feat: Add mixin module

Added a mixin module which is used to collect various scripts which
implement common functionality shared across the server and other
scripts.

Arrowgene.Ddon.GameServer/Handler/InstanceEnemyKillHandler.cs

@@ -1,6 +1,7 @@
 using Arrowgene.Ddon.GameServer.Characters;
 using Arrowgene.Ddon.GameServer.Party;
 using Arrowgene.Ddon.GameServer.Quests;
+using Arrowgene.Ddon.GameServer.Scripting.Interfaces;
 using Arrowgene.Ddon.Server;
 using Arrowgene.Ddon.Server.Network;
 using Arrowgene.Ddon.Shared.Entity.PacketStructure;
@@ -173,7 +174,18 @@ public override S2CInstanceEnemyKillRes Handle(GameClient client, C2SInstanceEne
                     }
                 }
 
-                uint baseEnemyExp = _gameServer.ExpManager.GetScaledPointAmount(RewardSource.Enemy, ExpType.ExperiencePoints, enemyKilled.GetDroppedExperience());
+                uint baseEnemyExp = 0;
+                if (Server.GameLogicSettings.Get<bool>("GameLogicSettings", "EnableExpCalculationMixin"))
+                {
+                    var expCurveMixin = Server.ScriptManager.MixinModule.Get<IExpCurveMixin>("exp_curve");
+                    baseEnemyExp = expCurveMixin.GetExpValue(enemyKilled);
+                }
+                else
+                {
+                    baseEnemyExp = enemyKilled.GetDroppedExperience();
+                }
+
+                baseEnemyExp = _gameServer.ExpManager.GetScaledPointAmount(RewardSource.Enemy, ExpType.ExperiencePoints, baseEnemyExp);
                 uint calcExp = _gameServer.ExpManager.GetAdjustedExp(client.GameMode, RewardSource.Enemy, client.Party, baseEnemyExp, enemyKilled.Lv);
                 uint calcPP = _gameServer.ExpManager.GetScaledPointAmount(RewardSource.Enemy, ExpType.PlayPoints, enemyKilled.GetDroppedPlayPoints());
 

Arrowgene.Ddon.GameServer/Scripting/GameServerScriptManager.cs

@@ -22,6 +22,7 @@ public class GameServerScriptManager : ScriptManager<GlobalVariables>
         private GlobalVariables Globals { get; }
         public NpcExtendedFacilityModule NpcExtendedFacilityModule { get; private set; } = new NpcExtendedFacilityModule();
         public GameItemModule GameItemModule { get; private set; } = new GameItemModule();
+        public MixinModule MixinModule { get; private set; } = new MixinModule();
 
         public GameServerScriptManager(DdonGameServer server) : base(server.AssetRepository.AssetsPath)
         {
@@ -31,6 +32,7 @@ public GameServerScriptManager(DdonGameServer server) : base(server.AssetReposit
             // Add modules to the list so the generic logic can iterate over all scripting modules
             ScriptModules[NpcExtendedFacilityModule.ModuleRoot] = NpcExtendedFacilityModule;
             ScriptModules[GameItemModule.ModuleRoot] = GameItemModule;
+            ScriptModules[MixinModule.ModuleRoot] = MixinModule;
         }
 
         public override void Initialize()

Arrowgene.Ddon.GameServer/Scripting/Interfaces/IExpCurveMixin.cs

@@ -0,0 +1,9 @@
+using Arrowgene.Ddon.Shared.Model;
+
+namespace Arrowgene.Ddon.GameServer.Scripting.Interfaces
+{
+    public abstract class IExpCurveMixin
+    {
+        public abstract uint GetExpValue(InstancedEnemy enemy);
+    }
+}

