Merge branch 'FiniteReality-feature/command-builders' into dev

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

@@ -0,0 +1,118 @@
+using System;
+using System.Linq;
+using System.Threading.Tasks;
+using System.Collections.Generic;
+
+namespace Discord.Commands.Builders
+{
+    public class CommandBuilder
+    {
+        private List<PreconditionAttribute> preconditions;
+        private List<ParameterBuilder> parameters;
+        private List<string> aliases;
+
+        internal CommandBuilder(ModuleBuilder module)
+        {
+            preconditions = new List<PreconditionAttribute>();
+            parameters = new List<ParameterBuilder>();
+            aliases = new List<string>();
+
+            Module = module;
+        }
+
+        public string Name { get; set; }
+        public string Summary { get; set; }
+        public string Remarks { get; set; }
+        public RunMode RunMode { get; set; }
+        public int Priority { get; set; }
+        public Func<CommandContext, object[], IDependencyMap, Task> Callback { get; set; }
+        public ModuleBuilder Module { get; }
+
+        public List<PreconditionAttribute> Preconditions => preconditions;
+        public List<ParameterBuilder> Parameters => parameters;
+        public List<string> Aliases => aliases;
+
+        public CommandBuilder SetName(string name)
+        {
+            Name = name;
+            return this;
+        }
+
+        public CommandBuilder SetSummary(string summary)
+        {
+            Summary = summary;
+            return this;
+        }
+
+        public CommandBuilder SetRemarks(string remarks)
+        {
+            Remarks = remarks;
+            return this;
+        }
+
+        public CommandBuilder SetRunMode(RunMode runMode)
+        {
+            RunMode = runMode;
+            return this;
+        }
+
+        public CommandBuilder SetPriority(int priority)
+        {
+            Priority = priority;
+            return this;
+        }
+
+        public CommandBuilder SetCallback(Func<CommandContext, object[], IDependencyMap, Task> callback)
+        {
+            Callback = callback;
+            return this;
+        }
+
+        public CommandBuilder AddPrecondition(PreconditionAttribute precondition)
+        {
+            preconditions.Add(precondition);
+            return this;
+        }
+
+        public CommandBuilder AddParameter(Action<ParameterBuilder> createFunc)
+        {
+            var param = new ParameterBuilder();
+            createFunc(param);
+            parameters.Add(param);
+            return this;
+        }
+
+        public CommandBuilder AddAliases(params string[] newAliases)
+        {
+            aliases.AddRange(newAliases);
+            return this;
+        }
+
+        internal CommandInfo Build(ModuleInfo info, CommandService service)
+        {
+            if (aliases.Count == 0)
+                throw new InvalidOperationException("Commands require at least one alias to be registered");
+
+            if (Callback == null)
+                throw new InvalidOperationException("Commands require a callback to be built");
+
+            if (Name == null)
+                Name = aliases[0];
+
+            if (parameters.Count > 0)
+            {
+                var lastParam = parameters[parameters.Count - 1];
+
+                var firstMultipleParam = parameters.FirstOrDefault(x => x.Multiple);
+                if ((firstMultipleParam != null) && (firstMultipleParam != lastParam))
+                    throw new InvalidOperationException("Only the last parameter in a command may have the Multiple flag.");
+                
+                var firstRemainderParam = parameters.FirstOrDefault(x => x.Remainder);
+                if ((firstRemainderParam != null) && (firstRemainderParam != lastParam))
+                    throw new InvalidOperationException("Only the last parameter in a command may have the Remainder flag.");
+            }
+
+            return new CommandInfo(this, info, service);
+        }
+    }
+}

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

@@ -0,0 +1,98 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+
+namespace Discord.Commands.Builders
+{
+    public class ModuleBuilder
+    {
+        private List<CommandBuilder> commands;
+        private List<ModuleBuilder> submodules;
+        private List<PreconditionAttribute> preconditions;
+        private List<string> aliases;
+
+        public ModuleBuilder()
+        {
+            commands = new List<CommandBuilder>();
+            submodules = new List<ModuleBuilder>();
+            preconditions = new List<PreconditionAttribute>();
+            aliases = new List<string>();
+        }
+
+        internal ModuleBuilder(ModuleBuilder parent)
+            : this()
+        {
+            ParentModule = parent;
+        }
+
+        public string Name { get; set; }
+        public string Summary { get; set; }
+        public string Remarks { get; set; }
+        public ModuleBuilder ParentModule { get; }
+
+        public List<CommandBuilder> Commands => commands;
+        public List<ModuleBuilder> Modules => submodules;
+        public List<PreconditionAttribute> Preconditions => preconditions;
+        public List<string> Aliases => aliases;
+
+        public ModuleBuilder SetName(string name)
+        {
+            Name = name;
+            return this;
+        }
+
+        public ModuleBuilder SetSummary(string summary)
+        {
+            Summary = summary;
+            return this;
+        }
+
+        public ModuleBuilder SetRemarks(string remarks)
+        {
+            Remarks = remarks;
+            return this;
+        }
+
+        public ModuleBuilder AddAliases(params string[] newAliases)
+        {
+            aliases.AddRange(newAliases);
+            return this;
+        }
+
+        public ModuleBuilder AddPrecondition(PreconditionAttribute precondition)
+        {
+            preconditions.Add(precondition);
+            return this;
+        }
+
+        public ModuleBuilder AddCommand(Action<CommandBuilder> createFunc)
+        {
+            var builder = new CommandBuilder(this);
+            createFunc(builder);
+            commands.Add(builder);
+            return this;
+        }
+
+        public ModuleBuilder AddSubmodule(Action<ModuleBuilder> createFunc)
+        {
+            var builder = new ModuleBuilder(this);
+            createFunc(builder);
+            submodules.Add(builder);
+            return this;
+        }
+
+        public ModuleInfo Build(CommandService service)
+        {
+            if (aliases.Count == 0)
+                throw new InvalidOperationException("Modules require at least one alias to be registered");
+
+            if (commands.Count == 0 && submodules.Count == 0)
+                throw new InvalidOperationException("Tried to build empty module");
+
+            if (Name == null)
+                Name = aliases[0];
+
+            return new ModuleInfo(this, service);
+        }
+    }
+}

