import pytest

from engine.timing import GameClock, Scheduler


def test_game_clock_yields_whole_ticks_and_keeps_remainder():
    clock = GameClock(tick_interval=1.0)
    assert clock.advance(0.4) == 0
    assert clock.advance(0.4) == 0
    assert clock.advance(0.4) == 1  # 1.2s total -> 1 whole tick, 0.2s carried over
    assert clock.tick_count == 1
    assert clock.total_time == pytest.approx(1.2)


def test_game_clock_handles_multiple_ticks_in_one_advance():
    clock = GameClock(tick_interval=0.5)
    assert clock.advance(1.7) == 3
    assert clock.tick_count == 3


def test_scheduler_runs_one_off_event_once_due():
    scheduler = Scheduler()
    calls = []
    scheduler.schedule_in(now=0.0, delay=5.0, event_id="e1", callback=lambda: calls.append("e1"))

    assert scheduler.run_due(4.9) == []
    assert scheduler.run_due(5.0) == ["e1"]
    assert calls == ["e1"]
    assert scheduler.run_due(100.0) == []  # already consumed, doesn't fire again


def test_scheduler_reschedules_repeating_event():
    scheduler = Scheduler()
    calls = []
    scheduler.schedule_in(now=0.0, delay=1.0, event_id="tick", callback=lambda: calls.append("tick"), interval=1.0)

    assert scheduler.run_due(1.0) == ["tick"]
    assert scheduler.run_due(1.9) == []
    assert scheduler.run_due(2.0) == ["tick"]
    assert calls == ["tick", "tick"]
    assert scheduler.pending_count() == 1


def test_scheduler_runs_multiple_due_events_in_run_at_order():
    scheduler = Scheduler()
    calls = []
    scheduler.schedule_at(2.0, "second", lambda: calls.append("second"))
    scheduler.schedule_at(1.0, "first", lambda: calls.append("first"))

    assert scheduler.run_due(2.0) == ["first", "second"]
    assert calls == ["first", "second"]