always uses @ for subdomain when on root

dyndns.sh

@@ -14,6 +14,10 @@ fi
 SCRIPT="$0"
 SCRIPT_DIR=$(cd "${SCRIPT%/*}" && pwd )
 SCRIPT_NAME=${SCRIPT##*/}
+CACHE_DIR=${CACHE_DIR:-~/.cache/dyndns}
+CONFIG_DIR=${CONFIG_DIR:-~/.config/dyndns}
+mkdir -p ${CACHE_DIR}
+mkdir -p ${CONFIG_DIR}
 
 IP="$($SCRIPT_DIR/get_ip_addr.sh $ip_version)"
 if [ -z "$IP" ]; then
@@ -21,20 +25,23 @@ if [ -z "$IP" ]; then
     exit 1
 fi
 
-DIGITALOCEAN_TOKEN=`cat $SCRIPT_DIR/DIGITALOCEAN_TOKEN`
-DOMAIN=${2:-`cat $SCRIPT_DIR/DIGITALOCEAN_DOMAIN`}
+DIGITALOCEAN_TOKEN=`cat ${CONFIG_DIR}/DIGITALOCEAN_TOKEN`
+DOMAIN=${2:-`cat ${CONFIG_DIR}/DIGITALOCEAN_DOMAIN`}
 SUBDOMAIN=`echo $DOMAIN | sed "s/[^.]\+\.[^.]\+$//g"`
 if [ -z "$SUBDOMAIN" ]; then
     SUBDOMAIN="@"
     ROOT_DOMAIN=$DOMAIN
+elif [ "$SUBDOMAIN" = "@." ]; then
+    SUBDOMAIN="@"
+    ROOT_DOMAIN=`echo $DOMAIN | sed "s/^@.//"`
 else
     SUBDOMAIN=`echo $SUBDOMAIN | sed "s/\.$//g"`
     ROOT_DOMAIN=`echo $DOMAIN | sed "s/^${SUBDOMAIN}\.//g"`
 fi
 
-REPEAT_CHECK_DIR=$SCRIPT_DIR
-REPEAT_CHECK_A=$REPEAT_CHECK_DIR/REPEAT_CHECK_${DOMAIN}_A
-REPEAT_CHECK_AAAA=$REPEAT_CHECK_DIR/REPEAT_CHECK_${DOMAIN}_AAAA
+REPEAT_CHECK_DIR=${CACHE_DIR}
+REPEAT_CHECK_A=$REPEAT_CHECK_DIR/REPEAT_CHECK_${SUBDOMAIN}.${ROOT_DOMAIN}_A
+REPEAT_CHECK_AAAA=$REPEAT_CHECK_DIR/REPEAT_CHECK_${SUBDOMAIN}.${ROOT_DOMAIN}_AAAA
 REPEAT_CHECK="$([ $ip_version = 4 ] && echo $REPEAT_CHECK_A || echo $REPEAT_CHECK_AAAA)"
 
 get_a_record_ids() {
@@ -86,7 +93,7 @@ add_aaaa_record() {
 }
 
 delete_record_by_id() {
-    echo deleting existing A/AAAA record for $DOMAIN
+    echo deleting existing A/AAAA record for ${SUBDOMAIN}.${ROOT_DOMAIN}
     curl -X DELETE \
       -H "Content-Type: application/json" \
       -H "Authorization: Bearer $DIGITALOCEAN_TOKEN" \
@@ -100,10 +107,10 @@ replace_a_records() {
 
     new_record_id=`add_a_record`
     if [ "$new_record_id" = "null" ] ; then
-        echo unable to add new A record for $DOMAIN with value: $IP
+        echo unable to add new A record for ${SUBDOMAIN}.${ROOT_DOMAIN} with value: $IP
         return 1
     fi
-    echo added new A record for $DOMAIN with value: $IP
+    echo added new A record for ${SUBDOMAIN}.${ROOT_DOMAIN} with value: $IP
 }
 
 
@@ -114,10 +121,10 @@ replace_aaaa_records() {
 
     new_record_id=`add_aaaa_record`
     if [ "$new_record_id" = "null" ] ; then
-        echo unable to add new AAAA record for $DOMAIN with value: $IP
+        echo unable to add new AAAA record for ${SUBDOMAIN}.${ROOT_DOMAIN} with value: $IP
         return 1
     fi
-    echo added new AAAA record for $DOMAIN with value: $IP
+    echo added new AAAA record for ${SUBDOMAIN}.${ROOT_DOMAIN} with value: $IP
 }
 
 replace_records() {