Begin script abstraction

ReallifeGamemode.Server.Core/Commands/CommandHandler.cs

@@ -0,0 +1,202 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using System.Text;
+using ReallifeGamemode.Server.Core.API;
+using ReallifeGamemode.Server.Types;
+using ReallifeGamemode.Server.Common;
+using ReallifeGamemode.Server.Log;
+using Microsoft.Extensions.Logging;
+
+namespace ReallifeGamemode.Server.Core.Commands
+{
+  class CommandHandler
+  {
+    private readonly Dictionary<string, Command> registeredCommands = new Dictionary<string, Command>();
+    private readonly ILogger logger = LogManager.GetLogger<CommandHandler>();
+
+    private readonly IAPI api;
+
+    private Random random = new Random();
+
+    public CommandHandler(IAPI api)
+    {
+      this.api = api;
+      Main.EventHandler.RegisterClientEvent("Command", OnPlayerCommand);
+    }
+
+    private void OnPlayerCommand(IPlayer player, object[] args)
+    {
+      var command = (args.First() as string)?.ToString()?.ToLower();
+
+      logger.LogInformation("Player '{Name}' executed command '{command}'", player.Name, command);
+
+      if (!registeredCommands.ContainsKey(command))
+      {
+        player.SendMessage($"Der Befehl ~b~/{command}~s~ existiert nicht", ChatPrefix.Error);
+        return;
+      }
+
+      var executor = registeredCommands[command];
+
+      if (!executor.CanExecute(player))
+      {
+        player.SendMessage($"Du darfst diesen Befehl nicht ausführen", ChatPrefix.Error);
+        return;
+      }
+
+      var methodInfo = executor.GetType().GetMethod("Handle");
+
+      var arguments = new List<object>
+      {
+          player
+      };
+
+      try
+      {
+        arguments.AddRange(ComputeParameters(methodInfo, args.Skip(1).ToArray()));
+
+        var result = methodInfo.Invoke(executor, arguments.ToArray());
+      }
+      catch (ArgumentException ex)
+      {
+        player.SendMessage($"Der Parameter ~y~'{ex.Message}'~s~ ist ungültig.", ChatPrefix.Error);
+      }
+      catch (SendHelpTextException)
+      {
+        player.SendMessage("/" + command + " " + executor.HelpText, ChatPrefix.Usage);
+      }
+      catch (TargetInvocationException ex)
+      {
+        var errorCode = GetNewErrorCode();
+        ex.Data.Add("ErrorCode", errorCode);
+        logger.LogError(ex, "Error (Code: {ErrorCode}) while executing command '{Command}' from user '{Name}'", errorCode, command, player.Name);
+        player.SendMessage($"Bei der Ausführung des Befehls gab es einen unbekannten Fehler. ~m~({errorCode})", ChatPrefix.Error);
+      }
+    }
+
+    public void RegisterCommand(string command, Command commandExecutor)
+    {
+      command = command.ToLower();
+      logger.LogDebug("Adding command '{command}'", command);
+
+      if (command.IsNullOrEmpty())
+      {
+        logger.LogError("Command name is null");
+        return;
+      }
+
+      if (commandExecutor == null)
+      {
+        logger.LogError("Command executor for command '{command}' is null", command);
+        return;
+      }
+
+      var methodInfo = commandExecutor.GetType().GetMethod("Handle");
+
+      if (methodInfo == null)
+      {
+        logger.LogError("The executor for command '{command}' does not have a 'Handle' Method", command);
+        return;
+      }
+
+      registeredCommands[command] = commandExecutor;
+    }
+
+    private object[] ComputeParameters(MethodInfo methodInfo, object[] arguments)
+    {
+      var computedParameters = new List<object>();
+
+      var parameterInfos = methodInfo.GetParameters();
+      var parameterCount = parameterInfos.Length - 1;
+
+      var argumentCount = arguments.Length;
+
+      for (var i = 1; i <= parameterCount; i++)
+      {
+        var currentParameter = parameterInfos[i];
+
+        var parameterType = currentParameter.ParameterType;
+
+        object currentArgument;
+
+        if (i < argumentCount + 1)
+        {
+          currentArgument = arguments[i - 1];
+        }
+        else if (argumentCount <= (i - 1) && currentParameter.HasDefaultValue)
+        {
+          currentArgument = currentParameter.DefaultValue;
+          computedParameters.Add(currentArgument);
+          continue;
+        }
+        else
+        {
+          throw new CommandArgumentCountMismatchException();
+        }
+
+        if (parameterType == typeof(IPlayer))
+        {
+          var player = api.GetPlayerFromNameOrId(currentArgument.ToString());
+
+          if (player == null)
+          {
+            throw new ArgumentException($"Der Spieler wurde nicht gefunden.");
+          }
+
+          computedParameters.Add(player);
+
+          continue;
+        }
+
+        if (parameterType == typeof(string))
+        {
+          if (i == parameterCount)
+          {
+            var str = string.Join(' ', arguments.Skip(i - 1));
+            computedParameters.Add(str);
+            break;
+          }
+          else
+          {
+            computedParameters.Add(currentArgument);
+          }
+        }
+
+        if (parameterType.IsEnum)
+        {
+          var stringArg = currentArgument.ToString();
+          if (stringArg.TryParseEnum(parameterType, out var result))
+          {
+            computedParameters.Add(result);
+          }
+          else
+          {
+            throw new ArgumentException(currentArgument.ToString());
+          }
+        }
+        else if (parameterType.IsPrimitive)
+        {
+          try
+          {
+            computedParameters.Add(Convert.ChangeType(currentArgument, parameterType));
+          }
+          catch
+          {
+            throw new ArgumentException(currentArgument.ToString());
+          }
+        }
+      }
+
+      return computedParameters.ToArray();
+    }
+
+    private string GetNewErrorCode()
+    {
+      const string chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789#?$";
+      return new string(Enumerable.Repeat(chars, 6)
+        .Select(s => s[random.Next(s.Length)]).ToArray());
+    }
+  }
+}