#!/usr/bin/env python3
"""Split the owner surface strate around a small, opt-in native maze strate."""
from __future__ import annotations

import argparse
import hashlib
import json
from pathlib import Path


def sha256(path: Path) -> str:
    digest = hashlib.sha256()
    with path.open("rb") as stream:
        for block in iter(lambda: stream.read(1024 * 1024), b""):
            digest.update(block)
    return digest.hexdigest()


def main() -> int:
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("--owner", type=Path, required=True)
    parser.add_argument("--out", type=Path, required=True)
    args = parser.parse_args()

    root = json.loads(args.owner.read_text(encoding="utf-8"))
    strates = root.get("strates")
    if not isinstance(strates, list):
        raise ValueError("owner input has no strates array")
    by_index = {int(row.get("index", -1)): row for row in strates if isinstance(row, dict)}
    if set(by_index) != {0, 1} or len(strates) != 2:
        raise ValueError("fixture requires the reviewed two-strate owner input")
    upper, surface = by_index[0], by_index[1]
    if (int(upper.get("asset", {}).get("GeneratorType", -1)) != 0
            or int(surface.get("asset", {}).get("GeneratorType", -1)) != 4):
        raise ValueError("fixture requires TunnelNetwork over SurfaceWorld")
    if int(upper.get("passage_config", {}).get("Connections", -1)) != 1:
        raise ValueError("owner arrival passage count differs from the reviewed input")

    # Keep both resolved mouths in the small synthetic Maze layer. The authored
    # owner reach ranges are intentionally broad and can place a synthetic mouth
    # hundreds of metres beyond a four-chunk prototype layer.
    upper["passage_config"].update({"ReachMin": 32, "ReachMax": 32})
    upper["asset"]["PassageConfig"].update({"ReachMin": 32, "ReachMax": 32})

    maze = json.loads(json.dumps(surface))
    maze.update({"index": 1, "top_chunk_z": -16, "bottom_chunk_z": -19,
                 "height_chunks": 4})
    maze["asset"].update({"StrateName": "L58 Native Lattice Maze",
                          "GeneratorType": 3, "StrateHeightInChunks": 4})
    maze["asset"].setdefault("MazeParams", {})["BoundarySealThickness"] = 8
    maze["passage_config"]["Connections"] = 1
    maze["passage_config"].update({"ReachMin": 32, "ReachMax": 32})
    maze["asset"]["PassageConfig"].update({"Connections": 1, "ReachMin": 32, "ReachMax": 32})

    lower = json.loads(json.dumps(surface))
    lower.update({"index": 2, "top_chunk_z": -20, "bottom_chunk_z": -23,
                  "height_chunks": 4})
    lower["asset"].update({"StrateName": "L58 Lower Surface", "GeneratorType": 4,
                           "StrateHeightInChunks": 4})
    lower["passage_config"]["Connections"] = 1
    lower["asset"]["PassageConfig"]["Connections"] = 1

    root["total_strates"] = 3
    root["strates"] = [upper, maze, lower]
    # Keep the legacy passage portals proportional to this compact native
    # prototype; the owner world remains at its authored scale.
    root.update({"owner_voxel_size_cm": 6.25,
                 "owner_voxel_size_microns": 62500,
                 "core_voxel_size_cm": 25,
                 "core_voxel_size_microns": 250000,
                 "owner_to_core_length_scale": 0.25})
    args.out.parent.mkdir(parents=True, exist_ok=True)
    args.out.write_text(json.dumps(root, indent=2, sort_keys=True) + "\n",
                        encoding="utf-8")
    print(f"[LatticeFixtureBuild] source={args.owner} source_sha256={sha256(args.owner)} "
          f"fixture={args.out} fixture_sha256={sha256(args.out)} "
          "strates=0:TunnelNetwork,1:Maze[4 chunks],2:SurfaceWorld[60 chunks] "
          "owner_input_untouched=true status=PASS")
    return 0


if __name__ == "__main__":
    raise SystemExit(main())