#!/bin/bash

set -euo pipefail

readonly source_dir="${RPM_ARTIFACT_SOURCE_DIR:-$PWD}"
readonly output_dir="${RPM_ARTIFACT_OUTPUT_DIR:-$PWD/rpm-artifacts}"
readonly kernel_devel_package="${RPM_ARTIFACT_KERNEL_DEVEL_PACKAGE:-kernel-devel}"

if ! git -C "${source_dir}" rev-parse --is-inside-work-tree >/dev/null 2>&1; then
	echo "Error: ${source_dir} is not an SCST Git worktree." >&2
	exit 1
fi

if [[ ! -d "${output_dir}" || ! -w "${output_dir}" ]]; then
	echo "Error: ${output_dir} is not a writable output directory." >&2
	exit 1
fi

mapfile -t kernel_releases < <(
	rpm -q --qf '%{VERSION}-%{RELEASE}.%{ARCH}\n' \
		"${kernel_devel_package}" 2>/dev/null | sort -V
)
if [[ ${#kernel_releases[@]} -ne 1 ]]; then
	echo "Error: expected exactly one ${kernel_devel_package} package." >&2
	printf 'Found kernel releases: %s\n' "${kernel_releases[*]:-none}" >&2
	exit 1
fi

readonly kernel_release="${kernel_releases[0]}"
readonly kernel_dir="/usr/src/kernels/${kernel_release}"
if [[ ! -d "${kernel_dir}" ]]; then
	echo "Error: kernel build directory ${kernel_dir} does not exist." >&2
	exit 1
fi

tmp_dir="$(mktemp -d)"
readonly tmp_dir
artifact_stage=""
cleanup() {
	rm -rf -- "${tmp_dir}"
	if [[ -n "${artifact_stage}" ]]; then
		rm -rf -- "${artifact_stage}"
	fi
}
trap cleanup EXIT

readonly build_dir="${tmp_dir}/scst"
readonly rpm_topdir="${tmp_dir}/rpmbuild"
mkdir -p "${build_dir}" "${rpm_topdir}"

git -C "${source_dir}" ls-files -z -- |
	tar --directory="${source_dir}" --null --files-from=- --create --file=- |
	tar --directory="${build_dir}" --extract --file=-

git_commit="${GIT_COMMIT:-$(git -C "${source_dir}" rev-parse --short=12 HEAD)}"
build_number="${BUILD_NUMBER:-$(git -C "${source_dir}" rev-list --count HEAD)}"
revision="${REVISION:-${build_number}.${git_commit}}"
readonly git_commit build_number revision

make -C "${build_dir}" \
	BUILD_NUMBER="${build_number}" \
	GIT_COMMIT="${git_commit}" \
	REVISION="${revision}" \
	KDIR="${kernel_dir}" \
	KVER="${kernel_release}" \
	RPMTOPDIR="${rpm_topdir}" \
	rpm

mapfile -d '' -t rpm_files < <(
	find "${rpm_topdir}/RPMS" "${rpm_topdir}/SRPMS" \
		-type f -name '*.rpm' -print0 | sort -z
)
if [[ ${#rpm_files[@]} -eq 0 ]]; then
	echo "Error: the RPM build produced no packages." >&2
	exit 1
fi
rpm --checksig --nosignature "${rpm_files[@]}"

artifact_stage="$(mktemp -d "${output_dir}/.scst-rpm.XXXXXX")"
cp -a "${rpm_topdir}/RPMS" "${rpm_topdir}/SRPMS" "${artifact_stage}/"
(
	cd "${artifact_stage}"
	find RPMS SRPMS -type f -name '*.rpm' -print0 |
		sort -z | xargs -0 sha256sum >SHA256SUMS
)

rm -rf -- "${output_dir}/RPMS" "${output_dir}/SRPMS"
rm -f -- "${output_dir}/SHA256SUMS"
mv "${artifact_stage}/RPMS" "${artifact_stage}/SRPMS" \
	"${artifact_stage}/SHA256SUMS" "${output_dir}/"
rmdir "${artifact_stage}"
artifact_stage=""

echo "Built SCST RPM packages for kernel ${kernel_release}:"
find "${output_dir}/RPMS" "${output_dir}/SRPMS" \
	-type f -name '*.rpm' -print | sort