0007", Evidence(True, True), now=0.0)
    machine.update("P-0007", Evidence(False, False), now=0.9)
    events = machine.update("P-0007", Evidence(True, True), now=1.1)

    assert events == []
    assert machine.state_of("P-0007") is FallState.SUSPECT


def test_recovery_must_persist_before_new_event_is_allowed():
    machine = FallStateMachine(confirm_window_seconds=1.0, recovery_window_seconds=2.0)
    machine.update("P-0007", Evidence(True, True), now=0.0)
    first_event = machine.update("P-0007", Evidence(True, True), now=1.0)
    assert len(first_event) == 1

    machine.update("P-0007", Evidence(True, False, True), now=1.1)
    machine.update("P-0007", Evidence(True, False, True), now=3.1)
    assert machine.state_of("P-0007") is FallState.NORMAL

    machine.update("P-0007", Evidence(True, True), now=4.0)
    second_event = machine.update("P-0007", Evidence(True, True), now=5.0)
    assert len(second_event) == 1
    assert first_event[0].event_id != second_event[0].event_id


def test_confirmation_window_must_remain_within_customer_target():
    with pytest.raises(ValueError, match="between 1 and 3"):
        FallStateMachine(confirm_window_seconds=0.9, recovery_window_seconds=2.0)


def test_each_track_has_an_independent_confirmation_window():
    machine = FallStateMachine(confirm_window_seconds=1.0, recovery_window_seconds=2.0)

    machine.update("P-0001", Evidence(True, True), now=0.0)
    machine.update("P-0002", Evidence(True, True), now=0.6)
    first_events = machine.update("P-0001", Evidence(True, True), now=1.0)
    second_events = machine.update("P-0002", Evidence(True, True), now=1.6)

    assert first_events[0].track_id == "P-0001"
    assert second_events[0].track_id == "P-0002"
    assert first_events[0].event_id != second_events[0].event_id