✨ AoG: Add amp-viewer-assistance extension. (ampproject#20725)

* Add amp-viewer-assistance extension (ampproject#15195).

Change-Id: I78dac3ec9f85c3bbd1ceb4ce88a61b3f7d0dc539

* Address PR comments 1.

Change-Id: I874c096e75e9428872b6609df4acb75a82ee5b09

* remove amp-viewer-integration styles

Change-Id: I6692ccec7eaccfce9227115c1ebca24b3a5fe118

* Fix javascript closure typing.

Change-Id: I3d282f2571cc48e388ddd222676a23ed0d61b67b

* Add copyright and license comments to amp-viewer-assistance files.

Change-Id: I5335d7d63843800a88319d760504fef7caab4d4f

* Remove newline.

Change-Id: If066222b53ed7912140c1e526e231aca43d9a38c

* Address PR comments 2.

Change-Id: I1c06c45a2159fcb5286db2a36e168907073a77fa

* Update amp-viewer-assistance documentation.

Change-Id: I9031cc6930c18de3ca691f41274f868670b72c7a

* Remove redundant amp-viewer-assistnace validator files.

Change-Id: I5c3194a511b64321500025e59375f618ed4660a4

* Remove amp-viewer-assistance-unstrusted experiement from experiments.js.

Change-Id: Ib20566f920d3c92da648d49dc7dd30fc78eb313f

* Address amp-viewer-assistance presubmit errors.

Change-Id: If962d4a174593b2eed997acfbc01844c0a3b0f72

* Lint.

Change-Id: Icaf921248e6f5f7f096c43cde4688d28f4943545

* Fix types.

Change-Id: I65dfc764cb7a1a226b6aac444392f5936b21478d

* Add expectAsyncConsoleError to catch error message in test.

Change-Id: I78849d7d82c98d3353b2a9ad5a1ed99d5c04e2d4

build-system/tasks/compile.js

@@ -241,6 +241,8 @@ function compile(entryModuleFilenames, outputDir, outputFilename, options) {
       'extensions/amp-consent/**/*.js',
       // Needed to access AmpGeo type for service locator
       'extensions/amp-geo/**/*.js',
+      // Needed for AmpViewerAssistanceService
+      'extensions/amp-viewer-assistance/**/*.js',
       // Needed for AmpViewerIntegrationVariableService
       'extensions/amp-viewer-integration/**/*.js',
       'src/*.js',

build-system/tasks/presubmit-checks.js

@@ -180,6 +180,7 @@ const forbiddenTerms = {
       'src/service/action-impl.js',
       'extensions/amp-access/0.1/amp-access.js',
       'extensions/amp-form/0.1/amp-form.js',
+      'extensions/amp-viewer-assistance/0.1/amp-viewer-assistance.js',
     ],
   },
   'installActivityService': {
@@ -416,6 +417,7 @@ const forbiddenTerms = {
       'src/inabox/inabox-viewer.js',
       'src/service/cid-impl.js',
       'src/impression.js',
+      'extensions/amp-viewer-assistance/0.1/amp-viewer-assistance.js',
     ],
   },
   'eval\\(': {

bundles.config.js

@@ -395,6 +395,7 @@ exports.extensionBundles = [
     ],
   },
   {name: 'amp-google-vrview-image', version: '0.1', type: TYPES.MISC},
+  {name: 'amp-viewer-assistance', version: '0.1', type: TYPES.MISC},
   {
     name: 'amp-viewer-integration',
     version: '0.1',

