Add callback method for when a module class has been added to the CommandService.

src/Discord.Net.Commands/Builders/ModuleBuilder.cs

@@ -1,5 +1,6 @@
-using System;
+using System;
 using System.Collections.Generic;
+using System.Reflection;
 using System.Threading.Tasks;
 using Microsoft.Extensions.DependencyInjection;
 
@@ -25,6 +26,8 @@ namespace Discord.Commands.Builders
         public IReadOnlyList<Attribute> Attributes => _attributes;
         public IReadOnlyList<string> Aliases => _aliases;
 
+        internal Optional<TypeInfo> TypeInfo { get; set; }
+
         //Automatic
         internal ModuleBuilder(CommandService service, ModuleBuilder parent)
         {

src/Discord.Net.Commands/Builders/ModuleClassBuilder.cs

@@ -98,6 +98,7 @@ namespace Discord.Commands
         private static void BuildModule(ModuleBuilder builder, TypeInfo typeInfo, CommandService service)
         {
             var attributes = typeInfo.GetCustomAttributes();
+            builder.TypeInfo = typeInfo;
 
             foreach (var attribute in attributes)
             {

src/Discord.Net.Commands/CommandService.cs

@@ -1,5 +1,3 @@
-using Discord.Commands.Builders;
-using Discord.Logging;
 using System;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
@@ -8,6 +6,9 @@ using System.Linq;
 using System.Reflection;
 using System.Threading;
 using System.Threading.Tasks;
+using Microsoft.Extensions.DependencyInjection;
+using Discord.Commands.Builders;
+using Discord.Logging;
 
 namespace Discord.Commands
 {
@@ -93,8 +94,8 @@ namespace Discord.Commands
                 _moduleLock.Release();
             }
         }
-        public Task<ModuleInfo> AddModuleAsync<T>() => AddModuleAsync(typeof(T));
-        public async Task<ModuleInfo> AddModuleAsync(Type type)
+        public Task<ModuleInfo> AddModuleAsync<T>(IServiceProvider services = null) => AddModuleAsync(typeof(T), services);
+        public async Task<ModuleInfo> AddModuleAsync(Type type, IServiceProvider services = null)
         {
             await _moduleLock.WaitAsync().ConfigureAwait(false);
             try
@@ -111,14 +112,14 @@ namespace Discord.Commands
 
                 _typedModuleDefs[module.Key] = module.Value;
 
-                return LoadModuleInternal(module.Value);
+                return LoadModuleInternal(module.Value, services);
             }
             finally
             {
                 _moduleLock.Release();
             }
         }
-        public async Task<IEnumerable<ModuleInfo>> AddModulesAsync(Assembly assembly)
+        public async Task<IEnumerable<ModuleInfo>> AddModulesAsync(Assembly assembly, IServiceProvider services = null)
         {
             await _moduleLock.WaitAsync().ConfigureAwait(false);
             try
@@ -129,7 +130,7 @@ namespace Discord.Commands
                 foreach (var info in moduleDefs)
                 {
                     _typedModuleDefs[info.Key] = info.Value;
-                    LoadModuleInternal(info.Value);
+                    LoadModuleInternal(info.Value, services);
                 }
 
                 return moduleDefs.Select(x => x.Value).ToImmutableArray();
@@ -139,10 +140,25 @@ namespace Discord.Commands
                 _moduleLock.Release();
             }
         }
-        private ModuleInfo LoadModuleInternal(ModuleInfo module)
+        private ModuleInfo LoadModuleInternal(ModuleInfo module, IServiceProvider services = null)
         {
             _moduleDefs.Add(module);
 
+            if (module.TypeInfo.IsSpecified)
+            {
+                services = services ?? EmptyServiceProvider.Instance;
+                try
+                {
+                    var moduleInstance = ReflectionUtils.CreateObject<IModuleBase>(module.TypeInfo.Value, this, services);
+                    moduleInstance.OnModuleAdded(this);
+                }
+                catch(Exception)
+                {
+                    //unsure of what to do here
+                    throw;
+                }
+            }
+
             foreach (var command in module.Commands)
                 _map.AddCommand(command);
 

src/Discord.Net.Commands/IModuleBase.cs

@@ -1,4 +1,4 @@
-namespace Discord.Commands
+namespace Discord.Commands
 {
     internal interface IModuleBase
     {
@@ -7,5 +7,7 @@
         void BeforeExecute(CommandInfo command);
         
         void AfterExecute(CommandInfo command);
+
+        void OnModuleAdded(CommandService commandService);
     }
 }

src/Discord.Net.Commands/Info/ModuleInfo.cs

@@ -2,7 +2,7 @@ using System;
 using System.Linq;
 using System.Collections.Generic;
 using System.Collections.Immutable;
-
+using System.Reflection;
 using Discord.Commands.Builders;
 
 namespace Discord.Commands
@@ -22,6 +22,8 @@ namespace Discord.Commands
         public ModuleInfo Parent { get; }
         public bool IsSubmodule => Parent != null;
 
+        internal Optional<TypeInfo> TypeInfo { get; }
+
         internal ModuleInfo(ModuleBuilder builder, CommandService service, ModuleInfo parent = null)
         {
             Service = service;
@@ -31,6 +33,8 @@ namespace Discord.Commands
             Remarks = builder.Remarks;
             Parent = parent;
 
+            TypeInfo = builder.TypeInfo;
+
             Aliases = BuildAliases(builder, service).ToImmutableArray();
             Commands = builder.Commands.Select(x => x.Build(this, service)).ToImmutableArray();
             Preconditions = BuildPreconditions(builder).ToImmutableArray();

src/Discord.Net.Commands/ModuleBase.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Threading.Tasks;
 
 namespace Discord.Commands
@@ -23,6 +23,10 @@ namespace Discord.Commands
         {
         }
 
+        protected virtual void OnModuleAdded(CommandService commandService)
+        {
+        }
+
         //IModuleBase
         void IModuleBase.SetContext(ICommandContext context)
         {
@@ -33,5 +37,7 @@ namespace Discord.Commands
         void IModuleBase.BeforeExecute(CommandInfo command) => BeforeExecute(command);
 
         void IModuleBase.AfterExecute(CommandInfo command) => AfterExecute(command);
+
+        void IModuleBase.OnModuleAdded(CommandService commandService) => OnModuleAdded(commandService);
     }
 }