"""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
import pathlib
import fractions

ROOT = pathlib.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, (pathlib.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') != (3 if name == 'accompaniment' else 1) or not value.get('provenance') or not value.get('license'):
      raise ValueError(f'{name}: unsupported or unprovenanced production vocabulary')
    if name == 'accompaniment':
      if fractions.Fraction(value['grid']) != fractions.Fraction(1, 2):
        raise ValueError('accompaniment requires an eighth-note placement grid')
      for part, lanes in (('electric', ('electric',)), ('acoustic', ('bass', 'upper'))):
        policy = value['instruments'][part]
        if fractions.Fraction(policy['attack_spacing']) < fractions.Fraction(1, 2):
          raise ValueError('accompaniment attacks must be at least an eighth apart')
        for lane in lanes:
          layer = policy['layers'][lane]
          if not 0 <= layer['attacks'][0] <= layer['attacks'][1] <= 3 or not layer['families']:
            raise ValueError('invalid accompaniment attack range or duration families')
          for family in layer['families']:
            durations = policy['families'][family]
            if not durations or any(fractions.Fraction(d) <= 0 for d in durations):
              raise ValueError('accompaniment durations must be positive')
            if part == 'acoustic' and any(fractions.Fraction(d) not in (fractions.Fraction(1, 2), 1) for d in durations):
              raise ValueError('acoustic rhythm uses quarter and eighth notes')
        families = policy['voicing_families']
        if not families.get('provenance'):
          raise ValueError('guitar voicing families require provenance')
        if part == 'electric':
          if set(families['rank']) != {'drop-two', 'close-position', 'compact-open', 'compact-doubled', 'three-note-shell'} or any(type(v) is not int or not 0 <= v <= 2 for v in families['rank'].values()):
            raise ValueError('invalid electric family ranking')
        else:
          if set(map(fractions.Fraction, policy['allowed_durations'])) != {fractions.Fraction(1, 2), fractions.Fraction(1)} or policy['connect_holds']:
            raise ValueError('acoustic rhythm must retain short quarter/eighth attacks')
          for kind in ('triad', 'tetrad', 'extended'):
            if set(families[kind]) != {'5/1', '5/5', '6/1', '6/5'}:
              raise ValueError('acoustic families require root/fifth bass on both bass strings')
            for orders in families[kind].values():
              if not orders or any(len(o) != 3 or set(o) - {'root', 'fifth', 'guide', 'terminal', 'color'} for o in orders):
                raise ValueError('invalid acoustic upper chord order')
      if not 1 <= value['lane_candidates'] <= 64 or not 1 <= value['measure_candidates'] <= 64:
        raise ValueError('accompaniment candidate budgets must be 1–64')
    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 accompaniment(part, resources=None):
  value = (resources or current()['data'])['accompaniment']
  return {**{k: v for k, v in value.items() if k != 'instruments'}, **value['instruments'][part]}

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()