snake_case

#!/usr/bin/env ruby
# snake_case by tlehman at 1404767579

def get_input
  input = nil

  input = (ARGV.count == 1) ? ARGV.first : ARGV.join(' ')

  if ARGV.empty?
    input = STDIN.read
  end

  input.strip.gsub(/[,]/, '').gsub(/\n/, '')
end

def camel_case?(str)
  /^([A-Z][a-z]*)+$/ =~ str
end

def split_camel_case(camel_case_string)
  camel_case_string.split(/(?<=[a-z])(?=[A-Z])/).to_a
end

def split(str)
  return split_camel_case(str) if camel_case?(str)

  return [str] if str.gsub(/\s/,'') == str

  str.split(/[\s_-]+/).flat_map { |s| split(s) }
end

def format_snake_case(str)
  str.split(/(\s+|)/).select{|s|s.length>0}.join("_").downcase
end

def snakify(words)
  words.map(&:downcase).join("_")
end

# (strip whitespace) => (detect form) => (split into parts) => (downcase & join)

puts snakify(split(get_input))