#!/bin/bash

export LC_ALL=C
CE="\033[31m" # Color red
CB="\033[1m"  # Color bold
CR="\033[0m"  # Color reset
CODE_OK=0
CODE_USAGE=1  # Bad usage
CODE_PERM=2   # Invalid rights
CODE_VALUE=3  # Bad value
CODE_CMD=4    # Missing command
CODE_FATAL=5  # Fatal error
PRGNAME=$(basename "$0")
CONFDIR="/etc/memtest86-efi"
CONFFILE="$CONFDIR/memtest86-efi.conf"
# shellcheck source=/etc/memtest86-efi/memtest86-efi.conf
source "$CONFFILE" || exit $CODE_FATAL
shopt -s extglob
[[ "$(uname -m)" == "i686" ]]    && ARCH="ia32"
[[ "$(uname -m)" == "x86_64" ]]  && ARCH="x64"
[[ "$(uname -m)" == "aarch64" ]] && ARCH="aa64"

warn() {
	echo -e "${CB}${CE}This script is unofficial, written by an AUR (Arch User Repository) user. Use it at YOUR OWN RISK.${CR}"
}

checkuid() {
	if [[ $EUID -ne 0 ]]; then
		echo -e "${CE}You must be root to run $PRGNAME. Aborted.${CR}" > /dev/stderr
		exit $CODE_PERM
	fi
}

checkcommand() {
	if ! $1 &> /dev/null; then
		echo -e "${CE}Command $1 not found. Aborted.${CR}" > /dev/stderr
		exit $CODE_CMD
	fi
}

promptuser() {
	local defaultvalue="$1"
	local newvalue=""
	while true; do
		read -r newvalue
		if [[ -n "$defaultvalue" ]] || [[ -n "$newvalue" ]]; then
			break
		else
			echo -en "Please enter a valid value: " > /dev/stderr
		fi
	done
	[[ -n "$newvalue" ]] && echo "$newvalue" || echo "$defaultvalue"
}

_common_install() {
	efidir="$1"
	efifile="$2"

	echo -e "MemTest86 is installed into ${CB}$efidir/${CR} directory."
	mkdir -pv "$efidir"
	cp -rv "$MEMTEST86_PATH/"!(*.efi) "$efidir/" # Move files in memtest ESP directory
	cp -v  "$MEMTEST86_PATH/boot$ARCH.efi" "$efidir/$efifile" # Copy and rename .efi file
}

_write_grub_cfg() {
	uuid="$1"

	cat > "/etc/grub.d/86_memtest" <<FOE
#!/bin/sh

cat <<EOF
if [ "\\\$grub_platform" = "efi" ]; then
	menuentry "Memtest86" {
		search --set=root --no-floppy --fs-uuid $uuid
		chainloader /EFI/memtest86/memtest$ARCH.efi
	}
fi
EOF
FOE
	chmod 755 "/etc/grub.d/86_memtest"
}

_write_systemd_boot_cfg() {
	systemdbootdir="$1"

	cat > "$systemdbootdir/memtest86-efi.conf" <<FOE
title MemTest86
efi   /EFI/memtest86/memtest$ARCH.efi
FOE
}

install() {
	if [[ $install == 1 ]]; then
		echo "MemTest86 is already installed in ESP. Nothing to do." > /dev/stderr
		exit $CODE_USAGE
	fi

	# Find ESP device number
	partition=$(fdisk -l | grep "EFI System" | awk '{print $1}' | tail -n1)
	if [[ -n "$partition" ]]; then
		echo -en "Press Enter if ${CB}$partition${CR} is your ESP partition, "
		echo -en "else enter device path manually (like ${CB}/dev/sdXY${CR}): "
	else
		echo -en "Enter device path for your ESP partition (like ${CB}/dev/sdXY${CR}): "
	fi
	partition=$(promptuser "$partition")
	if [[ ! -b "$partition" ]]; then
		echo -e "${CE}'$partition' is not a block device. Aborted.${CR}" > /dev/stderr
		exit $CODE_VALUE
	fi
	partnumber=$(echo "$partition" | grep -Eo '[0-9]+$')
	[[ $partition == "/dev/nvme"* ]] && device=$(echo "$partition" | cut -dp -f1) || device=${partition//$partnumber}
	if [[ -z "$partnumber" ]] || [[ -z "$device" ]]; then
		echo -e "${CE}Not able to find partition number for '$partition'. Aborted.${CR}" > /dev/stderr
		exit $CODE_VALUE
	fi

