Assignments now generate unique list of exams for each user

src/pages/api/assignments/index.ts

@@ -5,6 +5,10 @@ import {getFirestore, collection, getDocs, query, where, setDoc, doc} from "fire
 import {withIronSessionApiRoute} from "iron-session/next";
 import {sessionOptions} from "@/lib/session";
 import {uuidv4} from "@firebase/util";
+import { Module } from "@/interfaces";
+import { getExams } from "@/utils/exams.be";
+import { Exam } from "@/interfaces/exam";
+import { flatten } from "lodash";
 
 const db = getFirestore(app);
 
@@ -34,8 +38,65 @@ async function GET(req: NextApiRequest, res: NextApiResponse) {
 	res.status(200).json(docs);
 }
 
-async function POST(req: NextApiRequest, res: NextApiResponse) {
-	await setDoc(doc(db, "assignments", uuidv4()), {assigner: req.session.user?.id, ...req.body});
-
-	res.status(200).json({ok: true});
+interface ExamWithUser {
+  module: Module;
+  id: string;
+  assignee: string;
+}
+
+function getRandomIndex(arr: any[]): number {
+  const randomIndex = Math.floor(Math.random() * arr.length);
+  return randomIndex;
+}
+
+async function POST(req: NextApiRequest, res: NextApiResponse) {
+  const { selectedModules, assignees, ...body } = req.body as {
+    selectedModules: Module[];
+    assignees: string[];
+  };
+
+  // for optimization purposes, it would be better to create a new endpoint that returned the answers for all users at once
+  const allExams = await assignees.map(async (assignee) => {
+    const selectedModulePromises = await selectedModules.map(
+      async (module: Module) => {
+        try {
+          const exams: Exam[] = await getExams(db, module, "true", assignee);
+
+          const exam = exams[getRandomIndex(exams)];
+          if (exam) {
+            return { module: exam.module, id: exam.id, assignee };
+          }
+          return null;
+        } catch (e) {
+          console.error(e);
+          return null;
+        }
+      },
+      []
+    );
+    const newModules = await Promise.all(selectedModulePromises);
+
+    return newModules;
+  }, []);
+
+  const exams = flatten(await Promise.all(allExams)).filter(
+    (x) => x !== null
+  ) as ExamWithUser[];
+
+  if (exams.length === 0) {
+    res
+      .status(400)
+      .json({ ok: false, error: "No exams found for the selected modules" });
+    return;
+  }
+
+  await setDoc(doc(db, "assignments", uuidv4()), {
+    assigner: req.session.user?.id,
+    assignees,
+    results: [],
+    exams,
+    ...body,
+  });
+
+  res.status(200).json({ ok: true });
 }