module Music
module Performance

class ScoreSequencer
  def initialize score
    start_nps = NoteTimeConverter.notes_per_second(score.start_tempo,
      score.start_meter.beat_duration)
    @start_usec_per_qnote = MidiUtil.usec_per_qnote(start_nps)
    @parts = ScoreCollator.new(score).collate_parts
    
    # part names should all be strings, because 1) a midi track name needs to
    # be a string and 2) the instrument map used to map part names to MIDI
    # program numbers will use part name strings as keys.
    @parts = Hash[ @parts.map {|k,v| [k.to_s,v] } ]
  end

  def make_midi_seq instr_map = {}
    seq = MIDI::Sequence.new()
    
    # first track for the sequence holds time sig and tempo events
    track0 = MIDI::Track.new(seq)
    seq.tracks << track0
    track0.events << MIDI::Tempo.new(@start_usec_per_qnote)
    track0.events << MIDI::MetaEvent.new(MIDI::META_SEQ_NAME, 'Sequence Name')
    
    channel = 0
    @parts.each do |part_name,part|
      program = 1
      if instr_map.has_key?(part_name)
        program = instr_map[part_name]
      end
      
      pseq = PartSequencer.new(part)
      seq.tracks << pseq.make_midi_track(seq, part_name, channel, seq.ppqn, program)
      channel += 1
    end
    
    return seq
  end
end

end
end