Added basic service model, even more commands cleanup!

src/Discord.Net.Commands/CommandService.cs

@@ -0,0 +1,184 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Discord.Commands
+{
+	/// <summary> A Discord.Net client with extensions for handling common bot operations like text commands. </summary>
+	public partial class CommandService : IService
+    {
+		private DiscordClient _client;
+
+		CommandServiceConfig Config { get; }
+		public IEnumerable<Command> Commands => _commands;
+		private readonly List<Command> _commands;
+
+		internal CommandMap Map => _map;
+		private readonly CommandMap _map;
+
+		public CommandService(CommandServiceConfig config)
+		{
+			Config = config;
+			_commands = new List<Command>();
+			_map = new CommandMap(null);
+		}
+
+		void IService.Install(DiscordClient client)
+		{
+			_client = client;
+			Config.Lock();
+
+            if (Config.HelpMode != HelpMode.Disable)
+            {
+                CreateCommand("help")
+					.Parameter("command", ParameterType.Multiple)
+                    .Hide()
+                    .Info("Returns information about commands.")
+                    .Do(async e =>
+                    {
+						Channel channel = Config.HelpMode == HelpMode.Public ? e.Channel : await client.CreatePMChannel(e.User);
+						if (e.Args.Length > 0) //Show command help
+						{
+							var cmd = _map.GetCommand(string.Join(" ", e.Args));
+							if (cmd != null)
+								await ShowHelp(cmd, e.User, channel);
+							else
+								await client.SendMessage(channel, "Unable to display help: unknown command.");
+						}
+                        else //Show general help
+							await ShowHelp(e.User, channel);
+                    });
+            }
+
+            client.MessageReceived += async (s, e) =>
+            {
+                if (_commands.Count == 0)  return;
+                if (e.Message.IsAuthor) return;
+
+                string msg = e.Message.Text;
+                if (msg.Length == 0) return;
+
+				//Check for command char if one is provided
+				var chars = Config.CommandChars;
+                if (chars.Length > 0)
+                {
+					if (!chars.Contains(msg[0]))
+						return;
+                    msg = msg.Substring(1);
+                }
+
+				//Parse command
+				Command command;
+				int argPos;
+				CommandParser.ParseCommand(msg, _map, out command, out argPos);				
+				if (command == null)
+				{
+					CommandEventArgs errorArgs = new CommandEventArgs(e.Message, null, null, null);
+					RaiseCommandError(CommandErrorType.UnknownCommand, errorArgs);
+					return;
+				}
+				else
+				{
+					int userPermissions = Config.PermissionResolver?.Invoke(e.Message.User) ?? 0;
+
+					//Parse arguments
+					string[] args;
+					var error = CommandParser.ParseArgs(msg, argPos, command, out args);
+                    if (error != null)
+					{
+						var errorArgs = new CommandEventArgs(e.Message, command, userPermissions, null);
+						RaiseCommandError(error.Value, errorArgs);
+						return;
+					}
+					
+					var eventArgs = new CommandEventArgs(e.Message, command, userPermissions, args);
+
+					// Check permissions
+					if (userPermissions < command.MinPermissions)
+					{
+						RaiseCommandError(CommandErrorType.BadPermissions, eventArgs);
+						return;
+					}
+
+					// Run the command
+					try
+					{
+						RaiseRanCommand(eventArgs);
+						await command.Run(eventArgs).ConfigureAwait(false);
+					}
+					catch (Exception ex)
+					{
+						RaiseCommandError(CommandErrorType.Exception, eventArgs, ex);
+					}
+				}
+            };
+        }
+
+		public Task ShowHelp(User user, Channel channel)
+		{
+			int permissions = Config.PermissionResolver(user);
+
+			StringBuilder output = new StringBuilder();
+			output.AppendLine("These are the commands you can use:");
+			output.Append(string.Join(", ", _commands
+				.Where(x => permissions >= x.MinPermissions && !x.IsHidden)
+				.Select(x => '`' + x.Text + '`')));
+
+			var chars = Config.CommandChars;
+			if (chars.Length > 0)
+			{
+				if (chars.Length == 1)
+					output.AppendLine($"\nYou can use `{chars[0]}` to call a command.");
+				else
+					output.AppendLine($"\nYou can use `{string.Join(" ", chars.Take(chars.Length - 1))}` or `{chars.Last()}` to call a command.");
+			}
+
+			output.AppendLine("`help <command>` can tell you more about how to use a command.");
+
+			return _client.SendMessage(channel, output.ToString());
+		}
+        
+        public Task ShowHelp(Command command, User user, Channel channel)
+        {
+            StringBuilder output = new StringBuilder();
+
+            output.Append($"`{command.Text}`");
+
+            if (command.MinArgs != null && command.MaxArgs != null)
+            {
+                if (command.MinArgs == command.MaxArgs)
+                {
+                    if (command.MaxArgs != 0)
+                        output.Append($" {command.MinArgs.ToString()} Args");
+                }
+                else
+                    output.Append($" {command.MinArgs.ToString()} - {command.MaxArgs.ToString()} Args");
+            }
+            else if (command.MinArgs != null && command.MaxArgs == null)
+                output.Append($" ≥{command.MinArgs.ToString()} Args");
+            else if (command.MinArgs == null && command.MaxArgs != null)
+                output.Append($" ≤{command.MaxArgs.ToString()} Args");
+
+            output.Append($": {command.Description ?? "No description set for this command."}");
+
+			return _client.SendMessage(channel, output.ToString());
+		}
+
+		public void CreateCommandGroup(string cmd, Action<CommandGroupBuilder> config = null)
+			=> config(new CommandGroupBuilder(this, cmd, 0));
+		public CommandBuilder CreateCommand(string cmd)
+		{
+			var command = new Command(cmd);
+			_commands.Add(command);
+			return new CommandBuilder(this, command, "");
+		}
+
+		internal void AddCommand(Command command)
+		{
+			_commands.Add(command);
+			_map.AddCommand(command.Text, command);
+		}
+	}
+}