From 0a05d766d465617b2a95a2c78bc0bed9561eecae Mon Sep 17 00:00:00 2001
From: wmltogether <wmltogether@gmail.com>
Date: Wed, 15 Jan 2025 17:41:56 +0800
Subject: [PATCH 1/3] Fix the result of math.random is inconsistent with Lua
 standard library.

---
 src/Lua/Standard/MathematicsLibrary.cs | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/src/Lua/Standard/MathematicsLibrary.cs b/src/Lua/Standard/MathematicsLibrary.cs
index d72e453a..54a24c07 100644
--- a/src/Lua/Standard/MathematicsLibrary.cs
+++ b/src/Lua/Standard/MathematicsLibrary.cs
@@ -224,23 +224,34 @@ public ValueTask<int> Rad(LuaFunctionExecutionContext context, Memory<LuaValue>
     public ValueTask<int> Random(LuaFunctionExecutionContext context, Memory<LuaValue> buffer, CancellationToken cancellationToken)
     {
         var rand = context.State.Environment[RandomInstanceKey].Read<RandomUserData>().Random;
-
+        // When we call it without arguments, it returns a pseudo-random real number with uniform distribution in the interval [0,1
         if (context.ArgumentCount == 0)
         {
             buffer.Span[0] = rand.NextDouble();
         }
+        // When we call it with only one argument, an integer n, it returns an integer pseudo-random number.
+        // This is different from the C# random functions.
+        // See: https://www.lua.org/pil/18.html
         else if (context.ArgumentCount == 1)
         {
-            var arg0 = context.GetArgument<double>(0);
-            buffer.Span[0] = rand.NextDouble() * (arg0 - 1) + 1;
+            var arg0 = context.GetArgument<int>(0);
+            if (arg0 < 0)
+            {
+                LuaRuntimeException.BadArgument(context.State.GetTraceback(), 0, "random");
+            }
+            buffer.Span[0] = rand.Next(arg0 + 1);
         }
+        // Finally, we can call random with two integer arguments, l and u, to get a pseudo-random integer x such that l <= x <= u.
         else
         {
-            var arg0 = context.GetArgument<double>(0);
-            var arg1 = context.GetArgument<double>(1);
-            buffer.Span[0] = rand.NextDouble() * (arg1 - arg0) + arg0;
+            var arg0 = context.GetArgument<int>(0);
+            var arg1 = context.GetArgument<int>(1);
+            if (arg1 <= arg0)
+            {
+                LuaRuntimeException.BadArgument(context.State.GetTraceback(), 1, "random");
+            }
+            buffer.Span[0] = rand.Next(arg0, arg1 + 1);
         }
-
         return new(1);
     }
 

From 6f2391b2590321ef546a3f8538096fb1e9e0f5d9 Mon Sep 17 00:00:00 2001
From: wmltogether <wmltogether@gmail.com>
Date: Thu, 16 Jan 2025 17:35:44 +0800
Subject: [PATCH 2/3] Fix random input with only one argument.

---
 src/Lua/Standard/MathematicsLibrary.cs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Lua/Standard/MathematicsLibrary.cs b/src/Lua/Standard/MathematicsLibrary.cs
index 54a24c07..c01b8325 100644
--- a/src/Lua/Standard/MathematicsLibrary.cs
+++ b/src/Lua/Standard/MathematicsLibrary.cs
@@ -229,7 +229,7 @@ public ValueTask<int> Random(LuaFunctionExecutionContext context, Memory<LuaValu
         {
             buffer.Span[0] = rand.NextDouble();
         }
-        // When we call it with only one argument, an integer n, it returns an integer pseudo-random number.
+        // When we call it with only one argument, an integer n, it returns an integer pseudo-random number such that 1 <= x <= n.
         // This is different from the C# random functions.
         // See: https://www.lua.org/pil/18.html
         else if (context.ArgumentCount == 1)
@@ -239,7 +239,7 @@ public ValueTask<int> Random(LuaFunctionExecutionContext context, Memory<LuaValu
             {
                 LuaRuntimeException.BadArgument(context.State.GetTraceback(), 0, "random");
             }
-            buffer.Span[0] = rand.Next(arg0 + 1);
+            buffer.Span[0] = rand.Next(1, arg0 + 1);
         }
         // Finally, we can call random with two integer arguments, l and u, to get a pseudo-random integer x such that l <= x <= u.
         else

From 4bccb7d7a08f1938395ea5dba81925a7dcd07204 Mon Sep 17 00:00:00 2001
From: wmltogether <wmltogether@gmail.com>
Date: Thu, 16 Jan 2025 17:37:31 +0800
Subject: [PATCH 3/3] Fix random with two arguments MUST >= 1.

---
 src/Lua/Standard/MathematicsLibrary.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Lua/Standard/MathematicsLibrary.cs b/src/Lua/Standard/MathematicsLibrary.cs
index c01b8325..7eb16567 100644
--- a/src/Lua/Standard/MathematicsLibrary.cs
+++ b/src/Lua/Standard/MathematicsLibrary.cs
@@ -246,7 +246,7 @@ public ValueTask<int> Random(LuaFunctionExecutionContext context, Memory<LuaValu
         {
             var arg0 = context.GetArgument<int>(0);
             var arg1 = context.GetArgument<int>(1);
-            if (arg1 <= arg0)
+            if (arg0 < 1 || arg1 <= arg0)
             {
                 LuaRuntimeException.BadArgument(context.State.GetTraceback(), 1, "random");
             }