"""Self-check for generate.py. Run: python test_generate.py"""
import random
from generate import (TRANSFORMS, make_task, apply_rule, to_str, new_grid,
                      sample_params, t_max_pool2)


def _from_str(s):
    return [[int(v) for v in row.split()] for row in s.split(";")]


def test_transforms_are_total_and_rectangular():
    rng = random.Random(0)
    for name, (fn, _) in TRANSFORMS.items():
        for _ in range(50):
            h = rng.choice([4, 6]) if name == "max_pool2" else rng.randint(3, 5)
            w = rng.choice([4, 6]) if name == "max_pool2" else rng.randint(3, 5)
            g = new_grid(rng, h, w, 6)
            out = fn(g, sample_params(rng, 6))
            assert out and all(len(r) == len(out[0]) for r in out), name


def test_known_values():
    g = [[1, 2], [3, 4]]
    assert TRANSFORMS["flip_h"][0](g, {}) == [[2, 1], [4, 3]]
    assert TRANSFORMS["flip_v"][0](g, {}) == [[3, 4], [1, 2]]
    assert TRANSFORMS["transpose"][0](g, {}) == [[1, 3], [2, 4]]
    assert TRANSFORMS["rotate90"][0](g, {}) == [[3, 1], [4, 2]]
    assert t_max_pool2([[1, 9, 0, 0], [0, 0, 0, 0], [0, 0, 5, 0], [0, 0, 0, 7]], {}) == [[9, 0], [0, 7]]


def test_query_answer_matches_support_rule():
    rng = random.Random(1)
    for i in range(400):
        t = make_task(rng, f"t-{i}")
        rule = t["rule"].split("+")
        # re-derive every support output from the stated rule params is not
        # possible without params, but the rule must at least be self-consistent:
        # applying it to query_input must reproduce query_output.
        got = to_str(apply_rule(rule, _from_str(t["query_input"]),
                                _params_for(t)))
        assert got == t["query_output"], t["task_id"]


def _params_for(task):
    # generate.py freezes params inside make_task; reconstruct a compatible set by
    # brute force over the small param space so the check stays independent.
    from itertools import product
    n = task["num_colors"]
    qi = _from_str(task["query_input"])
    rule = task["rule"].split("+")
    for k, a, b, s, c in product(range(1, n), range(n), range(n), (1, 2), range(n)):
        p = {"ncolors": n, "k": k, "a": a, "b": b, "s": s, "c": c}
        if to_str(apply_rule(rule, qi, p)) == task["query_output"]:
            return p
    raise AssertionError(f"no params reproduce {task['task_id']}")


def test_deterministic():
    a = [make_task(random.Random(42), f"x{i}") for i in range(20)]
    b = [make_task(random.Random(42), f"x{i}") for i in range(20)]
    assert a == b


if __name__ == "__main__":
    test_transforms_are_total_and_rectangular()
    test_known_values()
    test_query_answer_matches_support_rule()
    test_deterministic()
    print("all checks passed")