Git branch information (as well as status comparing with the remote) in bash prompt

.gitrc

        RED="\[\033[0;31m\]"
     YELLOW="\[\033[0;33m\]"
      GREEN="\[\033[0;32m\]"
       BLUE="\[\033[0;34m\]"
  LIGHT_RED="\[\033[1;31m\]"
LIGHT_GREEN="\[\033[1;32m\]"
      WHITE="\[\033[1;37m\]"
 LIGHT_GRAY="\[\033[0;37m\]"
 COLOR_NONE="\[\e[0m\]"

parse_git_branch() {
  git_status="$(git status 2> /dev/null)"
  branch_pattern="On branch ([^${IFS}]*).*"
  remote_pattern="Your branch is (.*) of"
  diverge_pattern="Your branch and (.*) have diverged"

  pattern="^(.*)working directory clean"
  if [[ ! ${git_status} =~ $pattern ]]; then
    state="${LIGHT_RED}⚡"
  fi

  # add an else if or two here if you want to get more specific
  if [[ ${git_status} =~ ${remote_pattern} ]]; then
    if [ ${BASH_REMATCH[1]} == "ahead" ]; then
      remote="${YELLOW}↑"
    else
      remote="${YELLOW}↓"
    fi
  fi
  if [[ ${git_status} =~ ${diverge_pattern} ]]; then
    remote="${YELLOW}↕"
  fi

  if [[ ${git_status} =~ ${branch_pattern} ]]; then
    branch=${BASH_REMATCH[1]}
    echo " (${branch})${remote}${state}"
  fi

}


function prompt_func() {
    previous_return_value=$?;
    if [ "$TERM" != "linux" -a -z "$EMACS" ]
    then
        TITLEBAR="\[\e]2;\u@\h:\w\a\]"
    else
        TITLEBAR=""
    fi
    prompt="${TITLEBAR}${BLUE}[${YELLOW}\u@\h${RED} \w${GREEN}$(parse_git_branch)${BLUE}]${COLOR_NONE}"
    if test $previous_return_value -eq 0
    then
        PS1="${prompt}${GREEN}\\\$${COLOR_NONE} "
    else
        PS1="${prompt}${LIGHT_RED}\\\$${COLOR_NONE} "
    fi
}

PROMPT_COMMAND=prompt_func