Bash shell git coloration

# START : git, coloration

if [ -z "$PS1_ORIG" ]; then
    PS1_ORIG=$PS1
    OLD_PROMPT_COMMAND=$PROMPT_COMMAND
fi

RED='\001\033[31m\002'
YELLOW='\001\033[33m\002'
GREEN='\001\033[32m\002'
BLUE='\001\033[34m\002'
DARK_BLUE='\001\033[36m\002'
COLOR_NONE='\001\033[00m\002'

function parse_git_branch {
    local AHEAD='↑'
    local LATE='↓'
    local DIVERGE='↕'
    local NOT_CLEAN='⚡'

    git rev-parse --git-dir &> /dev/null

    if [ $? != 0 ]; then
        echo "NOT_A_GIT_REPO"
    else
        git_status="$(git status 2> /dev/null)"
        branch_pattern="^# On branch ([^${IFS}]*)"
        remote_pattern="# Your branch is (.*)"
        diverge_pattern="# Your branch and (.*) have diverged"

        if [[ ! ${git_status} =~ "working directory clean" ]]; then
            state="${RED}${NOT_CLEAN}"
        fi

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

        if [[ ${git_status} =~ ${diverge_pattern} ]]; then
            remote="${YELLOW}${DIVERGE}"
        fi

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

function prompt_func() {
    previous_return_value=$?;
    local git_result=$(parse_git_branch)

    if [ "$git_result" == "NOT_A_GIT_REPO" ]; then
        eval ${OLD_PROMPT_COMMAND}
        PS1=$PS1_ORIG
    else
        local GIT_TOPLEVEL=$(git rev-parse --show-toplevel)
        local prompt="${BLUE}[${RED}${PWD/#${GIT_TOPLEVEL%/*}/}${GREEN}${git_result}${BLUE}]${COLOR_NONE}"
        local SEP="➔"

        eval ${OLD_PROMPT_COMMAND} #Set the title value

        if test $previous_return_value -eq 0; then
            PS1="${prompt}${SEP}${COLOR_NONE} "
        else
            PS1="${prompt}${RED}${SEP}${COLOR_NONE} "
        fi
    fi
}

PROMPT_COMMAND=prompt_func

# END : git, coloration