Added mod manager

Fuyu.Backend/Fuyu.Backend.csproj

@@ -21,6 +21,8 @@
     <ProjectReference Include="../Fuyu.Backend.Arena/Fuyu.Backend.Arena.csproj" />
     <ProjectReference Include="../Fuyu.Backend.Core/Fuyu.Backend.Core.csproj" />
     <ProjectReference Include="../Fuyu.Backend.EFT/Fuyu.Backend.EFT.csproj" />
+    <ProjectReference Include="../Fuyu.DependencyInjection/Fuyu.DependencyInjection.csproj" />
+    <ProjectReference Include="../Fuyu.Modding/Fuyu.Modding.csproj" />
   </ItemGroup>
 
   <Target Name="PostClean" AfterTargets="Clean">

Fuyu.Backend/Program.cs

@@ -4,13 +4,18 @@
 using Fuyu.Backend.EFT;
 using Fuyu.Backend.EFT.Servers;
 using Fuyu.Backend.BSG.DTO.Services;
+using Fuyu.DependencyInjection;
+using Fuyu.Modding;
+using System.Threading.Tasks;
 
 namespace Fuyu.Backend
 {
     public class Program
     {
-        static void Main()
+        static async Task Main()
         {
+            var container = new DependencyContainer();
+
             CoreDatabase.Load();
             EftDatabase.Load();
             TraderDatabase.Load();
@@ -24,7 +29,9 @@ static void Main()
             eftMainServer.RegisterServices();
             eftMainServer.Start();
 
-            Terminal.WaitForInput();
-        }
+			await ModManager.Instance.Load(container);
+			Terminal.WaitForInput();
+			await ModManager.Instance.UnloadAll();
+		}
     }
 }

Fuyu.DependencyInjection/DependencyContainer.cs

@@ -173,6 +173,15 @@ public T Resolve<T>(string id) where T : class
 			return (T)Resolve(id, typeof(T));
 		}
 
+		/// <summary>
+		/// Used to resolve an object of the desired type and id
+		/// </summary>
+		public T Resolve<TBase, T>(string id) where T : class
+			where TBase : class
+		{
+			return (T)Resolve(id, typeof(TBase));
+		}
+
 		#endregion
 
 		#region ResolveAll

Fuyu.Modding/Extensions.cs

@@ -0,0 +1,12 @@
+using Fuyu.DependencyInjection;
+
+namespace Fuyu.Modding
+{
+	public static class Extensions
+	{
+		public static T ResolveMod<T>(this DependencyContainer container, string id) where T: Mod
+		{
+			return container.Resolve<Mod, T>(id);
+		}
+	}
+}

Fuyu.Modding/Fuyu.Modding.csproj

@@ -0,0 +1,9 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <TargetFrameworks>net8.0;netstandard2.0</TargetFrameworks>
+  </PropertyGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\Fuyu.Common\Fuyu.Common.csproj" />
+    <ProjectReference Include="..\Fuyu.DependencyInjection\Fuyu.DependencyInjection.csproj" />
+  </ItemGroup>
+</Project>

Fuyu.Modding/Mod.cs

@@ -0,0 +1,40 @@
+using System.Threading.Tasks;
+using Fuyu.DependencyInjection;
+
+namespace Fuyu.Modding
+{
+	public abstract class Mod
+	{
+		internal bool IsLoaded { get; set; }
+
+		/// <summary>
+		/// Your plugin will be automatically registered into this dependency container with this ID.
+		/// </summary>
+		public abstract string Id { get; }
+
+		/// <summary>
+		/// This is the name that will be used in logs.
+		/// </summary>
+		public abstract string Name { get; }
+
+		// TODO: Load dependencies first
+		public virtual string[] Dependencies { get; }
+
+		/// <summary>
+		/// Gets called after the server has set up everything.
+		/// </summary>
+		/// <param name="container"></param>
+		public virtual Task OnLoad(DependencyContainer container)
+		{
+			return Task.CompletedTask;
+		}
+
+		/// <summary>
+		/// Gets called whenever the server shuts down
+		/// </summary>
+		public virtual Task OnShutdown()
+		{
+			return Task.CompletedTask;
+		}
+	}
+}

