#!/bin/sh

set -e

version="$1"
STATEDIR=/var/lib/initramfs-tools

error()
{
	echo "E: ${1}" > /dev/stderr; exit 1
}

warning()
{
	echo "W: ${1}" > /dev/stderr
}

[ -z "${version}" ] && error "flash-kernel: kernel version is required"

# avoid running multiple times
if [ -n "$DEB_MAINT_PARAMS" ]; then
        eval set -- "$DEB_MAINT_PARAMS"
        if [ -z "$1" ] || [ "$1" != "configure" ]; then
                exit 0
        fi
fi

get_sorted_versions()
{
        version_list=""

        for gsv_x in "${STATEDIR}"/*; do
                gsv_x="$(basename "${gsv_x}")"
                if [ "${gsv_x}" = '*' ]; then
                        return 0
                fi
                worklist=""
                for gsv_i in $version_list; do
                        if dpkg --compare-versions "${gsv_x}" '>' "${gsv_i}"; then
                                worklist="${worklist} ${gsv_x} ${gsv_i}"
                                gsv_x=""
                        else
                                worklist="${worklist} ${gsv_i}"
                        fi
                done
                if [ "${gsv_x}" != "" ]; then
                        worklist="${worklist} ${gsv_x}"
                fi
                version_list="${worklist}"
        done
}

highest_installed_version()
{
        get_sorted_versions
        if [ -z "${version_list}" ]; then
                return
        fi
        set -- ${version_list}
        echo ${1}
}

installed="$(highest_installed_version)"

if dpkg --compare-versions "${installed}" gt "${version}"; then
	warning "There is already a newer kernel installed, the default is now ${version}"
	warning "If you instead want to use the latest installed kernel on your system, run"
	warning "sudo flash-kernel ${installed}"
fi

if flash-kernel --supported >/dev/null 2>&1; then
        flash-kernel ${version}
fi