"""Blender headless scene validation (collections and naming).

Usage (from repo root):
  blender -b sensors/finger/r01/source/geometry.blend -P blender/scripts/validate.py -- sensors/finger/r01

Note: this script loads design.yaml with PyYAML. Prefer installing PyYAML into
Blender's Python, or run metadata-only checks via: orisys-design validate <revision>
"""

from __future__ import annotations

import sys
from pathlib import Path

import bpy

try:
    import yaml
except ImportError:
    yaml = None


def _argv_after_double_dash() -> list[str]:
    if "--" not in sys.argv:
        return []
    return sys.argv[sys.argv.index("--") + 1 :]


def _load_design(revision_dir: Path) -> dict:
    if yaml is None:
        raise RuntimeError(
            "PyYAML is not installed in Blender's Python. "
            "Run: orisys-design validate <revision> without --blender, "
            "or pip install PyYAML into Blender's Python."
        )
    with (revision_dir / "design.yaml").open(encoding="utf-8") as handle:
        data = yaml.safe_load(handle)
    if not isinstance(data, dict):
        raise ValueError("design.yaml must be a mapping")
    return data


def main() -> int:
    args = _argv_after_double_dash()
    if not args:
        print("validate.py: pass revision directory after --", file=sys.stderr)
        return 2

    revision_dir = Path(args[0]).resolve()
    try:
        design = _load_design(revision_dir)
    except Exception as exc:
        print(f"ERROR: {exc}", file=sys.stderr)
        return 1

    collections = design.get("collections", {})
    objects = design.get("objects", {})

    errors: list[str] = []
    present = {col.name for col in bpy.data.collections}

    for key, expected_name in collections.items():
        if expected_name not in present:
            errors.append(f"Missing collection {expected_name!r} (design key: {key})")

    for key, expected_name in objects.items():
        obj = bpy.data.objects.get(expected_name)
        if obj is None:
            errors.append(f"Missing object {expected_name!r} (design key: {key})")

    if errors:
        for message in errors:
            print(f"ERROR: {message}", file=sys.stderr)
        print(f"Present collections: {sorted(present)}", file=sys.stderr)
        return 1

    print(f"OK: Blender scene matches conventions for {revision_dir.name}")
    return 0


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