#!/bin/sh

# Copyright (C) 2015
# Erik Jan Tromp <alphageek@slackware.com>
# Licensed under the GPL v2

# set file lists. verify nvidia fileset every rebuild!
NVIDIA_FILES="/usr/include/GL/gl.h-nvidia
/usr/include/GL/glext.h-nvidia
/usr/include/GL/glx.h-nvidia
/usr/include/GL/glxext.h-nvidia
/usr/lib/libEGL.so-nvidia
/usr/lib/libEGL.so.1-nvidia
/usr/lib/libGL.la-nvidia
/usr/lib/libGL.so-nvidia
/usr/lib/libGL.so.1-nvidia
/usr/lib/xorg/modules/extensions/libglx.so-nvidia"
BASE_FILES=${NVIDIA_FILES//-nvidia}
XORG_FILES=${NVIDIA_FILES//-nvidia/-xorg}

# set file counts
# '-e' seems somewhat unpredictable, hence '-f' & '-h'
BASE_COUNT=0
for BASE_FILE in $BASE_FILES ; do
  [ -f $BASE_FILE -o -h $BASE_FILE ] && BASE_COUNT=$(expr $BASE_COUNT + 1)
done
NVIDIA_COUNT=0
for NVIDIA_FILE in $NVIDIA_FILES ; do
  [ -f $NVIDIA_FILE -o -h $NVIDIA_FILE ] && NVIDIA_COUNT=$(expr $NVIDIA_COUNT + 1)
done
XORG_COUNT=0
for XORG_FILE in $XORG_FILES ; do
  [ -f $XORG_FILE -o -h $XORG_FILE ] && XORG_COUNT=$(expr $XORG_COUNT + 1)
done

# very simplistic. all or nothing:
# files should be in 1 of 2 possible states.
# if they're not, quietly do nothing & keep the user guessing :)
# 1: * & *-nvidia (the 'before' version)
# 2: *, *-nvidia, *-xorg (xorg files replaced by nvidia files)

case "$1" in
  -n|-nvidia|--nvidia)
    if [ $BASE_COUNT == $NVIDIA_COUNT -a $XORG_COUNT == 0 ] ; then
      for BASE_FILE in $BASE_FILES ; do
        if [ -f $BASE_FILE -o -h $BASE_FILE ] \
        && ! [ -f $BASE_FILE-xorg -o -h $BASE_FILE-xorg ] \
        && [ -f $BASE_FILE-nvidia -o -h $BASE_FILE-nvidia ] ; then
          BASE_DIR=$(dirname $BASE_FILE)
          BASE_TIME=$(date -r $BASE_DIR)
          mv -f $BASE_FILE $BASE_FILE-xorg
          cp -a $BASE_FILE-nvidia $BASE_FILE
          touch $BASE_DIR -d "$BASE_TIME"
        fi
      done
    fi
  ;;
  -x|-xorg|--xorg)
    if [ $BASE_COUNT == $NVIDIA_COUNT -a $XORG_COUNT == $NVIDIA_COUNT ] ; then
      for BASE_FILE in $BASE_FILES ; do
        if [ -f $BASE_FILE -o -h $BASE_FILE ] \
        && [ -f $BASE_FILE-xorg -o -h $BASE_FILE-xorg ] ; then
          BASE_DIR=$(dirname $BASE_FILE)
          BASE_TIME=$(date -r $BASE_DIR)
          rm -f $BASE_FILE
          mv -f $BASE_FILE-xorg $BASE_FILE
          touch $BASE_DIR -d "$BASE_TIME"
        fi
      done
    fi
  ;;
  -s|-status|--status)
    if [ $BASE_COUNT == $NVIDIA_COUNT -a $XORG_COUNT == 0 ] ; then
      echo "xorg files are active"
    elif [ $BASE_COUNT == $NVIDIA_COUNT -a $XORG_COUNT == $NVIDIA_COUNT ] ; then
      echo "nvidia files are active"
    else
      echo "congratulations! you managed to break something."
      echo "here's a list of missing files to get you started with diagnostics:"
      for FILE in $BASE_FILES $NVIDIA_FILES $XORG_FILES ; do
        if ! [ -f $FILE -o -h $FILE ] ; then
          echo $FILE
        fi
      done
    fi
  ;;
  *)
    echo "usage: $(basename $0) --nvidia|--xorg|--status"
  ;;
esac