#!/usr/bin/env bash
#shellcheck disable=SC2034

# Copyright 2024 Gentoo Authors
# This script is installed by sys-kernel/installkernel, it is executed by the
# traditional installkernel, NOT by systemd's kernel-install. I.e. this plugin
# is run when the systemd USE flag is disabled or SYSTEMD_KERNEL_INSTALL=0 is
# set in the environment.

ver=${1}
img=${2}
basedir=$(dirname "${img}")
initrd=${basedir}/initrd
uki=${basedir}/uki.efi

# familiar helpers, we intentionally don't use Gentoo functions.sh
die() {
	echo -e " ${NOCOLOR-\e[1;31m*\e[0m }${*}" >&2
	exit 1
}

einfo() {
	echo -e " ${NOCOLOR-\e[1;32m*\e[0m }${*}"
}

ewarn() {
	echo -e " ${NOCOLOR-\e[1;33m*\e[0m }${*}"
}

eerror() {
	echo -e " ${NOCOLOR-\e[1;31m*\e[0m }${*}" >&2
}

main() {
	# re-define for subst to work
	[[ -n ${NOCOLOR+yes} ]] && NOCOLOR=

	[[ ${EUID} -eq 0 ]] || die "Please run this script as root"

	local install_dir=/boot
	if [[ ${INSTALLKERNEL_LAYOUT} == "uki" ]]; then
		for candidate in /boot/EFI /boot/efi /boot /efi; do
			if [[ -d ${candidate}/EFI/Linux ]]; then
				install_dir=${candidate}/EFI/Linux
			else
				continue
			fi
		done
	elif [[ ${INSTALLKERNEL_LAYOUT} == "efistub" ]]; then
		for candidate in /boot/EFI /boot/efi /boot /efi; do
			if [[ -d ${candidate}/EFI/${NAME} ]]; then
				install_dir=${candidate}/EFI/${NAME}
			else
				continue
			fi
		done
	fi

	einfo "Checking available disk space on ${install_dir}..."
	local space_kbi
	space_kbi=$(df -Pk "${install_dir}" 2>/dev/null | awk 'FNR == 2 {print $4}')

	if [[ ${?} == 0 && -n ${space_kbi} ]]; then
		# Add the typical size of a refind icon(8), bls entry(4) file, typical
		# config (272) and System.map(9852)
		local required=10200
		if [[ ${INSTALLKERNEL_LAYOUT} == "uki" ]]; then
			if [[ -f ${uki} ]]; then
				required=$((required + $(du -kx "${uki}" | awk 'FNR == 1 {print $1}')))
			fi
		else
			required=$((required + $(du -kx "${img}" | awk 'FNR == 1 {print $1}')))
			if [[ -f ${initrd} ]]; then
				required=$((required + $(du -kx "${initrd}" | awk 'FNR == 1 {print $1}')))
			fi
		fi
		if [[ ${space_kbi} -lt ${required} ]]; then
			eerror "Not enough disk space. Need at least ${required} KiB, found ${space_kbi} KiB."
			die "Please use app-admin/eclean-kernel to clean up old kernels."
		else
			einfo "Disk space okay. Need at least ${required} KiB, found ${space_kbi} KiB."
		fi
	else
		ewarn "Failed to determine disk space."
	fi
}

main