extensions/amp-viewer-assistance/0.1/amp-viewer-assistance.js

@@ -0,0 +1,190 @@
+/**
+ * Copyright 2019 The AMP HTML Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS-IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import {ActionTrust} from '../../../src/action-constants';
+import {Services} from '../../../src/services';
+import {dev, user} from '../../../src/log';
+import {dict} from '../../../src/utils/object';
+import {isExperimentOn} from '../../../src/experiments';
+import {tryParseJson} from '../../../src/json';
+
+
+/** @const {string} */
+const TAG = 'amp-viewer-assistance';
+
+/** @const {string} */
+const GSI_TOKEN_PROVIDER = 'actions-on-google-gsi';
+
+export class AmpViewerAssistance {
+  /**
+   * @param {!../../../src/service/ampdoc-impl.AmpDoc} ampdoc
+   */
+  constructor(ampdoc) {
+    const assistanceElement = ampdoc.getElementById('amp-viewer-assistance');
+
+    /** @private {boolean} */
+    this.enabled_ = !!assistanceElement;
+    if (!this.enabled_) {
+      return;
+    }
+
+    /** @const @private */
+    this.ampdoc_ = ampdoc;
+
+    /** @const @private {!Element} */
+    this.assistanceElement_ = dev().assertElement(assistanceElement);
+
+    /** @const @private {JsonObject|null|undefined} */
+    this.configJson_ = tryParseJson(this.assistanceElement_.textContent, e => {
+      throw user().createError(
+          'Failed to parse "amp-viewer-assistance" JSON: ' + e);
+    });
+
+    /** @private @const {!../../../src/service/viewer-impl.Viewer} */
+    this.viewer_ = Services.viewerForDoc(ampdoc);
+
+    /** @private @const {!../../../src/service/action-impl.ActionService} */
+    this.action_ = Services.actionServiceForDoc(this.assistanceElement_);
+
+    /** @private @const {!../../../src/service/vsync-impl.Vsync} */
+    this.vsync_ = Services.vsyncFor(ampdoc.win);
+  }
+
+  /**
+   * @param {!../../../src/service/action-impl.ActionInvocation} invocation
+   * @return {?Promise}
+   * @private
+   */
+  actionHandler_(invocation) {
+    const {method, args} = invocation;
+    if (method == 'updateActionState' && !!args) {
+      this.viewer_./*OK*/sendMessageAwaitResponse(method, args).catch(error => {
+        user().error(TAG, error.toString());
+      });
+    } else if (method == 'signIn') {
+      this.requestSignIn_();
+    }
+
+    return null;
+  }
+
+  /**
+   * @private
+   * @restricted
+   * @return {!AmpViewerAssistance|Promise<!AmpViewerAssistance>}
+   */
+  start_() {
+    if (!this.enabled_) {
+      user().error(TAG, 'Could not find #amp-viewer-assistance element.');
+      return this;
+    }
+    return this.viewer_.isTrustedViewer().then(isTrustedViewer => {
+      if (!isTrustedViewer &&
+         !isExperimentOn(this.ampdoc_.win, 'amp-viewer-assistance-untrusted')) {
+        this.enabled_ = false;
+        user().error(TAG,
+            'amp-viewer-assistance is currently only supported on trusted'
+            + ' viewers.');
+        return this;
+      }
+      this.action_.installActionHandler(
+          this.assistanceElement_, this.actionHandler_.bind(this),
+          ActionTrust.HIGH);
+
+      this.getIdTokenPromise();
+
+      this.viewer_./*OK*/sendMessage('viewerAssistanceConfig',dict({
+        'config': this.configJson_,
+      }));
+      return this;
+    });
+  }
+
+  /**
+   * @return {!Promise<undefined>}
+   */
+  getIdTokenPromise() {
+    return this.viewer_./*OK*/sendMessageAwaitResponse('getAccessTokenPassive',
+        dict({
+          // For now there's only 1 provider option, so we just hard code it
+          'providers': [GSI_TOKEN_PROVIDER],
+        }))
+        .then(token => {
+          this.setIdTokenStatus_(Boolean(!!token));
+          return token;
+        }).catch(() => {
+          this.setIdTokenStatus_(/*available=*/false);
+        });
+  }
+
+  /**
+   * @private
+   */
+  requestSignIn_() {
+    this.viewer_./*OK*/sendMessageAwaitResponse('requestSignIn', dict({
+      'providers': [GSI_TOKEN_PROVIDER],
+    })).then(token => {
+      user().info(TAG, 'Token: ' + token);
+      if (token) {
+        this.setIdTokenStatus_(/*available=*/true);
+        this.action_.trigger(
+            this.assistanceElement_, 'signedIn', null, ActionTrust.HIGH);
+      } else {
+        this.setIdTokenStatus_(/*available=*/false);
+      }
+    });
+  }
+
+  /**
+   * Toggles the CSS classes related to the status of the identity token.
+   * @private
+   * @param {boolean} available
+   */
+  setIdTokenStatus_(available) {
+    this.toggleTopClass_(
+        'amp-viewer-assistance-identity-available', available);
+  }
+
+  /**
+   * Gets the root element of the AMP doc.
+   * @return {!Element}
+   * @private
+   */
+  getRootElement_() {
+    const root = this.ampdoc_.getRootNode();
+    return dev().assertElement(root.documentElement || root.body || root);
+  }
+
+  /**
+   * Toggles a class on the root element of the AMP doc.
+   * @param {string} className
+   * @param {boolean} on
+   * @private
+   */
+  toggleTopClass_(className, on) {
+    this.vsync_.mutate(() => {
+      this.getRootElement_().classList.toggle(className, on);
+    });
+
+  }
+}
+
+// Register the extension services.
+AMP.extension(TAG, '0.1', function(AMP) {
+  AMP.registerServiceForDoc('amp-viewer-assistance', function(ampdoc) {
+    return new AmpViewerAssistance(ampdoc).start_();
+  });
+});