Fuyu.Modding/ModManager.cs

@@ -0,0 +1,208 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Reflection;
+using System.Threading.Tasks;
+using Fuyu.Common.IO;
+using Fuyu.DependencyInjection;
+
+namespace Fuyu.Modding
+{
+	// This should live during the entire lifetime of the application
+	public class ModManager
+	{
+		private static ModManager _instance;
+
+		private readonly List<Mod> _sortedMods = new List<Mod>();
+
+		private static readonly object _lock = new object();
+
+		public static ModManager Instance
+		{
+			get
+			{
+				lock (_lock)
+				{
+					if (_instance == null)
+					{
+						_instance = new ModManager();
+					}
+
+					return _instance;
+				}
+			}
+		}
+
+		public ModManager()
+		{
+			AppDomain.CurrentDomain.AssemblyResolve += CurrentDomain_AssemblyResolve;
+		}
+
+		private Assembly CurrentDomain_AssemblyResolve(object sender, ResolveEventArgs args)
+		{
+			foreach (var mod in _sortedMods)
+			{
+				var modAssembly = mod.GetType().Assembly;
+				if (modAssembly.FullName == args.Name)
+				{
+					return modAssembly;
+				}
+			}
+
+			return null;
+		}
+
+		public Task Load(DependencyContainer container)
+		{
+			var modsDirectory = Path.Combine(Environment.CurrentDirectory, "Fuyu", "Mods");
+			if (!Directory.Exists(modsDirectory))
+			{
+				Directory.CreateDirectory(modsDirectory);
+				return Task.CompletedTask;
+			}
+
+			var dllFiles = Directory.GetFiles(modsDirectory, "*.dll");
+			if (dllFiles.Length == 0)
+			{
+				return Task.CompletedTask;
+			}
+
+			return Load_Internal(dllFiles, container);
+		}
+
+		private async Task Load_Internal(string[] filePaths, DependencyContainer container)
+		{
+			List<Mod> mods = new List<Mod>();
+			foreach (var filePath in filePaths)
+			{
+				// Load the dll
+				var bytes = File.ReadAllBytes(filePath);
+				var assembly = AppDomain.CurrentDomain.Load(bytes);
+
+				// Get types where T implements IMod
+				var modTypes = assembly.GetExportedTypes()
+					.Where(t => typeof(Mod).IsAssignableFrom(t));
+
+				// Technically you could export multiple mods per file
+				foreach (var modType in modTypes)
+				{
+					var mod = (Mod)Activator.CreateInstance(modType);
+
+					Terminal.WriteLine($"Adding mod {mod.Name}");
+
+					mods.Add(mod);
+				}
+			}
+
+			if (mods.Count == 0)
+			{
+				return;
+			}
+
+			CheckDependencies(mods);
+			SortMods(mods);
+
+			Terminal.WriteLine($"Current order: {string.Join(", ", _sortedMods.Select(p => p.Name))}");
+
+			foreach (var mod in _sortedMods)
+			{
+				// All mods will be registered to the container
+				container.RegisterSingleton(mod.Id, mod);
+			}
+
+			foreach (var mod in _sortedMods)
+			{
+				Terminal.WriteLine($"Loading mod {mod.Name}");
+				await mod.OnLoad(container);
+				mod.IsLoaded = true;
+			}
+		}
+
+		private void SortMods(List<Mod> mods)
+		{
+			foreach (var mod in mods)
+			{
+				AddModToSorted(mods, mod, null);
+			}
+		}
+
+		private void AddModToSorted(List<Mod> mods, Mod mod, Mod dependent)
+		{
+			if (_sortedMods.Contains(mod))
+			{
+				return;
+			}
+
+			if (mod.Dependencies != null)
+			{
+				foreach (var dependency in mod.Dependencies)
+				{
+					if (dependent != null && dependent.Id == dependency)
+					{
+						throw new Exception($"Cyclic dependency {mod.Id} <-> {dependency}");
+					}
+
+					AddModToSorted(mods, mods.Find(m => m.Id == dependency), mod);
+				}
+			}
+
+			_sortedMods.Add(mod);
+		}
+
+		private void CheckDependencies(List<Mod> mods)
+		{
+			var runAgain = false;
+
+			for (var i = 0; i < mods.Count; i++)
+			{
+				var mod = mods[i];
+				var hasAllDependencies = true;
+
+				if (mod.Dependencies != null)
+				{
+					foreach (var dependency in mod.Dependencies)
+					{
+						if (mods.FindIndex(m => m.Id == dependency) == -1)
+						{
+							hasAllDependencies = false;
+							Terminal.WriteLine($"{mod.Id} is missing dependency {dependency} and will not be loaded");
+						}
+					}
+				}
+
+				if (!hasAllDependencies)
+				{
+					mods.RemoveAt(i);
+					i--;
+					runAgain = true;
+				}
+			}
+
+			if (runAgain)
+			{
+				CheckDependencies(mods);
+			}
+		}
+
+		private async Task Unload(Mod mod)
+		{
+			if (mod.IsLoaded)
+			{
+				Terminal.WriteLine($"Unloading mod {mod.Name}");
+				await mod.OnShutdown();
+				mod.IsLoaded = false;
+			}
+
+			_sortedMods.Remove(mod);
+		}
+
+		public async Task UnloadAll()
+		{
+			while (_sortedMods.Count > 0)
+			{
+				await Unload(_sortedMods[_sortedMods.Count - 1]);
+			}
+		}
+	}
+}

Fuyu.sln

@@ -39,6 +39,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Fuyu.Tests.Backend.Core", "
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Fuyu.DependencyInjection", "Fuyu.DependencyInjection\Fuyu.DependencyInjection.csproj", "{8B94FFE8-658E-4261-8B96-7FBD0C08374B}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Fuyu.Modding", "Fuyu.Modding\Fuyu.Modding.csproj", "{1687E80C-E174-4844-9939-7AAF6E1139F0}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -117,8 +119,15 @@ Global
 		{8B94FFE8-658E-4261-8B96-7FBD0C08374B}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{8B94FFE8-658E-4261-8B96-7FBD0C08374B}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{8B94FFE8-658E-4261-8B96-7FBD0C08374B}.Release|Any CPU.Build.0 = Release|Any CPU
+		{1687E80C-E174-4844-9939-7AAF6E1139F0}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{1687E80C-E174-4844-9939-7AAF6E1139F0}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{1687E80C-E174-4844-9939-7AAF6E1139F0}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{1687E80C-E174-4844-9939-7AAF6E1139F0}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
 	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {67ADC3F3-9ADA-4F75-AEDC-DB5A17E9E5AF}
+	EndGlobalSection
 EndGlobal