	# Find ESP mount point
	esp=$(mount | grep "$partition" | awk '{print $3}' | tail -n1)
	if [[ -n "$esp" ]]; then
		echo -en "Press Enter if ${CB}$esp${CR} is your mount point for ESP partition, "
		echo -en "else enter mount point manually (like ${CB}/boot/efi${CR}): "
	else
		echo -en "Enter the mount point for the ESP partition (like ${CB}/boot/efi${CR}): "
	fi
	esp=$(promptuser "$esp")

	# Check if ESP is mounted
	if ! mount | grep "$partition" | grep -q "$esp"; then
		echo -e "ESP ${CB}$partition${CR} is not mounted, mounting..."
		if ! mount "$partition" "$esp"; then
			echo -e "${CE}Fail to mount $partition on $esp. Aborted.${CR}" > /dev/stderr
			exit $CODE_FATAL
		fi
	fi
	echo -e "The target is: ${CB}$partition${CR} (mounted on ${CB}$esp${CR}).\n"

	# Get user choice
	echo "Select $PRGNAME action to perform:"
	echo -e "${CB}1${CR}: Copy shellx64.efi file on ESP's root (bit safe)"
	echo -e "${CB}2${CR}: Add a new EFI boot entry (more safe)"
	echo -e "${CB}3${CR}: Add a boot entry for GRUB2 menu"
	echo -e "${CB}4${CR}: Add a boot entry for systemd-boot menu"
	echo -e "${CB}5${CR}: Cancel"
	choice=0
	while [[ $choice -lt 1 ]] || [[ $choice -gt 5 ]]; do
		read -r choice
		echo
	done

	case $choice in
		1) # Install MemTest86 in $esp/
			[[ -f "$esp/shell$ARCH.efi" ]] && mv -v "$esp/shell$ARCH.efi" "$esp/shell$ARCH.efi.bak" # Backup if exist
			_common_install "$esp" "shell$ARCH.efi"
		;;

		2) # Install MemTest86 in $esp/EFI/memtest86/ & add an EFI boot entry
			checkcommand efibootmgr
			_common_install "$esp/EFI/memtest86" "memtest$ARCH.efi"
			echo -e "\nAdd a new EFI boot entry..."
			efibootmgr -c -d "$device" -p "$partnumber" -w -L "MemTest86" -l "\EFI\memtest86\memtest$ARCH.efi" # Manage efi entry
		;;

		3) # Install MemTest86 in $esp/EFI/memtest86/ & add a file for GRUB2
			checkcommand grub-mkconfig
			if [[ ! -d "/etc/grub.d/" ]]; then
				echo -e "${CE}GRUB2 seems not installed on your system. Aborted.${CR}" > /dev/stderr
				exit $CODE_CMD
			fi
			_common_install "$esp/EFI/memtest86" "memtest$ARCH.efi"
			echo -e "\nAdd a new configuration file for GRUB..."
			uuid=$(blkid "$partition" -s UUID -o value)
			_write_grub_cfg "$uuid"
			grub-mkconfig -o "/boot/grub/grub.cfg"
		;;

		4) # Install MemTest86 in $esp/EFI/memtest86/ & add a file for systemd-boot
			checkcommand bootctl
			_common_install "$esp/EFI/memtest86" "memtest$ARCH.efi"
			echo -e "\nAdd a new configuration file for systemd-boot..."
			systemdbootdir="$esp/loader/entries"
			mkdir -pv "$systemdbootdir"
			_write_systemd_boot_cfg "$systemdbootdir"
			bootctl --path="$esp" update
		;;

		*) # Do nothing and quit
			echo -e "Canceled. MemTest86 will not be installed."
			exit $CODE_OK
		;;
	esac

	echo "Writting configuration..."
	sed -i "s|@PARTITION@|$partition|g" "$CONFFILE"
	sed -i "s|@ESP@|$esp|g"             "$CONFFILE"
	sed -i "s|@CHOICE@|$choice|g"       "$CONFFILE"
	sed -i "s|install=0|install=1|g"    "$CONFFILE"

	echo "MemTest86 has been installed in ESP."
}

update() {
	if [[ $install == 0 ]]; then
		echo "MemTest86 is not installed in ESP: it cannot be updated." > /dev/stderr
		exit $CODE_USAGE
	fi

	case $choice in
		1) # Update files in $esp/
			_common_install "$esp" "shell$ARCH.efi"
		;;

