"""Operator tests (oracle-free): every child is a valid, canonical genome."""

from pathlib import Path

import numpy as np
import pytest

from homemaker import dom, genome, operators

CORPUS = Path("/home/bruno/src/urb/examples/programme-house")
FILES = ["2f45907abd9accac2a124d311732f749.dom", "candidate-002.dom",
         "c964435454c459f86c3ed9a5a7621132.dom"]
TYPES = ["k1", "l1", "b1", "b2", "t1", "C", "O"]

pytestmark = pytest.mark.skipif(not CORPUS.is_dir(), reason="Urb corpus not available")


def canonical(root: dom.Node) -> None:
    """Child must encode to a genome that decode/encode holds fixed."""
    g1 = genome.encode(root)
    g2 = genome.encode(genome.decode(g1))
    assert g2 == g1


@pytest.mark.parametrize("name", sorted(operators.MUTATIONS))
def test_mutations_yield_canonical_genomes(name):
    op = operators.MUTATIONS[name]
    for f in FILES:
        root = genome.decode(genome.encode(dom.load(str(CORPUS / f))))
        for seed in range(5):
            child, desc = op(root, np.random.default_rng(seed), TYPES)
            assert desc.startswith(name.split("_")[0]) or "noop" in desc
            canonical(child)
            # the parent must never be mutated in place
            canonical(root)


def test_divide_grows_and_undivide_shrinks():
    root = genome.decode(genome.encode(dom.load(str(CORPUS / FILES[0]))))
    n_leaves = sum(len(lvl.leaves()) for lvl in dom.levels(root))
    child, _ = operators.mutate_divide(root, np.random.default_rng(0), TYPES)
    assert sum(len(lvl.leaves()) for lvl in dom.levels(child)) == n_leaves + 1
    child, desc = operators.mutate_undivide(root, np.random.default_rng(0), TYPES)
    if "noop" not in desc:
        assert sum(len(lvl.leaves()) for lvl in dom.levels(child)) < n_leaves


def test_level_add_delete():
    root = genome.decode(genome.encode(dom.load(str(CORPUS / FILES[0]))))
    n = len(dom.levels(root))
    up, _ = operators.mutate_level_add(root, np.random.default_rng(0), TYPES)
    assert len(dom.levels(up)) == n + 1
    canonical(up)
    down, _ = operators.mutate_level_delete(root, np.random.default_rng(0), TYPES)
    assert len(dom.levels(down)) == n - 1


def test_relink_clears_stale_below_after_base_undivide():
    # regression: dom._link must clear below-links whose path vanished, or
    # geometry on the mutated tree dereferences orphaned nodes
    from homemaker import geometry

    root = genome.decode(genome.encode(dom.load(str(CORPUS / FILES[0]))))
    # force an undivide on the BASE storey specifically
    base = dom.levels(root)[0]
    cands = [n for li, n in operators._owned_branches(root)
             if li == 0 and not n.left.divided and not n.right.divided]
    assert cands, "corpus design has no base leaf-pair branch"
    import copy as _copy

    child = _copy.deepcopy(root)
    target = dom.levels(child)[0].by_id(cands[0].id)
    target.division = None
    target.left = target.right = None
    target.type = "l1"
    dom._link(child)
    geometry.clear_cache()
    for lvl in dom.levels(child):
        for leaf in lvl.leaves():
            for i in range(4):
                geometry.coordinate(leaf, i)  # must not raise
    canonical(child)
    assert base.by_id(cands[0].id) is not None  # parent untouched


def test_crossover_yields_canonical_pair():
    a = genome.decode(genome.encode(dom.load(str(CORPUS / FILES[0]))))
    b = genome.decode(genome.encode(dom.load(str(CORPUS / FILES[1]))))
    for seed in range(5):
        ca, cb, desc = operators.crossover(a, b, np.random.default_rng(seed))
        assert desc.startswith("crossover")
        canonical(ca)
        canonical(cb)