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

@@ -0,0 +1,100 @@
+using System;
+using System.Threading.Tasks;
+using System.Collections.Generic;
+
+namespace Discord.Commands.Builders
+{
+    public class ParameterBuilder
+    {
+        public ParameterBuilder()
+        { }
+
+        public ParameterBuilder(string name)
+        {
+            Name = name;
+        }
+
+        public string Name { get; set; }
+        public string Summary { get; set; }
+        public object DefaultValue { get; set; }
+        public Type ParameterType { get; set; }
+
+        public TypeReader TypeReader { get; set; }
+
+        public bool Optional { get; set; }
+        public bool Remainder { get; set; }
+        public bool Multiple { get; set; }
+
+        public ParameterBuilder SetName(string name)
+        {
+            Name = name;
+            return this;
+        }
+
+        public ParameterBuilder SetSummary(string summary)
+        {
+            Summary = summary;
+            return this;
+        }
+
+        public ParameterBuilder SetDefault<T>(T defaultValue)
+        {
+            Optional = true;
+            DefaultValue = defaultValue;
+            ParameterType = typeof(T);
+
+            if (ParameterType.IsArray)
+                ParameterType = ParameterType.GetElementType();
+
+            return this;
+        }
+
+        public ParameterBuilder SetType(Type parameterType)
+        {
+            ParameterType = parameterType; 
+            return this;
+        }
+
+        public ParameterBuilder SetTypeReader(TypeReader reader)
+        {
+            TypeReader = reader;
+            return this;
+        }
+
+        public ParameterBuilder SetOptional(bool isOptional)
+        {
+            Optional = isOptional;
+            return this;
+        }
+
+        public ParameterBuilder SetRemainder(bool isRemainder)
+        {
+            Remainder = isRemainder;
+            return this;
+        }
+
+        public ParameterBuilder SetMultiple(bool isMultiple)
+        {
+            Multiple = isMultiple;
+            return this;
+        }
+
+        internal ParameterInfo Build(CommandInfo info, CommandService service)
+        {
+            // TODO: should we throw when we don't have a name?
+            if (Name == null)
+                Name = "[unknown parameter]";
+
+            if (ParameterType == null)
+                throw new InvalidOperationException($"Could not build parameter {Name} from command {info.Name} - An invalid parameter type was given");
+
+            if (TypeReader == null)
+                TypeReader = service.GetTypeReader(ParameterType);
+
+            if (TypeReader == null)
+                throw new InvalidOperationException($"Could not build parameter {Name} from command {info.Name} - A valid TypeReader could not be found");
+
+            return new ParameterInfo(this, info, service);
+        }
+    }
+}

src/Discord.Net.Commands/CommandParser.cs

@@ -15,7 +15,7 @@ namespace Discord.Commands
         
         public static async Task<ParseResult> ParseArgs(CommandInfo command, CommandContext context, string input, int startPos)
         {
-            CommandParameter curParam = null;
+            ParameterInfo curParam = null;
             StringBuilder argBuilder = new StringBuilder(input.Length);
             int endPos = input.Length;
             var curPart = ParserPart.None;

src/Discord.Net.Commands/CommandService.cs

@@ -7,24 +7,26 @@ using System.Reflection;
 using System.Threading;
 using System.Threading.Tasks;
 
+using Discord.Commands.Builders;
+
 namespace Discord.Commands
 {
     public class CommandService
     {
-        private static readonly TypeInfo _moduleTypeInfo = typeof(ModuleBase).GetTypeInfo();
-
         private readonly SemaphoreSlim _moduleLock;
-        private readonly ConcurrentDictionary<Type, ModuleInfo> _moduleDefs;
+        private readonly ConcurrentDictionary<Type, ModuleInfo> _typedModuleDefs; 
         private readonly ConcurrentDictionary<Type, TypeReader> _typeReaders;
+        private readonly ConcurrentBag<ModuleInfo> _moduleDefs;
         private readonly CommandMap _map;
 
-        public IEnumerable<ModuleInfo> Modules => _moduleDefs.Select(x => x.Value);
-        public IEnumerable<CommandInfo> Commands => _moduleDefs.SelectMany(x => x.Value.Commands);
+        public IEnumerable<ModuleInfo> Modules => _typedModuleDefs.Select(x => x.Value);
+        public IEnumerable<CommandInfo> Commands => _typedModuleDefs.SelectMany(x => x.Value.Commands);
 
         public CommandService()
         {
             _moduleLock = new SemaphoreSlim(1, 1);
-            _moduleDefs = new ConcurrentDictionary<Type, ModuleInfo>();
+            _typedModuleDefs = new ConcurrentDictionary<Type, ModuleInfo>();
+            _moduleDefs = new ConcurrentBag<ModuleInfo>();
             _map = new CommandMap();
             _typeReaders = new ConcurrentDictionary<Type, TypeReader>
             {
@@ -65,22 +67,40 @@ namespace Discord.Commands
         }
 
