# zshrc/85_git_prompt
#
# Make git information available to the prompt
#
# Copyright © 1994–2008 martin f. krafft <madduck@madduck.net>
# Released under the terms of the Artistic Licence 2.0
#
# Source repository: http://git.madduck.net/v/etc/zsh.git
#
# Shamelessly based on http://glandium.org/blog/?p=170
#

__git_get_repo_root()
{
  local relroot
  relroot="$(git rev-parse --show-cdup 2>/dev/null)" || return 1
  if [ -n "$relroot" ]; then
    readlink -f "$relroot"
  else
    echo $PWD
  fi
}

__git_get_branch()
{
  local ref
  ref=$(git symbolic-ref -q HEAD 2>/dev/null \
     || git-name-rev --name-only HEAD 2>/dev/null)
  echo "${ref#refs/heads/}"
}

__get_root_offsets()
{
  local pwda reporoot loc
  pwda=(${(s:/:)PWD})
  reporoot=(${(s:/:)1})
  echo $((1 - $#reporoot)) $(($#pwda - $#reporoot))
}

__get_prompt_path_components()
{
  local reporoot
  reporoot="$1"

  set -- $(__get_root_offsets "$reporoot")
  if [ "$2" -le 0 ]; then
    echo %~
  else
    echo "%${1}~" "%${2}~"
  fi
}

__vcs_get_repo_type()
{
  if __git_get_repo_root >/dev/null; then
    echo git
  else
    echo NONE
  fi
}

__vcs_set_prompt_variables()
{
  local pre branch post
  local MAXLEN=25

  case "${1:-$(__vcs_get_repo_type)}" in
    git)
      local reporoot="$(__git_get_repo_root)"
      set -- $(__get_prompt_path_components "$reporoot")
      branch="$(__git_get_branch)"
      post="${(%)2}"
      local prelen="$((MAXLEN - $#post - $#branch))"
      [ $prelen -lt 10 ] && prelen=10
      pre="%${prelen}<..<${1}%<<"
      pre="${(%)pre}"
      ;;
    *)
      local p="%${MAXLEN}<..<%~%<<"
      #TODO find a better way so we don't have to nuke $psvar, but since the
      #     %(nv.true.false) check for prompts checks element count, not
      #     content, that's all we get for now
      psvar=("${(%)p}")
      return
  esac

  psvar[1]="$pre"
  psvar[2]="$branch"
  psvar[3]="$post"
}

if ! is_root; then
  # too dangerous to be run as root

  _update_vcs_prompt_vars_if_vcs_ran() {
    local vcs="$(__vcs_get_repo_type)"
    case "$(history $(($HISTCMD - 1)))" in
      # $vcs appeared in last command, so be sure to update
      *${vcs}*) __vcs_set_prompt_variables
    esac
  }
  precmd_functions+=_update_vcs prompt_vars_if_vcs_ran

  _update_vcs_prompt_vars() {
    __vcs_set_prompt_variables
  }
  chpwd_functions+=_update_vcs_prompt_vars
fi

# call it once
_update_vcs_prompt_vars

# vim:ft=zsh