import {
  collection,
  getDocs,
  query,
  where,
  setDoc,
  doc,
  Firestore,
} from "firebase/firestore";
import { shuffle } from "lodash";
import { Exam } from "@/interfaces/exam";
import { Stat } from "@/interfaces/user";

export const getExams = async (
  db: Firestore,
  module: string,
  avoidRepeated: string,
  // added userId as due to assignments being set from the teacher to the student
  // we need to make sure we are serving exams not executed by the user and not
  // by the teacher that performed the request
  userId: string | undefined
): Promise<Exam[]> => {
  const moduleRef = collection(db, module);

  const q = query(moduleRef, where("isDiagnostic", "==", false));
  const snapshot = await getDocs(q);

  const exams: Exam[] = shuffle(
    snapshot.docs.map((doc) => ({
      id: doc.id,
      ...doc.data(),
      module,
    }))
  ) as Exam[];

  if (avoidRepeated === "true") {
    const statsQ = query(collection(db, "stats"), where("user", "==", userId));
    const statsSnapshot = await getDocs(statsQ);

    const stats: Stat[] = statsSnapshot.docs.map((doc) => ({
      id: doc.id,
      ...doc.data(),
    })) as unknown as Stat[];
    const filteredExams = exams.filter(
      (x) => !stats.map((s) => s.exam).includes(x.id)
    );

    return filteredExams.length > 0 ? filteredExams : exams;
  }

  return exams;
};