         //Modules
+        public async Task<ModuleInfo> BuildModule(Action<ModuleBuilder> buildFunc)
+        {
+            await _moduleLock.WaitAsync().ConfigureAwait(false);
+            try
+            {
+                var builder = new ModuleBuilder();
+                buildFunc(builder);
+
+                var module = builder.Build(this);
+                return LoadModuleInternal(module);
+            }
+            finally
+            {
+                _moduleLock.Release();
+            }
+        }
         public async Task<ModuleInfo> AddModule<T>()
         {
             await _moduleLock.WaitAsync().ConfigureAwait(false);
             try
             {
                 var typeInfo = typeof(T).GetTypeInfo();
-                if (!_moduleTypeInfo.IsAssignableFrom(typeInfo))
-                    throw new ArgumentException($"Modules must inherit ModuleBase.");
-
-                if (typeInfo.IsAbstract)
-                    throw new InvalidOperationException("Modules must not be abstract.");
 
-                if (_moduleDefs.ContainsKey(typeof(T)))
+                if (_typedModuleDefs.ContainsKey(typeof(T)))
                     throw new ArgumentException($"This module has already been added.");
 
-                return AddModuleInternal(typeInfo);
+                var module = ModuleClassBuilder.Build(this, typeInfo).FirstOrDefault();
+
+                if (module.Value == default(ModuleInfo))
+                    throw new InvalidOperationException($"Could not build the module {typeof(T).FullName}, did you pass an invalid type?");
+
+                _typedModuleDefs[module.Key] = module.Value;
+                
+                return LoadModuleInternal(module.Value);
             }
             finally
             {
@@ -89,39 +109,36 @@ namespace Discord.Commands
         }
         public async Task<IEnumerable<ModuleInfo>> AddModules(Assembly assembly)
         {
-            var moduleDefs = ImmutableArray.CreateBuilder<ModuleInfo>();
             await _moduleLock.WaitAsync().ConfigureAwait(false);
             try
             {
-                foreach (var type in assembly.ExportedTypes)
+                var types = ModuleClassBuilder.Search(assembly).ToArray();
+                var moduleDefs = ModuleClassBuilder.Build(types, this);
+
+                foreach (var info in moduleDefs)
                 {
-                    if (!_moduleDefs.ContainsKey(type))
-                    {
-                        var typeInfo = type.GetTypeInfo();
-                        if (_moduleTypeInfo.IsAssignableFrom(typeInfo))
-                        {
-                            var dontAutoLoad = typeInfo.GetCustomAttribute<DontAutoLoadAttribute>();
-                            if (dontAutoLoad == null && !typeInfo.IsAbstract)
-                                moduleDefs.Add(AddModuleInternal(typeInfo));
-                        }
-                    }
+                    _typedModuleDefs[info.Key] = info.Value;
+                    LoadModuleInternal(info.Value);
                 }
-                return moduleDefs.ToImmutable();
+
+                return moduleDefs.Select(x => x.Value).ToImmutableArray();
             }
             finally
             {
                 _moduleLock.Release();
             }
         }
-        private ModuleInfo AddModuleInternal(TypeInfo typeInfo)
+        private ModuleInfo LoadModuleInternal(ModuleInfo module)
         {
-            var moduleDef = new ModuleInfo(typeInfo, this);
-            _moduleDefs[typeInfo.AsType()] = moduleDef;
+            _moduleDefs.Add(module);
 
-            foreach (var cmd in moduleDef.Commands)
-                _map.AddCommand(cmd);
+            foreach (var command in module.Commands)
+                _map.AddCommand(command);
 
-            return moduleDef;
+            foreach (var submodule in module.Submodules)
+                LoadModuleInternal(submodule);
+            
+            return module;
         }
 
         public async Task<bool> RemoveModule(ModuleInfo module)
@@ -129,7 +146,7 @@ namespace Discord.Commands
             await _moduleLock.WaitAsync().ConfigureAwait(false);
             try
             {
-                return RemoveModuleInternal(module.Source.BaseType);
+                return RemoveModuleInternal(module);
             }
             finally
             {
@@ -141,24 +158,33 @@ namespace Discord.Commands
             await _moduleLock.WaitAsync().ConfigureAwait(false);
             try
             {
-                return RemoveModuleInternal(typeof(T));
+                ModuleInfo module;
+                _typedModuleDefs.TryGetValue(typeof(T), out module);
+                if (module == default(ModuleInfo))
+                    return false;
+                
+                return RemoveModuleInternal(module);
             }
             finally
             {
                 _moduleLock.Release();
             }
         }
-        private bool RemoveModuleInternal(Type type)
+        private bool RemoveModuleInternal(ModuleInfo module)
         {
-            ModuleInfo unloadedModule;
-            if (_moduleDefs.TryRemove(type, out unloadedModule))
+            var defsRemove = module;
+            if (!_moduleDefs.TryTake(out defsRemove))
+                return false;
+            
+            foreach (var cmd in module.Commands)
+                _map.RemoveCommand(cmd);
+
+            foreach (var submodule in module.Submodules)
             {
-                foreach (var cmd in unloadedModule.Commands)
-                    _map.RemoveCommand(cmd);
-                return true;
+                RemoveModuleInternal(submodule);
             }
-            else
-                return false;
+
+            return true;
         }
 
