"""Optional MusicXML views of finished production roles; never composes."""
from __future__ import annotations

import copy
import json
from pathlib import Path
from fractions import Fraction as F

from generator import model, musicxml_writer, score


def region(document, part):
  measures = document['staves'][0]['measures']
  first = next(i for i, m in enumerate(measures) if m.get('section_label') == part.capitalize() + ' Solo')
  end = next((i for i in range(first + 1, len(measures)) if measures[i].get('section_label')), len(measures))
  return first, end - first


def excerpt(document, first, count):
  result = copy.deepcopy(document)
  staff = result['staves'][0]
  original = staff['measures']
  staff['measures'] = original[first:first + count]
  if not staff['measures']:
    raise ValueError('Empty solo export region')
  notes = [n for m in staff['measures'] for n in score.measure_notes(m)]
  identities = {p['id'] for n in notes for p in n['pitches']}
  events = {n['id'] for n in notes}
  for note in notes:
    for pitch in note['pitches']:
      for key in ('tie_from', 'tie_to'):
        if pitch.get(key) not in identities:
          pitch.pop(key, None)
  staff['tuplets'] = [t for t in staff.get('tuplets', []) if t['start'] in events and t['end'] in events]
  tuplets = {t['id'] for t in staff['tuplets']}
  for note in notes:
    if 'tuplet_ids' in note:
      note['tuplet_ids'] = [i for i in note['tuplet_ids'] if i in tuplets]
  offset = sum((model.fraction(m['duration']) for m in original[:first]), F())
  end = offset + sum((model.fraction(m['duration']) for m in staff['measures']), F())
  for key in ('scale_spans', 'octave_shifts'):
    staff[key] = [{**s, 'start': model.rational(max(offset, model.fraction(s['start'])) - offset),
      'end': model.rational(min(end, model.fraction(s['end'])) - offset)} for s in staff.get(key, [])
      if model.fraction(s['start']) < end and model.fraction(s['end']) > offset]
  model.validate_document(result)
  return result


def write_role(result, path):
  role = result['role']
  if role not in ('acoustic_solo', 'electric_solo'):
    raise ValueError('Solo XML export requires an acoustic_solo or electric_solo role')
  part = role.split('_')[0]
  document = result['document']
  first, count = region(document, part)
  leadin=int(result.get('details',{}).get('allocation',{}).get('lead_in_measures',0))
  first-=leadin;count+=leadin
  selected = excerpt(document, first, count)
  numbers = [m['number'] for m in selected['staves'][0]['measures']]
  for i, measure in enumerate(selected['staves'][0]['measures'], 1):
    measure['number'] = str(i)
  path = Path(path)
  path.parent.mkdir(parents=True, exist_ok=True)
  musicxml_writer.write_musicxml(path, selected, tablature=True)
  return {'role': role, 'file': path.name, 'form_start_measure': 1+leadin,
    'measure_count': count, 'arrangement_measures': numbers,
    'arrangement_start_beat': str(sum((model.fraction(m['duration']) for m in document['staves'][0]['measures'][:first]), F())),
    'pitch_convention': 'guitar-written; explicit octave transposition -1',
    'trace': result['trace'], 'phrase_report': result.get('details', {})}


def export_tree(assets, output=None):
  assets = Path(assets)
  output = Path(output) if output else assets / 'solo_xml'
  output.mkdir(parents=True, exist_ok=True)
  entries = {}
  for path in sorted((assets / 'analysis').glob('*.roles')):
    roles = json.loads(path.read_text())
    for i, part in enumerate(('acoustic', 'electric'), 1):
      name = path.stem.replace('_', '-') + f'-solo{i}.xml'
      entries[path.stem + '/' + part] = write_role(roles[part + '_solo'], output / name)
  manifest = {'version': 1, 'composition_inputs': False, 'solos': entries}
  # Runtime score discovery treats *.json under assets as score documents.
  # Diagnostic manifests deliberately use a non-score extension, like .roles.
  (output / 'manifest.solo').write_text(json.dumps(manifest, sort_keys=True, indent=2) + '\n')
  return manifest