"""The single production entry point for independent phrase composition."""
from fractions import Fraction as F
import time
import dataclasses
from generator import harmony as chords, vocabulary
from generator.scales import timeline, selection
from generator.solo import types, profiles, harmonic, construction, placement, policy

def compose(analysis,measures,part,end,*,scales,sequences,rhythms,initial=None,expressions_enabled=True,start=F()):
  began=time.monotonic()
  choices=selection.select(timeline.read({'measures':measures},initial=initial),timeline.Solo(F(),end-start,part.capitalize()+' Solo'),scales)
  choices=tuple(dataclasses.replace(c,span=dataclasses.replace(c.span,start=c.span.start+start,end=c.span.end+start)) for c in choices)
  for c in choices:
    if c.span.chord and c.scale is None:raise ValueError(f'{part} solo, source measure {c.span.source_measure}, beat {c.span.beat}, {chords.symbol(c.span.chord)}: No exact match within the permitted catalog')
  profile=profiles.for_part(part,analysis);harmony=harmonic.Harmony(choices,profile)
  source=tuple((n.start,n.end,n.pitch) for n in analysis.melody)
  seed=vocabulary.role().get('choice_seed') or policy.stable_rank(part,(source,tuple((c.span.start,c.span.end,c.span.chord) for c in choices),vocabulary.role(part+'_solo'),policy.DEFAULT.composition_version))
  builder=construction.Builder(analysis,measures,harmony,sequences,rhythms,end,seed,expressions_enabled,start=start)
  phrases=builder.compose()
  # Resolve hand-position transitions over the selected whole melody. This
  # cannot reselect pitches, rhythm or another independently generated part.
  raw=tuple(n for p in phrases for n in p.notes)
  placed=placement.place(raw,analysis.tempo,profile=profile) if raw else (0,())
  if placed is None:raise construction.SearchExhausted('selected melody has no complete legal guitar path')
  by_id={n.event_id:n for n in placed[1]}
  phrases=tuple(dataclasses.replace(p,notes=tuple(by_id[n.event_id] for n in p.notes)) for p in phrases)
  result=types.Solo(part,choices,phrases,analysis.tempo,end,{'construction':'source_melodic_phrases','version':policy.DEFAULT.composition_version,
    'construction_seconds':time.monotonic()-began,**builder.timings,'operation_coverage':{k:dict(v) for k,v in builder.coverage.items()},
    'whole_stream_diagnostic':dataclasses.asdict(builder.winner_evaluation),
    'frontiers':builder.frontiers,'completed_candidates':[{'rank':i+1,'evaluation':{'selection_total': str(s.total / (end-start)), 'phrases': [dataclasses.asdict(p.evaluation) for p in s.phrases]},'events':[(str(n.start),str(n.end),n.pitch.number()) for n in s.notes]} for i,s in enumerate(builder.completed)],'rejections':dict(builder.failures),'decisions':builder.decisions,'expressions_enabled':expressions_enabled},profile,start)
  validate(result)
  return result

def validate(solo):
  previous=None
  for note in solo.notes():
    if note.start<solo.start or note.end>solo.end or note.end<=note.start or previous and previous.end>note.start:raise ValueError('overlapping/out-of-bounds sounding event')
    if note.position not in placement.positions(note.pitch.number(),solo.profile):raise ValueError('invalid guitar placement')
    previous=note
  expressions=tuple(c for p in solo.phrases for c in p.expressions)
  checked=harmonic.Harmony(solo.choices).evaluate(solo.notes(),until=solo.end,complete=True,expressions=expressions)
  if not checked.valid:raise ValueError(checked.error)
  cursor=solo.start
  for p in solo.phrases:
    if p.start!=cursor or p.end<=p.start:raise ValueError('phrase coverage gap or overlap')
    cursor=p.end
    valid,error=harmonic.anchors_valid((p.destination,) if p.destination else (),p.notes,p.end,complete=True,closure='closed' if p.ending in ('complete','handoff') else 'open')
    if not valid:raise ValueError(error)
  if cursor!=solo.end:raise ValueError('incomplete solo duration')