         //Type Readers

src/Discord.Net.Commands/Extensions/IEnumerableExtensions.cs

@@ -0,0 +1,22 @@
+using System;
+using System.Collections.Generic;
+
+namespace Discord.Commands
+{
+    public static class IEnumerableExtensions
+    {
+        public static IEnumerable<TResult> Permutate<TFirst, TSecond, TResult>(
+            this IEnumerable<TFirst> set,
+            IEnumerable<TSecond> others,
+            Func<TFirst, TSecond, TResult> func)
+        {
+            foreach (TFirst elem in set)
+            {
+                foreach (TSecond elem2 in others)
+                {
+                    yield return func(elem, elem2);
+                }
+            }
+        }
+    }
+}

src/Discord.Net.Commands/CommandInfo.cs → src/Discord.Net.Commands/Info/CommandInfo.cs

@@ -1,88 +1,52 @@
-using System;
-using System.Collections.Concurrent;
+using System;
+using System.Linq;
 using System.Collections.Generic;
 using System.Collections.Immutable;
-using System.Diagnostics;
-using System.Linq;
-using System.Reflection;
+using System.Collections.Concurrent;
 using System.Threading.Tasks;
+using System.Reflection;
+
+using Discord.Commands.Builders;
 
 namespace Discord.Commands
 {
-    [DebuggerDisplay(@"{DebuggerDisplay,nq}")]
     public class CommandInfo
     {
-        private static readonly MethodInfo _convertParamsMethod = typeof(CommandInfo).GetTypeInfo().GetDeclaredMethod(nameof(ConvertParamsList));
+        private static readonly System.Reflection.MethodInfo _convertParamsMethod = typeof(CommandInfo).GetTypeInfo().GetDeclaredMethod(nameof(ConvertParamsList));
         private static readonly ConcurrentDictionary<Type, Func<IEnumerable<object>, object>> _arrayConverters = new ConcurrentDictionary<Type, Func<IEnumerable<object>, object>>();
-        
+
         private readonly Func<CommandContext, object[], IDependencyMap, Task> _action;
 
-        public MethodInfo Source { get; }
         public ModuleInfo Module { get; }
         public string Name { get; }
         public string Summary { get; }
         public string Remarks { get; }
-        public string Text { get; }
         public int Priority { get; }
         public bool HasVarArgs { get; }
         public RunMode RunMode { get; }
+
         public IReadOnlyList<string> Aliases { get; }
-        public IReadOnlyList<CommandParameter> Parameters { get; }
+        public IReadOnlyList<ParameterInfo> Parameters { get; }
         public IReadOnlyList<PreconditionAttribute> Preconditions { get; }
 
-        internal CommandInfo(MethodInfo source, ModuleInfo module, CommandAttribute attribute, string groupPrefix)
+        internal CommandInfo(CommandBuilder builder, ModuleInfo module, CommandService service)
         {
-            try
-            {
-                Source = source;
-                Module = module;
-
-                Name = source.Name;
-
-                if (attribute.Text == null)
-                    Text = groupPrefix;
-                RunMode = attribute.RunMode;
-
-                if (groupPrefix != "")
-                    groupPrefix += " ";
-
-                if (attribute.Text != null)
-                    Text = groupPrefix + attribute.Text;
-
-                var aliasesBuilder = ImmutableArray.CreateBuilder<string>();
-
-                aliasesBuilder.Add(Text);
-
-                var aliasesAttr = source.GetCustomAttribute<AliasAttribute>();
-                if (aliasesAttr != null)
-                    aliasesBuilder.AddRange(aliasesAttr.Aliases.Select(x => groupPrefix + x));
-
-                Aliases = aliasesBuilder.ToImmutable();
-
-                var nameAttr = source.GetCustomAttribute<NameAttribute>();
-                if (nameAttr != null)
-                    Name = nameAttr.Text;
+            Module = module;
+            
+            Name = builder.Name;
+            Summary = builder.Summary;
+            Remarks = builder.Remarks;
 
-                var summary = source.GetCustomAttribute<SummaryAttribute>();
-                if (summary != null)
-                    Summary = summary.Text;
+            RunMode = builder.RunMode;
+            Priority = builder.Priority;
 
-                var remarksAttr = source.GetCustomAttribute<RemarksAttribute>();
-                if (remarksAttr != null)
-                    Remarks = remarksAttr.Text;
+            Aliases = module.Aliases.Permutate(builder.Aliases, (first, second) => first + " " + second).ToImmutableArray();
+            Preconditions = builder.Preconditions.ToImmutableArray();
 
-                var priorityAttr = source.GetCustomAttribute<PriorityAttribute>();
-                Priority = priorityAttr?.Priority ?? 0;
+            Parameters = builder.Parameters.Select(x => x.Build(this, service)).ToImmutableArray();
+            HasVarArgs = builder.Parameters.Count > 0 ? builder.Parameters[builder.Parameters.Count - 1].Multiple : false;
 
