"""Tests for real-benchmark loading (T1.6)."""
import numpy as np
import pytest

from tsmm.data import real_bench


def test_supported_dataset_registry_has_at_least_two():
    regs = real_bench.SUPPORTED_DATASETS
    assert len(regs) >= 2


def test_load_windows_shapes_and_dtypes():
    # 'toy' is a deterministic in-memory benchmark used to exercise the pipeline
    # without requiring an external download.
    windows, labels, meta = real_bench.load_windows("toy", T=64, stride=32)
    assert windows.ndim == 3 and labels.ndim == 2
    N, T, C = windows.shape
    assert labels.shape == (N, T)
    assert windows.shape[0] == labels.shape[0]
    assert np.isfinite(windows).all()  # normalized -> finite
    assert set(np.unique(labels)).issubset({0, 1})


def test_load_windows_normalizes_per_channel():
    windows, _, _ = real_bench.load_windows("toy", T=64, stride=32)
    # z-score normalization -> mean ~0, std ~1 per channel over the whole set
    mu = windows.reshape(-1, windows.shape[-1]).mean(0)
    sd = windows.reshape(-1, windows.shape[-1]).std(0)
    assert np.allclose(mu, 0, atol=1e-6)
    assert np.allclose(sd, 1, atol=1e-6)


def test_load_windows_stride_controls_count():
    w1, _, _ = real_bench.load_windows("toy", T=64, stride=32)
    w2, _, _ = real_bench.load_windows("toy", T=64, stride=64)
    # smaller stride -> at least as many windows
    assert w1.shape[0] >= w2.shape[0]


def test_windows_to_qa_produces_nonempty_pairs():
    windows, labels, meta = real_bench.load_windows("toy", T=64, stride=32)
    qa = real_bench.windows_to_qa(windows, labels, meta, seed=0)
    assert isinstance(qa, list) and len(qa) > 0
    for item in qa:
        assert set(item.keys()) >= {"instruction", "answer", "labels", "series", "category"}
        assert isinstance(item["instruction"], str) and item["instruction"].strip()
        assert isinstance(item["answer"], str) and item["answer"].strip()


def test_load_windows_unknown_dataset_raises():
    with pytest.raises(KeyError):
        real_bench.load_windows("does-not-exist", T=64, stride=32)


def test_load_windows_real_dataset_missing_data_raises_clear_error():
    # Real loaders must raise a helpful error when the local data path is absent,
    # rather than silently returning empty arrays.
    with pytest.raises((FileNotFoundError, RuntimeError)):
        # SMD is almost certainly not present in CI; should raise.
        real_bench.load_windows("smd", T=64, stride=32)