package de.mrbesen.telegram.commands;

import com.google.common.collect.ArrayListMultimap;
import com.google.common.collect.Multimap;

import de.mrbesen.telegram.TelegramUser;

public class CommandManager {
	
	private static String CMDPATTERN = "^[\\w-]+$";
	
	private Multimap<String, CommandHandler> handlerlist = ArrayListMultimap.create();//list of all registered CommandHandler

	public CommandManager() { }
	
	void onCommand(String line, TelegramUser sender) {//called by the api (/-prefix allready removed)
		line = line.trim();
		String[] split = line.split(" ",2);
		String cmd = split[0].toLowerCase();
		if(cmd.matches(CMDPATTERN)) {
			String[] args = new String[0];
			if(split.length == 2) {
				args = split[1].split(" ");
			}
			//call
			for(CommandHandler cmdhand : handlerlist.get(cmd)) {
				try {
					boolean result = cmdhand.onCommand(sender, cmd, args);
					if(result)
						break;
				} catch(Throwable t) {
					System.err.println("Error, while performing Command. ");
					t.printStackTrace();
				}
			}
		} else {
			//unknown cmd!
		}
	}
	
	public void registerCommand(String cmd, CommandHandler handler) {
		if(cmd == null) {
			throw new NullPointerException("cmd is not allowed to be null");
		}
		if(handler == null) {
			throw new NullPointerException("handler is not allowed to be null");
		}
		cmd = cmd.trim();
		if(cmd.startsWith("/")) {
			cmd = cmd.substring(1);
		}
		if(cmd.isEmpty()) {
			throw new RuntimeException("cmd is not allowed to be empty");
		}
		if(cmd.matches(CMDPATTERN)) {
			handlerlist.put(cmd.toLowerCase(), handler);
			//registered successfull!
		} else {
			throw new IllegalArgumentException("cmd contains unallowed characters. Allowed: a-zA-Z0-9_-");
		}
	}
}