#!/bin/bash
DISK=$1
ZFSHOST=$2
[ -z "$ZFSHOST" ] && ZFSHOST="debianzfs"

# Settings
export DEBIAN_FRONTEND=noninteractive
CODENAME="bullseye"
ZFSROOT="/mnt"

# Display commands
set -x

# Is the DISK path a block device?
DISK_TYPE=$(file "${DISK}" | awk '{ print $2$3 }')
if [ "$DISK_TYPE" != "blockspecial" ]; then
	echo "ERROR: Disk '${DISK}' is not a block device"
	exit 1;
fi

# Update sources list
SOURCES_LIST="/etc/apt/sources.list"
[ -f "$SOURCES_LIST" ] && mv "$SOURCES_LIST" "$SOURCES_LIST.$(date +%s).bak"
echo "deb http://deb.debian.org/debian/ ${CODENAME} main contrib" > "$SOURCES_LIST"
apt-get update

# Install tools and ZFS
apt-get install -y debootstrap gdisk pwgen zfsutils-linux

# Ensure swap isn't in use
swapoff --all

# Partition
sgdisk -n2:1M:+512M -t2:EF00 "$DISK"
sgdisk -n3:0:+1G -t3:BF01 "$DISK"
sgdisk -n4:0:0 -t4:BF00 "$DISK"

# Create boot pool
zpool create -f \
    -o ashift=12 \
    -o autotrim=on -d \
    -o cachefile=/etc/zfs/zpool.cache \
    -o feature@async_destroy=enabled \
    -o feature@bookmarks=enabled \
    -o feature@embedded_data=enabled \
    -o feature@empty_bpobj=enabled \
    -o feature@enabled_txg=enabled \
    -o feature@extensible_dataset=enabled \
    -o feature@filesystem_limits=enabled \
    -o feature@hole_birth=enabled \
    -o feature@large_blocks=enabled \
    -o feature@livelist=enabled \
    -o feature@lz4_compress=enabled \
    -o feature@spacemap_histogram=enabled \
    -o feature@zpool_checkpoint=enabled \
    -O devices=off \
    -O acltype=posixacl -O xattr=sa \
    -O compression=lz4 \
    -O normalization=formD \
    -O relatime=on \
    -O canmount=off -O mountpoint=/boot -R "$ZFSROOT" \
		bpool "${DISK}3"

# Create root pool with random 16 character password
RPOOLPW="$(pwgen -s 16 1)"
echo "$RPOOLPW" | \
zpool create -f \
    -o ashift=12 \
    -o autotrim=on \
    -O encryption=on -O keylocation=prompt -O keyformat=passphrase \
    -O acltype=posixacl -O xattr=sa -O dnodesize=auto \
    -O compression=lz4 \
    -O normalization=formD \
    -O relatime=on \
    -O canmount=off -O mountpoint=/ -R "$ZFSROOT" \
		rpool "${DISK}4"
unset RPOOLPW

# Create filesystem datasets to act as containers
zfs create -o canmount=off -o mountpoint=none rpool/ROOT
zfs create -o canmount=off -o mountpoint=none bpool/BOOT

# Create filesystem datasets for the root and boot filesystems
zfs create -o canmount=noauto -o mountpoint=/ rpool/ROOT/debian
zfs mount rpool/ROOT/debian
zfs create -o mountpoint=/boot bpool/BOOT/debian

# Create datasets
zfs create rpool/home
zfs create -o mountpoint=/root rpool/home/root
chmod 700 "$ZFSROOT/root"
zfs create -o canmount=off rpool/var
zfs create -o canmount=off rpool/var/lib
zfs create rpool/var/log
zfs create rpool/var/spool
zfs create -o com.sun:auto-snapshot=false rpool/var/cache
zfs create -o com.sun:auto-snapshot=false rpool/var/lib/nfs
zfs create -o com.sun:auto-snapshot=false rpool/var/tmp
chmod 1777 "$ZFSROOT/var/tmp"
zfs create -o canmount=off rpool/usr
zfs create rpool/usr/local
zfs create rpool/var/lib/AccountsService
zfs create rpool/var/lib/NetworkManager
zfs create -o com.sun:auto-snapshot=false rpool/var/lib/docker

# Mount a tmpfs at /run
mkdir "$ZFSROOT/run"
mount -t tmpfs tmpfs /mnt/run
mkdir "$ZFSROOT/run/lock"

# Install minimal system
debootstrap "$CODENAME" /mnt

# Copy in zpool.cache
mkdir "$ZFSROOT/etc/zfs"
cp /etc/zfs/zpool.cache "$ZFSROOT/etc/zfs/"

# Configure hostname
hostname "$ZFSHOST"
hostname > "$ZFSROOT/etc/hostname"
sed "/^127.0.0.1.*localhost/a 127.0.1.1\\t$ZFSHOST" "$ZFSROOT/etc/hosts" | tee "$ZFSROOT/etc/hosts"

# Configure network devices
NETWORK_DEVICES=$(ip a | awk '$1 ~ /^[0-9][:]/ {print substr($2, 0, length($2)-1)}')
while read -r INTER; do
	if [ ! "$INTER" = "lo" ]; then
		cat <<-EOF > "$ZFSROOT/etc/network/interfaces.d/$INTER"
			auto ${INTER}
			iface ${INTER} inet dhcp
		EOF
	fi
done <<< "$NETWORK_DEVICES"

