require 'yaml'
def putsheader(keys)
  output_line = ''
  keys.each do |key|
    output_line = key + "\t"
  end
  output_line << "\n"
end

def putsdata(data_values)
  output_line = ''
  data_values.values.each do |data|
    output_line = data + "\t"
  end
  output_line << "\n"
end

def yml_to_tsv(input, output)
  yaml_data = YAML.load_file(input)
  yaml_keys = yaml_data[1].keys
  write_file = nil
  write_file = File.open(output, 'w') unless output.nil?
  case write_file
  when nil
    puts(putsheader(yaml_keys)) # also put data
    (0...yaml_data.size).each do |line_number|
      puts(putsdata(yaml_data[line_number]))
    end
  else write_file.write(putsheader(yaml_keys))
    (0...yaml_data.size).each do |line_number|
      write_file.write(putsdata(yaml_data[line_number]))
    end
  end
end

input = ARGV[0]
output = ARGV[1]

yml_to_tsv(input, output) unless input.nil?