#
# lsblk
#
# -d, --nodeps      Do  not  print  holder  devices  or  slaves.
# -p, --paths       Print full device paths.
# -l, --list        Produce  output  in the form of a list.
# -n, --noheadings
# -x, --sort column

function get_partitions(){
  # $1 block-device
  # return: the following variables:
  #   PARTITIONS (array with one partition per entry)

  # Remove first line of output (which is just the block device $1 itself)
  # with sed: sed 1d
  PARTITIONS="$(lsblk -pln -o name "$1" | sed 1d)" || return $?

  newline_separated_to_array PARTITIONS PARTITIONS || return $?
}

function get_block_devices() {
  # return: the following variables:
  #   BLOCK_DEVICES (array with one entry for each block device)

  # Get list of devices, one per line
  BLOCK_DEVICES="$(lsblk -dplnx size -o name | grep -Ev "boot|rpmb|loop" | tac)" || return $?

  newline_separated_to_array BLOCK_DEVICES  BLOCK_DEVICES || return $?
}

function get_block_devices_with_size() {
  # return: the following variables:
  #   BLOCK_DEVICE_SIZES (array with two entries for each block device: device path and device size)

  # Get list of devices and their sizes, one pair per line
  # Use sed to remove multiple white spaces: sed 's|\s\s*| |'
  BLOCK_DEVICE_SIZES="$(lsblk -dplnx size -o name,size | grep -Ev "boot|rpmb|loop" | sed 's|\s\s*| |' | tac)"  || return $?

  newline_to_space BLOCK_DEVICE_SIZES || return $?
  space_separated_to_array BLOCK_DEVICE_SIZES BLOCK_DEVICE_SIZES || return $?
}


function partition() {
  # $1: target block device
  # $2: uefi or bios
  if [ "$#" -ne 2 ]; then
    echo "partition requires two args!";
    return 1
  fi
  for i in "$@"; do
    if [ -z "$i" ]; then
      echo "partition: all given args must not be empty";
      return 1;
    fi
  done

  # if BOOT_PART_SIZE not given, set to default value
  BOOT_PART_SIZE="${BOOT_PART_SIZE:='261'}"
  # if too small, print warning and exit
  if [ "${BOOT_PART_SIZE}" -lt "261" ]; then
    echo "BOOT_PART_SIZE should be larger than 260!";
    return 1;
  fi

  # As our data partition is encrypted,
  # we need a separate boot partition!
  case "$2" in
	uefi)
	  # EFI boot partition
    #
    # Create a partition with fat32 as the file system type and set the
    # esp flag on it.
    parted --script "$1" -- mklabel gpt \
      mkpart ESP fat32 2Mib "${BOOT_PART_SIZE}MiB" \
      set 1 esp on \
      mkpart primary "${BOOT_PART_SIZE}MiB" 100% || return $?

      get_partitions "$1" || return $?
      BOOT_PART="${PARTITIONS[0]}"
      LUKS_PART="${PARTITIONS[1]}"
		;;
	bios)
	  # > On a BIOS/GPT configuration, a BIOS boot partition is required. GRUB embeds its `core.img`
	  # > into this partition.
	  # > For parted set/activate the flag bios_grub on the partition.
	  #
	  # archwiki -> GRUB#GUID_Partition_Table_(GPT)_specific_instructions
	  # https://www.gnu.org/software/grub/manual/grub/html_node/BIOS-installation.html#BIOS-installation
	  parted --script "$1" -- mklabel gpt \
      mkpart primary 1MiB 2MiB \
      set 1 bios_grub on \
      mkpart primary 2MiB "${BOOT_PART_SIZE}MiB" \
      mkpart primary "${BOOT_PART_SIZE}MiB" 100% || return $?

      get_partitions "$1" || return $?
      BOOT_PART="${PARTITIONS[2]}"
      LUKS_PART="${PARTITIONS[3]}"
		;;
	*)
		echo "Expected uefi or bios but got $2 instead!"
		return 1
		;;
  esac

  echo "boot partition: ${BOOT_PART}"
  echo "luks partition: ${LUKS_PART}"
}

function format() {
  # $1: uefi or bios
  # $2: boot partition
  # $3: luks partition
  # $4: luks passphrase
  # $5: FS for data partition (opened luks partition): BTRFS, EXT4 or F2FS
  # $6: name of variable to store path to data partition (/dev/mapper/$(basename "$3"))
  # return:
  #  -> boot partition formatted
  #  -> luks partition formatted and opened at /dev/mapper/$(basename "$3")
  #  -> variable with name $6 assigned to path to data partition

  echo "Wiping old signatures from partitions ..."
  wipefs "${2}" || return $?
  wipefs "${3}" || return $?

  echo "Formatting boot partition $2 ..."
  mkfs.fat -F32 "$2" || return $?

  echo "Creating encrypted luks partition $3 ..."
  printf "%s" "$4" | cryptsetup luksFormat --type luks1 \
    --cipher aes-xts-plain64 --key-size 512 --hash sha512 \
    --iter-time 3500 --use-random "$3" || return $?

  local luks_name
  luks_name=$(basename "$3")
  local -n data_part=$6 || return $?
  data_part="/dev/mapper/${luks_name}"

  # open luks partition
  printf "%s" "$4" | cryptsetup luksOpen "$3" "${luks_name}" || return $?

  echo "Formatting the data partition ${data_part} ..."
  case "$5" in
	BTRFS)
      mkfs.btrfs "${data_part}" || return $?
		;;
	EXT4)
	    # archwiki -> Ext4#Enabling_metadata_checksums
      mkfs.ext4 -O metadata_csum "${data_part}" || return $?
		;;
	F2FS)
      # archwiki -> F2FS#Creating_a_F2FS_file_system
      # - requires f2fs-tools
      # - compression: "-O compression" and when mounting the filesystem, specify compress_algorithm=(lzo|lz4|zstd|lzo-rle)
      mkfs.f2fs -O extra_attr,inode_checksum,sb_checksum,compression "${data_part}" || return $?
		;;
	*)
		echo "Filesystem $5 is not yet supported!"
		return 1
		;;
  esac
}