Route theme body class (#1672)

* added body class for current route based on theme and routeName

* optimised method by setting/getting session

* fixed import order

imports/plugins/core/layout/client/templates/theme/theme.js

@@ -1,7 +1,73 @@
-import { Reaction } from "/client/api";
-import { Shops } from "/lib/collections";
 import { Meteor } from "meteor/meteor";
 import { Tracker } from "meteor/tracker";
+import { Reaction, Router } from "/client/api";
+import { Packages, Shops } from "/lib/collections";
+
+/**
+ * getRouteLayout
+ * Gets layout combo based on current route context
+ * @param  {Object} context - route context
+ * @returns {Object|null} The layout hash
+ */
+function getRouteLayout(context) {
+  const package = Packages.findOne({ "registry.name": context.route.name, "enabled": true });
+
+  if(package) {
+    const registryRoute = package.registry.find((x) => {
+      return x.name === context.route.name;
+    });
+
+    if (registryRoute) {
+      // set a default layout if none is given
+      if (!registryRoute.layout) {
+        registryRoute.layout = Session.get("DEFAULT_LAYOUT") || "coreLayout";
+      }
+
+      const shop = Shops.findOne(Reaction.getShopId());
+      const currentLayout = shop.layout.find((x) => {
+        if (x.layout === registryRoute.layout && x.workflow === registryRoute.workflow && x.enabled === true) {
+          return true;
+        }
+      });
+
+      return currentLayout;
+    }
+  }
+
+  return null;
+}
+
+/**
+ * addBodyClasses
+ * Adds body classes to help themes distinguish pages and components based on the current route name and layout theme
+ * @param  {Object} context - route context
+ */
+function addBodyClasses(context) {
+  let classes = [
+    // push clean route-name
+    "app-" + context.route.name.replace(/[\/_]/i, "-")
+  ];
+
+  // find the layout combo for this route
+  const currentLayout = getRouteLayout(context);
+
+  // add theme class for route layout or default
+  if (currentLayout && currentLayout.theme) {
+    classes.push(currentLayout.theme);
+  }
+  else {
+    classes.push("default");
+  }
+
+  classes = classes.join(" ");
+
+  $("body").removeClass(Session.get("BODY_CLASS")).addClass(classes);
+
+  // save for removal on next enter
+  Session.set("BODY_CLASS", classes);
+}
+
+Router.Hooks.onEnter(addBodyClasses);
 
 Meteor.startup(() => {
   Tracker.autorun(() => {