-                Parameters = BuildParameters(source);
-                HasVarArgs = Parameters.Count > 0 ? Parameters[Parameters.Count - 1].IsMultiple : false;
-                Preconditions = BuildPreconditions(source);
-                _action = BuildAction(source);
-            }
-            catch (Exception ex)
-            {
-                throw new Exception($"Failed to build command {source.DeclaringType.FullName}.{source.Name}", ex);
-            }
+            _action = builder.Callback;
         }
 
         public async Task<PreconditionResult> CheckPreconditions(CommandContext context, IDependencyMap map = null)
@@ -128,6 +92,7 @@ namespace Discord.Commands
 
             return await CommandParser.ParseArgs(this, context, input, 0).ConfigureAwait(false);
         }
+
         public Task<ExecuteResult> Execute(CommandContext context, ParseResult parseResult, IDependencyMap map)
         {
             if (!parseResult.IsSuccess)
@@ -179,72 +144,6 @@ namespace Discord.Commands
             }
         }
 
-        private IReadOnlyList<PreconditionAttribute> BuildPreconditions(MethodInfo methodInfo)
-        {
-            return methodInfo.GetCustomAttributes<PreconditionAttribute>().ToImmutableArray();
-        }
-
-        private IReadOnlyList<CommandParameter> BuildParameters(MethodInfo methodInfo)
-        {
-            var parameters = methodInfo.GetParameters();
-
-            var paramBuilder = ImmutableArray.CreateBuilder<CommandParameter>(parameters.Length);
-            for (int i = 0; i < parameters.Length; i++)
-            {
-                var parameter = parameters[i];
-                var type = parameter.ParameterType;
-
-                //Detect 'params'
-                bool isMultiple = parameter.GetCustomAttribute<ParamArrayAttribute>() != null;
-                if (isMultiple)
-                    type = type.GetElementType();
-
-                var reader = Module.Service.GetTypeReader(type);
-                var typeInfo = type.GetTypeInfo();
-
-                //Detect enums
-                if (reader == null && typeInfo.IsEnum)
-                {
-                    reader = EnumTypeReader.GetReader(type);
-                    Module.Service.AddTypeReader(type, reader);
-                }
-
-                if (reader == null)
-                    throw new InvalidOperationException($"{type.FullName} is not supported as a command parameter, are you missing a TypeReader?");
-
-                bool isRemainder = parameter.GetCustomAttribute<RemainderAttribute>() != null;
-                if (isRemainder && i != parameters.Length - 1)
-                    throw new InvalidOperationException("Remainder parameters must be the last parameter in a command.");
-
-                string name = parameter.Name;
-                string summary = parameter.GetCustomAttribute<SummaryAttribute>()?.Text;
-                bool isOptional = parameter.IsOptional;
-                object defaultValue = parameter.HasDefaultValue ? parameter.DefaultValue : null;
-
-                paramBuilder.Add(new CommandParameter(parameters[i], name, summary, type, reader, isOptional, isRemainder, isMultiple, defaultValue));
-            }
-            return paramBuilder.ToImmutable();
-        }
-        private Func<CommandContext, object[], IDependencyMap, Task> BuildAction(MethodInfo methodInfo)
-        {
-            if (methodInfo.ReturnType != typeof(Task))
-                throw new InvalidOperationException("Commands must return a non-generic Task.");
-
-            return (context, args, map) =>
-            {
-                var instance = Module.CreateInstance(map);
-                instance.Context = context;
-                try
-                {
-                    return methodInfo.Invoke(instance, args) as Task ?? Task.CompletedTask;
-                }
-                finally
-                {
-                    (instance as IDisposable)?.Dispose();
-                }
-            };
-        }
-
         private object[] GenerateArgs(IEnumerable<object> argList, IEnumerable<object> paramsList)
         {
             int argCount = Parameters.Count;
@@ -264,7 +163,7 @@ namespace Discord.Commands
 
             if (HasVarArgs)
             {
-                var func = _arrayConverters.GetOrAdd(Parameters[Parameters.Count - 1].ElementType, t =>
+                var func = _arrayConverters.GetOrAdd(Parameters[Parameters.Count - 1].ParameterType, t =>
                 {
                     var method = _convertParamsMethod.MakeGenericMethod(t);
                     return (Func<IEnumerable<object>, object>)method.CreateDelegate(typeof(Func<IEnumerable<object>, object>));
@@ -277,8 +176,5 @@ namespace Discord.Commands
 
         private static T[] ConvertParamsList<T>(IEnumerable<object> paramsList)
             => paramsList.Cast<T>().ToArray();
-
-        public override string ToString() => Name;
-        private string DebuggerDisplay => $"{Module.Name}.{Name} ({Text})";
     }
-}
+}

