1 files changed, 133 insertions, 0 deletions
diff --git a/browser/components/newtab/lib/RecommendationProvider.jsm b/browser/components/newtab/lib/RecommendationProvider.jsm
new file mode 100644
index 0000000000..b25e2f4185
--- /dev/null
+++ b/browser/components/newtab/lib/RecommendationProvider.jsm
@@ -0,0 +1,133 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+"use strict";
+
+// Use XPCOMUtils.defineLazyModuleGetters to make the test harness keeps working
+// after bug 1608279.
+//
+// The test harness's workaround for "lazy getter on a plain object" is to
+// set the `lazy` object's prototype to the global object, inside the lazy
+// getter API.
+//
+// ChromeUtils.defineModuleGetter is converted into a static import declaration
+// by babel-plugin-jsm-to-esmodules, and it doesn't work for the following
+// 2 reasons:
+//
+//   * There's no other lazy getter API call in this file, and the workaround
+//     above stops working
+//   * babel-plugin-jsm-to-esmodules ignores the first parameter of the lazy
+//     getter API, and the result is wrong
+const { XPCOMUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/XPCOMUtils.sys.mjs"
+);
+const lazy = {};
+XPCOMUtils.defineLazyModuleGetters(lazy, {
+  PersonalityProvider:
+    "resource://activity-stream/lib/PersonalityProvider/PersonalityProvider.jsm",
+});
+
+const { actionTypes: at, actionCreators: ac } = ChromeUtils.importESModule(
+  "resource://activity-stream/common/Actions.sys.mjs"
+);
+const PREF_PERSONALIZATION_MODEL_KEYS =
+  "discoverystream.personalization.modelKeys";
+const PREF_PERSONALIZATION = "discoverystream.personalization.enabled";
+
+// The main purpose of this class is to handle interactions with the recommendation provider.
+// A recommendation provider scores a list of stories, currently this is a personality provider.
+// So all calls to the provider, anything involved with the setup of the provider,
+// accessing prefs for the provider, or updaing devtools with provider state, is contained in here.
+class RecommendationProvider {
+  setProvider(scores) {
+    // A provider is already set. This can happen when new stories come in
+    // and we need to update their scores.
+    // We can use the existing one, a fresh one is created after startup.
+    // Using the existing one might be a bit out of date,
+    // but it's fine for now. We can rely on restarts for updates.
+    // See bug 1629931 for improvements to this.
+    if (this.provider) {
+      return;
+    }
+    // At this point we've determined we can successfully create a v2 personalization provider.
+    this.provider = new lazy.PersonalityProvider(this.modelKeys);
+    this.provider.setScores(scores);
+  }
+
+  /*
+   * This calls any async initialization that's required,
+   * and then signals to devtools when that's done.
+   */
+  async init() {
+    if (this.provider && this.provider.init) {
+      await this.provider.init();
+      this.store.dispatch(
+        ac.BroadcastToContent({
+          type: at.DISCOVERY_STREAM_PERSONALIZATION_INIT,
+        })
+      );
+    }
+  }
+
+  get modelKeys() {
+    if (!this._modelKeys) {
+      this._modelKeys = this.store.getState().Prefs.values[
+        PREF_PERSONALIZATION_MODEL_KEYS
+      ];
+    }
+
+    return this._modelKeys;
+  }
+
+  getScores() {
+    return this.provider.getScores();
+  }
+
+  async calculateItemRelevanceScore(item) {
+    if (this.provider) {
+      const scoreResult = await this.provider.calculateItemRelevanceScore(item);
+      if (scoreResult === 0 || scoreResult) {
+        item.score = scoreResult;
+      }
+    }
+  }
+
+  teardown() {
+    if (this.provider && this.provider.teardown) {
+      // This removes any in memory listeners if available.
+      this.provider.teardown();
+    }
+  }
+
+  resetState() {
+    this._modelKeys = null;
+    this.provider = null;
+  }
+
+  onAction(action) {
+    switch (action.type) {
+      case at.DISCOVERY_STREAM_CONFIG_CHANGE:
+        this.teardown();
+        this.resetState();
+        break;
+      case at.PREF_CHANGED:
+        switch (action.data.name) {
+          case PREF_PERSONALIZATION_MODEL_KEYS:
+            this.store.dispatch(
+              ac.BroadcastToContent({
+                type: at.DISCOVERY_STREAM_CONFIG_RESET,
+              })
+            );
+            break;
+        }
+        break;
+      case at.DISCOVERY_STREAM_PERSONALIZATION_TOGGLE:
+        let enabled = this.store.getState().Prefs.values[PREF_PERSONALIZATION];
+
+        this.store.dispatch(ac.SetPref(PREF_PERSONALIZATION, !enabled));
+        break;
+    }
+  }
+}
+
+const EXPORTED_SYMBOLS = ["RecommendationProvider"];