#!/usr/bin/env zsh
  
  ## setup ##
  
  [[ -o interactive ]] || return #interactive only!
  zmodload zsh/datetime || { print "can't load zsh/datetime"; return } # faster than date()
  autoload -Uz add-zsh-hook || { print "can't add zsh hook!"; return }
  
  (( ${+bgnotify_threshold} )) || bgnotify_threshold=5 #default 10 seconds
  
  
  ## definitions ##

  if ! (type bgnotify_formatted | grep -q 'function'); then ## allow custom function override
    function bgnotify_formatted { ## args: (exit_status, command, elapsed_seconds)
      elapsed="$(( $3 % 60 ))s"
      (( $3 >= 60 )) && elapsed="$((( $3 % 3600) / 60 ))m $elapsed"
      (( $3 >= 3600 )) && elapsed="$(( $3 / 3600 ))h $elapsed"
      [ $1 -eq 0 ] && bgnotify "#win (took $elapsed)" "$2" || bgnotify "#fail (took $elapsed)" "$2"

    }
  fi
  
  currentWindowId () {
    if hash osascript 2>/dev/null; then #osx
      osascript -e 'tell application (path to frontmost application as text) to id of front window' 2&> /dev/null || echo "0"

    elif (hash notify-send 2>/dev/null || hash kdialog 2>/dev/null); then #ubuntu!
      xprop -root 2> /dev/null | awk '/NET_ACTIVE_WINDOW/{print $5;exit} END{exit !$5}' || echo "0"

    else
      echo $EPOCHSECONDS #fallback for windows
    fi
  }

  bgnotify () { ## args: (title, subtitle)

    if hash terminal-notifier 2>/dev/null; then #osx

      [[ "$TERM_PROGRAM" == 'iTerm.app' ]] && term_id='com.googlecode.iterm2';
      [[ "$TERM_PROGRAM" == 'Apple_Terminal' ]] && term_id='com.apple.terminal';
      ## now call terminal-notifier, (hopefully with $term_id!)
      [ -z "$term_id" ] && terminal-notifier -message "$2" -title "$1" >/dev/null ||
      terminal-notifier -message "$2" -title "$1" -activate "$term_id" -sender "$term_id" >/dev/null

    elif hash growlnotify 2>/dev/null; then #osx growl

      growlnotify -m "$1" "$2"

    elif hash notify-send 2>/dev/null; then #ubuntu gnome!

      notify-send "$1" "$2"

    elif hash kdialog 2>/dev/null; then #ubuntu kde!
      kdialog  -title "$1" --passivepopup  "$2" 5

    elif hash notifu 2>/dev/null; then #cygwyn support!
      notifu /m "$2" /p "$1"
    fi
  }
  
  
  ## Zsh hooks ##
  
  bgnotify_begin() {
    bgnotify_timestamp=$EPOCHSECONDS

    bgnotify_lastcmd="$1"

    bgnotify_windowid=$(currentWindowId)
  }
  
  bgnotify_end() {
    didexit=$?
    elapsed=$(( EPOCHSECONDS - bgnotify_timestamp ))
    past_threshold=$(( elapsed >= bgnotify_threshold ))
    if (( bgnotify_timestamp > 0 )) && (( past_threshold )); then
      if [ $(currentWindowId) != "$bgnotify_windowid" ]; then
        print -n "\a"
        bgnotify_formatted "$didexit" "$bgnotify_lastcmd" "$elapsed"
      fi
    fi
    bgnotify_timestamp=0 #reset it to 0!
  }

  ## only enable if a local (non-ssh) connection
  if [ -z "$SSH_CLIENT" ] && [ -z "$SSH_TTY" ]; then
    add-zsh-hook preexec bgnotify_begin
    add-zsh-hook precmd bgnotify_end
  fi