recent-topics: Add module.

Add methods to extract recent topics from received messages.
Process new messages as they are received.
Use new messages received from the server to extract recent_topics.
Node tests added.

.eslintrc.json

@@ -325,6 +325,7 @@
                 "realm_logo": false,
                 "realm_night_logo": false,
                 "recent_senders": false,
+                "recent_topics": false,
                 "reload": false,
                 "reload_state": false,
                 "reminder": false,

frontend_tests/node_tests/general.js

@@ -99,6 +99,7 @@ alert_words.process_message = noop;
 zrequire('recent_senders');
 zrequire('unread');
 zrequire('stream_topic_history');
+zrequire('recent_topics');
 
 // And finally require the module that we will test directly:
 zrequire('message_store');

frontend_tests/node_tests/message_fetch.js

@@ -11,6 +11,7 @@ zrequire('FetchStatus', 'js/fetch_status');
 zrequire('Filter', 'js/filter');
 zrequire('MessageListData', 'js/message_list_data');
 zrequire('message_list');
+zrequire('recent_topics');
 zrequire('people');
 
 set_global('page_params', {

frontend_tests/node_tests/recent_topics.js

@@ -0,0 +1,210 @@
+const rt = zrequire('recent_topics');
+set_global('people', {
+    is_my_user_id: function (id) {
+        return id === 1;
+    },
+});
+
+// Custom Data
+
+// New stream
+const stream1 = 1;
+
+// Topics in the stream
+const topic1 = "topic-1";  // No Other sender
+const topic2 = "topic-2";  // Other sender
+const topic3 = "topic-3";  // User not present
+const topic4 = "topic-4";  // User not present
+const topic5 = "topic-5";  // other sender
+const topic6 = "topic-6";  // other sender
+const topic7 = "topic-7";  // muted topic
+
+set_global('muting', {
+    is_topic_muted: (stream_id, topic) => {
+        if (stream_id === stream1 && topic === topic7) {
+            return true;
+        }
+        return false;
+    },
+});
+
+// sender1 == current user
+// sender2 == any other user
+const sender1 = 1;
+const sender2 = 2;
+
+const messages = [];
+
+let id = 0;
+
+messages[0] = {
+    stream_id: stream1,
+    id: id += 1,
+    topic: topic1,
+    sender_id: sender1,
+    type: 'stream',
+};
+
+messages[1] = {
+    stream_id: stream1,
+    id: id += 1,
+    topic: topic2,
+    sender_id: sender1,
+    type: 'stream',
+};
+
+messages[2] = {
+    stream_id: stream1,
+    id: id += 1,
+    topic: topic2,
+    sender_id: sender2,
+    type: 'stream',
+    starred: true,
+};
+
+messages[3] = {
+    stream_id: stream1,
+    id: id += 1,
+    topic: topic3,
+    sender_id: sender2,
+    type: 'stream',
+};
+
+messages[4] = {
+    stream_id: stream1,
+    id: id += 1,
+    topic: topic4,
+    sender_id: sender2,
+    type: 'stream',
+    starred: true,
+};
+
+messages[5] = {
+    stream_id: stream1,
+    id: id += 1,
+    topic: topic5,
+    sender_id: sender1,
+    type: 'stream',
+};
+
+messages[6] = {
+    stream_id: stream1,
+    id: id += 1,
+    topic: topic5,
+    sender_id: sender2,
+    type: 'stream',
+};
+
+messages[7] = {
+    stream_id: stream1,
+    id: id += 1,
+    topic: topic6,
+    sender_id: sender1,
+    type: 'stream',
+};
+
+messages[8] = {
+    stream_id: stream1,
+    id: id += 1,
+    topic: topic6,
+    sender_id: sender2,
+    type: 'stream',
+};
+
+messages[9] = {
+    stream_id: stream1,
+    id: id += 1,
+    topic: topic7,
+    sender_id: sender1,
+    type: 'stream',
+};
+
+function verify_topic_data(all_topics, stream, topic, last_msg_id,
+                           participated, starred_count, is_muted) {
+    // default is_muted to false since most of the test cases will
+    // be not muted
+    is_muted = is_muted || false;
+    const topic_data = all_topics.get(stream + ':' + topic);
+    assert.equal(topic_data.last_msg_id, last_msg_id);
+    assert.equal(topic_data.participated, participated);
+    assert.equal(topic_data.starred.size, starred_count);
+    assert.equal(topic_data.muted, is_muted);
+}
+
+run_test('basic assertions', () => {
+
+    rt.process_messages(messages);
+    let all_topics = rt.get();
+
+    // Check for expected lengths.
+    // total 7 topics, 1 muted
+    assert.equal(all_topics.size, 7);
+    assert.equal(Array.from(all_topics.keys()).toString(),
+                 '1:topic-7,1:topic-6,1:topic-5,1:topic-4,1:topic-3,1:topic-2,1:topic-1');
+
+    rt.process_message({
+        type: 'private',
+    });
+
+    // Private msgs are not processed.
+    assert.equal(all_topics.size, 7);
+    assert.equal(Array.from(all_topics.keys()).toString(),
+                 '1:topic-7,1:topic-6,1:topic-5,1:topic-4,1:topic-3,1:topic-2,1:topic-1');
+
+    // participated but not starred
+    verify_topic_data(all_topics, stream1, topic1, messages[0].id, true, 0);
+
+    // starred and participated
+    verify_topic_data(all_topics, stream1, topic2, messages[2].id, true, 1);
+
+    // No message was sent by us.
+    verify_topic_data(all_topics, stream1, topic3, messages[3].id, false, 0);
+
+    // Not participated but starred
+    verify_topic_data(all_topics, stream1, topic4, messages[4].id, false, 1);
+
+    // topic1 now starred
+    rt.process_message({
+        stream_id: stream1,
+        id: id += 1,
+        topic: topic1,
+        sender_id: sender1,
+        type: 'stream',
+        starred: true,
+    });
+
+    all_topics = rt.get();
+
+    assert.equal(Array.from(all_topics.keys()).toString(),
+                 '1:topic-1,1:topic-7,1:topic-6,1:topic-5,1:topic-4,1:topic-3,1:topic-2');
+
+    verify_topic_data(all_topics, stream1, topic1, id, true, 1);
+
+    // topic3 now participated
+    rt.process_message({
+        stream_id: stream1,
+        id: id += 1,
+        topic: topic3,
+        sender_id: sender1,
+        type: 'stream',
+    });
+
+    all_topics = rt.get();
+    assert.equal(Array.from(all_topics.keys()).toString(),
+                 '1:topic-3,1:topic-1,1:topic-7,1:topic-6,1:topic-5,1:topic-4,1:topic-2');
+    verify_topic_data(all_topics, stream1, topic3, id, true, 0);
+
+    // Send new message to topic7 (muted)
+    rt.process_message({
+        stream_id: stream1,
+        id: id += 1,
+        topic: topic7,
+        sender_id: sender1,
+        type: 'stream',
+    });
+
+    all_topics = rt.get();
+    assert.equal(Array.from(all_topics.keys()).toString(),
+                 '1:topic-7,1:topic-3,1:topic-1,1:topic-6,1:topic-5,1:topic-4,1:topic-2');
+    verify_topic_data(all_topics, stream1, topic7, id, true, 0, true);
+});

