feat: add unmet exam prerequisites (#63131)

Co-authored-by: Oliver Eyton-Williams <ojeytonwilliams@gmail.com>

api/src/exam-environment/routes/exam-environment.test.ts

@@ -712,7 +712,8 @@ describe('/exam-environment/', () => {
               totalTimeInS: mock.exam.config.totalTimeInS,
               retakeTimeInS: mock.exam.config.retakeTimeInS
             },
-            id: mock.examId
+            id: mock.examId,
+            prerequisites: mock.exam.prerequisites
           }
         ]);
 
@@ -787,7 +788,8 @@ describe('/exam-environment/', () => {
               totalTimeInS: mock.exam.config.totalTimeInS,
               retakeTimeInS: mock.exam.config.retakeTimeInS
             },
-            id: mock.examId
+            id: mock.examId,
+            prerequisites: mock.exam.prerequisites
           }
         ]);
         expect(res.body).toMatchObject([{ canTake: true }]);

api/src/exam-environment/routes/exam-environment.ts

@@ -694,7 +694,11 @@ async function postExamAttemptHandler(
   return reply.code(200).send();
 }
 
-async function getExams(
+/**
+ * Get all the public information about all exams.
+ * @returns Public information about exams + whether Camper may take the exam or not.
+ */
+export async function getExams(
   this: FastifyInstance,
   req: UpdateReqType<typeof schemas.examEnvironmentExams>,
   reply: FastifyReply
@@ -763,7 +767,8 @@ async function getExams(
         retakeTimeInS: exam.config.retakeTimeInS,
         passingPercent: exam.config.passingPercent
       },
-      canTake: false
+      canTake: false,
+      prerequisites: exam.prerequisites
     };
 
     const isExamPrerequisitesMet = checkPrerequisites(user, exam.prerequisites);

api/src/exam-environment/schemas/exam-environment-exams.ts

@@ -2,7 +2,7 @@ import { Type } from '@fastify/type-provider-typebox';
 import { STANDARD_ERROR } from '../utils/errors.js';
 export const examEnvironmentExams = {
   headers: Type.Object({
-    'exam-environment-authorization-token': Type.String()
+    'exam-environment-authorization-token': Type.Optional(Type.String())
   }),
   response: {
     200: Type.Array(
@@ -15,7 +15,8 @@ export const examEnvironmentExams = {
           retakeTimeInS: Type.Number(),
           passingPercent: Type.Number()
         }),
-        canTake: Type.Boolean()
+        canTake: Type.Boolean(),
+        prerequisites: Type.Array(Type.String())
       })
     ),
     500: STANDARD_ERROR

api/src/routes/protected/user.ts

@@ -31,7 +31,8 @@ import { DEPLOYMENT_ENV, JWT_SECRET } from '../../utils/env.js';
 import {
   getExamAttemptHandler,
   getExamAttemptsByExamIdHandler,
-  getExamAttemptsHandler
+  getExamAttemptsHandler,
+  getExams
 } from '../../exam-environment/routes/exam-environment.js';
 import { ERRORS } from '../../exam-environment/utils/errors.js';
 
@@ -565,6 +566,13 @@ export const userRoutes: FastifyPluginCallbackTypebox = (
     },
     getExamAttemptsByExamIdHandler
   );
+  fastify.get(
+    '/user/exam-environment/exams',
+    {
+      schema: examEnvironmentSchemas.examEnvironmentExams
+    },
+    getExams
+  );
 
   done();
 };

client/src/templates/Challenges/exam-download/show.tsx

@@ -16,8 +16,13 @@ import { connect } from 'react-redux';
 import LearnLayout from '../../../components/layouts/learn';
 import ChallengeTitle from '../components/challenge-title';
 import useDetectOS from '../utils/use-detect-os';
-import { ChallengeNode } from '../../../redux/prop-types';
-import { isSignedInSelector } from '../../../redux/selectors';
+import { ChallengeNode, CompletedChallenge } from '../../../redux/prop-types';
+import {
+  completedChallengesSelector,
+  isSignedInSelector
+} from '../../../redux/selectors';
+import { examAttempts } from '../../../utils/ajax';
+import MissingPrerequisites from '../exam/components/missing-prerequisites';
 import { isChallengeCompletedSelector } from '../redux/selectors';
 import { Attempts } from './attempts';
 import ExamTokenControls from './exam-token-controls';
@@ -30,16 +35,26 @@ interface GitProps {
 }
 
