module RedisClient::Config::Common

def build_connection_prelude
  prelude = []
  pass = password
  if protocol == 3
    prelude << if pass
      ["HELLO", "3", "AUTH", username, pass]
    else
      ["HELLO", "3"]
    end
  elsif pass
    prelude << if @username && !@username.empty?
      ["AUTH", @username, pass]
    else
      ["AUTH", pass]
    end
  end
  if @db && @db != 0
    prelude << ["SELECT", @db.to_s]
  end
  # Deep freeze all the strings and commands
  prelude.map! do |commands|
    commands = commands.map { |str| str.frozen? ? str : str.dup.freeze }
    commands.freeze
  end
  prelude.freeze
end