"""Versioned production vocabulary. This module never reads audition inputs."""
from __future__ import annotations
import contextlib
import contextvars
import dataclasses
import functools
import hashlib
import json
from pathlib import Path
from fractions import Fraction as F

ROOT = Path(__file__).resolve().parents[1] / 'data' / 'composition'
ACTIVE = contextvars.ContextVar('composition_vocabulary', default=None)

def load(root=ROOT):
  # Content, not just the directory, keys memoization. Long-lived individual
  # role builds must observe edited production data without restarting Python.
  names = ('roles', 'harmony', 'lead_ins', 'accompaniment')
  return _load(tuple((name, (Path(root)/(name+'.json')).read_text()) for name in names))

@functools.lru_cache(maxsize=16)
def _load(contents):
  result = {}
  for name, text in contents:
    value = json.loads(text)
    if value.get('version') != 1 or not value.get('provenance') or not value.get('license'):
      raise ValueError(f'{name}: unsupported or unprovenanced production vocabulary')
    entries = value.get('cells', value.get('patterns', value.get('colors', value.get('transformations', []))))
    if len({v['id'] for v in entries}) != len(entries):
      raise ValueError(f'{name}: duplicate vocabulary ID')
    result[name] = value
  return result

@functools.lru_cache(maxsize=1)
def _default():
  return {'data': load(), 'role': '', 'settings': {}}

def current():
  return ACTIVE.get() or _default()

def data(name):
  return current()['data'][name]

def role(name=None):
  active = current()
  name = name or active['role']
  return {**active['data']['roles']['roles'].get(name, {}), **active['settings']}

@contextlib.contextmanager
def using(resources, name, settings=None):
  token = ACTIVE.set({'data': resources, 'role': name, 'settings': settings or {}})
  try:
    yield
  finally:
    ACTIVE.reset(token)

def fingerprint(value):
  return hashlib.sha256(json.dumps(value, sort_keys=True, separators=(',', ':')).encode()).hexdigest()