#!/usr/bin/env bash

baseUrl="https://kernel.ubuntu.com/~kernel-ppa/mainline/"

# read the current kernel version
currentVersion=$(uname -r | grep -oP [0-9.]+-[0-9]+)
echo "The currently used kernel version is $currentVersion."

# get all version folders, remove the duplicates and move the latest to top
versions="$(curl -s $baseUrl | grep -E v[0-9]+\\.[0-9]+\(\\.[0-9]+\)?\/ -o | sort -u -t . -k1.2,1nr -k2,2nr -k3,3nr)"

# store the first item in a variable
read latest <<< $versions

# find all .deb files for amd64 or all and filter out the ones which contain the current version
amd64Packages="$(curl -s $baseUrl$latest | grep -P linux.+?_\(amd64\|all\).deb -o | sort -u | grep -P \(generic\|all\) | grep -v $currentVersion)"

# create a temp folder, download the deb files and install them
if [ ! -z "$amd64Packages" ]; then
	# let the user confirm the installation
	shouldInstall="y"
	read -p "New kernel found: ${latest/v/}. Shall I install it? (Y/n)? " shouldInstall

	if [ "$shouldInstall" = "n" ]; then
		echo "New kernel $latest was not installed."
		exit
	fi

	targetDir="/tmp/updateKernel/$latest"

	mkdir -p $targetDir
	cd $targetDir

	for package in $amd64Packages; do
		wget $baseUrl$latest$package
	done;

	sudo dpkg -i *.deb
else 
	echo "No new kernel version found."
fi