#!/bin/sh

set -ef

prj_dir=$(readlink -f "$(dirname "$0")/../..")
cd "${prj_dir}"

[ -s debian/changelog ]
dpkg-parsechangelog --show-field Source | grep -Eq '^linux'

ch_ver=$(dpkg-parsechangelog --show-field Version)
ch_dist=$(dpkg-parsechangelog --show-field Distribution)

do_idle() {
	nice -n +40 chrt -i 0 ionice -c 3 "$@"
}

v=$1
if [ -z "$v" ] ; then
	v=$(echo "${ch_ver}" | sed -E 's/^\d+://;s/-[^-]+$//')
fi

IFS=. read -r major minor __patch <<-EOF
$v
EOF
[ -n "${minor}" ]
ver_path="v${major}.${minor}"
[ "${minor}" = 0 ] || ver_path="v${major}.x"

tarball_new="linux_${v}.orig.tar"
tarball_new_comp="${tarball_new}.xz"
do_compress() { do_idle xz -1vv "$1" ; }

while ! [ -s "../${tarball_new_comp}" ] ; do

	tarball_path_web="pub/linux/kernel/${ver_path}"
	tarball_path_git="pub/scm/linux/kernel/git/stable/linux.git/snapshot"
	tarball_orig="linux-${v}.tar.xz"
	tarball_fallback="linux-${v}.tar.gz"
	src_dir="linux-${v}"

	d=$(mktemp -d)
	cd "$d/"

	tarball_ok=0

	while [ ${tarball_ok} = 0 ] ; do
		[ -s "${prj_dir}/../${tarball_orig}" ] || break
		tar xf "${prj_dir}/../${tarball_orig}" || break
		tarball_ok=1 ; break
	done

	if [ "${tarball_ok}" = 0 ] ; then
		rm -rf "${src_dir}"

		do_download() { do_idle aria2c -c -V -j 8 -x 4 -s 16 "$@" ; }
		# aria_opts_pxy='--connect-timeout=5 --retry-wait=5 --timeout=30'
		aria_opts_web='--connect-timeout=15 --retry-wait=15 --timeout=240'

		set +e
		while : ; do
			do_download ${aria_opts_web} \
			  "https://cdn.kernel.org/${tarball_path_web}/${tarball_orig}" \
			  "https://kernel.org/${tarball_path_web}/${tarball_orig}" \
			&& break

			do_download ${aria_opts_web} \
			  "https://cdn.kernel.org/${tarball_path_web}/${tarball_fallback}" \
			  "https://kernel.org/${tarball_path_web}/${tarball_fallback}" \
			  "https://git.kernel.org/${tarball_path_git}/${tarball_fallback}" \
			&& break

			true ; break
		done
		set -e

		while [ "${tarball_ok}" = 0 ] ; do
			rm -rf "${src_dir}"

			[ -s "${tarball_orig}" ] || break
			tar xf "${tarball_orig}" || break
			cp -nv "${tarball_orig}" "${prj_dir}/../${tarball_orig}"
			tarball_ok=1 ; break
		done

		while [ "${tarball_ok}" = 0 ] ; do
			rm -rf "${src_dir}"

			[ -s "${tarball_fallback}" ] || break
			tar xf "${tarball_fallback}" || break
			tarball_ok=1 ; break
		done

		rm -f "${tarball_orig}" "${tarball_fallback}"
	fi

	[ "${tarball_ok}" = 1 ] || {
		cd "/"
		rm -rfv "$d"
		exit 1
	}

	list_excluded() {
		local file field
		file="${prj_dir}/debian/copyright"
		field='Files-Excluded'

		[ -s "${file}" ]

		sed -E -n \
		  -e "/^${field}:/,/^\S/{s/^${field}://;p;}" \
		< "${file}" \
		| sed -E \
		  -e '$!{/^.+$/H;d;};x;s/(\s|\n)+/ /g;s/^ //;'
	}

	files_exclude=$(list_excluded)

	for i in ${files_exclude} ; do
		case "$i" in
		*\** | *\?* )
			find "${src_dir}/" -path "${src_dir}/$i" -exec rm -rfv {} +
		;;
		* )
			rm -rfv "${src_dir}/$i"
		;;
		esac
	done

	tar_opts='--blocking-factor=1 --numeric-owner --owner=0 --group=0 --no-xattrs --no-selinux --no-acls'
	find "${src_dir}/" ! -type d -printf '%p\0' | sort -zuV \
	| tar ${tar_opts} --null -T - -cf "${tarball_new}"

	do_compress "${tarball_new}"
	cp -v "${tarball_new_comp}" "${prj_dir}/../"

	cd "${prj_dir}/"

	rm -rf "$d/"
done

if [ -z "$2" ] ; then
	pkg_ver="${v}-1"
	if [ "${pkg_ver}" != "${ch_ver}" ] ; then
		dch -D "${ch_dist}" -v "${pkg_ver}" \
		  'New upstream stable update:' \
		  "https://www.kernel.org/pub/linux/kernel/${ver_path}/ChangeLog-${v}"
	fi
else
	pkg_ver="${v}-$2"
	shift 2
	dch -D "${ch_dist}" -v "${pkg_ver}" "${@:-write reason here}"
fi