#!/bin/bash

# 3 modes:
# get
# set - absolute
# set - relative

(( DEBUG = ${DEBUG:-0} ))

(( PCIDEVICE = $( sudo reggie_se -D PentiumM -x 2>&1 | grep "Display controller: " | cut -d. -f 1 ) ))

NOARGS=65
PN="$( basename "$0" )"               # Program name
VER="$( echo '$Revision: 0.1 $' | cut -d' ' -f2 )"   # ==> VER=0.1

function Debug () {
    (( DEBUG )) && echo "DEBUG: $@" >&2
    return $(( DEBUG ))
}

Debug "PCIDEVICE is $PCIDEVICE"

# ==> Function to print usage message.
function Usage () {
     cat >&2 <<EOF
$PN - change LCD display brightness, (c) Timo Kosig 2008
Usage: $PN operation [number]

operation:   get -- return current display brightness
       set -- set new display brightness

number:      either absolute, 0 (darkest) - 255 (brightest)
       or relative expressed as +- value, e.g. - 15 or + 20
EOF
    exit $NOARGS
} # Usage

function SetRawBrightness() {
Debug "SetRawBrightness called"
    if [[ $BRIGHTNESS -gt 254 ]]; then
       BRIGHTNESS=255
    elif [[ $BRIGHTNESS -lt 1 ]]; then
       BRIGHTNESS=0
    fi
Debug "BRIGHTNESS is $BRIGHTNESS"
    if (( DEBUG )); then
       sudo reggie_se -D PCI -i $PCIDEVICE -w $BRIGHTNESS -a 0xF4 -B 8 2>&1
    else
       sudo reggie_se -D PCI -i $PCIDEVICE -w $BRIGHTNESS -a 0xF4 -B 8 >/dev/null 2>&1
    fi
Debug "reggie called"
} # SetRawBrightness

function GetBrightness() {
    HEX="$( sudo reggie_se -D PCI -i $PCIDEVICE -r -a 0xF4 -B 8 2>&1 | grep  "Offset" | cut -d"|" -f1 | cut -c 26-30 |  sed -e 's:^0[bBxX]::' | tr '[a-f]' '[A-F]' )"
    return $( echo "ibase=16;$HEX" | bc )
} # GetBrightness

function SetBrightness() {
Debug "SetBrightness called"
    if [[ $# -gt 1 ]]; then
Debug "More than one parameter"
       if [[ $2 -gt 254 || $2 -lt 1 ]]; then
          Usage
          break
       else
          if [[ "$1" == "+" ]]; then
             GetBrightness
             BRIGHTNESS=$(( $? + $2 ))
          else
             GetBrightness
             BRIGHTNESS=$(( $? - $2 ))
          fi
          SetRawBrightness
       fi
    else
Debug "One parameter"
       if [[ $1 -gt 255 || $2 -lt 0 ]]; then
          Usage
          break
       else
          BRIGHTNESS=$1
Debug "BRIGHTNESS is $BRIGHTNESS"
          SetRawBrightness
       fi
    fi
} # SetBrightness


[ $# -eq 0 ] && { Usage; exit 0; }

while [ $# -gt 0 ]; do
    case "$1" in
       get)   GetBrightness
          (( BRIGHTNESS = $? ))
          echo "Brightness: $BRIGHTNESS"
          exit $(( BRIGHTNESS ))
         ;;
       set)   if [[ -z $2 && -z $3 ]]; then
             Usage
          elif [[ -z $3 ]]; then
             SetBrightness $2
          else
             SetBrightness $2 $3
          fi
          break
         ;;
       -h)   Usage         # ==> Help message
         ;;
       *)   Usage         # first number
         ;;
    esac   # ==> More error checking for illegal input might be useful.
    shift
done