Help prompt + command arguments.

src/main/java/net/pingex/discordbot/CommandDispatcher.java

@@ -49,7 +49,11 @@ public class CommandDispatcher
 		String module = m.group(1);
 		String command = m.group(2);
 		String fullCommand = module + ":" + command;
-		String[] args = (m.group(3) != null) ? m.group(3).split(" ") : new String[0];
+
+		// Arg splitter
+		Matcher am = Pattern.compile("([^\"]\\S*|\".+?\")\\s*").matcher((m.group(3) != null) ? m.group(3) : "");
+		ArrayList<String> args = new ArrayList<>();
+		while(am.find()) args.add(am.group(1).replace("\"", ""));
 
 		logger.info("Command invoked (" + event.getMessage().getAuthor().getName() + "#" + event.getMessage().getAuthor().getDiscriminator() + "): " + fullCommand);
 
@@ -61,19 +65,19 @@ public class CommandDispatcher
 				Object[] parsedArray = new Object[foundMethod.getMethod().getParameterCount()];
 				parsedArray[0] = event;
 
-				if(foundMethod.getMethod().getParameterCount()-1 != args.length)
+				if(foundMethod.getMethod().getParameterCount()-1 != args.size())
 				{
-					event.getMessage().reply("Invalid arguments"); // TODO: Call !help
+					event.getMessage().reply("Invalid arguments. " + getHelp(fullCommand));
 					return;
 				}
 
 				for(int i=1; i < foundMethod.getMethod().getParameterCount(); i++)
 					try
 					{
-						parsedArray[i] = parse(foundMethod.getMethod().getParameterTypes()[i], args[i-1]);
+						parsedArray[i] = parse(foundMethod.getMethod().getParameterTypes()[i], args.get(i-1));
 					} catch (IllegalArgumentException e)
 					{
-						event.getMessage().reply("Failed to parse arguments"); // TODO: Call !help
+						event.getMessage().reply("Failed to parse arguments, are they correct ? " + getHelp(fullCommand));
 					}
 
 				String answer = (String) commandList.get(fullCommand).invoke(parsedArray);
@@ -83,10 +87,10 @@ public class CommandDispatcher
 				event.getMessage().reply("Unknown command");
 		} catch (MissingPermissionsException | HTTP429Exception | DiscordException e)
 		{
-			logger.warning("Couldn't reply to command: " + e.getMessage());
+			logger.warning("Couldn't reply to command (" + e.getClass().getName() + "): " + e.getMessage());
 		} catch (IllegalArgumentException | IllegalAccessException | InvocationTargetException e)
 		{
-			logger.severe("Couldn't call target method: " + e.getMessage());
+			logger.severe("Couldn't call target method (" + e.getClass().getName() + "): " + e.getMessage());
 		}
 	}
 
@@ -116,7 +120,7 @@ public class CommandDispatcher
 						if(j.getParameterCount() >= 1 && j.getParameterTypes()[0] == MessageReceivedEvent.class && j.getReturnType() == String.class)
 							commandList.put(id, new InvokableMethod(j, i));
 						else
-							logger.warning(id + ": incorrect function prototype, thus won't be added to the command list.");
+							logger.warning("Command [" + id + "]: incorrect function prototype, thus won't be added to the command list.");
 					}
 
 		logger.info("... Done");
@@ -142,4 +146,22 @@ public class CommandDispatcher
 		if(String.class  == target)                           return value;
 		throw new IllegalArgumentException("Unknown target type");
 	}
+
+	/**
+	 * Scans and print the usage of a command
+	 * @param command Full command `module:command`
+	 * @return Human-readable string
+	 */
+	private String getHelp(String command)
+	{
+		if(!commandList.containsKey(command)) return "No help available for this command.";
+		InvokableMethod matchingMethod = commandList.get(command);
+
+		StringBuffer toReturn = new StringBuffer("Usage: ");
+		toReturn.append("!" + command + " ");
+		for(int i=1; i<matchingMethod.getMethod().getParameterCount(); i++)
+			toReturn.append(matchingMethod.getMethod().getParameterTypes()[i].getName() + " ");
+
+		return toReturn.toString();
+	}
 }