action sheet: Add delete topic feature.

The webapp offers the feature to delete all messages within a
topic for a stream. This feature is missing in the mobile app.

Create action `deleteMessagesForTopic()`. Create API function
'deleteTopic'. Add 'Delete topic' action in message action sheet.

src/api/index.js

@@ -18,6 +18,7 @@ import markAllAsRead from './mark_as_read/markAllAsRead';
 import markStreamAsRead from './mark_as_read/markStreamAsRead';
 import markTopicAsRead from './mark_as_read/markTopicAsRead';
 import deleteMessage from './messages/deleteMessage';
+import deleteTopic from './messages/deleteTopic';
 import getRawMessageContent from './messages/getRawMessageContent';
 import getMessages from './messages/getMessages';
 import getMessageHistory from './messages/getMessageHistory';
@@ -72,6 +73,7 @@ export {
   markStreamAsRead,
   markTopicAsRead,
   deleteMessage,
+  deleteTopic,
   getRawMessageContent,
   getMessages,
   getMessageHistory,

src/api/messages/deleteTopic.js

@@ -0,0 +1,11 @@
+/* @flow strict-local */
+import type { ApiResponse, Auth } from '../transportTypes';
+import { apiPost } from '../apiFetch';
+
+/**
+ * Delete all messages in a stream for a given topic.
+ */
+export default async (auth: Auth, streamId: number, topicName: string): Promise<ApiResponse> =>
+  apiPost(auth, `streams/${streamId}/delete_topic`, {
+    topic_name: topicName,
+  });

src/message/messageActionSheet.js

@@ -14,6 +14,7 @@ import * as api from '../api';
 import { showToast } from '../utils/info';
 import { doNarrow, startEditMessage, deleteOutboxMessage, navigateToEmojiPicker } from '../actions';
 import { navigateToMessageReactionScreen } from '../nav/navActions';
+import { deleteMessagesForTopic } from '../topics/topicActions';
 
 // TODO really this belongs in a libdef.
 export type ShowActionSheetWithOptions = (
@@ -90,6 +91,34 @@ const muteTopic = async ({ auth, message }) => {
 muteTopic.title = 'Mute topic';
 muteTopic.errorMessage = 'Failed to mute topic';
 
+const deleteTopic = async ({ auth, message, dispatch, ownEmail, _ }) => {
+  Alert.alert(
+    `Are you sure you want to delete the topic '${message.subject}' ?`,
+    'This will also delete all messages in the topic.',
+    [
+      {
+        text: 'Delete topic',
+        onPress: async () => {
+          dispatch(deleteMessagesForTopic(getNarrowFromMessage(message, ownEmail), message)).catch(
+            err => {
+              Alert.alert(`${_(deleteTopic.errorMessage)} '${message.subject}'`, err.message);
+            },
+          );
+        },
+        style: 'destructive',
+      },
+      {
+        text: 'Cancel',
+        onPress: () => {},
+        style: 'cancel',
+      },
+    ],
+    { cancelable: true },
+  );
+};
+deleteTopic.title = 'Delete topic';
+deleteTopic.errorMessage = 'Failed to delete topic';
+
 const unmuteStream = async ({ auth, message, subscriptions }) => {
   const sub = subscriptions.find(x => x.name === message.display_recipient);
   if (sub) {
@@ -159,6 +188,7 @@ const allButtonsRaw = {
   // For headers
   unmuteTopic,
   muteTopic,
+  deleteTopic,
   muteStream,
   unmuteStream,
 
@@ -181,11 +211,14 @@ type ConstructSheetParams = {|
 |};
 
 export const constructHeaderActionButtons = ({
-  backgroundData: { mute, subscriptions },
+  backgroundData: { mute, subscriptions, ownUser },
   message,
 }: ConstructSheetParams): ButtonCode[] => {
   const buttons: ButtonCode[] = [];
   if (message.type === 'stream') {
+    if (ownUser.is_admin) {
+      buttons.push('deleteTopic');
+    }
     if (isTopicMuted(message.display_recipient, message.subject, mute)) {
       buttons.push('unmuteTopic');
     } else {

src/topics/topicActions.js

@@ -1,9 +1,11 @@
 /* @flow strict-local */
-import type { GetState, Dispatch, Narrow, Topic, Action } from '../types';
+import type { GetState, Dispatch, Message, Narrow, Topic, Action, Outbox, Stream } from '../types';
 import * as api from '../api';
 import { INIT_TOPICS } from '../actionConstants';
 import { isStreamNarrow } from '../utils/narrow';
 import { getAuth, getStreams } from '../selectors';
+import { deleteOutboxMessage } from '../actions';
+import { getOutbox } from '../directSelectors';
 
 export const initTopics = (topics: Topic[], streamId: number): Action => ({
   type: INIT_TOPICS,
@@ -34,3 +36,27 @@ export const fetchTopicsForActiveStream = (narrow: Narrow) => async (
   }
   dispatch(fetchTopics(stream.stream_id));
 };
+
+export const deleteMessagesForTopic = (narrow: Narrow, message: Message | Outbox) => async (
+  dispatch: Dispatch,
+  getState: GetState,
+) => {
+  const state = getState();
+  const outbox = getOutbox(state);
+  outbox.forEach((outboxMessage: Outbox) => {
+    if (
+      outboxMessage.display_recipient === narrow[0].operand
+      && outboxMessage.subject === narrow[1].operand
+    ) {
+      dispatch(deleteOutboxMessage(outboxMessage.id));
+    }
+  });
+  const currentStream: Stream | void = getStreams(state).find(
+    (stream: Stream) => stream.name === message.display_recipient,
+  );
+  if (currentStream) {
+    await api.deleteTopic(getAuth(state), currentStream.stream_id, narrow[1].operand).catch(err => {
+      throw err;
+    });
+  }
+};

static/translations/messages_en.json

@@ -50,6 +50,7 @@
   "Copy to clipboard": "Copy to clipboard",
   "Link copied to clipboard": "Link copied to clipboard",
   "Mute topic": "Mute topic",
+  "Delete topic": "Delete topic",
   "Unmute topic": "Unmute topic",
   "Mute stream": "Mute stream",
   "Unmute stream": "Unmute stream",
@@ -135,6 +136,7 @@
   "Failed to mute topic": "Failed to mute topic",
   "Failed to mute stream": "Failed to mute stream",
   "Failed to unmute stream": "Failed to unmute stream",
+  "Failed to delete topic": "Failed to delete topic",
   "show": "show",
   "hide": "hide",
   "Debug": "Debug",