"""
blender_compare_bones.py
Usage: tooling/blender --background --python tooling/blender_compare_bones.py -- <file_a.glb> <file_b.glb>

Compares bone names between two GLB/GLTF files. Reports missing or extra bones.
"""

import sys
import bpy


def get_bones(path: str) -> set:
    bpy.ops.wm.read_factory_settings(use_empty=True)
    bpy.ops.import_scene.gltf(filepath=path)
    for obj in bpy.context.scene.objects:
        if obj.type == 'ARMATURE':
            return {b.name for b in obj.data.bones}
    return set()


if __name__ == "__main__":
    argv = sys.argv
    if "--" not in argv:
        print("Usage: tooling/blender --background --python tooling/blender_compare_bones.py -- <a.glb> <b.glb>")
        sys.exit(1)

    args = argv[argv.index("--") + 1:]
    if len(args) < 2:
        print("ERROR: Need two GLB/GLTF paths.")
        sys.exit(1)

    path_a, path_b = args[0], args[1]

    print(f"Loading A: {path_a}")
    bones_a = get_bones(path_a)
    print(f"A has {len(bones_a)} bones")

    print(f"Loading B: {path_b}")
    bones_b = get_bones(path_b)
    print(f"B has {len(bones_b)} bones")

    only_in_a = bones_a - bones_b
    only_in_b = bones_b - bones_a
    shared = bones_a & bones_b

    print(f"Shared: {len(shared)}")
    if only_in_a:
        print(f"Only in A ({len(only_in_a)}):")
        for name in sorted(only_in_a):
            print(f"  - {name}")
    if only_in_b:
        print(f"Only in B ({len(only_in_b)}):")
        for name in sorted(only_in_b):
            print(f"  + {name}")
    if not only_in_a and not only_in_b:
        print("BONE_MATCH=OK")
    else:
        print("BONE_MATCH=MISMATCH")