bash_prompt

# vi: set ft=sh :

red="38;5;1"
light_red="38;5;9"
dark_red="38;5;124"
yellow="38;5;220"
light_yellow="38;5;11"
dark_yellow="38;5;142"
blue="38;5;4"
light_blue="38;5;12"
dark_blue="38;5;25"
green="38;5;34"
light_green="38;5;2"
dark_green="38;5;35"
magenta="38;5;165"
light_magenta="38;5;5"
dark_magenta="38;5;127"
orange="38;5;130"
light_orange="38;5;202"
dark_orange="38;5;94"
white="38;5;7"
black="38;5;0"
gray="38;5;248"
reset="\[\e[0m\]"

function _show_venv_status {
    if [[ -z "$VIRTUAL_ENV" ]]; then
        echo -n ""
    else
        echo -n " \[\033[[${green}m\]$(basename $VIRTUAL_ENV)]${reset}"
    fi
}

function _show_git_status {
  # Get the current git branch and colourize to indicate branch state
  # branch_name+ indicates there are stash(es)
  # branch_name? indicates there are untracked files
  # branch_name! indicates your branches have diverged
  local unknown untracked stash clean ahead behind staged unstaged diverged
  unknown="${dark_blue}"
  untracked="${dark_green}"
  stash="${light_green}"
  clean="${green}"
  ahead="${yellow}"
  behind="${dark_yellow}"
  staged="${light_orange}"
  unstaged="${orange}"
  diverged="${red}"

  branch=$(git rev-parse --abbrev-ref HEAD 2>/dev/null)
  if [ -n "$branch" ]; then
    git_status=$(git status 2> /dev/null)
    # If nothing changes the colour, we can spot unhandled cases.
    colour=$unknown
    if echo $git_status | grep -qe 'Untracked files'; then
      colour=$untracked
      branch="${branch}?"
    fi
    if git stash show &>/dev/null; then
      colour=$stash
      branch="${branch}+"
    fi
    if echo $git_status | grep -qe 'working directory clean'; then
      colour=$clean
    fi
    if echo $git_status | grep -qe 'Your branch is ahead'; then
      colour=$ahead
    fi
    if echo $git_status | grep -qe 'Your branch is behind'; then
      colour=$behind
    fi
    if echo $git_status | grep -qe 'Changes to be committed'; then
      colour=$staged
    fi
    if echo $git_status | grep -qe 'Changed but not updated' \
                               -e 'Changes not staged'; then
      colour=$unstaged
    fi
    if echo $git_status | grep -qe 'Your branch.*diverged'; then
      colour=$diverged
      branch="${branch}!"
    fi
    echo -n " \[\033[${colour}m\](${branch})\[\033[0m\]"
  fi
  return 0
}

function _build_prompt {
  git_status=$(_show_git_status)
  venv_status=$(_show_venv_status)
  PS1="\u@\h${venv_status}${git_status} \w\$ "
  return 0
}
PROMPT_COMMAND="_build_prompt; $PROMPT_COMMAND"