#!/bin/bash

# form https://github.com/pocopico/tinycore-redpill/blob/main/serialnumbergen.sh

function beginArray() {
  case $1 in
  DS3615xs)
    permanent="LWN"
    serialstart="1130 1230 1330 1430"
    ;;
  DS3617xs)
    permanent="ODN"
    serialstart="1130 1230 1330 1430"
    ;;
  DS916+)
    permanent="NZN"
    serialstart="1130 1230 1330 1430"
    ;;
  DS918+)
    permanent="PDN"
    serialstart="1780 1790 1860 1980"
    ;;
  DS920+)
    permanent="SBR"
    serialstart="2030 2040 20C0 2150"
    ;;
  DS3622xs+)
    permanent="SQR"
    serialstart="2030 2040 20C0 2150"
    ;;
  FS6400)
    permanent="PSN"
    serialstart="1960"
    ;;
  DVA3219)
    permanent="RFR"
    serialstart="1930 1940"
    ;;
  DVA3221)
    permanent="SJR"
    serialstart="2030 2040 20C0 2150"
    ;;
  esac
}


function random() {
  printf "%06d" $(($RANDOM %30000 +1 ))
}
function randomhex() {
  val=$(( $RANDOM %255 +1))
  echo "obase=16; $val" | bc
}

function generateRandomLetter() {
  for i in a b c d e f g h j k l m n p q r s t v w x y z
  do echo $i
  done | sort -R|tail -1
}


function generateRandomValue() {
  for i in 0 1 2 3 4 5 6 7 8 9 a b c d e f g h j k l m n p q r s t v w x y z
  do echo $i
  done | sort -R|tail -1
}

function toupper() {
  echo $1 | tr 'a-z' 'A-Z'
}

function generateMacAddress() {
  #toupper "Mac Address: 00:11:32:$(randomhex):$(randomhex):$(randomhex)"
  printf '00:11:32:%02X:%02X:%02X' $[RANDOM%256]  $[RANDOM%256]  $[RANDOM%256]
}

function generateSerial(){
	beginArray $1
	case $1 in
    DS3615xs)
      serialnum="`echo "$serialstart" |  tr ' ' '\n' | sort -R | tail -1`$permanent"$(random)
      ;;
    DS3617xs)
      serialnum="`echo "$serialstart" |  tr ' ' '\n' | sort -R | tail -1`$permanent"$(random)
      ;;
    DS916+)
      serialnum="`echo "$serialstart" |  tr ' ' '\n' | sort -R | tail -1`$permanent"$(random)
      ;;
    DS918+)
      serialnum="`echo "$serialstart" |  tr ' ' '\n' | sort -R | tail -1`$permanent"$(random)
      ;;
    FS6400)
      serialnum="`echo "$serialstart" |  tr ' ' '\n' | sort -R | tail -1`$permanent"$(random)
      ;;
    DS920+)
      serialnum=$(toupper "`echo "$serialstart" |  tr ' ' '\n' | sort -R | tail -1`$permanent"$(generateRandomLetter)$(generateRandomValue)$(generateRandomValue)$(generateRandomValue)$(generateRandomValue)$(generateRandomLetter))
      ;;
    DS3622xs+)
      serialnum=$(toupper "`echo "$serialstart" |  tr ' ' '\n' | sort -R | tail -1`$permanent"$(generateRandomLetter)$(generateRandomValue)$(generateRandomValue)$(generateRandomValue)$(generateRandomValue)$(generateRandomLetter))
      ;;
    DVA3219)
      serialnum=$(toupper "`echo "$serialstart" |  tr ' ' '\n' | sort -R | tail -1`$permanent"$(generateRandomLetter)$(generateRandomValue)$(generateRandomValue)$(generateRandomValue)$(generateRandomValue)$(generateRandomLetter))
      ;;
    DVA3221)
      serialnum=$(toupper "`echo "$serialstart" |  tr ' ' '\n' | sort -R | tail -1`$permanent"$(generateRandomLetter)$(generateRandomValue)$(generateRandomValue)$(generateRandomValue)$(generateRandomValue)$(generateRandomLetter))
      ;;
  esac
	echo $serialnum
}


function showhelp() {
cat << EOF
$(basename ${0})
----------------------------------------------------------------------------------------
Usage: ${0} <platform>
Available platforms :
----------------------------------------------------------------------------------------
DS3615xs DS3617xs DS916+ DS918+ DS920+ DS3622xs+ FS6400 DVA3219 DVA3221
e.g. $(basename ${0}) DS3615xs
----------------------------------------------------------------------------------------
EOF
}

if [ -z "$1" ] ; then
  showhelp
else
  if [ "$1" = "DS3615xs" ] || [ "$1" = "DS3617xs" ] || [ "$1" = "DS916+" ] || [ "$1" = "DS918+" ] || [ "$1" = "DS920+" ] || [ "$1" = "DS3622xs+" ] || [ "$1" = "FS6400" ] || [ "$1" = "DVA3219" ] || [ "$1" = "DVA3221" ]; then
    echo -e "Model:\t\t\t$1"
    echo -e "Mac Address:\t\t$(generateMacAddress)"
    echo -e "Serial Number:\t\t$(generateSerial $1)"
  else
    echo "Error : $1 is not an available model for serial number generation. "
    echo "Available Models : DS3615xs DS3617xs DS916+ DS918+ DS920+ DS3622xs+ DVA3219 DVA3221"
    exit 1
  fi
fi