#!/usr/bin/env python3
"""Generate a native Blender material node fixture for one WBV2 reader batch."""

from __future__ import annotations

import argparse
import json
import subprocess
from pathlib import Path


ROOT = Path(__file__).resolve().parents[1]
NATIVE_BLENDER = ROOT / "build_blender_native/bin/blender"


def main() -> int:
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("--output", required=True)
    parser.add_argument("--node", action="append", required=True)
    args = parser.parse_args()
    output = Path(args.output)
    if output.is_absolute() or ".." in output.parts or output.suffix != ".blend" or not str(output).startswith("tests/files/web/"):
        parser.error("--output must be a repository-relative .blend path under tests/files/web/")
    nodes = list(dict.fromkeys(args.node))
    if not nodes or any(not node.startswith("ShaderNode") or not node.replace("_", "").isalnum() for node in nodes):
        parser.error("every --node must be a Blender ShaderNode identifier")
    if not NATIVE_BLENDER.is_file():
        raise SystemExit(f"native Blender fixture generator is unavailable: {NATIVE_BLENDER.relative_to(ROOT)}")
    destination = ROOT / output
    destination.parent.mkdir(parents=True, exist_ok=True)
    script = (
        "import bpy\n"
        f"destination = {str(destination)!r}\n"
        f"node_types = {nodes!r}\n"
        "material = bpy.data.materials.new('WBV2 Shader Batch')\n"
        "material.use_nodes = True\n"
        "mesh = bpy.data.meshes.new('WBV2 Shader Mesh')\n"
        "mesh.from_pydata([(-1,-1,0),(1,-1,0),(0,1,0)], [], [(0,1,2)])\n"
        "obj = bpy.data.objects.new('WBV2 Shader Object', mesh)\n"
        "bpy.context.collection.objects.link(obj)\n"
        "obj.data.materials.append(material)\n"
        "tree = material.node_tree\n"
        "tree.nodes.clear()\n"
        "for node_type in node_types:\n"
        "    node = tree.nodes.new(node_type)\n"
        "    node.name = 'WBV2 ' + node_type\n"
        "bpy.ops.wm.save_as_mainfile(filepath=destination)\n"
    )
    result = subprocess.run([str(NATIVE_BLENDER), "--background", "--factory-startup", "--python-expr", script], cwd=ROOT, text=True, capture_output=True, check=False)
    if result.returncode or not destination.is_file():
        raise SystemExit(f"native shader fixture generation failed ({result.returncode}):\n{result.stdout}{result.stderr}")
    print(json.dumps({"status": "PASS", "fixture": output.as_posix(), "nodes": nodes, "bytes": destination.stat().st_size}))
    return 0


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