#!/bin/sh

error () # error
{
	echo "$1"
	exit 1
}

kerneldir="$HOME/.local/src"
kernelsite="ftp://www.kernel.org/pub/linux/kernel/v3.x"
currentver="$(uname -r)"
basever="$(uname -r | rev | cut -d. -f1 --complement | rev)"
newver="$(lftp -c "open $kernelsite; ls" | awk '{ print $9 }' | grep "patch-$basever.*\.xz" | sort -V | tail -n1 | sed 's/patch-//' | sed 's/\.xz//')"

if test "$currentver" = "$newver"
then
	echo 'Kernel is up to date.'
else
	echo "Updating kernel to $newver"
	cd "$kerneldir"
	tar -xf "linux-$basever.tar.xz" || exit 1
	mv "linux-$basever" "linux-$newver" || exit 1
	cd "linux-$newver"
	lftp -c "open $kernelsite; get patch-$newver.xz patch-$newver.sign" || exit 1
	unxz "patch-$newver.xz"
	gpg --verify "patch-$newver.sign" || exit 1
	patch -p1 < "patch-$newver" || exit 1
	make mrproper
	zcat /proc/config.gz > .config
	make oldconfig
	echo "cd $PWD"
fi

exit 0