From d4dc30bd7a01b99b740fdcc34b18fcd3101a52bb Mon Sep 17 00:00:00 2001
From: Gabriel Kaszewski <gabrielkaszewski@gmail.com>
Date: Thu, 14 May 2026 01:05:31 +0200
Subject: [PATCH] fix: speed effects stack multiplicatively

---
 .../Status/Effects/LightFootedEffect.cs       |  2 +-
 .../Domain/Status/Effects/SpeedBoostEffect.cs |  2 +-
 Assets/Tests/EditMode/StatusManagerTests.cs   | 26 +++++++++++++++++++
 3 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/Assets/Scripts/Core/Domain/Status/Effects/LightFootedEffect.cs b/Assets/Scripts/Core/Domain/Status/Effects/LightFootedEffect.cs
index ff47bee..48cd203 100644
--- a/Assets/Scripts/Core/Domain/Status/Effects/LightFootedEffect.cs
+++ b/Assets/Scripts/Core/Domain/Status/Effects/LightFootedEffect.cs
@@ -19,7 +19,7 @@ namespace Core.Domain.Status.Effects
         public void ModifyCapabilities(ref PlayerCapabilities caps)
         {
             caps.CanTriggerDecay = false;
-            caps.SpeedMultiplier = 1.2f;
+            caps.SpeedMultiplier *= 1.2f;
         }
 
         public void OnApply()
diff --git a/Assets/Scripts/Core/Domain/Status/Effects/SpeedBoostEffect.cs b/Assets/Scripts/Core/Domain/Status/Effects/SpeedBoostEffect.cs
index ab54019..97da305 100644
--- a/Assets/Scripts/Core/Domain/Status/Effects/SpeedBoostEffect.cs
+++ b/Assets/Scripts/Core/Domain/Status/Effects/SpeedBoostEffect.cs
@@ -20,7 +20,7 @@ namespace Core.Domain.Status.Effects
 
         public void ModifyCapabilities(ref PlayerCapabilities caps)
         {
-            caps.SpeedMultiplier = _multiplier;
+            caps.SpeedMultiplier *= _multiplier;
         }
 
         public void OnApply() { }
diff --git a/Assets/Tests/EditMode/StatusManagerTests.cs b/Assets/Tests/EditMode/StatusManagerTests.cs
index 4700536..c913097 100644
--- a/Assets/Tests/EditMode/StatusManagerTests.cs
+++ b/Assets/Tests/EditMode/StatusManagerTests.cs
@@ -1,5 +1,6 @@
 using NUnit.Framework;
 using Core.Domain.Status;
+using Core.Domain.Status.Effects;
 
 namespace DecayGrid.Tests
 {
@@ -14,5 +15,30 @@ namespace DecayGrid.Tests
             Assert.AreEqual(1f, caps.SpeedMultiplier, 0.001f);
             Assert.IsFalse(caps.CanHover);
         }
+
+        [Test]
+        public void SpeedBoostAlone_AppliesMultiplier()
+        {
+            var sm = new StatusManager();
+            sm.AddEffect(new SpeedBoostEffect(10f, 1.5f));
+            Assert.AreEqual(1.5f, sm.CurrentCapabilities.SpeedMultiplier, 0.001f);
+        }
+
+        [Test]
+        public void LightFootedAlone_AppliesMultiplier()
+        {
+            var sm = new StatusManager();
+            sm.AddEffect(new LightFootedEffect(10f));
+            Assert.AreEqual(1.2f, sm.CurrentCapabilities.SpeedMultiplier, 0.001f);
+        }
+
+        [Test]
+        public void TwoSpeedEffectsStack_Multiplicatively()
+        {
+            var sm = new StatusManager();
+            sm.AddEffect(new LightFootedEffect(10f));      // *1.2
+            sm.AddEffect(new SpeedBoostEffect(10f, 1.5f)); // *1.5
+            Assert.AreEqual(1.8f, sm.CurrentCapabilities.SpeedMultiplier, 0.001f); // 1.0 * 1.2 * 1.5
+        }
     }
 }