#!/usr/bin/env python3
"""Snapshot/verify reference sources without writing to the reference workspace."""
import argparse,hashlib,json,sys
from pathlib import Path
p=argparse.ArgumentParser(description=__doc__)
p.add_argument('mode',choices=['snapshot','verify'])
p.add_argument('reference',type=Path)
p.add_argument('manifest',type=Path)
a=p.parse_args();ref=a.reference.resolve();manifest=a.manifest.resolve()
if manifest.is_relative_to(ref):p.error('Manifest must be outside the read-only reference')
suffixes={'.c','.et','.ent','.layer','.conf','.gproj','.meta','.layout','.emat','.md','.py'}
current={str(f.relative_to(ref)):hashlib.sha256(f.read_bytes()).hexdigest() for f in sorted(ref.rglob('*')) if f.is_file() and f.suffix in suffixes and not any(part in {'.git','.agents','.codex','__pycache__'} for part in f.relative_to(ref).parts)}
if a.mode=='snapshot':
 if manifest.exists():p.error('Refusing to overwrite an existing baseline')
 manifest.write_text(json.dumps(current,indent=2)+'\n');print(f'Recorded {len(current)} reference source hashes')
else:
 before=json.loads(manifest.read_text())
 changed=sorted(k for k in before.keys()|current.keys() if before.get(k)!=current.get(k))
 if changed:
  print('Reference changes detected; no files were reverted:');print('\n'.join(changed));sys.exit(1)
 print(f'PASS: {len(current)} reference sources unchanged')