FIX: Include sub-sub-categories in new/unread counts (#8710)

The count used to be less than the real one because the topics in
sub-sub-categories and deeper were not taken into account.

app/assets/javascripts/discourse/models/topic-tracking-state.js.es6

@@ -76,15 +76,6 @@ const TopicTrackingState = EmberObject.extend({
         }
       }
 
-      // fill parent_category_id we need it for counting new/unread
-      if (data.payload && data.payload.category_id) {
-        var category = Category.findById(data.payload.category_id);
-
-        if (category && category.parent_category_id) {
-          data.payload.parent_category_id = category.parent_category_id;
-        }
-      }
-
       if (data.message_type === "latest") {
         tracker.notify(data);
       }
@@ -364,30 +355,43 @@ const TopicTrackingState = EmberObject.extend({
     this.incrementProperty("messageCount");
   },
 
-  countNew(category_id) {
+  getSubCategoryIds(categoryId) {
+    const result = [categoryId];
+    const categories = Category.list();
+
+    for (let i = 0; i < result.length; ++i) {
+      for (let j = 0; j < categories.length; ++j) {
+        if (result[i] === categories[j].parent_category_id) {
+          result[result.length] = categories[j].id;
+        }
+      }
+    }
+
+    return new Set(result);
+  },
+
+  countNew(categoryId) {
+    const subcategoryIds = this.getSubCategoryIds(categoryId);
     return _.chain(this.states)
       .filter(isNew)
       .filter(
         topic =>
           topic.archetype !== "private_message" &&
           !topic.deleted &&
-          (topic.category_id === category_id ||
+          (!categoryId || subcategoryIds.has(topic.category_id))
-            topic.parent_category_id === category_id ||
-            !category_id)
       )
       .value().length;
   },
 
-  countUnread(category_id) {
+  countUnread(categoryId) {
+    const subcategoryIds = this.getSubCategoryIds(categoryId);
     return _.chain(this.states)
       .filter(isUnread)
       .filter(
         topic =>
           topic.archetype !== "private_message" &&
           !topic.deleted &&
-          (topic.category_id === category_id ||
+          (!categoryId || subcategoryIds.has(topic.category_id))
-            topic.parent_category_id === category_id ||
-            !category_id)
       )
       .value().length;
   },
@@ -434,10 +438,6 @@ const TopicTrackingState = EmberObject.extend({
     // I am taking some shortcuts here to avoid 500 gets for a large list
     if (data) {
       data.forEach(topic => {
-        let category = Category.findById(topic.category_id);
-        if (category && category.parent_category_id) {
-          topic.parent_category_id = category.parent_category_id;
-        }
         states["t" + topic.topic_id] = topic;
       });
     }

test/javascripts/models/topic-tracking-state-test.js.es6

@@ -1,6 +1,7 @@
 import TopicTrackingState from "discourse/models/topic-tracking-state";
 import createStore from "helpers/create-store";
 import Category from "discourse/models/category";
+import { NotificationLevels } from "discourse/lib/notification-levels";
 
 QUnit.module("model:topic-tracking-state");
 
@@ -91,3 +92,79 @@ QUnit.test("subscribe to category", function(assert) {
     "expect to properly track incoming for subcategory"
   );
 });
+
+QUnit.test("getSubCategoryIds", assert => {
+  const store = createStore();
+  const foo = store.createRecord("category", { id: 1, slug: "foo" });
+  const bar = store.createRecord("category", {
+    id: 2,
+    slug: "bar",
+    parent_category_id: foo.id
+  });
+  const baz = store.createRecord("category", {
+    id: 3,
+    slug: "baz",
+    parent_category_id: bar.id
+  });
+  sandbox.stub(Category, "list").returns([foo, bar, baz]);
+
+  const state = TopicTrackingState.create();
+  assert.deepEqual(Array.from(state.getSubCategoryIds(1)), [1, 2, 3]);
+  assert.deepEqual(Array.from(state.getSubCategoryIds(2)), [2, 3]);
+  assert.deepEqual(Array.from(state.getSubCategoryIds(3)), [3]);
+});
+
+QUnit.test("countNew", assert => {
+  const store = createStore();
+  const foo = store.createRecord("category", { id: 1, slug: "foo" });
+  const bar = store.createRecord("category", {
+    id: 2,
+    slug: "bar",
+    parent_category_id: foo.id
+  });
+  const baz = store.createRecord("category", {
+    id: 3,
+    slug: "baz",
+    parent_category_id: bar.id
+  });
+  sandbox.stub(Category, "list").returns([foo, bar, baz]);
+
+  const state = TopicTrackingState.create();
+
+  assert.equal(state.countNew(1), 0);
+  assert.equal(state.countNew(2), 0);
+  assert.equal(state.countNew(3), 0);
+
+  state.states["t112"] = {
+    last_read_post_number: null,
+    id: 112,
+    notification_level: NotificationLevels.TRACKING,
+    category_id: 2
+  };
+
+  assert.equal(state.countNew(1), 1);
+  assert.equal(state.countNew(2), 1);
+  assert.equal(state.countNew(3), 0);
+
+  state.states["t113"] = {
+    last_read_post_number: null,
+    id: 113,
+    notification_level: NotificationLevels.TRACKING,
+    category_id: 3
+  };
+
+  assert.equal(state.countNew(1), 2);
+  assert.equal(state.countNew(2), 2);
+  assert.equal(state.countNew(3), 1);
+
+  state.states["t111"] = {
+    last_read_post_number: null,
+    id: 111,
+    notification_level: NotificationLevels.TRACKING,
+    category_id: 1
+  };
+
+  assert.equal(state.countNew(1), 3);
+  assert.equal(state.countNew(2), 2);
+  assert.equal(state.countNew(3), 1);
+});