"""Accepted, paired pitch/rhythm examples; production uses contextual profiles."""
from __future__ import annotations

import dataclasses
import fractions
import hashlib
import json
import pathlib

import generator.harmony
import generator.model
import generator.solo.types as types

F = fractions.Fraction

@dataclasses.dataclass(frozen=True)
class ReferencePhrase:
  id: str
  version: str
  notes: tuple[types.Note, ...]
  decorated: tuple[types.Note, ...]
  duration: F
  tonic: int
  harmony: tuple[tuple[F, str], ...]
  features: tuple[tuple[str, F, F], ...]
  runs: tuple[tuple[F, F], ...]
  acceptance: str
  development: tuple[tuple[str, F, F, tuple[int, ...]], ...] = ()
  def windows(self):
    # Windows retain their parent and context; they are not separate approvals.
    result = []
    for length in (F(8), F(16)):
      for start in range(0, int(self.duration), int(length)):
        end = min(self.duration, start + length)
        selected = tuple(dataclasses.replace(n, start=n.start - start, end=n.end - start) for n in self.notes if start <= n.start and n.end <= end)
        if len(selected) >= 2:
          chords = tuple(chord for time, chord in self.harmony if start <= time < end)
          result.append(types.Motif(f'{self.id}:{start}:{end}', selected, end - start, chords, 'accepted reference profile'))
    return tuple(result)

def read(path):
  raw = path.read_bytes()
  data = json.loads(raw)
  if data['pitch_convention'] != 'sounding' or not data.get('acceptance'):
    raise ValueError(f'{path}: reference requires sounding pitches and explicit acceptance provenance')

  def notes(variant):
    result, cursor = [], F()
    for i, event in enumerate(data['variants'][variant]['events']):
      start, duration = F(event['onset_beats']), F(event['duration_beats'])
      if start != cursor or duration <= 0:
        raise ValueError(f'{path}: reference events must fill exact sequential time')
      cursor = start + duration
      if event['pitch'] is None:
        continue
      name = event['pitch']
      pitch = types.Pitch(name[0].lower(), F(1 if '#' in name else -1 if 'b' in name else 0), int(name[-1]))
      if pitch.number() != event['midi_pitch']:
        raise ValueError(f'{path}: inconsistent sounding pitch {name}')
      result.append(types.Note(start, cursor, pitch, (data['id'],), event_id=f'{variant}_{i}'))
    return tuple(result), cursor

  plain, duration = notes('lead_theme')
  decorated, other_duration = notes('lead_with_runs')
  if duration != other_duration or len(plain) != data['variants']['lead_theme']['attacks'] or len(decorated) != data['variants']['lead_with_runs']['attacks']:
    raise ValueError(f'{path}: inconsistent reference variants')
  tonic = generator.model.parse_pitch_name(data['tonic'])
  number = int(generator.model.NATURAL[tonic['letter']] + generator.model.alteration(tonic['alter']))
  harmony = tuple((F(4 * (h['bar'] - 1)), h['chord']) for h in data['harmony'])
  for _, chord in harmony:
    generator.harmony.parse_symbol(chord)
  return ReferencePhrase(data['id'], hashlib.sha256(raw).hexdigest(), plain, decorated, duration, number, harmony,
    tuple((f['id'], F(f['start']), F(f['end'])) for f in data['features']), tuple((F(w['start']), F(w['end'])) for w in data['run_windows']), data['acceptance'],
    tuple((d['role'], F(d['start']), F(d['end']), tuple(d.get('degrees', ()))) for d in data.get('development', ())))

def load_library(root: pathlib.Path):
  return tuple(read(path) for path in sorted(root.glob('*.json')))

from generator.solo.features import identifying_features, feature_error, relationship