Setting color on git status in bash prompt

I'm trying to set my bash prompt to with the following script. Everything works, but the part where I print out the branch name in a Git repository and the status of the branch in color. The colors are somewhat arbitrary, but needless to say it would be red if any files are uncommitted, or yellow if files are unstaged, and green for anything else. It's printing out the part i want in white thought. When I run the part of the script where, towards the end, I define $branchStyle individually, it works, but its not within here. What am I doing wrong?

prompt_git() {
  local s=""
  local branchName=""

  # check if the current directory is in a git repository
  if [ $(git rev-parse --is-inside-work-tree &>/dev/null; printf "%s" $?) == 0 ]; then

      # check if the current directory is in .git before running git checks
      if [ "$(git rev-parse --is-inside-git-dir 2> /dev/null)" == "false" ]; then

          # ensure index is up to date
          git update-index --really-refresh  -q &>/dev/null

          # check for uncommitted changes in the index
          if ! $(git diff --quiet --ignore-submodules --cached); then
              s="$s+";
          fi

          # check for unstaged changes
          if ! $(git diff-files --quiet --ignore-submodules --); then
              s="$s!";
          fi

          # check for untracked files
          if [ -n "$(git ls-files --others --exclude-standard)" ]; then
              s="$s?";
          fi

          # check for stashed files
          if $(git rev-parse --verify refs/stash &>/dev/null); then
              s="$s$";
          fi

      fi

      # get the short symbolic ref
      # if HEAD isn't a symbolic ref, get the short SHA
      # otherwise, just give up
      branchName="$(git symbolic-ref --quiet --short HEAD 2> /dev/null || \
                  git rev-parse --short HEAD 2> /dev/null || \
                  printf "(unknown)")"

      [ -n "$s" ] && s=" [$s]"

      printf "%s" "$1$branchName$s"
  else
      return
  fi
}

set_prompts() {

    local bold=$(tput bold)
    local reset=$(tput sgr0)
    local base05=$(tput setaf 188) # light grey
    local base08=$(tput setaf 210) # red
    local base0A=$(tput setaf 221) # yellow
    local base0B=$(tput setaf 114) # green

    if git rev-parse --git-dir >/dev/null 2>&1; then
        # check for uncommitted changes in the index
        if ! git diff-index --quiet --cached HEAD --ignore-submodules -- >&2; then
            branchStyle=$base08
        # check for unstaged changes
        elif ! git diff-files --quiet --ignore-submodules -- >&2; then
            branchStyle=$base0A
        else
            branchStyle=$base0B
        fi
    fi

    PS1+="\$(prompt_git \"$bold$base05 on $branchStyle\")" # git repository details

    export PS1
}

set_prompts
unset set_prompts