From 3df97bf2663d911e718d3d06b0d982a595ef5513 Mon Sep 17 00:00:00 2001
From: Mariki <68015763+Marikider@users.noreply.github.com>
Date: Mon, 28 Oct 2024 23:18:53 +0300
Subject: [PATCH] Recoded Player.PreAuthenticating via Patch (#2786)

---
 .../Player/PreAuthenticatingEventArgs.cs      |  2 +-
 Exiled.Events/Handlers/Player.cs              | 27 +-----
 .../Events/Player/PreAuthenticating.cs        | 93 +++++++++++++++++++
 3 files changed, 96 insertions(+), 26 deletions(-)
 create mode 100644 Exiled.Events/Patches/Events/Player/PreAuthenticating.cs

diff --git a/Exiled.Events/EventArgs/Player/PreAuthenticatingEventArgs.cs b/Exiled.Events/EventArgs/Player/PreAuthenticatingEventArgs.cs
index 0b10296f2a..9ccc35e912 100644
--- a/Exiled.Events/EventArgs/Player/PreAuthenticatingEventArgs.cs
+++ b/Exiled.Events/EventArgs/Player/PreAuthenticatingEventArgs.cs
@@ -103,7 +103,7 @@ public PreAuthenticatingEventArgs(
         /// <summary>
         /// Gets a value indicating whether the player can be authenticated or not.
         /// </summary>
-        public bool IsAllowed { get; private set; } = true;
+        public bool IsAllowed { get; set; } = true;
 
