#!/bin/bash
set -e

# argv
DISK=$1
ZFSHOST=$2
[ -z "$ZFSHOST" ] && ZFSHOST="debianzfs"

# Settings
CODENAME="bullseye"
ZFSROOT="/mnt"

# Confirm DISK choice
if [ -n "$DISK" ]; then
  read -rp "You selected to OVERWRITE '${DISK}' as hostname '${ZFSHOST}', are you sure? [y/N] " yn
else
	echo "ERROR: No disk selected. Pass through a disk path, e.g., ./zfslive.sh /dev/sdX"
	exit 1;
fi

case $yn in
	[yY] ) ;;
	* ) echo "ERROR: User aborted"
		exit 1;;
esac

# Stop on error
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 ZFS
apt-get install -y debootstrap gdisk 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
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"

# 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 device
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 bullseye main contrib
deb-src http://deb.debian.org/debian bullseye main contrib

deb http://deb.debian.org/debian-security bullseye-security main contrib
deb-src http://deb.debian.org/debian-security bullseye-security main contrib

deb http://deb.debian.org/debian bullseye-updates main contrib
deb-src http://deb.debian.org/debian bullseye-updates main contrib
EOF

# Copy env under ZFSROOT
env > "$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 << EOF | chroot /mnt bash --login
. /var/tmp/zfsenv
unset CDPATH
cd
apt-get update
apt-get upgrade -y
EOF