bash prompt and logging of bash history with path/git branch

#!/bin/bash
# Custom bash prompt from: http://www.linuxdoc.org/HOWTO/Bash-Prompt-HOWTO/x848.html
#   termwide prompt with tty number
#      by Giles - created 2 November 98, last tweaked 31 July 2001
#
#     This is a variant on "termwide" that incorporates the tty number.
#

hostnam=$(hostname -s)
usernam=$(whoami)
##temp="$(tty)"
#   Chop off the first five chars of tty (ie /dev/):
##cur_tty="${temp:5}"
unset temp

function prompt_command {
  #   Find the width of the prompt:
  TERMWIDTH=${COLUMNS}

  # Replace home dir with ~. The # prior to ${HOME} restricts the match
  # to the start of the string only.
  TILDEPWD="${PWD/#${HOME}/~}"

  # Git branch name
  gitBRANCH=$(__git_ps1 "[%s]")
  #gitBRANCH=UNKNOWN
  # Fixup for |BISECTING noise that started with git 1.6.5
  gitBRANCH="${gitBRANCH/|BISECTING/}"


  #   Add all the accessories below ...
  local temp="--(${TILDEPWD})---\D{%a %H:%M:%S}--${gitBRANCH}--(${usernam}@${hostnam})--"

  let fillsize=${TERMWIDTH}-${#temp}
  if [ "$fillsize" -gt "0" ]; then
      fill="                                                                                                                                                                                                                                                                                      "
    #   It's theoretically possible someone could need more
      #   dashes than above, but very unlikely!  HOWTO users,
    #   the above should be ONE LINE, it may not cut and
      #   paste properly
    fill="${fill:0:${fillsize}}"
    newPWD="${TILDEPWD}"
  fi

  if [ "$fillsize" -lt "0" ]; then
      fill=""
    let cut=3-${fillsize}
      newPWD="...${TILDEPWD:${cut}}"
  fi

  if [ "$(id -u)" -ne 0 ]; then echo "[$(__git_ps1 "%s")]" `date` `pwd` `history 1` >> ~/.shell.log; fi

  twtty
}

PROMPT_COMMAND=prompt_command

function twtty {
  local NO_COLOR="\[\e[0m\]"

  local BG_BLACK="40;"
  local BG_RED="41;"
  local BG_GREEN="42;"
  local BG_YELLOW="43;"
  local BG_BLUE="44;"
  local BG_MAGENTA="45;"
  local BG_CYAN="46;"
  local BG_WHITE="47;"

  local FG_BLACK="1;30m"
  local FG_RED="1;31m"
  local FG_GREEN="1;32m"
  local FG_YELLOW="1;33m"
  local FG_BLUE="1;34m"
  local FG_MAGENTA="1;35m"
  local FG_CYAN="1;36m"
  local FG_WHITE="1;37m"

  local COLOR1="\[\e[${BG_GREEN}${FG_BLACK}\]"
  local COLOR2="\[\e[${BG_GREEN}${FG_WHITE}\]"

  if [ -z $gitBRANCH ]; then
    COLOR1="\[\e[${BG_WHITE}${FG_BLACK}\]"
    COLOR2="\[\e[${BG_WHITE}${FG_BLACK}\]"
  fi

  case $TERM in
    xterm*|rxvt*)
        if [ -z $gitBRANCH ]; then
          TITLEBAR='\[\e]0;\u@\h: (\w)\007\]'
        else
          TITLEBAR='\[\e]0;\u@\h: (\w) - ${gitBRANCH}\007\]'
        fi
        ;;
    *)
        TITLEBAR=""
        ;;
  esac

# Bugger... TODO: put  a # in as the prompt
export PS1="$TITLEBAR\
${COLOR2}  (\${newPWD})\
${COLOR1}   \D{%a %H:%M:%S}   ${COLOR2}\${gitBRANCH}${COLOR1}   \${fill}\
 (\$usernam@\$hostnam)  ${NO_COLOR}\nLaptop $ "

}