#!/usr/bin/env python3
"""Inspect GLB file attributes. Usage: python inspect_glb.py model.glb"""

import json, sys, struct

def inspect_glb(path):
    with open(path, 'rb') as f:
        if f.read(4) != b'glTF':
            print("Not a GLB file")
            return
        f.read(8)  # version + length
        chunk_len = struct.unpack('I', f.read(4))[0]
        if f.read(4) != b'JSON':
            print("JSON chunk not found")
            return
        gltf = json.loads(f.read(chunk_len).decode())
    
    print("=" * 50 + "\nGLB FILE INSPECTION\n" + "=" * 50)
    
    for mesh in gltf.get('meshes', []):
        print(f"\n📦 {mesh.get('name', 'Unnamed')}")
        for prim in mesh.get('primitives', []):
            print("  Attributes:")
            for name, idx in prim.get('attributes', {}).items():
                acc = gltf['accessors'][idx]
                print(f"    - {name}: {acc['type']}, count={acc['count']}")
    
    print("\n💡 Name vertex colors as _COLOR2, _COLOR3, etc. in Blender")

if __name__ == "__main__":
    inspect_glb(sys.argv[1]) if len(sys.argv) > 1 else print("Usage: python inspect_glb.py model.glb")