Compose: Show 'Replying to a post' if unchecked all mentions

Signed-off-by: marcin mikołajczak <git@mkljczk.pl>

app/soapbox/features/compose/components/reply_mentions.js

@@ -11,6 +11,7 @@ class ReplyMentions extends ImmutablePureComponent {
     onOpenMentionsModal: PropTypes.func.isRequired,
     explicitAddressing: PropTypes.bool,
     to: ImmutablePropTypes.orderedSet,
+    parentTo: ImmutablePropTypes.orderedSet,
     isReply: PropTypes.bool,
   };
 
@@ -21,12 +22,23 @@ class ReplyMentions extends ImmutablePureComponent {
   }
 
   render() {
-    const { explicitAddressing, to, isReply } = this.props;
+    const { explicitAddressing, to, parentTo, isReply } = this.props;
 
-    if (!explicitAddressing || !isReply || !to || to.size === 0) {
+    if (!explicitAddressing || !isReply || !to || (parentTo.size === 0)) {
       return null;
     }
 
+    if (to.size === 0) {
+      return (
+        <a href='#' className='reply-mentions' onClick={this.handleClick}>
+          <FormattedMessage
+            id='reply_mentions.reply_empty'
+            defaultMessage='Replying to post'
+          />
+        </a>
+      );
+    }
+
     return (
       <a href='#' className='reply-mentions' onClick={this.handleClick}>
         <FormattedMessage

app/soapbox/features/compose/containers/reply_mentions_container.js

@@ -1,6 +1,7 @@
 import { connect } from 'react-redux';
 
 import { openModal } from 'soapbox/actions/modal';
+import { statusToMentionsAccountIdsArray } from 'soapbox/reducers/compose';
 import { makeGetStatus } from 'soapbox/selectors';
 import { getFeatures } from 'soapbox/utils/features';
 
@@ -28,8 +29,14 @@ const makeMapStateToProps = () => {
     }
     const to = state.getIn(['compose', 'to']);
 
+    const me = state.get('me');
+    const account = state.getIn(['accounts', me]);
+
+    const parentTo = statusToMentionsAccountIdsArray(state, status, account);
+
     return {
       to,
+      parentTo,
       isReply: true,
       explicitAddressing: true,
     };