#!/bin/bash

Help()
{
   # Display Help
   echo "create a rotating backup of the var folder"
   echo
   echo "Syntax: varbackup [-h|s]"
   echo "options:"
   echo "h     Print this Help."
   echo "s     Silent mode."
   echo
}

while getopts ":hs" option; do
   case $option in
      h) # display Help
         Help
         exit;;
      s) # enable silent mode
         isSilent=true;;
   esac
done

# main program
currDir="$(pwd)/backup/var/"

if [ ! -d "$currDir" ]; then
  [ -z ${isSilent} ] && echo "creating backup directory ${currDir}"
  mkdir -p "${currDir}" 
fi

if [ ! -f "${currDir}../rotatemap_var.conf" ]; then
  [ -z ${isSilent} ] && echo "creating config file"
  printf "${currDir}var.tar.gz {\nrotate 100\n}" > ${currDir}/../rotatemap_var.conf
fi

[ -z ${isSilent} ] && echo "pack var directory"
tar -cf ${currDir}var.new.tar ./var;

if [ ! -f "${currDir}var.tar" ] || [ "$(cmp ${currDir}var.tar ${currDir}var.new.tar)" ]; then
  gzip -c ${currDir}var.tar > ${currDir}var.tar.gz
  logrotate -f -s "${currDir}../rotatemap_var.state" "${currDir}../rotatemap_var.conf"
  mv ${currDir}var.new.tar ${currDir}var.tar
else
  rm ${currDir}var.new.tar
fi

[ -z ${isSilent} ] && echo "finished"