"""Toolpath-Thinning: ganze Schichten dicht, keine gesprenkelten Stichproben."""

from grotti.toolpath import TOOLPATH_VERSION, _thin_points, build_toolpath


def _fake_points(layers=40, per_layer=800):
    points = []
    breaks = []
    seq = 0
    for layer in range(layers):
        z = 0.2 + layer * 0.2
        breaks.append(len(points))
        for i in range(per_layer):
            extrude = 1 if i > 0 else 0
            points.append([float(i), float(layer), z, extrude, seq])
            seq += 1
    return points, breaks


def test_thin_keeps_consecutive_extrude_pairs():
    points, breaks = _fake_points()
    kept, new_breaks = _thin_points(points, breaks, max_points=8_000)
    assert len(kept) <= 8_000
    assert new_breaks
    consec = 0
    for i in range(1, len(kept)):
        if kept[i][3] and kept[i][4] == kept[i - 1][4] + 1:
            consec += 1
    assert consec > 500, "Thinning darf keine zeichnbaren Segmente übrig lassen"


def test_thin_keeps_solid_layers():
    points, breaks = _fake_points(layers=50, per_layer=600)
    kept, _ = _thin_points(points, breaks, max_points=10_000)
    # Pro behaltener Z-Höhe: hoher Anteil aufeinanderfolgender Extrusionen
    by_z = {}
    for i in range(1, len(kept)):
        if not (kept[i][3] and kept[i][4] == kept[i - 1][4] + 1):
            continue
        z = round(kept[i][2], 2)
        by_z[z] = by_z.get(z, 0) + 1
    assert by_z, "keine Extrusionssegmente"
    assert max(by_z.values()) >= 40, "behaltene Schichten sollen dicht sein"


def test_toolpath_version():
    assert TOOLPATH_VERSION >= 8


def test_build_empty(tmp_path):
    path = tmp_path / "empty.gcode"
    path.write_text("; nix\n", encoding="utf-8")
    data = build_toolpath(path)
    assert data["points"] == []
    assert data["version"] == TOOLPATH_VERSION