#!/bin/sh

scriptcommand=genpass
runcommand=getpassword

batchdate="26.10.2021"

programtitle1="****  Zyxel VMG8823/8825"
programtitle2="****  Calculate admin/supervisor/wifi password by serial number"
programtitle3="****  Script by maximux/bovirus v. $batchdate"

# mask for check first part of serial nuimber
serialstartok1="172"
serialstartok2="182"
serialstartok3="190"
serialstartok4="192"

# mask for check midlle part of serial nuimber
serialmiddleok1="H"
serialmiddleok2="S"
serialmiddleok3="V"
serialmiddleok4="Y"

# default value for the operation
debug=0
exec=1
error=0

echo ""
echo "$programtitle1"
echo "$programtitle2"
echo "$programtitle3"
echo ""

if [ $# -eq 0 ]; then 
   error=1   # no modem serial number provided
else

   export SERIAL=$1
   SERIAL=$(echo "$SERIAL" | tr '[:lower:]' '[:upper:]')
   seriallenght=${#SERIAL}
   serialsubstring1=$(echo $SERIAL | cut -c1-1)  # extract first part of modem serial
   serialsubstring2=$(echo $SERIAL | cut -c2-4)  # extract secndo part of modem serial
   serialsubstring3=$(echo $SERIAL | cut -c5-5)  # extract third part of modem serial
   serialsubstring4=$(echo $SERIAL | cut -c6-13) # extract fourth part of modem serial

   #----------------------------------------------- check serial lenght of 13 charcaters
   if [ $seriallenght -ne 13 ]; then 
      if [ $error -eq 0 ]; then 
         error=2   
      fi
   fi

   #----------------------------------------------- check that first character is S
   if [ "$serialsubstring1" != "S" ]; then  
      if [ $error -eq 0 ]; then 
         error=3  
      fi
   fi

   #----------------------------------------------- check che 2nd part is all numeric
   if ! [ "$(echo $serialsubstring2 | grep -E "^[0-9]{1,}$")" ]; then   
      if [ $error -eq 0 ]; then 
         error=4
      fi
   fi

   #----------------------------------------------- check che 3rd part is a letter

   if ! [ "$(echo $serialsubstring3 | grep -E "^[A-Z]{1,}$")" ]; then   
      if [ $error -eq 0 ]; then 
         error=5
      fi
   fi

   #----------------------------------------------- check that 4th part is all numeric
   if ! [ "$(echo $serialsubstring4 | grep -E "^[0-9]{1,}$")" ]; then  
      if [ $error -eq 0 ]; then 
         error=6
      fi
   fi
fi

if [ $error -ne 0 ]; then
   if [ $error -ne 1 ]; then
      echo "-----------------------------------------"
      echo " Modem serial number = "$SERIAL
      echo "-----------------------------------------"
      echo ""
   fi
   echo "error   = $error"
   echo ""
   echo "error 1 = no serial number provided"
   echo "error 2 = serial number lenght is not 13 characters"
   echo "error 3 = character n. 1 of serial number is not 'S'"
   echo "error 4 = characters n. 2-3-4  of serial number are not numbers"
   echo "error 5 = character n. 5  of serial number is not a letter"
   echo "error 6 = characters from 6 to 13  of serial number are not numbers"
   echo ""
   echo "-----------------------------------------"
   echo ""
   echo "command syntax:" 
   echo ""
   echo "    genpass ModemSerialNumber"
   echo ""
   echo "ModemSerialNumber is a 13 character string"
   echo ""
   echo "Example: genpass S123V12345678"
else
   echo "-----------------------------------------"
   echo " Modem serial number = "$SERIAL
   echo "-----------------------------------------"
   if [ $exec -eq 1 ]; then
      export LD_LIBRARY_PATH=/opt/zyxel/lib:/opt/zyxel/lib/private:/opt/zyxel/lib/public:/opt/zyxel/usr/lib
      export LD_PRELOAD=/opt/genpass/libhook.so
      /opt/genpass/$runcommand
   fi
fi
echo ""
echo ""