Resolve "Add random question controller"

Closes #145 (closed)

controllers/question.controller.js

@@ -150,8 +150,75 @@ async function getRandomQuestionsByCategory(category_id, count) {
     }
 }
 
+async function getRandomQuestions(count) {
+    let client;
+    try {
+        client = await connectToDatabase();
+        const db = client.db("TrioTech");
+        const questionCollection = db.collection("questions");
+
+        // Calculate the number of questions to fetch for each difficulty level
+        const totalQuestions = count;
+        const countDifficult0 = Math.floor(0.4 * totalQuestions);
+        const countDifficult1 = Math.floor(0.3 * totalQuestions);
+        const countDifficult2 = totalQuestions - countDifficult0 - countDifficult1;
+
+        // Define the aggregation pipeline to select questions based on difficulty
+        const pipeline = [
+            {
+                $match: {
+                    $and: [{ difficult: 0 }],
+                },
+            },
+            {
+                $sample: { size: countDifficult0 },
+            },
+            {
+                $unionWith: {
+                    coll: "questions",
+                    pipeline: [
+                        {
+                            $match: {
+                                $and: [{ difficult: 1 }],
+                            },
+                        },
+                        {
+                            $sample: { size: countDifficult1 },
+                        },
+                    ],
+                },
+            },
+            {
+                $unionWith: {
+                    coll: "questions",
+                    pipeline: [
+                        {
+                            $match: {
+                                $and: [{ difficult: 2 }],
+                            },
+                        },
+                        {
+                            $sample: { size: countDifficult2 },
+                        },
+                    ],
+                },
+            },
+        ];
+
+        const response = await questionCollection.aggregate(pipeline).toArray();
+        return response;
+    } catch (error) {
+        throw error;
+    } finally {
+        if (client) {
+            await client.close();
+        }
+    }
+}
+
 module.exports = {
     createQuestion,
     getQuestion,
     getRandomQuestionsByCategory,
+    getRandomQuestions,
 };