#!/usr/bin/bash

function usage {
  echo "Usage: vmclone -s|--source <SOURCE_VM> -t|--target <TARGET_VM> -o|--scriptonly"
  echo "  o| --scriptonly, only clone script is generated, the clone command will not be executed"
}

########
# MAIN #
########

typeset SOURCE_VM
typeset TARGET_VM
typeset SCRIPTONLY
typeset CLONESCRIPT="/tmp/kvmclone.sh"
typeset -i DISK_COUNT_SOURCE
typeset -i I
typeset RC
typeset REPLACE

# parameter processing
while [ "$1" != "" ]; do
    case $1 in
        -s | --source )         shift
                                SOURCE_VM="$1"
                                ;;
        -t | --target )         shift
                                TARGET_VM="$1"
                                ;;
        -o | --scriptonly )     SCRIPTONLY=true
                                ;;                               
        -r | --replace )        REPLACE=true
                                ;;   
        -h | --help )           usage
                                exit
                                ;;
        * )                     usage
                                exit 1
    esac
    shift
done


if [ -z "$SOURCE_VM" ] || [ -z "$TARGET_VM" ]; then
  usage
  exit
fi

# check if source VM exists
I=$(virsh list --all | grep $SOURCE_VM | wc -l)
if (( I == 0 )); then
	echo "Source VM ($SOURCE_VM) does not exists"
	exit 1
fi

# check if source VM is shut off
RC=$(virsh domstate $SOURCE_VM)
if [ "$RC" != "shut off" ]; then
	echo "Source VM ($SOURCE_VM) is $RC, please shut it down first"
	exit 1
fi

# check if target VM exists
I=$(virsh list --all | grep $TARGET_VM | wc -l)
if (( I > 0 )); then
	# -r|--replace option was used
	if [ "$REPLACE" == true ] ; then
		# destroy the VM and the underlayng storage
		echo "Shutdown VM $TARGET_VM"
		virsh destroy $TARGET_VM > /dev/null 2>&1
		echo "Remove VM $TARGET_VM"
		virsh undefine $TARGET_VM --remove-all-storage > /dev/null 2>&1
	else
	  echo "Target VM ($TARGET_VM) already exists, use -r|--replace option to replace it"
	  exit 1		
	fi
fi

# generate KVM clone shell
rm -rf $CLONESCRIPT
echo -e "#!/usr/bin/bash"'\n' >> $CLONESCRIPT
chmod +x $CLONESCRIPT

echo "virt-clone \\" >> $CLONESCRIPT
echo "  --original $SOURCE_VM \\" >> $CLONESCRIPT
echo "  --name $TARGET_VM \\" >> $CLONESCRIPT

DISK_COUNT_SOURCE=$(virsh domblklist ${SOURCE_VM} --details | grep -v cdrom | grep "file" | wc -l)

I=0
for DISK in $(virsh domblklist ${SOURCE_VM} --details | grep -v cdrom | grep "file" | awk -F " " '{ print $4}')
do
  I=$((I+1))
  NEWDISK=${DISK/$SOURCE_VM/$TARGET_VM}
  if (( I < DISK_COUNT_SOURCE )); then
    echo "  --file $NEWDISK \\" >> $CLONESCRIPT
  else
    echo "  --file $NEWDISK" >> $CLONESCRIPT
  fi
done

echo "KVM clone script [$SOURCE_VM -> $TARGET_VM] has been generated: $CLONESCRIPT"

if [ "$SCRIPTONLY" != true ] ; then
	# recreate VM storage directories
	cat $CLONESCRIPT | grep '\-\-file' | xargs -I{} echo {} | sed "s/--file//g" |  sed 's/ //g' | xargs -I{} dirname {} | sort -u | xargs -I{} rm -rf {}
	cat $CLONESCRIPT | grep '\-\-file' | xargs -I{} echo {} | sed "s/--file//g" |  sed 's/ //g' | xargs -I{} dirname {} | sort -u | xargs -I{} mkdir -p {}
	# Run generated KVM clone shell
	echo "Executing $CLONESCRIPT.."
    $CLONESCRIPT
fi