#!/usr/bin/env ruby
 
ALLOWED_LENGTHS = [2, 4, 8, 16].freeze
Note = Struct.new(:length, :is_pause)
 
Dir.chdir(File.dirname(__FILE__))
 
print "Ausgabedatei festlegen: "
path = $stdin.gets.chomp
 
puts "Ausgabe erfolgt nach #{File.expand_path(path)}."
 
notes = []
loop do
  print "Notenwert eingeben ('ENDE' beendet die Eingabe): "
  line = $stdin.gets.chomp
 
  break if line.downcase.strip == "ende"
 
  note = Note.new
  note.is_pause = line.start_with?("_")
 
  length = line.sub("_", "").to_i
  fail "Ungueltige Notenlaenge: #{length}" unless ALLOWED_LENGTHS.include?( _
    length)
 
  note.length = length
  notes << note
end
 
File.open(path, "w") do |file|
  notes.permutation.each do |perm_ary|
    perm_ary.each_with_index do |note, i|
      file.print " " unless i == 0
      file.print "_" if note.is_pause
      file.print note.length
    end
    file.puts
  end
end
 
puts "Fertig."
sleep 5