#!/usr/bin/env bash
set -Eeuo pipefail

# Docker environment variables

: ${DISK_IO:='native'}          # I/O Mode, can be set to 'native', 'threads' or 'io_turing'
: ${DISK_FMT:='raw'}            # Disk file format, 'raw' by default for best performance
: ${DISK_CACHE:='none'}         # Caching mode, can be set to 'writeback' for better performance
: ${DISK_DISCARD:='on'}         # Controls whether unmap (TRIM) commands are passed to the host.
: ${DISK_ROTATION:='1'}         # Rotation rate, set to 1 for SSD storage and increase for HDD
: ${DISK_FLAGS:='nocow=on'}     # Specifies the options for use with the qcow2 disk format

BOOT="$STORAGE/$BASE.boot.img"
SYSTEM="$STORAGE/$BASE.system.img"

[ ! -f "$BOOT" ] && error "Virtual DSM boot-image does not exist ($BOOT)" && exit 81
[ ! -f "$SYSTEM" ] && error "Virtual DSM system-image does not exist ($SYSTEM)" && exit 82

DISK_OPTS="\
    -object iothread,id=io1 -object iothread,id=io2 \
    -device virtio-scsi-pci,id=hw-synoboot,iothread=io1,bus=pcie.0,addr=0xa \
    -drive file=$BOOT,if=none,id=drive-synoboot,format=raw,cache=$DISK_CACHE,aio=$DISK_IO,discard=$DISK_DISCARD,detect-zeroes=on \
    -device scsi-hd,bus=hw-synoboot.0,channel=0,scsi-id=0,lun=0,drive=drive-synoboot,id=synoboot0,rotation_rate=$DISK_ROTATION,bootindex=1 \
    -device virtio-scsi-pci,id=hw-synosys,iothread=io1,bus=pcie.0,addr=0xb \
    -drive file=$SYSTEM,if=none,id=drive-synosys,format=raw,cache=$DISK_CACHE,aio=$DISK_IO,discard=$DISK_DISCARD,detect-zeroes=on \
    -device scsi-hd,bus=hw-synosys.0,channel=0,scsi-id=0,lun=0,drive=drive-synosys,id=synosys0,rotation_rate=$DISK_ROTATION,bootindex=2"

fmt2ext() {
  local DISK_FMT=$1

  case "${DISK_FMT,,}" in
    qcow2)
      echo "qcow2"
      ;;
    raw)
      echo "img"
      ;;
    *)
      error "Unrecognized disk format: $DISK_FMT" && exit 78
      ;;
  esac
}

ext2fmt() {
  local DISK_EXT=$1

  case "${DISK_EXT,,}" in
    qcow2)
      echo "qcow2"
      ;;
    img)
      echo "raw"
      ;;
    *)
      error "Unrecognized file extension: .$DISK_EXT" && exit 78
      ;;
  esac
}

getSize() {
  local DISK_FILE=$1
  local DISK_EXT DISK_FMT

  DISK_EXT="$(echo "${DISK_FILE//*./}" | sed 's/^.*\.//')"
  DISK_FMT="$(ext2fmt "$DISK_EXT")"

  case "${DISK_FMT,,}" in
    raw)
      stat -c%s "$DISK_FILE"
      ;;
    qcow2)
      qemu-img info "$DISK_FILE" -f "$DISK_FMT" | grep '^virtual size: ' | sed 's/.*(\(.*\) bytes)/\1/'
      ;;
    *)
      error "Unrecognized disk format: $DISK_FMT" && exit 78
      ;;
  esac
}

createDisk() {
  local DISK_FILE=$1
  local DISK_SPACE=$2
  local DISK_DESC=$3
  local DISK_FMT=$4
  local DIR SPACE DATA_SIZE

  if [[ "$ALLOCATE" != [Nn]* ]]; then

    # Check free diskspace
    DIR=$(dirname "$DISK_FILE")
    SPACE=$(df --output=avail -B 1 "$DIR" | tail -n 1)
    local SPACE_GB=$(( (SPACE + 1073741823)/1073741824 ))
    DATA_SIZE=$(numfmt --from=iec "$DISK_SPACE")

    if (( DATA_SIZE > SPACE )); then
      error "Not enough free space to create a $DISK_DESC of $DISK_SPACE in $DIR, it has only $SPACE_GB GB available..."
      error "Please specify a smaller ${DISK_DESC^^}_SIZE or disable preallocation by setting ALLOCATE=N." && exit 76
    fi
  fi

  local FAIL="Could not create a $DISK_SPACE $DISK_FMT file for $DISK_DESC ($DISK_FILE)"

