"""Role cache persistence; cache identity never supplies musical randomness."""
import json

import generator.cache
import generator.fretboard
import generator.validation

ENTRYPOINTS = ('generator.composition',)

def code_key():
  return generator.cache.fingerprint(generator.cache.source_identity(ENTRYPOINTS))

def restore(path, key):
  if path is None or not path.is_file() or path.is_symlink():
    return None
  try:
    entry = json.loads(path.read_text())
    value = entry['result']
    if entry['key'] == key and entry['digest'] == generator.cache.fingerprint(value):
      generator.validation.validate_document(value['document'])
      generator.fretboard.validate_document(value['document'])
      return {**value, 'cache_hit': True}
  except (OSError, ValueError, KeyError, TypeError):
    pass
  return None

def store(path, key, value):
  if path is not None:
    generator.cache.write_json(path, {'key': key, 'digest': generator.cache.fingerprint(value), 'result': value})