# Copyright 2020-2024 Gentoo Authors, projectmoon
# Distributed under the terms of the GNU General Public License v2

EAPI=8

inherit kernel-build verify-sig

BASE_VER="$(ver_cut 1).$(ver_cut 2).$(ver_cut 3)"
RESTRICT="mirror"

GENPATCHES_P=genpatches-${PV%.*}-$(( ${PV##*.} + 8 ))
CONFIG_VER=6.6.12-gentoo
GENTOO_CONFIG_VER=g14

DESCRIPTION="GNU Linux-libre kernel built from upstream sources"
HOMEPAGE="https://www.fsfla.org/ikiwiki/selibre/linux-libre/"
SRC_URI+="
	https://git.agnos.is/projectmoon/projectmoon-overlay-files/media/branch/main/sys-kernel/libre-kernel/linux-libre-${BASE_VER}-gnu.tar.xz
	https://linux-libre.fsfla.org/pub/linux-libre/releases/${BASE_VER}-gnu/linux-libre-${BASE_VER}-gnu.tar.xz
	https://dev.gentoo.org/~mpagano/dist/genpatches/${GENPATCHES_P}.base.tar.xz
	https://dev.gentoo.org/~mpagano/dist/genpatches/${GENPATCHES_P}.extras.tar.xz
	https://github.com/projg2/gentoo-kernel-config/archive/${GENTOO_CONFIG_VER}.tar.gz
		-> gentoo-kernel-config-${GENTOO_CONFIG_VER}.tar.gz
	verify-sig? (
		https://git.agnos.is/projectmoon/projectmoon-overlay-files/media/branch/main/sys-kernel/libre-kernel/linux-libre-${BASE_VER}-gnu.tar.xz.sign
		https://linux-libre.fsfla.org/pub/linux-libre/releases/${BASE_VER}-gnu/linux-libre-${BASE_VER}-gnu.tar.xz.sign
	)
	amd64? (
		https://raw.githubusercontent.com/projg2/fedora-kernel-config-for-gentoo/${CONFIG_VER}/kernel-x86_64-fedora.config
			-> kernel-x86_64-fedora.config.${CONFIG_VER}
	)
"

# Workdir is named linux-PV.
MY_P=linux-${PV}
S=${WORKDIR}/${MY_P}

LICENSE="GPL-2"
KEYWORDS="amd64"
IUSE="debug +gentoo"

BDEPEND="
	debug? ( dev-util/pahole )
	verify-sig? ( sec-keys/openpgp-keys-linux-libre )
"
PDEPEND="
	>=virtual/dist-kernel-${PV}
"

VERIFY_SIG_OPENPGP_KEY_PATH=${BROOT}/usr/share/openpgp-keys/linux-libre.asc

pkg_pretend() {
	if has_version -d sys-kernel/linux-firmware[redistributable]; then
		ewarn "sys-kernel/linux-firmware was found installed on your system,"
		ewarn "but it is configured to install non-Free firmware files."
		ewarn "The non-Free firmware files may be required for some hardware"
		ewarn "work. The Linux-libre kernel cannot load non-Free firmware."
		ewarn "To install only the Free firmware, set the -redistributable"
		ewarn "USE flag on sys-kernel/linux-firmware."

		if use initramfs; then
			elog
			elog "If you decide to change or remove linux-firmware later, you"
			elog "can rebuild the initramfs via issuing a command equivalent to:"
			elog
			elog "    emerge --config ${CATEGORY}/${PN}:${SLOT}"
		fi
	else
		if ! has_version -d sys-kernel/linux-firmware; then
			ewarn "sys-kernel/linux-firmware[-redistributable] not found installed"
			ewarn "on your system. This package provides various firmware files that"
			ewarn "may be needed for your hardware to work.  If in doubt, it is recommended"
			ewarn "to pause or abort the build process and install it before"
			ewarn "resuming."

			if use initramfs; then
				elog
				elog "If you decide to install linux-firmware later, you can rebuild"
				elog "the initramfs via issuing a command equivalent to:"
				elog
				elog "    emerge --config ${CATEGORY}/${PN}:${SLOT}"
			fi
		fi
	fi
}

src_unpack() {
	if use verify-sig; then
		FILE="${DISTDIR}"/linux-libre-${PV}-gnu.tar.xz
		SIGFILE="${DISTDIR}"/linux-libre-${PV}-gnu.tar.xz.sign
		verify-sig_verify_detached $FILE $SIGFILE
	fi

	default
}

src_prepare() {
	local PATCHES
	if use gentoo; then
		# Fiters out the kernel incremental version upgrade patches,
		# leaving only the Gentoo bug fix/functionality changes. The
		# regex removes any patches starting with 10XX to 14XX.
		MY_PATCHES=$(find "${WORKDIR}"/*.patch -printf "%f\n" | grep -v -E -e '^1[01234][[:digit:]][[:digit:]]_.+.patch')
		PATCHES=$(echo "$MY_PATCHES" | sed 's|^|'"${WORKDIR}/"'|g')
	else
		# If no patches are to be applied, apply only the config changes
		# for a Gentoo installation, as this does not change any actual
		# Kernel functionality.
		PATCHES="${WORKDIR}/4567_distro-Gentoo-Kconfig.patch"
	fi

	default

	local biendian=false

	# prepare the default config
	case ${ARCH} in
		amd64)
			cp "${DISTDIR}/kernel-x86_64-fedora.config.${CONFIG_VER}" .config || die
			;;
		*)
			die "Unsupported arch ${ARCH}"
			;;
	esac

	sed -i 's/EXTRAVERSION = -gnu/EXTRAVERSION = /' "${S}"/Makefile || \
		die 'could not remove EXTRAVERSION'

	local myversion="-gnu-dist"
	echo "CONFIG_LOCALVERSION=\"${myversion}\"" > "${T}"/version.config || die
	local dist_conf_path="${WORKDIR}/gentoo-kernel-config-${GENTOO_CONFIG_VER}"

	local merge_configs=(
		"${T}"/version.config
		"${dist_conf_path}"/base.config
	)
	use debug || merge_configs+=(
		"${dist_conf_path}"/no-debug.config
	)

	# this covers ppc64 and aarch64_be only for now
	if [[ ${biendian} == true && $(tc-endian) == big ]]; then
		merge_configs+=( "${dist_conf_path}/big-endian.config" )
	fi

	kernel-build_merge_configs "${merge_configs[@]}"
}