#!/bin/bash
#
# gl-select: select active gl/glx libraries/extensions
#

infoUsage() {
  echo "Usage: $(basename $0) [ status | use [xorg|nvidia|ati] ]"
  exit 0
}

infoMissing() {
  echo "One or more of the non-xorg gl/glx backup files are missing."
  echo "This means either you're not using a non-xorg gl/glx setup, in which"
  echo "case nothing needs to be changed, OR your xorg backups are missing,"
  echo "which can be solved by reinstalling xorg-server and mesa3d packages."
  echo
  echo "Files:"
  getMissBackups
  exit 1
}

infoRevert() {
  echo "You appear to already be using a non-xorg gl/glx setup. Check that by"
  echo "using 'gl-select status', OR if the one selected isn't the correct one,"
  echo "revert to xorg and then select the correct new setup using:"
  echo "'gl-select use xorg; gl-select use <new gl/glx>'."
  echo
  echo "Files:"
  getExistBackups
  exit 1
}

infoOldStuff() {
  echo "You appear to be using a non-xorg gl/glx setup. You should revert your"
  echo "selection to xorg and then select the correct new setup, but seems you"
  echo "are using the old stuff setup due to gl-select 1.3, so you need to use"
  echo "something like:"
  echo "'gl-select use xorg --old-stuff; gl-select use <new gl/glx>'."
  exit 1
}

checkInstalled() {
  # checks either a single port or list of ports
  local notInstalled=1
  for arg in $@; do
    if [ -d "/var/lib/pkg/DB/$arg" ]; then
      notInstalled=0
    fi
  done
  if [ $notInstalled -eq 1 ]; then
    if [ $# -eq 1 ]; then
      echo "$arg isn't installed!"
    else
      echo "None of the following ports are installed! (one is required)"
      for i in $@; do echo "  $i"; done
    fi
    exit 1
  fi
}

getMissBackups() {
  # get missing xorg backup'ed files
  for b in $BACKUPS; do if [ ! -f $b ]; then echo $b; fi; done
}

getExistBackups() {
  # get existing xorg backup'ed files
  for b in $BACKUPS; do if [ -f $b ]; then echo $b; fi; done
}

doGLsymlinks() {
  [ ! -L /usr/lib/libGL.so.1 ] && ln -sf libGL.so.1.2 /usr/lib/libGL.so.1
  [ ! -L /usr/lib/libGL.so ] && ln -sf libGL.so.1 /usr/lib/libGL.so
  return 0
}

doStatus() {
  # check which selection its being used
  local file=$(file -h /usr/lib/libGL.so.1.2.0 | awk '{ if (/symbolic link/) print $5; else print $1; }' | sed 's|:||')
  case $file in
    *libGL.so.1.2.0) echo "* xorg gl/glx is selected" ;;
    *libGL_so_1_2_nvidia) echo "* nvidia gl/glx is selected" ;;
    *libGL_so_1_2_ati) echo "* ati gl/glx is selected" ;;
    *) echo "unsupported: $file"; infoOldStuff ;;
  esac
}

doUse() {
  # perform the selection for the following supported gl/glx setups
  local selection=$1
  local options=$2
  [ -z "$selection" ] && infoUsage
  case $selection in
    "xorg")
      [ "$options" == "--old-stuff" ] && oldStuff
      # check for missing xorg backup'ed files
      local mbackups="$(getMissBackups)"
      [ ! -z "$mbackups" ] && infoMissing $mbackups
      # switch to xorg stuff
      (
      # libglx
      rm -f /usr/lib/xorg/modules/extensions/libglx.so
      mv /usr/lib/xorg/modules/extensions/libglx{_so,.so}
      # libGL
      rm -f usr/lib/libGL.so.1.2.0
      mv /usr/lib/libGL{_so_1_2,.so.1.2.0}
      doGLsymlinks
      ) && echo "* xorg gl/glx selected"
      ;;
    "nvidia")
      # is an nvidia port installed?
      checkInstalled nvidia nvidia-sl nvidia-legacy-96xx nvidia-legacy-71xx
      # check for the existence of xorg backups
      local ebackups="$(getExistBackups)"
      [ ! -z "$ebackups" ] && infoRevert $ebackups
      # switch to nvidia stuff
      # conflicting files which ati provides:
      # libglx_so_nvidia, libGL_so_1_2_nvidia
      (
      # libglx
      mv /usr/lib/xorg/modules/extensions/libglx{.so,_so}
      ln -s libglx_so_nvidia /usr/lib/xorg/modules/extensions/libglx.so
      # libGL
      mv /usr/lib/libGL{.so.1.2.0,_so_1_2}
      ln -sf libGL_so_1_2_nvidia /usr/lib/libGL.so.1.2.0
      doGLsymlinks
      ) && echo "* nvidia gl/glx selected"
      ;;
    "ati")
      # is the ati port installed?
      checkInstalled ati
      # check for the existence of xorg backups
      local ebackups="$(getExistBackups)"
      [ ! -z "$ebackups" ] && infoRevert $ebackups
      # switch to ati stuff
      # conflicting files which ati provides:
      # libglx_so_ati, libGL_so_1_2_ati
      (
      # libglx
      mv /usr/lib/xorg/modules/extensions/libglx{.so,_so}
      ln -s libglx_so_ati /usr/lib/xorg/modules/extensions/libglx.so
      # libGL
      mv /usr/lib/libGL{.so.1.2.0,_so_1_2}
      ln -sf libGL_so_1_2_ati /usr/lib/libGL.so.1.2.0
      doGLsymlinks
      ) && echo "* ati gl/glx selected"
      ;;
    *)
      infoUsage
      ;;
  esac
  /sbin/ldconfig > /dev/null 2>&1
}

oldStuff() {
  for f in /usr/lib/xorg/modules/extensions/libglx_so \
           /usr/lib/libGL_so_1_2; do
    [ ! -e $f ] && infoMissing $f
  done
  # move the old xorg backups back into place
  (
  # libglx
  rm -f /usr/lib/xorg/modules/extensions/libglx.so
  mv /usr/lib/xorg/modules/extensions/libglx{_so,.so}
  # libGL
  mv /usr/lib/libGL{_so_1_2,.so.1.2.0}
  rm -f /usr/lib/libGL.so /usr/lib/libGL.so.1
  doGLsymlinks || echo "done"
  ) && echo "* xorg gl/glx selected"
  exit 0
}

# backup files which are also provided by nvidia and ati ports
BACKUPS="
/usr/lib/xorg/modules/extensions/libglx_so
/usr/lib/libGL_so_1_2
"

# check for xorg ports; if they are not installed, why is this script even run?
checkInstalled xorg-server xorg-mesa

case $1 in
  status) doStatus ;;
  use) shift 1; doUse $@ ;;
  *) infoUsage ;;
esac

# End of file
