oh-my-zsh/lib/git.zsh

# get the name of the branch we are on
function git_prompt_info() {
  ref=$(git symbolic-ref HEAD 2> /dev/null) || \
  ref=$(git rev-parse --short HEAD 2> /dev/null) || return
  echo "$ZSH_THEME_GIT_PROMPT_PREFIX${ref#refs/heads/}$(parse_git_dirty)$ZSH_THEME_GIT_PROMPT_SUFFIX"
}


# Checks if working tree is dirty
parse_git_dirty() {
  local SUBMODULE_SYNTAX=''
  local GIT_STATUS=''
  local CLEAN_MESSAGE='nothing to commit (working directory clean)'
  if [[ "$(git config --get oh-my-zsh.hide-status)" != "1" ]]; then
    if [[ $POST_1_7_2_GIT -gt 0 ]]; then
          SUBMODULE_SYNTAX="--ignore-submodules=dirty"
    fi
    if [[ "$DISABLE_UNTRACKED_FILES_DIRTY" != "true" ]]; then
        GIT_STATUS=$(git status -s ${SUBMODULE_SYNTAX} 2> /dev/null | tail -n1)
    else
        GIT_STATUS=$(git status -s ${SUBMODULE_SYNTAX} -uno 2> /dev/null | tail -n1)
    fi
    if [[ -n $(git status -s ${SUBMODULE_SYNTAX} -uno  2> /dev/null) ]]; then
      echo "$ZSH_THEME_GIT_PROMPT_DIRTY"
    else
      echo "$ZSH_THEME_GIT_PROMPT_CLEAN"
    fi
  else
    echo "$ZSH_THEME_GIT_PROMPT_CLEAN"
  fi
}

# get the difference between the local and remote branches
git_remote_status() {
    remote=${$(git rev-parse --verify ${hook_com[branch]}@{upstream} --symbolic-full-name 2>/dev/null)/refs\/remotes\/}
    if [[ -n ${remote} ]] ; then
        ahead=$(git rev-list ${hook_com[branch]}@{upstream}..HEAD 2>/dev/null | wc -l)
        behind=$(git rev-list HEAD..${hook_com[branch]}@{upstream} 2>/dev/null | wc -l)

        if [ $ahead -eq 0 ] && [ $behind -gt 0 ]
        then
            echo "$ZSH_THEME_GIT_PROMPT_BEHIND_REMOTE"
        elif [ $ahead -gt 0 ] && [ $behind -eq 0 ]
        then
            echo "$ZSH_THEME_GIT_PROMPT_AHEAD_REMOTE"
        elif [ $ahead -gt 0 ] && [ $behind -gt 0 ]
        then
            echo "$ZSH_THEME_GIT_PROMPT_DIVERGED_REMOTE"
        fi
    fi
}

# Checks if there are commits ahead from remote
function git_prompt_ahead() {
  if $(echo "$(git log origin/$(current_branch)..HEAD 2> /dev/null)" | grep '^commit' &> /dev/null); then
    echo "$ZSH_THEME_GIT_PROMPT_AHEAD"
  fi
}

# Formats prompt string for current git commit short SHA
function git_prompt_short_sha() {
  SHA=$(git rev-parse --short HEAD 2> /dev/null) && echo "$ZSH_THEME_GIT_PROMPT_SHA_BEFORE$SHA$ZSH_THEME_GIT_PROMPT_SHA_AFTER"
}

# Formats prompt string for current git commit long SHA
function git_prompt_long_sha() {
  SHA=$(git rev-parse HEAD 2> /dev/null) && echo "$ZSH_THEME_GIT_PROMPT_SHA_BEFORE$SHA$ZSH_THEME_GIT_PROMPT_SHA_AFTER"
}

# Get the status of the working tree
git_prompt_status() {
  INDEX=$(git status --porcelain -b 2> /dev/null)
  STATUS=""
  if $(echo "$INDEX" | grep -E '^\?\? ' &> /dev/null); then
    STATUS="$ZSH_THEME_GIT_PROMPT_UNTRACKED$STATUS"
  fi
  if $(echo "$INDEX" | grep '^A  ' &> /dev/null); then
    STATUS="$ZSH_THEME_GIT_PROMPT_ADDED$STATUS"
  elif $(echo "$INDEX" | grep '^M  ' &> /dev/null); then
    STATUS="$ZSH_THEME_GIT_PROMPT_ADDED$STATUS"
  fi
  if $(echo "$INDEX" | grep '^ M ' &> /dev/null); then
    STATUS="$ZSH_THEME_GIT_PROMPT_MODIFIED$STATUS"
  elif $(echo "$INDEX" | grep '^AM ' &> /dev/null); then
    STATUS="$ZSH_THEME_GIT_PROMPT_MODIFIED$STATUS"
  elif $(echo "$INDEX" | grep '^ T ' &> /dev/null); then
    STATUS="$ZSH_THEME_GIT_PROMPT_MODIFIED$STATUS"
  fi
  if $(echo "$INDEX" | grep '^R  ' &> /dev/null); then
    STATUS="$ZSH_THEME_GIT_PROMPT_RENAMED$STATUS"
  fi
  if $(echo "$INDEX" | grep '^ D ' &> /dev/null); then
    STATUS="$ZSH_THEME_GIT_PROMPT_DELETED$STATUS"
  elif $(echo "$INDEX" | grep '^D  ' &> /dev/null); then
    STATUS="$ZSH_THEME_GIT_PROMPT_DELETED$STATUS"
  elif $(echo "$INDEX" | grep '^AD ' &> /dev/null); then
    STATUS="$ZSH_THEME_GIT_PROMPT_DELETED$STATUS"
  fi
  if $(git rev-parse --verify refs/stash >/dev/null 2>&1); then
    STATUS="$ZSH_THEME_GIT_PROMPT_STASHED$STATUS"
  fi
  if $(echo "$INDEX" | grep '^UU ' &> /dev/null); then
    STATUS="$ZSH_THEME_GIT_PROMPT_UNMERGED$STATUS"
  fi
  if $(echo "$INDEX" | grep '^## .*ahead' &> /dev/null); then
    STATUS="$ZSH_THEME_GIT_PROMPT_AHEAD$STATUS"
  fi
  if $(echo "$INDEX" | grep '^## .*behind' &> /dev/null); then
    STATUS="$ZSH_THEME_GIT_PROMPT_BEHIND$STATUS"
  fi
  if $(echo "$INDEX" | grep '^## .*diverged' &> /dev/null); then
    STATUS="$ZSH_THEME_GIT_PROMPT_DIVERGED$STATUS"
  fi
  echo $STATUS
}

#compare the provided version of git to the version installed and on path
#prints 1 if input version <= installed version
#prints -1 otherwise
function git_compare_version() {
  local INPUT_GIT_VERSION=$1;
  local INSTALLED_GIT_VERSION
  INPUT_GIT_VERSION=(${(s/./)INPUT_GIT_VERSION});
  INSTALLED_GIT_VERSION=($(git --version 2>/dev/null));
  INSTALLED_GIT_VERSION=(${(s/./)INSTALLED_GIT_VERSION[3]});

  for i in {1..3}; do
    if [[ $INSTALLED_GIT_VERSION[$i] -lt $INPUT_GIT_VERSION[$i] ]]; then
      echo -1
      return 0
    fi
  done
  echo 1
}

#this is unlikely to change so make it all statically assigned
POST_1_7_2_GIT=$(git_compare_version "1.7.2")
#clean up the namespace slightly by removing the checker function
unset -f git_compare_version