require 'digest'

def prompt(*args)
    print(*args)
    gets.chomp
end

WHITESPACE = " \t\u200b\u2006\u2007\u2008\u2009\u200A\u202F\u205F\u3000"

def doit(message, regex, limit = 10)
  return unless limit > 0

  digest = Digest::SHA256.hexdigest message
  if regex.match? digest
    p message
    puts digest
    exit 0
  end

  WHITESPACE.each_char do |ws|
    doit(message + ws, regex, limit - 1)
  end
end

message = prompt "Message: "
hash_regex = Regexp.new(prompt "Digest regex: ")

doit(message, hash_regex)

puts "i give up :("
exit 1