  case "${DISK_FMT,,}" in
    raw)
      if [[ "$ALLOCATE" == [Nn]* ]]; then

        # Create an empty file
        if ! truncate -s "$DISK_SPACE" "$DISK_FILE"; then
          rm -f "$DISK_FILE"
          error "$FAIL" && exit 77
        fi

      else

        # Create an empty file
        if ! fallocate -l "$DISK_SPACE" "$DISK_FILE"; then
          if ! truncate -s "$DISK_SPACE" "$DISK_FILE"; then
            rm -f "$DISK_FILE"
            error "$FAIL" && exit 77
          fi
        fi

      fi
      ;;
    qcow2)
      local DISK_OPTS="$DISK_ALLOC"
      [ -n "$DISK_FLAGS" ] && DISK_OPTS="$DISK_OPTS,$DISK_FLAGS"
      if ! qemu-img create -f "$DISK_FMT" -o "$DISK_OPTS" -- "$DISK_FILE" "$DISK_SPACE" ; then
        rm -f "$DISK_FILE"
        error "$FAIL" && exit 70
      fi
      ;;
  esac

  return 0
}

resizeDisk() {
  local DISK_FILE=$1
  local DISK_SPACE=$2
  local DISK_DESC=$3
  local DISK_FMT=$4
  local CUR_SIZE DATA_SIZE DIR SPACE

  CUR_SIZE=$(getSize "$DISK_FILE")
  DATA_SIZE=$(numfmt --from=iec "$DISK_SPACE")
  local REQ=$((DATA_SIZE-CUR_SIZE))
  (( REQ < 1 )) && error "Shrinking disks is not supported yet, please increase ${DISK_DESC^^}_SIZE." && exit 71

  if [[ "$ALLOCATE" != [Nn]* ]]; then

    # Check free diskspace
    DIR=$(dirname "$DISK_FILE")
    SPACE=$(df --output=avail -B 1 "$DIR" | tail -n 1)
    local SPACE_GB=$(( (SPACE + 1073741823)/1073741824 ))

    if (( REQ > SPACE )); then
      error "Not enough free space to resize $DISK_DESC to $DISK_SPACE in $DIR, it has only $SPACE_GB GB available.."
      error "Please specify a smaller ${DISK_DESC^^}_SIZE or disable preallocation by setting ALLOCATE=N." && exit 74
    fi
  fi

  local GB=$(( (CUR_SIZE + 1073741823)/1073741824 ))
  info "Resizing $DISK_DESC from ${GB}G to $DISK_SPACE..."
  local FAIL="Could not resize $DISK_FMT file of $DISK_DESC ($DISK_FILE) from ${GB}G to $DISK_SPACE .."

  case "${DISK_FMT,,}" in
    raw)
      if [[ "$ALLOCATE" == [Nn]* ]]; then

        # Resize file by changing its length
        if ! truncate -s "$DISK_SPACE" "$DISK_FILE"; then
          error "$FAIL" && exit 75
        fi

      else

        # Resize file by allocating more space
        if ! fallocate -l "$DISK_SPACE" "$DISK_FILE"; then
          if ! truncate -s "$DISK_SPACE" "$DISK_FILE"; then
            error "$FAIL" && exit 75
          fi
        fi

      fi
      ;;
    qcow2)
      if ! qemu-img resize -f "$DISK_FMT" "--$DISK_ALLOC" "$DISK_FILE" "$DISK_SPACE" ; then
        error "$FAIL" && exit 72
      fi
      ;;
  esac

  return 0
}

convertDisk() {
  local SOURCE_FILE=$1
  local SOURCE_FMT=$2
  local DST_FILE=$3
  local DST_FMT=$4
  local DISK_BASE=$5
  local DISK_DESC=$6
  local CONV_FLAGS="-p"
  local DISK_OPTS="$DISK_ALLOC"
  local TMP_FILE="$DISK_BASE.tmp"
  local DIR CUR_SIZE SPACE

  [ -f "$DST_FILE" ] && error "Conversion failed, destination file $DST_FILE already exists?" && exit 79
  [ ! -f "$SOURCE_FILE" ] && error "Conversion failed, source file $SOURCE_FILE does not exists?" && exit 79

  if [[ "$ALLOCATE" != [Nn]* ]]; then

    # Check free diskspace
    DIR=$(dirname "$TMP_FILE")
    CUR_SIZE=$(getSize "$SOURCE_FILE")
    SPACE=$(df --output=avail -B 1 "$DIR" | tail -n 1)
    local SPACE_GB=$(( (SPACE + 1073741823)/1073741824 ))

    if (( CUR_SIZE > SPACE )); then
      error "Not enough free space to convert $DISK_DESC to $DST_FMT in $DIR, it has only $SPACE_GB GB available..."
      error "Please free up some disk space or disable preallocation by setting ALLOCATE=N." && exit 76
    fi
  fi

  info "Converting $DISK_DESC to $DST_FMT, please wait until completed..."

