#!/bin/sh
# Copyright 1999-2019 Gentoo Authors
# Distributed under the terms of the GNU General Public License v2

. /usr/share/grub/grub-mkconfig_lib

if [ -r /etc/default/systemrescuecd ] ; then
	. /etc/default/systemrescuecd
fi

COPY_SRCD_TO_BOOT=${COPY_SRCD_TO_BOOT:-no}

bootdir="/boot"
installdir="/usr/share/systemrescuecd"

isorex='^(/.*/)?systemrescuecd-.*[.]iso$'

# Path of the link to the newest ISO, created by ebuild
srcd="${installdir}/systemrescuecd-x86-newest.iso"

# Extract ISO version
isovsed() {
	sed -E 's|^.*systemrescuecd(-x86)?-||;s|.iso$||'
}

# Find ISOs in a given directory
isofind() {
	find "${1}" -maxdepth 1 -type f -regextype egrep -regex ${isorex}
}

# Copy ISO to boot partition
copy_srcd_iso() {
	if [ ! -f "${bootdir}/"$(basename "${1}") ]; then
		if [ $(df -k --output=avail "${bootdir}" | tail -1) -gt $(du -k "${1}" | cut -f 1) ]; then
			cp "${1}" "${bootdir}/"
		else
			# Before complaining, check if the installed ISO is actually newer
			if $(printf '%s\n' $(isofind "${bootdir}" | isovsed | sort -V) $(echo "${1}" | isovsed) | sort -VC); then
				gettext_printf "Error: Not enough free disk space on ${bootdir}!\n" >&2
				gettext_printf "Error: Failed to copy the new iso!\n" >&2
			fi
		fi
	fi
}

write_srcd() {
	cat <<EOF
	menuentry "${longname} [${1}] (Copy to RAM${bootops}" --class rescue {
${grub_string}
		set gfxpayload=keep
		set isofile=${path}
		loopback loop \${isofile}
		linux (loop)/sysresccd/boot/x86_64/vmlinuz archisobasedir=sysresccd img_loop=\${isofile} img_dev=${diskuuid} copytoram ${SRCD_BOOTOPTIONS}
		initrd (loop)/sysresccd/boot/intel_ucode.img (loop)/sysresccd/boot/amd_ucode.img (loop)/sysresccd/boot/x86_64/sysresccd.img
	}
	menuentry "${longname} [${1}] (Copy to RAM with persistence${bootops}" --class rescue {
${grub_string}
		set gfxpayload=keep
		set isofile=${path}
		loopback loop \${isofile}
		linux (loop)/sysresccd/boot/x86_64/vmlinuz archisobasedir=sysresccd img_loop=\${isofile} img_dev=${diskuuid} cow_device=${diskuuid} cow_directory=/persistent_sysresccd-${1}/x86_64 copytoram ${SRCD_BOOTOPTIONS}
		initrd (loop)/sysresccd/boot/intel_ucode.img (loop)/sysresccd/boot/amd_ucode.img (loop)/sysresccd/boot/x86_64/sysresccd.img
	}
	menuentry "${longname} [${1}] (Minimal${bootops}" --class rescue {
${grub_string}
		set gfxpayload=keep
		set isofile=${path}
		loopback loop \${isofile}
		linux (loop)/sysresccd/boot/x86_64/vmlinuz archisobasedir=sysresccd img_loop=\${isofile} img_dev=${diskuuid} ${SRCD_BOOTOPTIONS}
		initrd (loop)/sysresccd/boot/intel_ucode.img (loop)/sysresccd/boot/amd_ucode.img (loop)/sysresccd/boot/x86_64/sysresccd.img
	}
EOF
}

write_srcd_5() {
	cat <<EOF
	menuentry "${longname} [${1}] (64bit${bootops}" --class rescue {
${grub_string}
		set isofile=${path}
		loopback loop \${isofile}
		linux (loop)/isolinux/rescue64 ${SRCD_BOOTOPTIONS} isoloop=\${isofile}
		initrd (loop)/isolinux/initram.igz
	}
	menuentry "${longname} [${1}] (32bit${bootops}" --class rescue {
${grub_string}
		set isofile=${path}
		loopback loop \${isofile}
		linux (loop)/isolinux/rescue32 ${SRCD_BOOTOPTIONS} isoloop=\${isofile}
		initrd (loop)/isolinux/initram.igz
	}
EOF
}

# Get v5 ISOs
# Use: isogrep5 [-v]
#   -v invert match
isogrep5() {
	ls -rv "${isopref}"/systemrescuecd-*.iso | grep ${1} -e '-x86-5'
}

write_srcd_submenu() {
	# Start submenu
	echo "submenu \"${longname}\" --class submenu {"

	# Make sure to reverse-sort by version
	for iso in $(isogrep5 -v; isogrep5); do
		path=$(make_system_path_relative_to_its_root "${iso}")
		gettext_printf "  image: ${iso}\n" >&2
		if $(printf '%s\n' "6.0.0" $(echo ${iso} | isovsed) | sort -VC); then
			write_srcd $(echo ${iso} | isovsed)
		else
			write_srcd_5 $(echo ${iso} | isovsed)
		fi
	done

	# End submenu
	echo "}"
}

bootops=")"

if [ ! -z "${SRCD_BOOTOPTIONS}" ]; then
	bootops=" with bootoptions)"
fi

if [ "${COPY_SRCD_TO_BOOT}" = yes ]; then
	srcd=$(realpath "${srcd}")
	copy_srcd_iso "${srcd}"
fi

# Build menu entries
for isopref in "${bootdir}" "${installdir}"; do
	# Make sure there are any ISOs
	ls "${isopref}" | grep -E -q -e "${isorex}" || continue

	diskuuid=/dev/disk/by-uuid/$(${grub_probe} --target=fs_uuid "${isopref}")
	device=$(${grub_probe} --target=device "${isopref}")
	label=$(${grub_probe} --target=fs_label "${isopref}")
	[ "${label}" = "(null)" ] && label=${device}
	grub_string=$(prepare_grub_to_access_device "${device}" | grub_add_tab | grub_add_tab)
	longname="SystemRescueCD on ${label}"

	gettext_printf "Found %s on %s\n" "${longname}" "${device}" >&2

	write_srcd_submenu
done