"""Import a browser-produced binary STL in pinned Blender 5.2."""

import hashlib
import json
import sys
from pathlib import Path

import bpy


def sha256_file(path):
    digest = hashlib.sha256()
    with open(path, "rb") as handle:
        for chunk in iter(lambda: handle.read(1024 * 1024), b""):
            digest.update(chunk)
    return digest.hexdigest()


def main(stl_path, report_path):
    stl_path = Path(stl_path).resolve()
    report_path = Path(report_path).resolve()
    bpy.ops.wm.read_factory_settings(use_empty=True)
    result = bpy.ops.wm.stl_import(
        filepath=str(stl_path),
        directory=str(stl_path.parent),
        forward_axis="NEGATIVE_Z",
        up_axis="Y",
        global_scale=1.0,
        use_scene_unit=False,
        use_facet_normal=True,
        use_mesh_validate=True,
    )
    objects = [obj for obj in bpy.context.scene.objects if obj.type == "MESH"]
    if "FINISHED" not in result or not objects:
        raise RuntimeError("Blender Web STL import did not produce a mesh")
    mesh = objects[0].data
    mesh.calc_loop_triangles()
    report = {
        "schemaVersion": 1,
        "operation": "DESKTOP_IMPORT_WEB_STL",
        "sourceSha256": sha256_file(stl_path),
        "sourceBytes": stl_path.stat().st_size,
        "objectCount": len(objects),
        "vertexCount": len(mesh.vertices),
        "polygonCount": len(mesh.polygons),
        "triangleCount": len(mesh.loop_triangles),
        "polygonNormals": [[float(value) for value in polygon.normal] for polygon in mesh.polygons],
    }
    report_path.parent.mkdir(parents=True, exist_ok=True)
    report_path.write_text(json.dumps(report, indent=2, sort_keys=True) + "\n", encoding="utf-8")
    print("stl-web-roundtrip-desktop-imported triangles=%s" % report["triangleCount"])


if __name__ == "__main__":
    args = sys.argv[sys.argv.index("--") + 1 :] if "--" in sys.argv else []
    if len(args) != 2:
        raise SystemExit("usage: blender --background --python check-stl-web-roundtrip.py -- STL REPORT")
    main(args[0], args[1])