		2|3|4) # Update files in $esp/EFI/memtest86/
			## Check if efi partition is mounted, if not mount it
			if ! mount | grep "$partition" | grep -q "$esp"; then
				echo -e "ESP ${CB}$partition${CR} is not mounted, mounting..."
				if ! mount "$partition" "$esp"; then
					echo -e "${CE}Fail to mount $partition on $esp. Aborted.${CR}" > /dev/stderr
					exit $CODE_FATAL
				fi
			fi
			_common_install "$esp/EFI/memtest86" "memtest$ARCH.efi"
		;;
	esac

	echo "MemTest86 has been updated in ESP."
}

remove() {
	if [[ $install == 0 ]]; then
		echo "MemTest86 is not installed in ESP: it cannot be removed." > /dev/stderr
		exit $CODE_USAGE
	fi

	case $choice in
		1) # Remove files in $esp/
			echo -e "MemTest86 will be removed from ${CB}$esp/${CR}."
			rm -v "$esp/shell$ARCH.efi" "$esp/blacklist.cfg" "$esp/mt86.png" "$esp/unifont.bin"
			[[ -f "$esp/shell$ARCH.efi.bak" ]] && mv -v "$esp/shell$ARCH.efi.bak" "$esp/shell$ARCH.efi"
		;;

		2) # Remove files in $esp/EFI/memtest86/ & delete EFI boot entry
			checkcommand efibootmgr

			echo -e "MemTest86 will be removed from ${CB}$esp/EFI/memtest86/${CR}."
			rm -rfv "$esp/EFI/memtest86/"

			echo -e "\nRemove MemTest86 EFI boot entry..."
			entry=$(efibootmgr | grep MemTest86 | cut -c 5-8)
			[[ -n $entry ]] && efibootmgr -b "$entry" -B
		;;

		3) # Remove files in $esp/EFI/memtest86/ & delete file for GRUB2
			checkcommand grub-mkconfig

			echo -e "MemTest86 will be removed from ${CB}$esp/EFI/memtest86/${CR}."
			rm -rfv "$esp/EFI/memtest86/"

			echo -e "\nRemove configuration file for GRUB..."
			rm -v "/etc/grub.d/86_memtest"
			grub-mkconfig -o "/boot/grub/grub.cfg"
		;;

		4) # Remove files in $esp/EFI/memtest86/ & delete file for systemd-boot
			echo -e "MemTest86 will be removed from ${CB}$esp/EFI/memtest86/${CR}."
			rm -rfv "$esp/EFI/memtest86/"

			echo -e "\nRemove configuration file for systemd-boot..."
			rm -v "$esp/loader/entries/memtest86-efi.conf"
		;;
	esac

	echo "Writting configuration..."
	sed -i "s|$partition|@PARTITION@|g" "$CONFFILE"
	sed -i "s|$esp|@ESP@|g"             "$CONFFILE"
	sed -i "s|$choice|@CHOICE@|g"       "$CONFFILE"
	sed -i "s|install=1|install=0|g"    "$CONFFILE"

	echo "MemTest86 has been removed from ESP."
}

status() {
	echo -e "${CB}Default MemTest86 directories:${CR}"
	echo -e "Configuration directory: $CONFDIR/"
	echo -e "Data directory: $MEMTEST86_PATH/\n"

	if [[ $install == 0 ]]; then
		echo -e "${CB}MemTest86 is not installed on your system.${CR}"
		exit $CODE_USAGE
	else
		echo -e "${CB}MemTest86 is installed on your system with following parameters:${CR}"
		echo -e "ESP device name: $partition"
		echo -e "ESP mount point: $esp"
		echo -e "Type of installation: $choice"
		exit $CODE_OK
	fi
}

help() {
	echo -e "Usage: $PRGNAME ACTION\n"
	echo -e "Available ACTION:"
	echo -e "\t-i, --install\t Install MemTest86 in ESP"
	echo -e "\t-u, --update\t Update an existing installation of MemTest86"
	echo -e "\t-r, --remove\t Remove MemTest86 from ESP"
	echo -e "\t-s, --status\t Print and return status"
	echo -e "\t-h, --help\t Print this help and exit"
	echo -e "\t-a, --about\t Print informations about $PRGNAME and exit"
}

about() {
	echo -e "MemTest86 is a stand alone memory testing software, it cannot be run under an operating system."
	echo -e "$PRGNAME is a script which helps you to easily use MemTest86 with your UEFI, as an EFI application."
}

if [[ -z $ARCH ]]; then
	echo -e "${CE} Unsupported ARCH: $(uname -m). Aborted.${CR}" > /dev/stderr
	exit $CODE_FATAL
fi

case "$1" in
	-i|--install) warn; checkuid; install; exit $CODE_OK;;
	-u|--update)  checkuid; update; exit $CODE_OK;;
	-r|--remove)  checkuid; remove; exit $CODE_OK;;
	-s|--status)  status;;
	-h|--help)    help; exit $CODE_OK;;
	-a|--about)   warn; about; exit $CODE_OK;;
	*)            help; exit $CODE_USAGE;;
esac