From fc6103ddda344b37595a032a26e394fe8f1225d2 Mon Sep 17 00:00:00 2001
From: user1823 <92206575+user1823@users.noreply.github.com>
Date: Sun, 6 Apr 2025 15:18:20 +0530
Subject: [PATCH] Display median ease in Stats instead of mean

---
 rslib/src/stats/graphs/eases.rs | 33 +++++++++++++++++++++------------
 1 file changed, 21 insertions(+), 12 deletions(-)

diff --git a/rslib/src/stats/graphs/eases.rs b/rslib/src/stats/graphs/eases.rs
index d70be4e7c..bb7ae2aa1 100644
--- a/rslib/src/stats/graphs/eases.rs
+++ b/rslib/src/stats/graphs/eases.rs
@@ -10,37 +10,46 @@ impl GraphsContext {
     /// (SM-2, FSRS)
     pub(super) fn eases(&self) -> (Eases, Eases) {
         let mut eases = Eases::default();
-        let mut card_with_ease_count: usize = 0;
+        let mut ease_values = Vec::new();
         let mut difficulty = Eases::default();
-        let mut card_with_difficulty_count: usize = 0;
+        let mut difficulty_values = Vec::new();
         for card in &self.cards {
             if let Some(state) = card.memory_state {
                 *difficulty
                     .eases
                     .entry(percent_to_bin(state.difficulty() * 100.0))
                     .or_insert_with(Default::default) += 1;
-                difficulty.average += state.difficulty();
-                card_with_difficulty_count += 1;
+                difficulty_values.push(state.difficulty());
             } else if matches!(card.ctype, CardType::Review | CardType::Relearn) {
                 *eases
                     .eases
                     .entry((card.ease_factor / 10) as u32)
                     .or_insert_with(Default::default) += 1;
-                eases.average += card.ease_factor as f32;
-                card_with_ease_count += 1;
+                ease_values.push(card.ease_factor as f32);
             }
         }
-        if card_with_ease_count != 0 {
-            eases.average = eases.average / 10.0 / card_with_ease_count as f32;
-        }
-        if card_with_difficulty_count != 0 {
-            difficulty.average = difficulty.average * 100.0 / card_with_difficulty_count as f32;
-        }
+        
+        eases.average = median(&mut ease_values) / 10.0;
+        difficulty.average = median(&mut difficulty_values) * 100.0;
 
         (eases, difficulty)
     }
 }
 
+/// Helper function to calculate the median of a vector
+fn median(data: &mut Vec<f32>) -> f32 {
+    if data.is_empty() {
+        return 0.0;
+    }
+    data.sort_by(|a, b| a.partial_cmp(b).unwrap());
+    let mid = data.len() / 2;
+    if data.len() % 2 == 0 {
+        (data[mid - 1] + data[mid]) / 2.0
+    } else {
+        data[mid]
+    }
+}
+
 /// Bins the number into a bin of 0, 5, .. 95
 pub(super) fn percent_to_bin(x: f32) -> u32 {
     if x == 100.0 {