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

@@ -0,0 +1,91 @@
+using System;
+using System.Linq;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+
+using Discord.Commands.Builders;
+
+namespace Discord.Commands
+{
+    public class ModuleInfo
+    {
+        public CommandService Service { get; }
+        public string Name { get; }
+        public string Summary { get; }
+        public string Remarks { get; }
+
+        public IReadOnlyList<string> Aliases { get; }
+        public IEnumerable<CommandInfo> Commands { get; }
+        public IReadOnlyList<PreconditionAttribute> Preconditions { get; }
+        public IReadOnlyList<ModuleInfo> Submodules { get; }
+
+        internal ModuleInfo(ModuleBuilder builder, CommandService service)
+        {
+            Service = service;
+
+            Name = builder.Name;
+            Summary = builder.Summary;
+            Remarks = builder.Remarks;
+
+            Aliases = BuildAliases(builder).ToImmutableArray();
+            Commands = builder.Commands.Select(x => x.Build(this, service));
+            Preconditions = BuildPreconditions(builder).ToImmutableArray();
+
+            Submodules = BuildSubmodules(builder, service).ToImmutableArray();
+        }
+
+        private static IEnumerable<string> BuildAliases(ModuleBuilder builder)
+        {
+            IEnumerable<string> result = null;
+
+            Stack<ModuleBuilder> builderStack = new Stack<ModuleBuilder>();
+            builderStack.Push(builder);
+
+            ModuleBuilder parent = builder.ParentModule;
+            while (parent != null)
+            {
+                builderStack.Push(parent);
+                parent = parent.ParentModule;
+            }
+
+            while (builderStack.Count() > 0)
+            {
+                ModuleBuilder level = builderStack.Pop(); // get the topmost builder
+                if (result == null)
+                    result = level.Aliases.ToList(); // create a shallow copy so we don't overwrite the builder unexpectedly
+                else if (result.Count() > level.Aliases.Count)
+                    result = result.Permutate(level.Aliases, (first, second) => first + " " + second);
+                else
+                    result = level.Aliases.Permutate(result, (second, first) => first + " " + second);
+            }
+
+            return result;
+        }
+
+        private static List<ModuleInfo> BuildSubmodules(ModuleBuilder parent, CommandService service)
+        {
+            var result = new List<ModuleInfo>();
+
+            foreach (var submodule in parent.Modules)
+            {
+                result.Add(submodule.Build(service));
+            }
+
+            return result;
+        }
+
+        private static List<PreconditionAttribute> BuildPreconditions(ModuleBuilder builder)
+        {
+            var result = new List<PreconditionAttribute>();
+
+            ModuleBuilder parent = builder;
+            while (parent != null)
+            {
+                result.AddRange(parent.Preconditions);
+                parent = parent.ParentModule;
+            }
+
+            return result;
+        }
+    }
+}

src/Discord.Net.Commands/CommandParameter.cs → src/Discord.Net.Commands/Info/ParameterInfo.cs

@@ -1,37 +1,40 @@
-using System;
-using System.Diagnostics;
-using System.Reflection;
+using System;
+using System.Linq;
 using System.Threading.Tasks;
 
+using Discord.Commands.Builders;
+
 namespace Discord.Commands
 {
-    [DebuggerDisplay(@"{DebuggerDisplay,nq}")]
-    public class CommandParameter
+    public class ParameterInfo
     {
         private readonly TypeReader _reader;
 
-        public ParameterInfo Source { get; }
+        internal ParameterInfo(ParameterBuilder builder, CommandInfo command, CommandService service)
+        {
+            Command = command;
+
+            Name = builder.Name;
+            Summary = builder.Summary;
+            IsOptional = builder.Optional;
+            IsRemainder = builder.Remainder;
+            IsMultiple = builder.Multiple;
+
+            ParameterType = builder.ParameterType;
+            DefaultValue = builder.DefaultValue;
+
+            _reader = builder.TypeReader;
+        }
+
+        public CommandInfo Command { get; }
         public string Name { get; }
         public string Summary { get; }
         public bool IsOptional { get; }
         public bool IsRemainder { get; }
         public bool IsMultiple { get; }
-        public Type ElementType { get; }
+        public Type ParameterType { get; }
         public object DefaultValue { get; }
 
-        public CommandParameter(ParameterInfo source, string name, string summary, Type type, TypeReader reader, bool isOptional, bool isRemainder, bool isMultiple, object defaultValue)
-        {
-            Source = source;
-            Name = name;
-            Summary = summary;
-            ElementType = type;
-            _reader = reader;
-            IsOptional = isOptional;
-            IsRemainder = isRemainder;
-            IsMultiple = isMultiple;
-            DefaultValue = defaultValue;
-        }
-
         public async Task<TypeReaderResult> Parse(CommandContext context, string input)
         {
             return await _reader.Read(context, input).ConfigureAwait(false);
@@ -40,4 +43,4 @@ namespace Discord.Commands
         public override string ToString() => Name;
         private string DebuggerDisplay => $"{Name}{(IsOptional ? " (Optional)" : "")}{(IsRemainder ? " (Remainder)" : "")}";
     }
-}
+}

