#!/usr/bin/env bash
set -e

pprint () {
    local cyan="\e[96m"
    local default="\e[39m"
    # ISO8601 timestamp + ms
    local timestamp
    timestamp=$(date +%FT%T.%3NZ)
    echo -e "${cyan}${timestamp} $1${default}" 1>&2
}

echo "These are the disks available:"
ls -l /dev/disk/by-id/ | awk '{print $11, $10, $9}' | tr -d './' | column -t
echo

# Set DISK
select ENTRY in $(ls /dev/disk/by-id/);
do
    echo $ENTRY
    DISK="/dev/disk/by-id/$ENTRY"
    echo "Installing system on $ENTRY."
    break
done

echo -n "Enter Swap size (e.g. 10GiB, 5MiB)"
echo
read SWAP_SIZE
if [[ $SWAP_SIZE =~ ^[0-9]*(GiB|MiB)$ ]]
then
  echo "Swap size set to $SWAP_SIZE"
else
  echo "Please enter correct size"
  break
fi

read -p "> Do you want to wipe all data on $ENTRY ?" -n 1 -r
echo # move to a new line
if [[ "$REPLY" =~ ^[Yy]$ ]]
then
    # Clear disk
    wipefs -af "$DISK"
    sgdisk -Zo "$DISK"
    partprobe $DISK
else
    exit 1
fi

parted $DISK -- mklabel gpt

pprint "Creating system partition"
parted $DISK -- mkpart primary 512MiB -${SWAP_SIZE}
ROOT="$DISK-part1"

pprint "Creating swap partition"
parted $DISK -- mkpart primary linux-swap -${SWAP_SIZE} 100%
SWAP="$DISK-part2"

pprint "Creating boot (EFI) partition"
parted $DISK -- mkpart ESP fat32 1MiB 512MiB
parted $DISK -- set 3 boot on
BOOT="$DISK-part3"

pprint "Running partprobe on $DISK"
partprobe $DISK

sleep 2 # not sure why, but if we don't wait, the following swap does not work properly

pprint "Enable SWAP on $SWAP"
mkswap -L swap $SWAP
swapon -L swap

# ZFS partition
pprint "Create zfs pool rpool"
zpool create -f -O mountpoint=none -O acltype=posixacl -O xattr=sa -R /mnt rpool $ROOT

pprint "Create zfs dataset rpool/root"
zfs create -o mountpoint=none   rpool/root
pprint "Create zfs dataset rpool/root/nixos"
zfs create -o mountpoint=legacy rpool/root/nixos
pprint "Create zfs dataset rpool/home"
zfs create -o mountpoint=legacy rpool/home

pprint "Mount datasets: rpool/root/nixos"
mount -t zfs rpool/root/nixos /mnt

pprint "Mount datasets: rpool/home"
mkdir /mnt/home
mount -t zfs rpool/home /mnt/home

pprint "Mount boot partition"
mkfs.fat -F 32 -n boot $BOOT
mkdir /mnt/boot
mount $BOOT /mnt/boot

pprint "Generate NixOS configuration"
nixos-generate-config --root /mnt

# Add ZFS configuration
HOSTID=$(head -c8 /etc/machine-id)

HARDWARE_CONFIG=$(mktemp)
cat << CONFIG > "$HARDWARE_CONFIG"
networking.hostId = "$HOSTID";
boot.supportedFilesystems = [ "zfs" ];
boot.zfs.devNodes = "$ROOT";
}
CONFIG

#pprint "Append configuration to hardware-configuration.nix"
sed -i "\$ s/.}\$//;\$e cat $HARDWARE_CONFIG" /mnt/etc/nixos/configuration.nix

pprint "You can now install nixos using the 'nixos-install' command."