         /// <summary>
         /// Gets or sets the cached <see cref="CachedPreauthData"/> that is returned back to the NwPluginAPI.
diff --git a/Exiled.Events/Handlers/Player.cs b/Exiled.Events/Handlers/Player.cs
index e81c94cf3c..d9bebcd9b1 100644
--- a/Exiled.Events/Handlers/Player.cs
+++ b/Exiled.Events/Handlers/Player.cs
@@ -1120,30 +1120,7 @@ public static void OnItemRemoved(ReferenceHub referenceHub, InventorySystem.Item
         /// <summary>
         /// Called before pre-authenticating a <see cref="API.Features.Player"/>.
         /// </summary>
-        /// <param name="userId"><inheritdoc cref="PreAuthenticatingEventArgs.UserId"/></param>
-        /// <param name="ipAddress"><inheritdoc cref="PreAuthenticatingEventArgs.IpAddress"/></param>
-        /// <param name="expiration"><inheritdoc cref="PreAuthenticatingEventArgs.Expiration"/></param>
-        /// <param name="flags"><inheritdoc cref="PreAuthenticatingEventArgs.Flags"/></param>
-        /// <param name="country"><inheritdoc cref="PreAuthenticatingEventArgs.Country"/></param>
-        /// <param name="signature"><inheritdoc cref="PreAuthenticatingEventArgs.Signature"/></param>
-        /// <param name="request"><inheritdoc cref="PreAuthenticatingEventArgs.Request"/></param>
-        /// <param name="readerStartPosition"><inheritdoc cref="PreAuthenticatingEventArgs.ReaderStartPosition"/></param>
-        /// <returns>Returns the <see cref="PreauthCancellationData"/> instance.</returns>
-        [PluginEvent(ServerEventType.PlayerPreauth)]
-        public PreauthCancellationData OnPreAuthenticating(
-            string userId,
-            string ipAddress,
-            long expiration,
-            CentralAuthPreauthFlags flags,
-            string country,
-            byte[] signature,
-            LiteNetLib.ConnectionRequest request,
-            int readerStartPosition)
-        {
-            PreAuthenticatingEventArgs ev = new(userId, ipAddress, expiration, flags, country, signature, request, readerStartPosition);
-            PreAuthenticating.InvokeSafely(ev);
-
-            return ev.CachedPreauthData;
-        }
+        /// <param name="ev"><The cref="PreAuthenticatingEventArgs"/> instance.</param>
+        public static void OnPreAuthenticating(PreAuthenticatingEventArgs ev) => PreAuthenticating.InvokeSafely(ev);
     }
 }
diff --git a/Exiled.Events/Patches/Events/Player/PreAuthenticating.cs b/Exiled.Events/Patches/Events/Player/PreAuthenticating.cs
new file mode 100644
index 0000000000..84968d88bf
--- /dev/null
+++ b/Exiled.Events/Patches/Events/Player/PreAuthenticating.cs
@@ -0,0 +1,93 @@
+// -----------------------------------------------------------------------
+// <copyright file="PreAuthenticating.cs" company="Exiled Team">
+// Copyright (c) Exiled Team. All rights reserved.
+// Licensed under the CC BY-SA 3.0 license.
+// </copyright>
+// -----------------------------------------------------------------------
+
+namespace Exiled.Events.Patches.Events.Player
+{
+    using System;
+    using System.Collections.Generic;
+    using System.Reflection.Emit;
+
+    using API.Features.Pools;
+    using Exiled.Events.Attributes;
+    using Exiled.Events.EventArgs.Player;
+
+    using HarmonyLib;
+
+    using Hazards;
+    using LiteNetLib;
+
+    using static HarmonyLib.AccessTools;
+
+    /// <summary>
+    /// Patches <see cref="CustomLiteNetLib4MirrorTransport.ProcessConnectionRequest(ConnectionRequest)" />.
+    /// Adds the <see cref="Handlers.Player.PreAuthenticating" /> event.
+    /// </summary>
+    [EventPatch(typeof(Handlers.Player), nameof(Handlers.Player.PreAuthenticating))]
+    [HarmonyPatch(typeof(CustomLiteNetLib4MirrorTransport), nameof(CustomLiteNetLib4MirrorTransport.ProcessConnectionRequest))]
+    internal static class PreAuthenticating
+    {
+        private static IEnumerable<CodeInstruction> Transpiler(IEnumerable<CodeInstruction> instructions, ILGenerator generator)
+        {
+            List<CodeInstruction> newInstructions = ListPool<CodeInstruction>.Pool.Get(instructions);
+
+            Label ret = generator.DefineLabel();
+            newInstructions[newInstructions.Count - 1].labels.Add(ret);
+
+            LocalBuilder ev = generator.DeclareLocal(typeof(PreAuthenticatingEventArgs));
+            int index = newInstructions.FindIndex(instruction => instruction.opcode == OpCodes.Ldstr && instruction.operand == (object)"{0};{1};{2};{3}");
+
+            newInstructions.InsertRange(
+                index,
+                new CodeInstruction[]
+                {
+                    // userid
+                    new CodeInstruction(OpCodes.Ldloc_S, 10),
+
+                    // ipaddress
+                    new (OpCodes.Ldloc_S, 15),
+
+                    // expiration
+                    new (OpCodes.Ldloc_S, 11),
+
+                    // flags
+                    new (OpCodes.Ldloc_S, 12),
+
+                    // country
+                    new (OpCodes.Ldloc_S, 13),
+
+                    // signature
+                    new (OpCodes.Ldloc_S, 14),
+
+                    // request
+                    new (OpCodes.Ldarg_1),
+
+                    // position
+                    new (OpCodes.Ldloc_S, 9),
+
+                    // PreAuthenticatingEventArgs ev = new (userid, ipaddress, expiration, flags, country, signature, request, position)
+                    new (OpCodes.Newobj, GetDeclaredConstructors(typeof(PreAuthenticatingEventArgs))[0]),
+                    new (OpCodes.Dup),
+                    new (OpCodes.Stloc_S, ev.LocalIndex),
+
+                    // OnPreAuthenticating(ev)
+                    new (OpCodes.Call, AccessTools.Method(typeof(Handlers.Player), nameof(Handlers.Player.OnPreAuthenticating))),
+                    new (OpCodes.Ldloc_S, ev.LocalIndex),
+
+                    // ev.isallowed
+                    new (OpCodes.Callvirt, PropertyGetter(typeof(PreAuthenticatingEventArgs), nameof(PreAuthenticatingEventArgs.IsAllowed))),
+
+                    // ret
+                    new (OpCodes.Brfalse_S, ret),
+                });
+
+            for (int z = 0; z < newInstructions.Count; z++)
+                yield return newInstructions[z];
+
+            ListPool<CodeInstruction>.Pool.Return(newInstructions);
+        }
+    }
+}