#!/bin/bash

set -e

case "$1" in
	configure)
		# This package replaces /etc/grub.d/10_linux and so
		# this removes the executable bit
		if [ -x /etc/grub.d/10_linux ]; then
			chmod -x /etc/grub.d/10_linux
		fi
		# Update grub to apply above changes
		if [ -e /boot/grub/grub.cfg ] && which update-grub >/dev/null 2>&1; then
			update-grub
		fi
		# If refind is installed or a configuration for refind
		# exists, let's add a lowlatency entry (threadirqs)
		if [ -e /boot/refind_linux.conf ]; then
			if ! grep -qi 'lowlatency' /boot/refind_linux.conf; then
				_rootUuid=$(lsblk -no UUID "$(df -P / | awk 'END{print $1}')");
				_refindWrite="\"Boot with lowlatency options\" \"root=UUID=${_rootUuid} ro quiet splash threadirqs vt.handoff=1\"";
				sed -i "1i ${_refindWrite}" /boot/refind_linux.conf;
			fi
			# Ensure lastest lowlatency kernel is the default for refind, based on timestamp
			_lowLatencyKernels=(/boot/vmlinuz-*-lowlatency)
			touch "${_lowLatencyKernels[-1]}"
		fi
		;;
esac

# Tag to allow some debhelper commands to inject relevant code