src/Discord.Net.Commands/ModuleInfo.cs

@@ -1,85 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Collections.Immutable;
-using System.Diagnostics;
-using System.Reflection;
-
-namespace Discord.Commands
-{
-    [DebuggerDisplay(@"{DebuggerDisplay,nq}")]
-    public class ModuleInfo
-    {
-        internal readonly Func<IDependencyMap, ModuleBase> _builder;
-
-        public TypeInfo Source { get; }
-        public CommandService Service { get; }
-        public string Name { get; }
-        public string Prefix { get; }
-        public string Summary { get; }
-        public string Remarks { get; }
-        public IEnumerable<CommandInfo> Commands { get; }
-        public IReadOnlyList<PreconditionAttribute> Preconditions { get; }
-
-        internal ModuleInfo(TypeInfo source, CommandService service)
-        {
-            Source = source;
-            Service = service;
-            Name = source.Name;
-            _builder = ReflectionUtils.CreateBuilder<ModuleBase>(source, Service);
-
-            var groupAttr = source.GetCustomAttribute<GroupAttribute>();
-            if (groupAttr != null)
-                Prefix = groupAttr.Prefix;
-            else
-                Prefix = "";
-
-            var nameAttr = source.GetCustomAttribute<NameAttribute>();
-            if (nameAttr != null)
-                Name = nameAttr.Text;
-
-            var summaryAttr = source.GetCustomAttribute<SummaryAttribute>();
-            if (summaryAttr != null)
-                Summary = summaryAttr.Text;
-
-            var remarksAttr = source.GetCustomAttribute<RemarksAttribute>();
-            if (remarksAttr != null)
-                Remarks = remarksAttr.Text;
-
-            List<CommandInfo> commands = new List<CommandInfo>();
-            SearchClass(source, commands, Prefix);
-            Commands = commands;
-
-            Preconditions = Source.GetCustomAttributes<PreconditionAttribute>().ToImmutableArray();
-        }
-        private void SearchClass(TypeInfo parentType, List<CommandInfo> commands, string groupPrefix)
-        {
-            foreach (var method in parentType.DeclaredMethods)
-            {
-                var cmdAttr = method.GetCustomAttribute<CommandAttribute>();
-                if (cmdAttr != null)
-                    commands.Add(new CommandInfo(method, this, cmdAttr, groupPrefix));
-            }
-            foreach (var type in parentType.DeclaredNestedTypes)
-            {
-                var groupAttrib = type.GetCustomAttribute<GroupAttribute>();
-                if (groupAttrib != null)
-                {
-                    string nextGroupPrefix;
-
-                    if (groupPrefix != "")
-                        nextGroupPrefix = groupPrefix + " " + (groupAttrib.Prefix ?? type.Name.ToLowerInvariant());
-                    else
-                        nextGroupPrefix = groupAttrib.Prefix ?? type.Name.ToLowerInvariant();
-
-                    SearchClass(type, commands, nextGroupPrefix);
-                }
-            }
-        }
-
-        internal ModuleBase CreateInstance(IDependencyMap map)
-            => _builder(map);
-
-        public override string ToString() => Name;
-        private string DebuggerDisplay => Name;
-    }
-}

