From fdc8024a61b21314fb1ca1ab6d8adf45c9c7b063 Mon Sep 17 00:00:00 2001
From: salmonik <salmonik@tuta.io>
Date: Mon, 24 Aug 2026 18:30:25 +0200
Subject: Balance slots payouts: EV=0.972 (2.8% house edge). Three-of-a-kind:
 2-28x, two-of-a-kind: 1-3x.

---
 src/bin/client/games/slots.rs |  4 ++--
 src/bin/server/games/slots.rs | 27 ++++++++++++++-------------
 tests/slots.rs                | 16 ++++++++--------
 3 files changed, 24 insertions(+), 23 deletions(-)

diff --git a/src/bin/client/games/slots.rs b/src/bin/client/games/slots.rs
index d664dbc..bc0a9b4 100644
--- a/src/bin/client/games/slots.rs
+++ b/src/bin/client/games/slots.rs
@@ -50,8 +50,8 @@ impl Game for SlotsGame {
         Match symbols to win!\n\
         \n\
         Payouts:\n\
-        Three of a kind: 5x-100x bet\n\
-        Two of a kind: 2x-20x bet\n\
+        Three of a kind: 2x-28x bet\n\
+        Two of a kind: 1x-3x bet\n\
         \n\
         Symbols: C=Cherry, L=Lemon, O=Orange, G=Grapes, D=Diamond, S=Seven\n\
         \n\
diff --git a/src/bin/server/games/slots.rs b/src/bin/server/games/slots.rs
index 3d285ef..04ac175 100644
--- a/src/bin/server/games/slots.rs
+++ b/src/bin/server/games/slots.rs
@@ -12,19 +12,20 @@ impl SlotsGame {
         let symbols = vec!['C', 'L', 'O', 'G', 'D', 'S'];
         let mut payouts = HashMap::new();
 
-        payouts.insert("CCC".to_string(), 5);
-        payouts.insert("LLL".to_string(), 10);
-        payouts.insert("OOO".to_string(), 15);
-        payouts.insert("GGG".to_string(), 20);
-        payouts.insert("DDD".to_string(), 50);
-        payouts.insert("SSS".to_string(), 100);
-
-        payouts.insert("CC".to_string(), 2);
-        payouts.insert("LL".to_string(), 3);
-        payouts.insert("OO".to_string(), 4);
-        payouts.insert("GG".to_string(), 5);
-        payouts.insert("DD".to_string(), 10);
-        payouts.insert("SS".to_string(), 20);
+        // Balanced payouts: EV = 210/216 ≈ 0.972 (2.8% house edge)
+        payouts.insert("CCC".to_string(), 2);
+        payouts.insert("LLL".to_string(), 3);
+        payouts.insert("OOO".to_string(), 5);
+        payouts.insert("GGG".to_string(), 8);
+        payouts.insert("DDD".to_string(), 14);
+        payouts.insert("SSS".to_string(), 28);
+
+        payouts.insert("CC".to_string(), 1);
+        payouts.insert("LL".to_string(), 1);
+        payouts.insert("OO".to_string(), 1);
+        payouts.insert("GG".to_string(), 2);
+        payouts.insert("DD".to_string(), 2);
+        payouts.insert("SS".to_string(), 3);
 
         Self { symbols, payouts }
     }
diff --git a/tests/slots.rs b/tests/slots.rs
index c50f425..6babd98 100644
--- a/tests/slots.rs
+++ b/tests/slots.rs
@@ -12,9 +12,9 @@ fn make_game() -> SlotsGame {
 fn three_of_a_kind_pays() {
     let game = make_game();
     // CCC = 5x
-    assert_eq!(game.calculate_payout(&['C', 'C', 'C'], 100), 500);
+    assert_eq!(game.calculate_payout(&['C', 'C', 'C'], 100), 200);
     // SSS = 100x
-    assert_eq!(game.calculate_payout(&['S', 'S', 'S'], 10), 1000);
+    assert_eq!(game.calculate_payout(&['S', 'S', 'S'], 10), 280);
 }
 
 /// Two adjacent matching symbols pays the two-of-a-kind multiplier.
@@ -22,9 +22,9 @@ fn three_of_a_kind_pays() {
 fn two_adjacent_pays() {
     let game = make_game();
     // CC? = 2x
-    assert_eq!(game.calculate_payout(&['C', 'C', 'D'], 100), 200);
+    assert_eq!(game.calculate_payout(&['C', 'C', 'D'], 100), 100);
     // ?LL = 3x
-    assert_eq!(game.calculate_payout(&['D', 'L', 'L'], 50), 150);
+    assert_eq!(game.calculate_payout(&['D', 'L', 'L'], 50), 50);
 }
 
 /// Non-adjacent matching symbols (e.g. [C,D,C]) must also pay.
@@ -33,11 +33,11 @@ fn two_adjacent_pays() {
 fn two_non_adjacent_pays() {
     let game = make_game();
     // C,D,C — two cherries at positions 0 and 2
-    assert_eq!(game.calculate_payout(&['C', 'D', 'C'], 100), 200);
+    assert_eq!(game.calculate_payout(&['C', 'D', 'C'], 100), 100);
     // S,X,S — two sevens at positions 0 and 2
-    assert_eq!(game.calculate_payout(&['S', 'L', 'S'], 10), 200);
+    assert_eq!(game.calculate_payout(&['S', 'L', 'S'], 10), 30);
     // L,O,L
-    assert_eq!(game.calculate_payout(&['L', 'O', 'L'], 50), 150);
+    assert_eq!(game.calculate_payout(&['L', 'O', 'L'], 50), 50);
 }
 
 /// No matching symbols returns 0.
@@ -80,7 +80,7 @@ fn calculate_result_on_finished_state() {
 
     let result = game.calculate_result(&state).unwrap();
     assert_eq!(result.bet_amount, 100);
-    assert_eq!(result.winnings, 200); // CC = 2x
+    assert_eq!(result.winnings, 100); // CC = 1x
 }
 
 /// calculate_result on a non-finished state returns an error.
-- 
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