modbison/backend/tests/fixtures/chunks/generate_fixtures.py

"""Generates the golden-file chunk fixtures in this directory.

These pin the world.md §3.6 binary format so the Python codec
(app/services/chunk_codec.py) and any future Godot-side test fixture can be
checked for drift (world_persistence_impl.md §5.5's "drift control"
requirement). No Godot-side golden fixture existed at the time this was
written (searched scripts/ and tests/ for AGPC / binary-format test
vectors -- none found), so these are authored here, from this
implementation, as the first golden files for the format. The client/editor
follow-on task should decode these same files with
`ChunkDataDecoder.decode_binary()` and assert the same logical values
(see the note in chunk_codec.py about a confirmed float32 handling bug in
that decoder that will need fixing for full byte parity on non-integer
transforms).

Run with: `python tests/fixtures/chunks/generate_fixtures.py` from `backend/`.
Fixtures are checked in; this script is for regenerating them if the format
or these examples change, not run as part of the test suite.
"""

import sys
from pathlib import Path

sys.path.insert(0, str(Path(__file__).resolve().parents[3]))  # backend/

from app.services import chunk_codec as cc

FIXTURES_DIR = Path(__file__).resolve().parent


def _empty_chunk() -> cc.ChunkPayload:
    return cc.ChunkPayload(
        world_id="7", room_id="main", coord=(0, 0, 0),
        bounds=cc.ChunkBounds(min=(0.0, 0.0, 0.0), size=(32.0, 32.0, 1.0)),
        tile_layers=[], objects=[],
        flags=cc.ContentFlags(),
        created_at=1_700_000_000, updated_at=1_700_000_000, revision=1, author="fixture-gen",
    )


def _simple_tile_chunk() -> cc.ChunkPayload:
    layer = cc.TileLayer(
        name="ground", layer_id=0, width=4, height=4, depth=1,
        palette=[
            cc.TileDef(id=0, asset_id="", solid=False, flags=0, variants=1),
            cc.TileDef(id=1, asset_id="tiles/grass", solid=False, flags=1, variants=4),
            cc.TileDef(id=2, asset_id="tiles/stone", solid=True, flags=2, variants=2),
        ],
        tiles=[0, 1, 1, 0, 1, 2, 2, 1, 1, 2, 2, 1, 0, 1, 1, 0],
    )
    return cc.ChunkPayload(
        world_id="12", room_id="main", coord=(3, -1, 0),
        bounds=cc.ChunkBounds(min=(96.0, -32.0, 0.0), size=(32.0, 32.0, 1.0)),
        tile_layers=[layer], objects=[],
        flags=cc.ContentFlags(violence=0, mature=False, sources=[]),
        created_at=1_700_000_000, updated_at=1_700_000_500, revision=2, author="fixture-gen",
    )


def _chunk_with_objects() -> cc.ChunkPayload:
    layer = cc.TileLayer(
        name="ground", layer_id=0, width=2, height=2, depth=1,
        palette=[cc.TileDef(id=0, asset_id="", solid=False, flags=0, variants=1)],
        tiles=[0, 0, 0, 0],
    )
    obj1 = cc.WorldObject(
        id="obj_0001", type="interactable", asset_id="props/chest",
        pos=(101.5, -110.25, 0.5), rot=(0.0, 0.0, 0.0, 1.0), scale=(1.0, 1.0, 1.0),
        dynamic=False,
        properties={"locked": False, "loot_table": "chest_basic"},
        flags=cc.ContentFlags(violence=0, mature=False, sources=[]),
    )
    obj2 = cc.WorldObject(
        id="obj_0002", type="spawn_point", asset_id="",
        pos=(96.0, -128.0, 1.0), rot=(0.0, 0.7071, 0.0, 0.7071), scale=(1.0, 1.0, 1.0),
        dynamic=True,
        properties={},
        flags=cc.ContentFlags(violence=1, mature=False, sources=["asset:props/chest"]),
    )
    return cc.ChunkPayload(
        world_id="12", room_id="main", coord=(3, -4, 0),
        bounds=cc.ChunkBounds(min=(96.0, -128.0, 0.0), size=(32.0, 32.0, 1.0)),
        tile_layers=[layer], objects=[obj1, obj2],
        flags=cc.ContentFlags(violence=1, mature=False, sources=["asset:props/chest"]),
        created_at=1_700_000_000, updated_at=1_700_001_000, revision=5, author="agent-bot",
    )


FIXTURES = {
    "empty_chunk.bin": _empty_chunk,
    "simple_tile_chunk.bin": _simple_tile_chunk,
    "chunk_with_objects.bin": _chunk_with_objects,
}


def main() -> None:
    for filename, builder in FIXTURES.items():
        payload = builder()
        data = cc.encode_binary(payload)
        (FIXTURES_DIR / filename).write_bytes(data)
        print(f"wrote {filename} ({len(data)} bytes)")


if __name__ == "__main__":
    main()