autocomplete: Warn on @-mention when user is not subscribed.

Show a warning when @-mentioning a user who is not subscribe to
the stream the user was mentioned in, with an option to subscribe
them to the stream. Set up pipeline to enable the same.

Closes #M3373.

src/autocomplete/AutocompleteView.js

@@ -20,12 +20,15 @@ type Props = $ReadOnly<{|
   text: string,
   selection: InputSelection,
   onAutocomplete: (input: string) => void,
+  processAutoComplete: (completion: string, completionType: string) => void,
 |}>;
 
 export default class AutocompleteView extends PureComponent<Props> {
   handleAutocomplete = (autocomplete: string) => {
-    const { text, onAutocomplete, selection } = this.props;
+    const { text, onAutocomplete, selection, processAutoComplete } = this.props;
+    const { lastWordPrefix } = getAutocompleteFilter(text, selection);
     const newText = getAutocompletedText(text, autocomplete, selection);
+    processAutoComplete(autocomplete, lastWordPrefix);
     onAutocomplete(newText);
   };
 

src/compose/ComposeBox.js

@@ -13,6 +13,7 @@ import type {
   UserOrBot,
   Dispatch,
   Dimensions,
+  Subscription,
 } from '../types';
 import { connect } from '../react-redux';
 import {
@@ -27,18 +28,27 @@ import * as api from '../api';
 import { FloatingActionButton, Input } from '../common';
 import { showErrorAlert } from '../utils/info';
 import { IconDone, IconSend } from '../common/Icons';
-import { isStreamNarrow, isStreamOrTopicNarrow, topicNarrow } from '../utils/narrow';
+import {
+  isStreamNarrow,
+  isStreamOrTopicNarrow,
+  topicNarrow,
+  isPrivateNarrow,
+} from '../utils/narrow';
 import ComposeMenu from './ComposeMenu';
 import getComposeInputPlaceholder from './getComposeInputPlaceholder';
 import NotSubscribed from '../message/NotSubscribed';
 import AnnouncementOnly from '../message/AnnouncementOnly';
+import MentionedUserNotSubscribed from '../message/MentionedUserNotSubscribed';
+import AnimatedScaleComponent from '../animation/AnimatedScaleComponent';
 
 import {
   getAuth,
   getIsAdmin,
   getSession,
   getLastMessageTopic,
   getActiveUsersByEmail,
+  getStreamInNarrow,
+  getSubscriptionForId,
 } from '../selectors';
 import {
   getIsActiveStreamSubscribed,
@@ -60,6 +70,7 @@ type SelectorProps = {|
   editMessage: ?EditMessage,
   draft: string,
   lastMessageTopic: string,
+  subscription: Subscription | void,
 |};
 
 type Props = $ReadOnly<{|
@@ -83,6 +94,7 @@ type State = {|
   message: string,
   height: number,
   selection: InputSelection,
+  unsubscribedMentions: UserOrBot[],
 |};
 
 export const updateTextInput = (textInput: ?TextInput, text: string): void => {
@@ -122,6 +134,7 @@ class ComposeBox extends PureComponent<Props, State> {
     topic: this.props.lastMessageTopic,
     message: this.props.draft,
     selection: { start: 0, end: 0 },
+    unsubscribedMentions: [],
   };
 
   componentWillUnmount() {
@@ -184,6 +197,64 @@ class ComposeBox extends PureComponent<Props, State> {
     dispatch(draftUpdate(narrow, message));
   };
 
