(zsh) Colorize iTerm2 prompt when connecting to SSH servers

.zshrc

alias sww="iterm_bg_color 30 0 0; ssh web-production; iterm_bg_color 0 0 0"
alias swt="iterm_bg_color 0 20 20; ssh web-test; iterm_bg_color 0 0 0"

function iterm_bg_color() {
  local tty=$(tty)
  osascript -e "
    tell application \"iTerm\"
      repeat with theTerminal in terminals
        tell theTerminal
          try
            tell session id \"$tty\"
              set background color to {(($1 * 257)), (($2 * 257)), (($3 * 257))} as RGB color
            end tell
          on error errmesg number errn
          end try
        end tell
      end repeat
    end tell"
}