  case "$DST_FMT" in
    qcow2)
      if [[ "$ALLOCATE" == [Nn]* ]]; then
        CONV_FLAGS="$CONV_FLAGS -c"
      fi
      [ -n "$DISK_FLAGS" ] && DISK_OPTS="$DISK_OPTS,$DISK_FLAGS"
      ;;
  esac

  rm -f "$TMP_FILE"

  # shellcheck disable=SC2086
  if ! qemu-img convert -f "$SOURCE_FMT" $CONV_FLAGS -o "$DISK_OPTS" -O "$DST_FMT" -- "$SOURCE_FILE" "$TMP_FILE"; then
    rm -f "$TMP_FILE"
    error "Failed to convert $DISK_DESC to $DST_FMT format in $DIR, is there enough space available?" && exit 79
  fi

  rm -f "$SOURCE_FILE"
  mv "$TMP_FILE" "$DST_FILE"

  info "Conversion of $DISK_DESC to $DST_FMT completed succesfully!"

  return 0
}

addDisk () {
  local DISK_ID=$1
  local DISK_BASE=$2
  local DISK_EXT=$3
  local DISK_DESC=$4
  local DISK_SPACE=$5
  local DISK_INDEX=$6
  local DISK_ADDRESS=$7
  local DISK_FMT=$8
  local DISK_FILE="$DISK_BASE.$DISK_EXT"
  local DIR FS DATA_SIZE PREV_FMT PREV_EXT CUR_SIZE

  DIR=$(dirname "$DISK_FILE")
  [ ! -d "$DIR" ] && return 0

  FS=$(stat -f -c %T "$DIR")
  if [[ "$FS" == "overlay"* ]]; then
    info "Warning: the filesystem of $DIR is OverlayFS, this usually means it was binded to an invalid path!"
  fi
  if [[ "$FS" == "btrfs"* ]]; then
    FA=$(lsattr -d "$DIR")
    if [[ "$FA" != *"C"* ]]; then
      info "Warning: the filesystem of $DIR is BTRFS, and COW (copy on write) is not disabled for that folder!"
      info "This will negatively affect write performance, please empty the folder and disable COW (chattr +C <path>)."
    fi
  fi

  [ -z "$DISK_SPACE" ] && DISK_SPACE="16G"
  DISK_SPACE=$(echo "$DISK_SPACE" | sed 's/MB/M/g;s/GB/G/g;s/TB/T/g')
  DATA_SIZE=$(numfmt --from=iec "$DISK_SPACE")

  if (( DATA_SIZE < 6442450944 )); then
    error "Please increase ${DISK_DESC^^}_SIZE to at least 6 GB." && exit 73
  fi

  if ! [ -f "$DISK_FILE" ] ; then

    if [[ "${DISK_FMT,,}" != "raw" ]]; then
      PREV_FMT="raw"
    else
      PREV_FMT="qcow2"
    fi
    PREV_EXT="$(fmt2ext "$PREV_FMT")"

    if [ -f "$DISK_BASE.$PREV_EXT" ] ; then
      convertDisk "$DISK_BASE.$PREV_EXT" "$PREV_FMT" "$DISK_FILE" "$DISK_FMT" "$DISK_BASE" "$DISK_DESC" || exit $?
    fi
  fi

  if [ -f "$DISK_FILE" ]; then

    CUR_SIZE=$(getSize "$DISK_FILE")

    if (( DATA_SIZE > CUR_SIZE )); then
      resizeDisk "$DISK_FILE" "$DISK_SPACE" "$DISK_DESC" "$DISK_FMT" || exit $?
    fi

  else

    createDisk "$DISK_FILE" "$DISK_SPACE" "$DISK_DESC" "$DISK_FMT" || exit $?

  fi

  DISK_OPTS="$DISK_OPTS \
    -device virtio-scsi-pci,id=hw-$DISK_ID,iothread=io2,bus=pcie.0,addr=$DISK_ADDRESS \
    -drive file=$DISK_FILE,if=none,id=drive-$DISK_ID,format=$DISK_FMT,cache=$DISK_CACHE,aio=$DISK_IO,discard=$DISK_DISCARD,detect-zeroes=on \
    -device scsi-hd,bus=hw-$DISK_ID.0,channel=0,scsi-id=0,lun=0,drive=drive-$DISK_ID,id=$DISK_ID,rotation_rate=$DISK_ROTATION,bootindex=$DISK_INDEX"

  return 0
}

DISK_EXT="$(fmt2ext "$DISK_FMT")" || exit $?

if [[ "$ALLOCATE" == [Nn]* ]]; then
  DISK_ALLOC="preallocation=off"
else
  DISK_ALLOC="preallocation=falloc"
fi

