#!/usr/bin/env python3
"""Generate a minimal native Blender compositor fixture for one WBV2 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, help="repository-relative .blend output under tests/files/web")
    parser.add_argument("--node", action="append", required=True, help="Blender CompositorNode type identifier")
    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("CompositorNode") or not node.replace("_", "").isalnum() for node in nodes):
        parser.error("every --node must be a Blender CompositorNode 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"
        "scene = bpy.context.scene\n"
        "tree = bpy.data.node_groups.new('WBV2 Compositor Native Batch', 'CompositorNodeTree')\n"
        "scene.compositing_node_group = tree\n"
        "tree.interface.new_socket(name='Image', in_out='OUTPUT', socket_type='NodeSocketColor')\n"
        "source = tree.nodes.new('CompositorNodeRGB')\n"
        "source.name = 'WBV2 Batch Source'\n"
        "output = tree.nodes.new('NodeGroupOutput')\n"
        "output.name = 'WBV2 Batch Output'\n"
        "tree.links.new(source.outputs[0], output.inputs[0])\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 compositor 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())