# Update sources list in ZFSROOT
ZFS_SOURCES_LIST="$ZFSROOT/etc/apt/sources.list"
[ -f "$ZFS_SOURCES_LIST" ] && mv "$ZFS_SOURCES_LIST" "$ZFS_SOURCES_LIST.$(date +%s).bak"
cat <<-EOF > "$ZFS_SOURCES_LIST"
deb http://deb.debian.org/debian ${CODENAME} main contrib
deb-src http://deb.debian.org/debian ${CODENAME} main contrib

deb http://deb.debian.org/debian-security ${CODENAME}-security main contrib
deb-src http://deb.debian.org/debian-security ${CODENAME}-security main contrib

deb http://deb.debian.org/debian ${CODENAME}-updates main contrib
deb-src http://deb.debian.org/debian ${CODENAME}-updates main contrib
EOF

# Copy DISK var under ZFSROOT
echo "DISK=${DISK}" > "$ZFSROOT/var/tmp/zfsenv"

# Bind the virtual filesystems from the LiveCD environment to the new system
mount --make-private --rbind /dev /mnt/dev
mount --make-private --rbind /proc /mnt/proc
mount --make-private --rbind /sys /mnt/sys

# Chroot
cat << CHROOT | chroot /mnt bash --login
# Setup
set -ex
. /var/tmp/zfsenv
unset CDPATH
cd

# Configure a basic system environment
export DEBIAN_FRONTEND=noninteractive
export LC_CTYPE=en_US.UTF-8
export LC_ALL=en_US.UTF-8
ln -s /proc/self/mounts /etc/mtab
apt-get update
apt-get upgrade -y
apt-get install -y console-setup locales
dpkg-reconfigure locales tzdata keyboard-configuration console-setup
apt-get install -y dpkg-dev linux-headers-generic linux-image-generic zfs-initramfs
echo REMAKE_INITRD=yes > /etc/dkms/zfs.conf

# Install Grub for UEFI
apt-get install -y dosfstools
echo REMAKE_INITRD=yes > /etc/dkms/zfs.conf
mkdosfs -F 32 -s 1 -n EFI "${DISK}2"
mkdir /boot/efi
echo "${DISK}2" /boot/efi vfat defaults 0 0 >> /etc/fstab
mount /boot/efi
apt-get install -y grub-efi-amd64 shim-signed
apt-get purge -y os-prober
ROOTPW=$(pwgen 8 1)
echo "root:\$ROOTPW" | chpasswd
unset ROOTPW

# Add bpool import service
cat <<- BPOOL > /etc/systemd/system/zfs-import-bpool.service
[Unit]
DefaultDependencies=no
Before=zfs-import-scan.service
Before=zfs-import-cache.service

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/sbin/zpool import -N -o cachefile=none bpool
# Work-around to preserve zpool cache:
ExecStartPre=-/bin/mv /etc/zfs/zpool.cache /etc/zfs/preboot_zpool.cache
ExecStartPost=-/bin/mv /etc/zfs/preboot_zpool.cache /etc/zfs/zpool.cache

[Install]
WantedBy=zfs-import.target
BPOOL

# Enable importing bpool service
systemctl enable zfs-import-bpool.service

#  Mount a tmpfs to /tmp
cp /usr/share/systemd/tmp.mount /etc/systemd/system/
systemctl enable tmp.mount

# Verify that the ZFS boot filesystem is recognized
grub-probe /boot

# Refresh the initrd files
update-initramfs -c -k all

# Workaround GRUB's missing zpool-features support
sed -i "s/^\(GRUB_CMDLINE_LINUX=\).*/\1\"root=ZFS=rpool\/ROOT\/debian\"/" /etc/default/grub
sed -i "s/^\(GRUB_CMDLINE_LINUX_DEFAULT=\).*/\1\"\"/" /etc/default/grub
sed -i '/GRUB_TERMINAL/s/^#//g' /etc/default/grub
cat /etc/default/grub

# Update the boot configuration
update-grub

# Install GRUB to the ESP
grub-install --target=x86_64-efi --efi-directory=/boot/efi \
						 --bootloader-id=debian --recheck --no-floppy

# Fix filesystem mount ordering
mkdir /etc/zfs/zfs-list.cache
touch /etc/zfs/zfs-list.cache/bpool
touch /etc/zfs/zfs-list.cache/rpool
timeout 10 zed -F || \
test -s /etc/zfs/zfs-list.cache/bpool &&
test -s /etc/zfs/zfs-list.cache/rpool

# Fix the paths to eliminate /mnt
sed -Ei "s|/mnt/?|/|" /etc/zfs/zfs-list.cache/*

# Snapshot the initial installation
zfs snapshot bpool/BOOT/debian@install
zfs snapshot rpool/ROOT/debian@install
exit
CHROOT

mount | grep -v zfs | tac | awk '/\/mnt/ {print $3}' | \
    xargs -I{} umount -lf {}
zpool export -a || exit 0
exit 0