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

@@ -0,0 +1,226 @@
+using System;
+using System.Linq;
+using System.Collections.Generic;
+using System.Reflection;
+using System.Threading.Tasks;
+
+using Discord.Commands.Builders;
+
+namespace Discord.Commands
+{
+    internal static class ModuleClassBuilder
+    {
+        private static readonly TypeInfo _moduleTypeInfo = typeof(ModuleBase).GetTypeInfo();
+
+        public static IEnumerable<TypeInfo> Search(Assembly assembly)
+        {
+            foreach (var type in assembly.ExportedTypes)
+            {
+                var typeInfo = type.GetTypeInfo();
+                if (IsValidModuleDefinition(typeInfo) &&
+                    !typeInfo.IsDefined(typeof(DontAutoLoadAttribute)))
+                {
+                    yield return typeInfo;
+                }
+            }
+        }
+
+        public static Dictionary<Type, ModuleInfo> Build(CommandService service, params TypeInfo[] validTypes) => Build(validTypes, service);
+        public static Dictionary<Type, ModuleInfo> Build(IEnumerable<TypeInfo> validTypes, CommandService service)
+        {
+            if (!validTypes.Any())
+                throw new InvalidOperationException("Could not find any valid modules from the given selection");
+            
+            var topLevelGroups = validTypes.Where(x => x.DeclaringType == null);
+            var subGroups = validTypes.Intersect(topLevelGroups);
+
+            var builtTypes = new List<TypeInfo>();
+
+            var result = new Dictionary<Type, ModuleInfo>();
+
+            foreach (var typeInfo in topLevelGroups)
+            {
+                // this shouldn't be the case; may be safe to remove?
+                if (result.ContainsKey(typeInfo.AsType()))
+                    continue;
+
+                var module = new ModuleBuilder();
+
+                BuildModule(module, typeInfo, service);
+                BuildSubTypes(module, typeInfo.DeclaredNestedTypes, builtTypes, service);
+
+                result[typeInfo.AsType()] = module.Build(service);
+            }
+
+            return result;
+        }
+
+        private static void BuildSubTypes(ModuleBuilder builder, IEnumerable<TypeInfo> subTypes, List<TypeInfo> builtTypes, CommandService service)
+        {
+            foreach (var typeInfo in subTypes)
+            {
+                if (!IsValidModuleDefinition(typeInfo))
+                    continue;
+                
+                if (builtTypes.Contains(typeInfo))
+                    continue;
+                
+                builder.AddSubmodule((module) => {
+                    BuildModule(module, typeInfo, service);
+                    BuildSubTypes(module, typeInfo.DeclaredNestedTypes, builtTypes, service);
+                });
+
+                builtTypes.Add(typeInfo);
+            }
+        }
+
+        private static void BuildModule(ModuleBuilder builder, TypeInfo typeInfo, CommandService service)
+        {
+            var attributes = typeInfo.GetCustomAttributes();
+
+            foreach (var attribute in attributes)
+            {
+                // TODO: C#7 type switch
+                if (attribute is NameAttribute)
+                    builder.Name = (attribute as NameAttribute).Text;
+                else if (attribute is SummaryAttribute)
+                    builder.Summary = (attribute as SummaryAttribute).Text;
+                else if (attribute is RemarksAttribute)
+                    builder.Remarks = (attribute as RemarksAttribute).Text;
+                else if (attribute is AliasAttribute)
+                    builder.AddAliases((attribute as AliasAttribute).Aliases);
+                else if (attribute is GroupAttribute)
+                {
+                    var groupAttr = attribute as GroupAttribute;
+                    builder.Name = builder.Name ?? groupAttr.Prefix;
+                    builder.AddAliases(groupAttr.Prefix);
+                }
+                else if (attribute is PreconditionAttribute)
+                    builder.AddPrecondition(attribute as PreconditionAttribute);
+            }
+
+            var validCommands = typeInfo.DeclaredMethods.Where(x => IsValidCommandDefinition(x));
+
+            foreach (var method in validCommands)
+            {
+                builder.AddCommand((command) => {
+                    BuildCommand(command, typeInfo, method, service);
+                });
+            }
+        }
+
+        private static void BuildCommand(CommandBuilder builder, TypeInfo typeInfo, MethodInfo method, CommandService service)
+        {
+            var attributes = method.GetCustomAttributes();
+
+            foreach (var attribute in attributes)
+            {
+                // TODO: C#7 type switch
+                if (attribute is CommandAttribute)
+                {
+                    var cmdAttr = attribute as CommandAttribute;
+                    builder.AddAliases(cmdAttr.Text);
+                    builder.RunMode = cmdAttr.RunMode;
+                    builder.Name = builder.Name ?? cmdAttr.Text;
+                }
+                else if (attribute is NameAttribute)
+                    builder.Name = (attribute as NameAttribute).Text;
+                else if (attribute is PriorityAttribute)
+                    builder.Priority = (attribute as PriorityAttribute).Priority;
+                else if (attribute is SummaryAttribute)
+                    builder.Summary = (attribute as SummaryAttribute).Text;
+                else if (attribute is RemarksAttribute)
+                    builder.Remarks = (attribute as RemarksAttribute).Text;
+                else if (attribute is AliasAttribute)
+                    builder.AddAliases((attribute as AliasAttribute).Aliases);
+                else if (attribute is PreconditionAttribute)
+                    builder.AddPrecondition(attribute as PreconditionAttribute);
+            }
+
+            var parameters = method.GetParameters();
+            int pos = 0, count = parameters.Length;
+            foreach (var paramInfo in parameters)
+            {
+                builder.AddParameter((parameter) => {
+                    BuildParameter(parameter, paramInfo, pos++, count, service);
+                });
+            }
+
+            var createInstance = ReflectionUtils.CreateBuilder<ModuleBase>(typeInfo, service);
+
+            builder.Callback = (ctx, args, map) => {
+                var instance = createInstance(map);
+                instance.Context = ctx;
+                try
+                {
+                    return method.Invoke(instance, args) as Task ?? Task.CompletedTask;
+                }
+                finally{
+                    (instance as IDisposable)?.Dispose();
+                }
+            };
+        }
+
+        private static void BuildParameter(ParameterBuilder builder, System.Reflection.ParameterInfo paramInfo, int position, int count, CommandService service)
+        {
+            var attributes = paramInfo.GetCustomAttributes();
+            var paramType = paramInfo.ParameterType;
+
+            builder.Name = paramInfo.Name;
+
+            builder.Optional = paramInfo.IsOptional;
+            builder.DefaultValue = paramInfo.HasDefaultValue ? paramInfo.DefaultValue : null;
+
+            foreach (var attribute in attributes)
+            {
+                // TODO: C#7 type switch
+                if (attribute is SummaryAttribute)
+                    builder.Summary = (attribute as SummaryAttribute).Text;
+                else if (attribute is ParamArrayAttribute)
+                {
+                    builder.Multiple = true;
+                    paramType = paramType.GetElementType();
+                }
+                else if (attribute is RemainderAttribute)
+                {
+                    if (position != count-1)
+                        throw new InvalidOperationException("Remainder parameters must be the last parameter in a command.");
+                    
+                    builder.Remainder = true;
+                }
+            }
+
+            var reader = service.GetTypeReader(paramType);
+            if (reader == null)
+            {
+                var paramTypeInfo = paramType.GetTypeInfo();
+                if (paramTypeInfo.IsEnum)
+                {
+                    reader = EnumTypeReader.GetReader(paramType);
+                    service.AddTypeReader(paramType, reader);
+                }
+                else
+                {
+                    throw new InvalidOperationException($"{paramType.FullName} is not supported as a command parameter, are you missing a TypeReader?");
+                }
+            }
+
+            builder.ParameterType = paramType;
+            builder.TypeReader = reader;
+        }
+
+        private static bool IsValidModuleDefinition(TypeInfo typeInfo)
+        {
+            return _moduleTypeInfo.IsAssignableFrom(typeInfo) &&
+                   !typeInfo.IsAbstract;
+        }
+
+        private static bool IsValidCommandDefinition(MethodInfo methodInfo)
+        {
+            return methodInfo.IsDefined(typeof(CommandAttribute)) &&
+                   methodInfo.ReturnType == typeof(Task) &&
+                   !methodInfo.IsStatic &&
+                   !methodInfo.IsGenericMethod;
+        }
+    }
+}

src/Discord.Net.Commands/ReflectionUtils.cs → src/Discord.Net.Commands/Utilities/ReflectionUtils.cs

@@ -18,7 +18,7 @@ namespace Discord.Commands
                 throw new InvalidOperationException($"Multiple constructors found for \"{typeInfo.FullName}\"");
 
             var constructor = constructors[0];
-            ParameterInfo[] parameters = constructor.GetParameters();
+            System.Reflection.ParameterInfo[] parameters = constructor.GetParameters();
 
             return (map) =>
             {