#!/system/bin/sh

check_root()
{
  if [ `id -u` != 0 ]; then
    echo "Must be root to run script!"
    exit 1
  fi
}

mount_partitions()
{
  echo "Mounting partitions..."
  mkdir /mnt/boot
  mount -o rw -t vfat /dev/block/mmcblk0p1 /mnt/boot
}

change_properties()
{
  echo "Changing properties..."
  sed -i 's/hdmi_group=1/hdmi_group=2/' /mnt/boot/config.txt
  sed -i 's/hdmi_mode=4/hdmi_mode=87/' /mnt/boot/config.txt
  sed -i 's/disable_overscan=1/hdmi_cvt=800 480 60 6 0 0 0/' /mnt/boot/config.txt
}

restore_properties()
{
  echo "Restoring properties..."
  sed -i 's/hdmi_group=2/hdmi_group=1/' /mnt/boot/config.txt
  sed -i 's/hdmi_mode=47/hdmi_mode=4/' /mnt/boot/config.txt
  sed -i 's/hdmi_cvt=800 480 60 6 0 0 0/disable_overscan=1/' /mnt/boot/config.txt
}

unmount_partitions()
{
  echo "Unmounting partitions..."
  umount /mnt/boot
  rm -rf /mnt/boot
}

finish()
{
  echo "Done, reboot device!"
  exit 0
}

if [ -z $1 ]; then
  check_root
  mount_partitions
  change_properties
  unmount_partitions
  finish
elif [ $1 == "restore" ]; then
  check_root
  mount_partitions
  restore_properties
  unmount_partitions
  finish
else
  echo "Usage: rpi3-display.sh [restore]"
fi