DISK1_FILE="$STORAGE/data"
if [[ ! -f "$DISK1_FILE.img" ]] && [[ -f "$STORAGE/data${DISK_SIZE}.img" ]]; then
  # Fallback for legacy installs
  mv "$STORAGE/data${DISK_SIZE}.img" "$DISK1_FILE.img"
fi

DISK2_FILE="/storage2/data2"
if [ ! -f "$DISK2_FILE.img" ]; then
  # Fallback for legacy installs
  FALLBACK="/storage2/data.img"
  if [[ -f "$DISK1_FILE.img" ]] && [[ -f "$FALLBACK" ]]; then
    SIZE1=$(stat -c%s "$FALLBACK")
    SIZE2=$(stat -c%s "$DISK1_FILE.img")
    if [[ SIZE1 -ne SIZE2 ]]; then
      mv "$FALLBACK" "$DISK2_FILE.img"
    fi
  fi
fi

DISK3_FILE="/storage3/data3"
if [ ! -f "$DISK3_FILE.img" ]; then
  # Fallback for legacy installs
  FALLBACK="/storage3/data.img"
  if [[ -f "$DISK1_FILE.img" ]] && [[ -f "$FALLBACK" ]]; then
    SIZE1=$(stat -c%s "$FALLBACK")
    SIZE2=$(stat -c%s "$DISK1_FILE.img")
    if [[ SIZE1 -ne SIZE2 ]]; then
      mv "$FALLBACK" "$DISK3_FILE.img"
    fi
  fi
fi

DISK4_FILE="/storage4/data4"
DISK5_FILE="/storage5/data5"
DISK6_FILE="/storage6/data6"

: ${DISK2_SIZE:=''}
: ${DISK3_SIZE:=''}
: ${DISK4_SIZE:=''}
: ${DISK5_SIZE:=''}
: ${DISK6_SIZE:=''}

addDisk "userdata" "$DISK1_FILE" "$DISK_EXT" "disk" "$DISK_SIZE" "3" "0xc" "$DISK_FMT" || exit $?
addDisk "userdata2" "$DISK2_FILE" "$DISK_EXT" "disk2" "$DISK2_SIZE" "4" "0xd" "$DISK_FMT" || exit $?
addDisk "userdata3" "$DISK3_FILE" "$DISK_EXT" "disk3" "$DISK3_SIZE" "5" "0xe" "$DISK_FMT" || exit $?
addDisk "userdata4" "$DISK4_FILE" "$DISK_EXT" "disk4" "$DISK4_SIZE" "9" "0x7" "$DISK_FMT" || exit $?
addDisk "userdata5" "$DISK5_FILE" "$DISK_EXT" "disk5" "$DISK5_SIZE" "10" "0x8" "$DISK_FMT" || exit $?
addDisk "userdata6" "$DISK6_FILE" "$DISK_EXT" "disk6" "$DISK6_SIZE" "11" "0x9" "$DISK_FMT" || exit $?

addDevice () {

  local DISK_ID=$1
  local DISK_DEV=$2
  local DISK_INDEX=$3
  local DISK_ADDRESS=$4

  [ -z "$DISK_DEV" ] && return 0
  [ ! -b "$DISK_DEV" ] && error "Device $DISK_DEV cannot be found! Please add it to the 'devices' section of your compose file." && exit 55

  DISK_OPTS="$DISK_OPTS \
    -device virtio-scsi-pci,id=hw-$DISK_ID,iothread=io2,bus=pcie.0,addr=$DISK_ADDRESS \
    -drive file=$DISK_DEV,if=none,id=drive-$DISK_ID,format=raw,cache=$DISK_CACHE,aio=$DISK_IO,discard=$DISK_DISCARD,detect-zeroes=on \
    -device scsi-hd,bus=hw-$DISK_ID.0,channel=0,scsi-id=0,lun=0,drive=drive-$DISK_ID,id=$DISK_ID,rotation_rate=$DISK_ROTATION,bootindex=$DISK_INDEX"

  return 0
}

: ${DEVICE:=''}        # Docker variable to passthrough a block device, like /dev/vdc1.
: ${DEVICE2:=''}
: ${DEVICE3:=''}
: ${DEVICE4:=''}
: ${DEVICE5:=''}
: ${DEVICE6:=''}

addDevice "userdata7" "$DEVICE" "6" "0xf" || exit $?
addDevice "userdata8" "$DEVICE2" "7" "0x5" || exit $?
addDevice "userdata9" "$DEVICE3" "8" "0x6" || exit $?
addDevice "userdata4" "$DEVICE4" "9" "0x7" || exit $?
addDevice "userdata5" "$DEVICE5" "10" "0x8" || exit $?
addDevice "userdata6" "$DEVICE6" "11" "0x9" || exit $?

return 0