SHELL = bash

snapshot_uri_base = https://snapshot.debian.org/package

kernel_version          != uname -r
kernel_package_name     != dpkg -S /boot/vmlinuz-$(kernel_version) | sed 's/:.*//'
kernel_package_version  != dpkg-query --showformat='$${Version}\n' -W "$(kernel_package_name)"
kernel_source_package   != dpkg-query --showformat='$${source:Package}\n'  -W "$(kernel_package_name)"
arch                    != dpkg-architecture -q DEB_HOST_ARCH

want_version = ${kernel_package_version}
want_package = linux-image-${arch}
wantvencoded != sed 's/-/%2B/g' <<< "${want_version}"
snapshot_uri = ${snapshot_uri_base}/${kernel_source_package}/${wantvencoded}/\#${want_package}_${want_version}
want_filename = ${want_package}_${want_version}_${arch}.deb

sudo != [ $$(id -u) = 0 ] || echo sudo
dpkg := $(sudo) dpkg

ifeq (,$(shell command -v hxprintlinks))
$(shell $(sudo) apt install html-xml-utils >&2)
endif

ifeq (,$(shell command -v wget))
$(shell $(sudo) apt install wget >&2)
endif

wanted_deb_uri != hxprintlinks "${snapshot_uri}" | \
		hxcopy -i "${snapshot_uri_base}" -o . | \
		hxclean | \
		hxselect -c -s '\n' 'a::attr(href)' | \
		grep -Fw -e '${want_filename}' | \
		head -1

.PHONY: install
install: ${want_filename}
	${dpkg} -E -i $^
	echo "${want_package} hold" | ${dpkg} --set-selections

${want_filename}:
	flock wget-log.txt \
		wget -a wget-log.txt --show-progress -c '${wanted_deb_uri}' -O $@.partial
	mv -T -- $@.partial $@

info:
	: '${want_package}' '${want_version}'
	: '${want_filename}'
	: '${wanted_deb_uri}'
	dpkg -l linux-image\* | grep '^.i '