#!/bin/zsh
setopt extendedglob

keepver=()
arch=i586
mydir=$(pwd)
for url ( \
	http://download.opensuse.org/update/11.1/rpm/$arch/ \
	http://download.opensuse.org/repositories/Kernel://HEAD/openSUSE_11.1/$arch/ \
) {
versions=($(wget -nv $url -O-|perl -nE'say if (undef,$_) = m{<a href=("|'"'"'|)kernel-default-(\d.*?-.*?)\.i586\.rpm\1(?:\s.*?)?>}'))
if [[ ! $#versions -gt 0 ]] {
	echo Could not get kernel version, aborting...
	exit 1
}

tempdir=$(mktemp -d)
if [[ $tempdir != /* ]] {
	echo No valid tempdir found, got $tempdir, aborting...
	exit 2
}
trap '
	trap - INT
	cd $tempdir
	rm *(L0)
	cd
	rmdir $tempdir 
	return $((128+$1))
' INT
cd $tempdir
touch $versions
keepver+=$(ls -rv|head -1)
rm *(L0)
cd
rmdir $tempdir
trap - INT
}

echo
echo Newest stable kernel: $keepver[1]
echo Newest head kernel: \  $keepver[2]
echo

echo Getting installed packages list...
inst_kernel_pkgs=($(rpm -qa kernel\*))

keep_stable=(${(M)inst_kernel_pkgs:#*-$keepver[1]})
keep_head=(${(M)inst_kernel_pkgs:#*-$keepver[2]})

error==false
if [[ ! $#keep_stable -gt 0 ]] {
	echo Linux $keepver[1] \(the most recent stable kernel\) is not installed
	error==true
}
if [[ ! $#keep_head -gt 0 ]] {
	echo Linux $keepver[2] \(the most recent head kernel\) is not installed
	error==true
}
if { $error } {
	echo Aborting...
	exit 3
}

inst_kernel_pkg_names=(${keep_stable/-$keepver[1]} ${keep_head/-$keepver[2]})

remove_kernel_pkgs2=($inst_kernel_pkgs)

remove_kernel_pkgs2=(${remove_kernel_pkgs2:#*-$keepver[1]})
remove_kernel_pkgs2=(${remove_kernel_pkgs2:#*-$keepver[2]})

remove_kernel_pkgs=()

typeset -U remove_kernel_pkgs

for pkg_name ($inst_kernel_pkg_names) {
	remove_kernel_pkgs+=(${(M)remove_kernel_pkgs2:#$pkg_name-[[:digit:]].[[:digit:]][^-]#-[^-]#[[:digit:]]})
}

running=$(uname -r)
running2=${running%-*}
running=${running##*-}-${running2%%-*}-$(echo ${running2#*-}|tr - .)

running_removes=(${(M)remove_kernel_pkgs:#kernel-$running.*})

if [[ $#running_removes -gt 0 ]] {
	echo You are not running the most recent kernel, but we want to remove $running
	echo Aborting...
	exit 4
}

if [[ ! $#remove_kernel_pkgs -gt 0 ]] {
	echo No stale kernels found. Nothing to do.
	exit
}

echo Going to remove the following packages:

print -l ${(n)remove_kernel_pkgs}

echo
echo TODO: sudo rpm -ev $remove_kernel_pkgs
echo -n Really uninstall\? \[yn\]
if { read -q } {
	sudo rpm -ev $remove_kernel_pkgs
} \
else {
	echo run $0 again if you want to clean old kernels at any time
}

cd $mydir