INSTALL_TGT=/dev/sda
INSTALL_SRC=/dev/disk/by-label/installer

install_enabled() {
	if [ -z "$bootparam_install" ]; then
		return 1
	fi
	return 0
}

install_probe_target() {
	until [ -e $INSTALL_TGT ]; do
		info "Waiting for target block device '$INSTALL_TGT' to appear ..."
		sleep 5
	done
	info "Found target block device 'sda'"
	return 0
}

install_probe_source() {
	until [ -e $INSTALL_SRC ]; do
		info "Waiting for filesystem with label "installer" to appear ..."
		sleep 5
	done
	info "Found update filesystem: $INSTALL_SRC"

	mkdir -p /mnt/install || exit 1
	if ! mount -o ro $INSTALL_SRC /mnt/install; then
		fatal "Unable to mount $INSTALL_SRC"
	fi
	return 0
}

install_confirm() {
	info "Current partitions on $INSTALL_TGT:"
	parted $INSTALL_TGT print || true
	sleep 1
	until read -p "Enter 'INSTALL' to begin installation to /dev/sda: " RESULT && [ "$RESULT" = "INSTALL" ]; do
		sleep 1
	done
	return 0
}

install_partitions() {
	info "Clearing beginning of $INSTALL_TGT"
	dd if=/dev/zero bs=512 count=64 of=$INSTALL_TGT || exit 1
	info "Creating partitions on $INSTALL_TGT"
	parted $INSTALL_TGT mklabel msdos || exit 1
	parted $INSTALL_TGT -- \
		mkpart primary 4MiB 512MiB \
		mkpart primary 512MiB 1536MiB \
		mkpart primary 1536MiB 2560MiB \
		mkpart primary 2560MiB 100% \
		print|| exit 1
	return 0
}

install_format() {
	info "Creating filesystems on $INSTALL_TGT"
	mkfs.ext4 ${INSTALL_TGT}1 || exit 1
	mkfs.ext4 ${INSTALL_TGT}2 || exit 1
	mkfs.ext4 ${INSTALL_TGT}3 || exit 1
	mkfs.ext4 ${INSTALL_TGT}4 || exit 1
	return 0
}

install_boot() {
	mkdir -p /mnt/boot || exit 1
	if ! mount -o rw -t ext4 ${INSTALL_TGT}1 /mnt/boot; then
		fatal "Unable to mount ${INSTALL_TGT}1"
	fi

	info "Installing grub configuration to ${INSTALL_TGT}1"
	mkdir /mnt/boot/grub || exit 1
	GRUBCFG=/mnt/boot/grub/grub.cfg

	cat > $GRUBCFG << EOF || exit 1
default=0
timeout=3

serial --unit=0 --speed=115200

terminal_input serial
terminal_output serial
EOF

	BOOTPASSWD=
	BOOTUSER=
	if [ -n "${BOOTPASSWD}" ] && [ -n "${BOOTUSER}" ]; then
	cat >> $GRUBCFG << EOF || exit 1
set superusers="$BOOTUSER"
password $BOOTUSER $BOOTPASSWD
EOF
	fi

	if [ -n "${BOOTPASSWD}" ] && [ -n "${BOOTUSER}" ]; then
		ENTRY_ARGS="--unrestricted "
	fi

	CMDLINE="console=$bootparam_console net.ifnames=0 panic=60 ro quiet"

	cat >> $GRUBCFG << EOF
set ORDER="A B"
set A_OK=0
set B_OK=0
set A_TRY=0
set B_TRY=0
load_env

# select bootable slot
for SLOT in \$ORDER; do
	if [ "\$SLOT" == "A" ]; then
		INDEX=1
		OK=\$A_OK
		TRY=\$A_TRY
		A_TRY=1
	fi
	if [ "\$SLOT" == "B" ]; then
		INDEX=2
		OK=\$B_OK
		TRY=\$B_TRY
		B_TRY=1
	fi
	if [ "\$OK" -eq 1 -a "\$TRY" -eq 0 ]; then
		default=\$INDEX
		break
	fi
done

# reset booted flags
if [ "\$default" -eq 0 ]; then
	if [ "\$A_OK" -eq 1 -a "\$A_TRY" -eq 1 ]; then
		A_TRY=0
	fi
	if [ "\$B_OK" -eq 1 -a "\$B_TRY" -eq 1 ]; then
		B_TRY=0
	fi
fi

save_env A_TRY B_TRY

CMDLINE="$CMDLINE"

menuentry "Rescue" $ENTRY_ARGS{
	linux (hd0,1)/kernel root=${INSTALL_TGT}1 \$CMDLINE rauc.slot=R
	initrd (hd0,1)/initramfs
}

menuentry "Slot A (OK=\$A_OK TRY=\$A_TRY)" ${ENTRY_ARGS}{
	linux (hd0,2)/kernel root=${INSTALL_TGT}2 \$CMDLINE rauc.slot=A
	initrd (hd0,2)/initramfs
}

menuentry "Slot B (OK=\$B_OK TRY=\$B_TRY)" ${ENTRY_ARGS}{
	linux (hd0,3)/kernel root=${INSTALL_TGT3} \$CMDLINE rauc.slot=B
	initrd (hd0,3)/initramfs
}
EOF
	chmod 0444 $GRUBCFG || exit 1

	info "Installing grub bootloader to ${INSTALL_TGT}1"
	grub-install --boot-directory=/mnt/boot ${INSTALL_TGT} || exit 1
	echo "(hd0) ${INSTALL_TGT}" > /mnt/boot/grub/device.map || exit 1

	info "Installing 'kernel' to ${INSTALL_TGT}1"
	cp /mnt/install/kernel /mnt/boot/kernel || exit 1

	info "Installing 'initramfs' to ${INSTALL_TGT}1"
	cp /mnt/install/rescue-initramfs /mnt/boot/initramfs || exit 1
	umount /mnt/boot || exit 1
}

install_run() {
    install_probe_target || fatal "Failed to find installer target disk"
    install_probe_source || fatal "Failed to find installer source filesystem"
    install_confirm || fatal "Failed to get confirmation from user"
    install_partitions || fatal "Failed to partition disk"
    install_format || fatal "Failed to format disk"
    install_boot || fatal "Failed to create boot filesystem"
    info "Installation complete, rebooting"
    sync
    sleep 5
    reboot -f
}