From 9f7f55f9aad5bf6e67e969584f8f7253c78edd59 Mon Sep 17 00:00:00 2001
From: Mohamed <mohamed.bennekrouf@gmail.com>
Date: Tue, 9 Jan 2024 09:24:00 +0100
Subject: [PATCH] Only shuffle incorrect answer

---
 src/domain/exercise/generate_one_exercise.rs | 27 ++++++++++++++------
 1 file changed, 19 insertions(+), 8 deletions(-)

diff --git a/src/domain/exercise/generate_one_exercise.rs b/src/domain/exercise/generate_one_exercise.rs
index e24faae..c45b1fb 100644
--- a/src/domain/exercise/generate_one_exercise.rs
+++ b/src/domain/exercise/generate_one_exercise.rs
@@ -1,5 +1,4 @@
 use rand::seq::SliceRandom;
-
 use crate::domain::exercise::extract_and_shuffle_options::extract_and_shuffle_options;
 use crate::domain::exercise::select_random_verse_index::select_random_verse_index;
 use crate::domain::similar::sourate_from_verse::sourate_name_from_verse;
@@ -15,7 +14,12 @@ pub fn generate_one_exercise(dbs: &Database, exercise: &mut ExerciseOutput, exer
     let exclude_verse = Some(exercise.verses[valid_verse_index].verse.clone());
 
     let extracted_values = extract_and_shuffle_options(&mut exercise.verses, exercise_type, &exclude_verse);
-    let mut alternatives: Vec<Alternative> = extracted_values.into_iter().map(|value| {
+
+    // Extract and keep the correct answer separate
+    let correct_alternative = Alternative { verse: Some(exercise.verses[valid_verse_index].verse.clone()) };
+
+    // Prepare incorrect alternatives and shuffle them
+    let mut incorrect_alternatives: Vec<Alternative> = extracted_values.into_iter().map(|value| {
         match exercise_type {
             ExerciseType::FindDiscriminant => {
                 Alternative {
@@ -43,19 +47,26 @@ pub fn generate_one_exercise(dbs: &Database, exercise: &mut ExerciseOutput, exer
             },
             _ => unimplemented!(),
         }
-    }).take(2).collect();
+    }).filter(|alt| alt.verse != Some(exercise.verses[valid_verse_index].verse.clone()))
+      .collect();
+
+    incorrect_alternatives.shuffle(&mut rand::thread_rng());
+
+    // Combine correct and incorrect alternatives, correct answer at the end
+    incorrect_alternatives.push(correct_alternative);
+
+    // Truncate the alternatives to the desired length (e.g., 4)
+    incorrect_alternatives.truncate(4);
 
-    // Add the correct answer
-    let valid_verse = exercise.verses.get(valid_verse_index).unwrap();
-    alternatives.push(Alternative { verse: Some(valid_verse.verse.clone()) });
-    alternatives.shuffle(&mut rand::thread_rng());
+    // Use the combined and truncated list as the final alternatives
+    let alternatives = incorrect_alternatives;
 
     // Return None if there are not enough alternatives
     if alternatives.len() <= 1 {
         None
     } else {
         let mut generated_exercise = Exercise {
-            statement: valid_verse.clone(),
+            statement: exercise.verses[valid_verse_index].clone(),
             alternatives,
             exercise_type: exercise_type.clone(),
         };