Arrowgene.Ddon.GameServer/Scripting/Modules/MixinModule.cs

@@ -0,0 +1,69 @@
+using Arrowgene.Ddon.Shared;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.Scripting;
+using System;
+using System.Collections.Generic;
+using System.Dynamic;
+using System.IO;
+using System.Runtime.CompilerServices;
+
+namespace Arrowgene.Ddon.GameServer.Scripting
+{
+    public class MixinModule : ScriptModule
+    {
+        public override string ModuleRoot => "mixins";
+        public override string Filter => "*.csx";
+        public override bool ScanSubdirectories => true;
+        public override bool EnableHotLoad => true;
+
+        private Dictionary<string, object> Mixins { get; set; }
+
+        public MixinModule()
+        {
+            Mixins = new Dictionary<string, object>();
+        }
+
+        public T Get<T>(string scriptName)
+        {
+            if (!Mixins.ContainsKey(scriptName))
+            {
+                throw new Exception($"A mixin with the name '{scriptName}' doesn't exist");
+            }
+
+            return (T) Mixins[scriptName];
+        }
+
+        public override ScriptOptions Options()
+        {
+            return ScriptOptions.Default
+                .AddReferences(MetadataReference.CreateFromFile(typeof(DdonGameServer).Assembly.Location))
+                .AddReferences(MetadataReference.CreateFromFile(typeof(AssetRepository).Assembly.Location))
+                .AddReferences(MetadataReference.CreateFromFile(typeof(DynamicAttribute).Assembly.Location))
+                .AddImports("System", "System.Collections", "System.Collections.Generic")
+                .AddImports("System.Runtime.CompilerServices")
+                .AddImports("Arrowgene.Ddon.Shared")
+                .AddImports("Arrowgene.Ddon.Shared.Model")
+                .AddImports("Arrowgene.Ddon.GameServer")
+                .AddImports("Arrowgene.Ddon.GameServer.Characters")
+                .AddImports("Arrowgene.Ddon.GameServer.Scripting")
+                .AddImports("Arrowgene.Ddon.GameServer.Scripting.Interfaces")
+                .AddImports("Arrowgene.Ddon.Shared.Entity.PacketStructure")
+                .AddImports("Arrowgene.Ddon.Shared.Entity.Structure")
+                .AddImports("Arrowgene.Ddon.Shared.Model.Quest");
+        }
+
+        public override bool EvaluateResult(string path, ScriptState<object> result)
+        {
+            if (result == null)
+            {
+                return false;
+            }
+
+            // Mixins are c# Func<> with arbitary return and params based on the functionality
+            string mixinName = Path.GetFileNameWithoutExtension(path);
+            Mixins[mixinName] = result.ReturnValue;
+
+            return true;
+        }
+    }
+}

Arrowgene.Ddon.Shared/Files/Assets/scripts/mixins/README.md

@@ -0,0 +1,3 @@
+# Mixins
+
+Mixins are a collection of configurable functionality which can be shared across various server components and scripts, but is not tied to a particular feature.

Arrowgene.Ddon.Shared/Files/Assets/scripts/mixins/exp_curve.csx

@@ -0,0 +1,17 @@
+/**
+ * @breif This mixin is used to calculate the exp amount for a given
+ * enemy based on observations from realworld exp data. It should be
+ * possible to call this script directly from the server code or from
+ * other scripts.
+ */
+
+public class Mixin : IExpCurveMixin
+{
+    public override uint GetExpValue(InstancedEnemy enemy)
+    {
+        // TODO: Implement algorithm to calculate exp amount
+        return enemy.GetDroppedExperience();
+    }
+}
+
+return new Mixin();

Arrowgene.Ddon.Shared/Files/Assets/scripts/settings/GameLogicSettings.csx

@@ -17,6 +17,15 @@ bool EnableVisualEquip = true;
 uint DefaultWarpFavorites = 3;
 uint LaternBurnTimeInSeconds = 1500;
 
+/**
+ * @brief If enabled, overrides default EXP values assigned to enemies
+ * in the InstanceEnemyKillHandler and uses the calculations inside of
+ * <scriptroot>/mixins/exp_curve.csx.
+ *
+ * @note Currently returns same exp amount as the default setting.
+ */
+bool EnableExpCalculationMixin = false;
+
 // Crafting Settings
 double AdditionalProductionSpeedFactor = 1.0;
 double AdditionalCostPerformanceFactor = 1.0;