from src import gpu_timing


def test_callback_timing_records_unavailable_queue_wait_without_cuda(monkeypatch):
    monkeypatch.setattr(gpu_timing.torch.cuda, "is_available", lambda: False)
    timing = gpu_timing.start_gpu_callback_timing()
    snapshot = timing.to_dict()
    assert snapshot["zerogpu_queue_allocation_wait_seconds"] is None
    assert snapshot["zerogpu_queue_allocation_wait_status"].startswith("unavailable-by-design")
    assert snapshot["browser_click_to_callback_seconds"] is None
    assert snapshot["cuda_ready_status"] == "cuda-unavailable"
    assert snapshot["gpu_callback_body_seconds"] >= 0


def test_callback_timing_synchronizes_once_at_entry(monkeypatch):
    calls = []
    monkeypatch.setattr(gpu_timing.torch.cuda, "is_available", lambda: True)
    monkeypatch.setattr(gpu_timing.torch.cuda, "synchronize", lambda: calls.append("sync"))
    timing = gpu_timing.start_gpu_callback_timing()
    snapshot = timing.to_dict()
    assert calls == ["sync"]
    assert snapshot["cuda_ready_status"] == "ready-after-synchronize"
    assert snapshot["cuda_initial_sync_seconds"] is not None
    assert snapshot["callback_entry_to_cuda_ready_seconds"] is not None


def test_synchronized_wall_time_wraps_operation_with_cuda_sync(monkeypatch):
    events = []
    monkeypatch.setattr(gpu_timing.torch.cuda, "synchronize", lambda: events.append("sync"))

    def operation():
        events.append("operation")
        return "ok"

    result, elapsed, error = gpu_timing.synchronized_wall_time(operation, use_cuda=True)
    assert result == "ok"
    assert elapsed >= 0
    assert error is None
    assert events == ["sync", "operation", "sync"]