ps1_git.sh

# git repo status in prompt functions
# ripped from <https://github.com/twolfson/sexy-bash-prompt/blob/master/.bash_prompt>
# with small changes
#
function _get_git_branch() {
  # On branches, this will return the branch name
  # On non-branches, (no branch)
  _REF="$(git symbolic-ref HEAD 2> /dev/null | sed -e 's/refs\/heads\///')"
  if [[ $_REF != "" ]]; then
    echo $_REF
  else
    echo "(no branch)"
  fi
}

function _is_branch1_behind_branch2 () {
  # $ git log origin/master..master -1
  # commit 4a633f715caf26f6e9495198f89bba20f3402a32
  # Author: Todd Wolfson <[email protected]>
  # Date:   Sun Jul 7 22:12:17 2013 -0700
  #
  #     Unsynced commit

  # Find the first log (if any) that is in branch1 but not branch2
  _FIRST_LOG="$(git log $1..$2 -1 2> /dev/null)"

  # Exit with 0 if there is a first log, 1 if there is not
  [[ -n $_FIRST_LOG ]]
}

function _branch_exists () {
  # List remote branches           | # Find our branch and exit with 0 or 1 if found/not found
  git branch --remote 2> /dev/null | grep --quiet "$1"
}

function _parse_git_ahead () {
  # Grab the local and remote branch
  _BRANCH="$(_get_git_branch)"
  _REMOTE_BRANCH=origin/"$_BRANCH"

  # $ git log origin/master..master
  # commit 4a633f715caf26f6e9495198f89bba20f3402a32
  # Author: Todd Wolfson <[email protected]>
  # Date:   Sun Jul 7 22:12:17 2013 -0700
  #
  #     Unsynced commit

  # If the remote branch is behind the local branch
  # or it has not been merged into origin (remote branch doesn't exist)
  if (_is_branch1_behind_branch2 "$_REMOTE_BRANCH" "$_BRANCH" ||
      ! _branch_exists "$_REMOTE_BRANCH"); then
    # echo our character
    echo 1
  fi
}

function _parse_git_behind () {
  # Grab the branch
  _BRANCH="$(_get_git_branch)"
  _REMOTE_BRANCH=origin/"$_BRANCH"

  # $ git log master..origin/master
  # commit 4a633f715caf26f6e9495198f89bba20f3402a32
  # Author: Todd Wolfson <[email protected]>
  # Date:   Sun Jul 7 22:12:17 2013 -0700
  #
  #     Unsynced commit

  # If the local branch is behind the remote branch
  if _is_branch1_behind_branch2 "$_BRANCH" "$_REMOTE_BRANCH"; then
    # echo our character
    echo 1
  fi
}

function _parse_git_dirty () {
  # ?? file.txt # Unstaged new files
  # A  file.txt # Staged new files
  #  M file.txt # Unstaged modified files
  # M  file.txt # Staged modified files
  #  D file.txt # Unstaged deleted files
  # D  file.txt # Staged deleted files

  # If the git status has *any* changes (i.e. dirty)
  if [[ -n "$(git status --porcelain 2> /dev/null)" ]]; then
    # echo our character
    echo 1
  fi
}

function _is_on_git() {
  git rev-parse 2> /dev/null
}

function _get_git_status() {
  # Grab the git dirty and git behind
  _DIRTY_BRANCH="$(_parse_git_dirty)"
  _BRANCH_AHEAD="$(_parse_git_ahead)"
  _BRANCH_BEHIND="$(_parse_git_behind)"

  # Iterate through all the cases and if it matches, then echo
  if [[ $_DIRTY_BRANCH == 1 && $_BRANCH_AHEAD == 1 && $_BRANCH_BEHIND == 1 ]]; then
    echo "⬢ "
  elif [[ $_DIRTY_BRANCH == 1 && $_BRANCH_AHEAD == 1 ]]; then
    echo "▲ "
  elif [[ $_DIRTY_BRANCH == 1 && $_BRANCH_BEHIND == 1 ]]; then
    echo "▼ "
  elif [[ $_BRANCH_AHEAD == 1 && $_BRANCH_BEHIND == 1 ]]; then
    echo "⬡ "
  elif [[ $_BRANCH_AHEAD == 1 ]]; then
    echo "△ "
  elif [[ $_BRANCH_BEHIND == 1 ]]; then
    echo "▽ "
  elif [[ $_DIRTY_BRANCH == 1 ]]; then
    echo "* "
  fi
}

function _get_git_info () {
  # Grab the branch
  _BRANCH="$(_get_git_branch)"

  _REPO_NAME="$(basename `git rev-parse --show-toplevel`)"

  # If there are any branches
  if [[ $_BRANCH != "" ]]; then
    # Echo the branch
    _OUTPUT=$_BRANCH

    # Add on the git status
    _OUTPUT="$(_get_git_status)"$_OUTPUT

    # Echo our output
    echo -en $"$_YELLOW| $_BLUE$_REPO_NAME$_YELLOW [$_GREEN$_OUTPUT$_YELLOW]$_NO_COLOR "
  fi
}

# all those pretty colours
#
PS1=$"${_PURPLE}\n    ʎ \$(_is_on_git && \
  echo -n \"\$(_get_git_info)\" && \
  echo -n \"\" )${_NO_COLOR}"