#!/bin/bash
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.
#
# This script should format the given disk for ZFS partition
#
# Taken from https://github.com/proxmox/pve-installer/blob/master/proxinstall
#
# Legacy Layout
# 1 - GRUB boot partition: 1M 
# 2 - OS/Data partition
# 9 - ZFS reserved partition
#
# EFI Layout
# 1 - GRUB boot partition: 1M 
# 2 - EFI ESP: 128M 
# 3 - OS/Data partition

TARGET_DEV="$1"
if [ ! -b "$TARGET_DEV" -o -z "$TARGET_DEV" ]; then
  echo "Usage:"
  echo "  zfs-format-disk <device>"
  echo "  zfs-format-disk /dev/sda"
  exit 1
fi

# Since Proxmox v6, EFI layout might be in used even if efi is not used for booting.
# For this reason, we need to check if EFI layout is in used for other disk.
EFI=0
if fdisk -l | grep 'EFI System' > /dev/null; then
  EFI=1
fi

CMD="/sbin/sgdisk -a1"

if [ $EFI -eq 1 ]; then
  # GRUB boot partition
  CMD="$CMD -n1:34:2047 -t1:EF02"
  # EFI Boot
  CMD="$CMD -n2:2048:1050623 -t2:ef00"
  # OS/DATA partition
  CMD="$CMD -n3:1050624:0 -t3:BF01 -c 3:zfs"

else
  # GRUB boot partition: 1M 
  CMD="$CMD -n1:34:2047 -t1:EF02"
  # ZFS reserved partition
  CMD="$CMD -n3:-8M:0 -t3:BF07"
  # OS/Data partition
  CMD="$CMD -n2:2048:0 -t2:BF01 -c 2:zfs"
fi
CMD="$CMD $TARGET_DEV"

# Zap-all partition tale
/sbin/sgdisk -Z "$TARGET_DEV"

# Execute the command line.
$CMD

# Install grub on it
/usr/sbin/grub-install "$TARGET_DEV"

# Install EFI if required
if [ $EFI -eq 1 ]; then
  partprobe "${TARGET_DEV}"
  while [ ! -e "${TARGET_DEV}2" ]; do
    sleep 1
    echo "."
  done
  pve-efiboot-tool format ${TARGET_DEV}2 --force
  pve-efiboot-tool init ${TARGET_DEV}2
fi