+  handleMentionSubscribedCheck = (message: string) => {
+    const { usersByEmail, subscription, narrow } = this.props;
+    if (isPrivateNarrow(narrow)) {
+      return;
+    }
+
+    const unformattedMessage = message.split('**')[1];
+
+    // We skip user groups, for which autocompletes are of the form
+    // `*<user_group_name>*`, and therefore, message.split('**')[1]
+    // is undefined.
+    if (unformattedMessage === undefined) {
+      return;
+    }
+    const [userFullName, userId] = unformattedMessage.split('|');
+    const unsubscribedMentions = this.state.unsubscribedMentions.slice();
+    let mentionedUser;
+    // eslint-disable-next-line no-unused-vars
+    for (const [email, user] of usersByEmail) {
+      if (userId !== undefined) {
+        if (user.user_id === userId) {
+          mentionedUser = user;
+          break;
+        }
+      } else if (user.full_name === userFullName) {
+        mentionedUser = user;
+        break;
+      }
+    }
+    if (
+      mentionedUser
+      && subscription
+      && !subscription.subscribers.includes(mentionedUser.user_id)
+      && !unsubscribedMentions.includes(mentionedUser)
+    ) {
+      unsubscribedMentions.push(mentionedUser);
+      this.setState({ unsubscribedMentions });
+    }
+  };
+
+  handleMentionWarningDismiss = (user: UserOrBot) => {
+    this.setState(prevState => ({
+      unsubscribedMentions: prevState.unsubscribedMentions.filter(
+        (x: UserOrBot) => x.user_id !== user.user_id,
+      ),
+    }));
+  };
+
+  clearMentionWarnings = () => {
+    this.setState({ unsubscribedMentions: [] });
+  };
+
+  processAutocomplete = (completion: string, completionType: string) => {
+    if (completionType === '@') {
+      this.handleMentionSubscribedCheck(completion);
+    }
+  };
+
   handleMessageAutocomplete = (message: string) => {
     this.setMessageInputValue(message);
   };
@@ -250,6 +321,7 @@ class ComposeBox extends PureComponent<Props, State> {
     dispatch(addToOutbox(this.getDestinationNarrow(), message));
 
     this.setMessageInputValue('');
+    this.clearMentionWarnings();
     dispatch(sendTypingStop(narrow));
   };
 
@@ -332,7 +404,15 @@ class ComposeBox extends PureComponent<Props, State> {
   };
 
   render() {
-    const { isTopicFocused, isMenuExpanded, height, message, topic, selection } = this.state;
+    const {
+      isTopicFocused,
+      isMenuExpanded,
+      height,
+      message,
+      topic,
+      selection,
+      unsubscribedMentions,
+    } = this.state;
     const {
       ownEmail,
       narrow,
@@ -344,6 +424,18 @@ class ComposeBox extends PureComponent<Props, State> {
       isSubscribed,
     } = this.props;
 
+    const mentionWarnings = [];
+    for (const user of unsubscribedMentions) {
+      mentionWarnings.push(
+        <MentionedUserNotSubscribed
+          narrow={narrow}
+          user={user}
+          onDismiss={this.handleMentionWarningDismiss}
+          key={user.user_id}
+        />,
+      );
+    }
+
     if (!isSubscribed) {
       return <NotSubscribed narrow={narrow} />;
     } else if (isAnnouncementOnly && !isAdmin) {
@@ -358,6 +450,9 @@ class ComposeBox extends PureComponent<Props, State> {
 
     return (
       <View style={this.styles.wrapper}>
+        <AnimatedScaleComponent visible={mentionWarnings.length !== 0}>
+          {mentionWarnings}
+        </AnimatedScaleComponent>
         <View style={[this.styles.autocompleteWrapper, { marginBottom: height }]}>
           <TopicAutocomplete
             isFocused={isTopicFocused}
@@ -370,6 +465,7 @@ class ComposeBox extends PureComponent<Props, State> {
             selection={selection}
             text={message}
             onAutocomplete={this.handleMessageAutocomplete}
+            processAutoComplete={this.processAutocomplete}
           />
         </View>
         <View style={[this.styles.composeBox, style]} onLayout={this.handleLayoutChange}>
@@ -435,4 +531,7 @@ export default connect<SelectorProps, _, _>((state, props) => ({
   editMessage: getSession(state).editMessage,
   draft: getDraftForNarrow(state, props.narrow),
   lastMessageTopic: getLastMessageTopic(state, props.narrow),
+  subscription: isPrivateNarrow(props.narrow)
+    ? undefined
+    : getSubscriptionForId(state, getStreamInNarrow(state, props.narrow).stream_id),
 }))(ComposeBox);