fix: handle course access errors in Course Home side of things too (#558)

The courseware was properly reading the access errors and
redirecting the user as appropriate (like to the dashboard or
whatever).

This requires a backend change to push the error along.

src/shared/access-denied-redirect/AccessDeniedRedirect.jsx

@@ -0,0 +1,67 @@
+import React from 'react';
+import PropTypes from 'prop-types';
+import { getLocale } from '@edx/frontend-platform/i18n';
+import { Redirect } from 'react-router';
+import { useModel } from '../../generic/model-store';
+
+// This component inspects an access denied error and redirects to a /redirect/... path, which then renders a nice
+// little message while the browser loads the next page.
+// This is basically a frontend version of check_course_access_with_redirect in the backend.
+
+function AccessDeniedRedirect(props) {
+  const {
+    courseId,
+    metadataModel,
+    unitId,
+  } = props;
+
+  const {
+    courseAccess,
+    start,
+  } = useModel(metadataModel, courseId);
+
+  let url = `/redirect/course-home/${courseId}`;
+  switch (courseAccess.errorCode) {
+    case 'audit_expired':
+      url = `/redirect/dashboard?access_response_error=${courseAccess.additionalContextUserMessage}`;
+      break;
+    case 'course_not_started':
+      // eslint-disable-next-line no-case-declarations
+      const startDate = (new Intl.DateTimeFormat(getLocale())).format(new Date(start));
+      url = `/redirect/dashboard?notlive=${startDate}`;
+      break;
+    case 'survey_required':
+      url = `/redirect/survey/${courseId}`;
+      break;
+    case 'unfulfilled_milestones':
+      url = '/redirect/dashboard';
+      break;
+    case 'microfrontend_disabled':
+      // This code path is only used by the courseware right now. The course home tabs each have their own check for
+      // this in the tab-specific API calls. In those cases, the API will return an http status code if the MFE version
+      // of those tabs are disabled, rather than an access error like this. We could try to unify these approaches, but
+      // hopefully the legacy code isn't around long enough for that to be worth it.
+      if (unitId) {
+        url = `/redirect/courseware/${courseId}/unit/${unitId}`;
+      }
+      break;
+    case 'authentication_required':
+    case 'enrollment_required':
+    default:
+  }
+  return (
+    <Redirect to={url} />
+  );
+}
+
+AccessDeniedRedirect.defaultProps = {
+  unitId: null,
+};
+
+AccessDeniedRedirect.propTypes = {
+  courseId: PropTypes.string.isRequired,
+  metadataModel: PropTypes.string.isRequired,
+  unitId: PropTypes.string,
+};
+
+export default AccessDeniedRedirect;

src/shared/access-denied-redirect/index.js

@@ -0,0 +1,3 @@
+import AccessDeniedRedirect from './AccessDeniedRedirect';
+
+export default AccessDeniedRedirect;