static/js/bundles/app.js

@@ -192,6 +192,7 @@ import "../ui_init.js";
 import "../emoji_picker.js";
 import "../compose_ui.js";
 import "../panels.js";
+import "../recent_topics.js";
 import "../settings_ui.js";
 import "../search_pill.js";
 import "../search_pill_widget.js";

static/js/global.d.ts

@@ -99,6 +99,7 @@ declare let reactions: any;
 declare let realm_icon: any;
 declare let realm_logo: any;
 declare let recent_senders: any;
+declare let recent_topics: any;
 declare let reload: any;
 declare let reload_state: any;
 declare let reminder: any;

static/js/message_events.js

@@ -99,6 +99,7 @@ exports.insert_new_messages = function insert_new_messages(messages, sent_by_thi
     notifications.received_messages(messages);
     stream_list.update_streams_sidebar();
     pm_list.update_private_messages();
+    recent_topics.process_messages(messages);
 };
 
 exports.update_messages = function update_messages(events) {

static/js/message_fetch.js

@@ -49,6 +49,7 @@ function process_result(data, opts) {
     activity.process_loaded_messages(messages);
     stream_list.update_streams_sidebar();
     pm_list.update_private_messages();
+    recent_topics.process_messages(messages);
 
     if (opts.pre_scroll_cont !== undefined) {
         opts.pre_scroll_cont(data);

static/js/recent_topics.js

@@ -0,0 +1,48 @@
+const topics = new Map(); // Key is stream-id:topic.
+
+exports.process_messages = function (messages) {
+    for (const msg of messages) {
+        exports.process_message(msg);
+    }
+};
+
+exports.process_message = function (msg) {
+    if (msg.type !== 'stream') {
+        return false;
+    }
+    // Initialize topic data
+    const key = msg.stream_id + ':' + msg.topic;
+    if (!topics.has(key)) {
+        topics.set(key, {
+            last_msg_id: -1,
+            starred: new Set(),
+            participated: false,
+            muted: false,
+        });
+    }
+    // Update topic data
+    const is_ours = people.is_my_user_id(msg.sender_id);
+    const topic_data = topics.get(key);
+    if (topic_data.last_msg_id < msg.id) {
+        topic_data.last_msg_id = msg.id;
+    }
+    if (msg.starred) {
+        topic_data.starred.add(msg.id);
+    }
+    topic_data.participated = is_ours || topic_data.participated;
+    topic_data.muted = topic_data.muted || muting.is_topic_muted(msg.stream_id, msg.topic);
+    return true;
+};
+
+function get_sorted_topics() {
+    // Sort all recent topics by last message time.
+    return new Map(Array.from(topics.entries()).sort(function (a, b) {
+        return  b[1].last_msg_id -  a[1].last_msg_id;
+    }));
+}
+
+exports.get = function () {
+    return get_sorted_topics();
+};
+
+window.recent_topics = exports;