#!/bin/bash

helpFunction()
{
   echo ""
   echo "Usage: $0 -v VmName -t TargetHost -d TargetDataset"
   echo -e "\t-v Name of the vm to backup"
   echo -e "\t-t Backup target host name"
   echo -e "\t-s VM source zfs dataset"
   echo -e "\t-d Backup target zfs dataset"
   exit 1 # Exit script after printing help
}

while getopts "v:t:s:d:" opt
do
   case "$opt" in
      v ) VM="$OPTARG" ;;
      t ) DESTHOST="$OPTARG" ;;
      s ) SRCZFS="$OPTARG" ;;
      d ) DESTZFS="$OPTARG" ;;
      ? ) helpFunction ;; # Print helpFunction in case parameter is non-existent
   esac
done

# Print helpFunction in case parameters are empty
if [ -z "$VM" ] || [ -z "$DESTHOST" ] || [ -z "$DESTZFS" ] || [ -z "$SRCZFS" ]
then
   echo "Some or all of the parameters are empty";
   helpFunction
fi

DATE=$(date "+%Y%m%d")
DATE30=$(date -d "-30day" "+%Y%m%d")
SNAPNAME="backup_$DATE"

VMDISKS=$(virsh domblklist $VM | egrep -o vd.)
DISKSPEC=""
for disk in $VMDISKS
do
    DISKSPEC+="--discspec $disk,file=/srv/snapshots/$VM/$VM-$disk-$SNAPNAME.qcow2,snapshot=external "
done
echo $DISKSPEC