 const mapStateToProps = createSelector(
+  completedChallengesSelector,
   isChallengeCompletedSelector,
   isSignedInSelector,
-  (isChallengeCompleted: boolean, isSignedIn: boolean) => ({
+  (
+    completedChallenges: CompletedChallenge[],
+    isChallengeCompleted: boolean,
+    isSignedIn: boolean
+  ) => ({
+    completedChallenges,
     isChallengeCompleted,
     isSignedIn
   })
 );
 
 interface ShowExamDownloadProps {
-  data: { challengeNode: ChallengeNode };
+  data: {
+    challengeNode: ChallengeNode;
+    allChallengeNode: { nodes: ChallengeNode[] };
+  };
+  completedChallenges: CompletedChallenge[];
   isChallengeCompleted: boolean;
   isSignedIn: boolean;
 }
@@ -48,8 +63,10 @@ function ShowExamDownload({
   data: {
     challengeNode: {
       challenge: { id, title, translationPending }
-    }
+    },
+    allChallengeNode: { nodes }
   },
+  completedChallenges,
   isChallengeCompleted,
   isSignedIn
 }: ShowExamDownloadProps): JSX.Element {
@@ -58,6 +75,9 @@ function ShowExamDownload({
   const [downloadLink, setDownloadLink] = useState<string | undefined>('');
   const [downloadLinks, setDownloadLinks] = useState<string[]>([]);
 
+  const getExamsQuery = examAttempts.useGetExamsQuery();
+  const examIdsQuery = examAttempts.useGetExamIdsByChallengeIdQuery(id);
+
   const os = useDetectOS();
 
   const { t } = useTranslation();
@@ -135,6 +155,22 @@ function ShowExamDownload({
     // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [os]);
 
+  const examId = examIdsQuery.data?.at(0)?.examId;
+  const exam = getExamsQuery.data?.find(examItem => examItem.id === examId);
+  const unmetPrerequisites = exam?.prerequisites?.filter(
+    prereq => !completedChallenges.some(challenge => challenge.id === prereq)
+  );
+  const challenges = nodes.filter(({ challenge }) =>
+    unmetPrerequisites?.includes(challenge.id)
+  );
+  const missingPrerequisites = challenges.map(({ challenge }) => {
+    return {
+      id: challenge.id,
+      title: challenge.title,
+      slug: challenge.fields?.slug || ''
+    };
+  });
+
   return (
     <LearnLayout>
       <Helmet>
@@ -151,6 +187,9 @@ function ShowExamDownload({
           {title}
         </ChallengeTitle>
         <Spacer size='l' />
+        {!!missingPrerequisites.length && (
+          <MissingPrerequisites missingPrerequisites={missingPrerequisites} />
+        )}
         <h2>{t('exam.download-header')}</h2>
         <p>{t('exam.explanation')}</p>
         <Spacer size='l' />
@@ -228,5 +267,16 @@ export const query = graphql`
         translationPending
       }
     }
+    allChallengeNode {
+      nodes {
+        challenge {
+          id
+          title
+          fields {
+            slug
+          }
+        }
+      }
+    }
   }
 `;

client/src/utils/ajax.ts

@@ -430,6 +430,19 @@ export interface ExamEnvironmentChallenge {
   challengeId: string;
 }
 
+export type GetExamsResponse = Array<{
+  id: string;
+  config: {
+    name: string;
+    note: string;
+    totalTimeInS: number;
+    retakeTimeInS: number;
+    passingPercent: number;
+  };
+  canTake: boolean;
+  prerequisites: string[];
+}>;
+
 export const examAttempts = createApi({
   reducerPath: 'exam-attempts',
   baseQuery: fetchBaseQuery({
@@ -446,6 +459,9 @@ export const examAttempts = createApi({
     getExamIdsByChallengeId: build.query<ExamEnvironmentChallenge[], string>({
       query: challengeId =>
         `/exam-environment/exam-challenge?challengeId=${challengeId}`
+    }),
+    getExams: build.query<GetExamsResponse, void>({
+      query: () => '/user/exam-environment/exams'
     })
   })
 });