DEV: Make bread-crumb component work with sub-sub-categories

app/assets/javascripts/discourse/components/bread-crumbs.js.es6

@@ -1,15 +1,64 @@
 import { alias, filter, or } from "@ember/object/computed";
 import Component from "@ember/component";
 import { default as discourseComputed } from "discourse-common/utils/decorators";
+import deprecated from "discourse-common/lib/deprecated";
 
 //  A breadcrumb including category drop downs
 export default Component.extend({
   classNameBindings: ["hidden:hidden", ":category-breadcrumb"],
   tagName: "ol",
 
-  parentCategory: alias("category.parentCategory"),
+  @discourseComputed("categories")
+  filteredCategories(categories) {
+    return categories.filter(
+      category =>
+        this.siteSettings.allow_uncategorized_topics ||
+        category.id !== this.site.uncategorized_category_id
+    );
+  },
+
+  @discourseComputed(
+    "category.ancestors",
+    "filteredCategories",
+    "noSubcategories"
+  )
+  categoryBreadcrumbs(categoryAncestors, filteredCategories, noSubcategories) {
+    categoryAncestors = categoryAncestors || [];
+    const parentCategories = [undefined, ...categoryAncestors];
+    const categories = [...categoryAncestors, undefined];
+    const zipped = parentCategories.map((x, i) => [x, categories[i]]);
+
+    return zipped.map(record => {
+      const [parentCategory, category] = record;
+
+      const options = filteredCategories.filter(
+        c =>
+          c.get("parentCategory.id") === (parentCategory && parentCategory.id)
+      );
+
+      return {
+        category,
+        parentCategory,
+        options,
+        isSubcategory: !!parentCategory,
+        noSubcategories: !category && noSubcategories,
+        hasOptions: options.length !== 0
+      };
+    });
+  },
+
+  @discourseComputed("category")
+  parentCategory(category) {
+    deprecated(
+      "The parentCategory property of the bread-crumbs component is deprecated"
+    );
+    return category && category.parentCategory;
+  },
 
   parentCategories: filter("categories", function(c) {
+    deprecated(
+      "The parentCategories property of the bread-crumbs component is deprecated"
+    );
     if (
       c.id === this.site.get("uncategorized_category_id") &&
       !this.siteSettings.allow_uncategorized_topics
@@ -23,6 +72,9 @@ export default Component.extend({
 
   @discourseComputed("parentCategories")
   parentCategoriesSorted(parentCategories) {
+    deprecated(
+      "The parentCategoriesSorted property of the bread-crumbs component is deprecated"
+    );
     if (this.siteSettings.fixed_category_positions) {
       return parentCategories;
     }
@@ -35,16 +87,27 @@ export default Component.extend({
     return this.site.mobileView && !category;
   },
 
-  firstCategory: or("{parentCategory,category}"),
+  @discourseComputed("category", "parentCategory")
+  firstCategory(category, parentCategory) {
+    deprecated(
+      "The firstCategory property of the bread-crumbs component is deprecated"
+    );
+    return parentCategory || category;
+  },
 
   @discourseComputed("category", "parentCategory")
   secondCategory(category, parentCategory) {
-    if (parentCategory) return category;
-    return null;
+    deprecated(
+      "The secondCategory property of the bread-crumbs component is deprecated"
+    );
+    return parentCategory && category;
   },
 
   @discourseComputed("firstCategory", "hideSubcategories")
   childCategories(firstCategory, hideSubcategories) {
+    deprecated(
+      "The childCategories property of the bread-crumbs component is deprecated"
+    );
     if (hideSubcategories) {
       return [];
     }

app/assets/javascripts/discourse/models/category.js.es6

@@ -55,6 +55,11 @@ const Category = RestModel.extend({
     return { type: "category", id, category: this };
   },
 
+  @discourseComputed("parentCategory.ancestors")
+  ancestors(parentAncestors) {
+    return [...(parentAncestors || []), this];
+  },
+
   @discourseComputed("notification_level")
   isMuted(notificationLevel) {
     return notificationLevel === NotificationLevels.MUTED;

app/assets/javascripts/discourse/templates/components/bread-crumbs.hbs

@@ -1,16 +1,13 @@
-{{category-drop
-  category=firstCategory
-  categories=parentCategoriesSorted
-  countSubcategories=true}}
-
-{{#if childCategories}}
-  {{category-drop
-    category=secondCategory
-    parentCategory=firstCategory
-    categories=childCategories
-    subCategory=true
-    noSubcategories=noSubcategories}}
-{{/if}}
+{{#each categoryBreadcrumbs as |breadcrumb|}}
+  {{#if breadcrumb.hasOptions}}
+    {{category-drop
+        category=breadcrumb.category
+        parentCategory=breadcrumb.parentCategory
+        categories=breadcrumb.options
+        subCategory=breadcrumb.isSubcategory
+        noSubcategories=breadcrumb.noSubcategories}}
+  {{/if}}
+{{/each}}
 
 {{#if siteSettings.tagging_enabled}}
   {{tag-drop