/*
Yaaic - Yet Another Android IRC Client

Copyright 2009-2010 Sebastian Kaspari

This file is part of Yaaic.

Yaaic is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

Yaaic is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with Yaaic.  If not, see <http://www.gnu.org/licenses/>.
*/
package org.yaaic.command;

import java.util.HashMap;

import android.content.Intent;

import org.yaaic.command.handler.AwayHandler;
import org.yaaic.command.handler.CloseHandler;
import org.yaaic.command.handler.DCCHandler;
import org.yaaic.command.handler.DeopHandler;
import org.yaaic.command.handler.DevoiceHandler;
import org.yaaic.command.handler.EchoHandler;
import org.yaaic.command.handler.HelpHandler;
import org.yaaic.command.handler.JoinHandler;
import org.yaaic.command.handler.KickHandler;
import org.yaaic.command.handler.MeHandler;
import org.yaaic.command.handler.ModeHandler;
import org.yaaic.command.handler.MsgHandler;
import org.yaaic.command.handler.NamesHandler;
import org.yaaic.command.handler.NickHandler;
import org.yaaic.command.handler.NoticeHandler;
import org.yaaic.command.handler.OpHandler;
import org.yaaic.command.handler.PartHandler;
import org.yaaic.command.handler.QueryHandler;
import org.yaaic.command.handler.QuitHandler;
import org.yaaic.command.handler.TopicHandler;
import org.yaaic.command.handler.VoiceHandler;
import org.yaaic.command.handler.WhoisHandler;
import org.yaaic.exception.CommandException;
import org.yaaic.irc.IRCService;
import org.yaaic.model.Broadcast;
import org.yaaic.model.Conversation;
import org.yaaic.model.Message;
import org.yaaic.model.Server;

/**
 * Parser for commands
 *  
 * @author Sebastian Kaspari <sebastian@yaaic.org>
 */
public class CommandParser
{
	private HashMap<String, BaseHandler> commands;
	private HashMap<String, String> aliases;
	private static CommandParser instance;
	
	private final static String[] serverCommands = {
		// whitelist of server commands
		"admin", "motd",    "version",            "knock",   "rules",
		"vhost", "credits", "license", "setname", "watch",   "pong",
		"cycle", "links",   "silence", "who",     "dalinfo", "userhost",
		"list",  "stats",              "invite",  "lusers",  "ping",
		"time",  "whowas",  "ison",    "map",
		
		// services
		"nickserv", "ns", "chanserv", "cs", "authserv", "hostserv",
		"memoserv", "operserv"
	};

	/**
	 * Create a new CommandParser instance
	 */
	private CommandParser()
	{
		commands = new HashMap<String, BaseHandler>();
		
		// Commands
		commands.put("nick", new NickHandler());
		commands.put("join", new JoinHandler());
		commands.put("me", new MeHandler());
		commands.put("names", new NamesHandler());
		commands.put("echo", new EchoHandler());
		commands.put("topic", new TopicHandler());
		commands.put("quit", new QuitHandler());
		commands.put("op", new OpHandler());
		commands.put("voice", new VoiceHandler());
		commands.put("deop", new DeopHandler());
		commands.put("devoice", new DevoiceHandler());
		commands.put("kick", new KickHandler());
		commands.put("query", new QueryHandler());
		commands.put("part", new PartHandler());
		commands.put("close", new CloseHandler());
		commands.put("notice", new NoticeHandler());
		commands.put("dcc", new DCCHandler());
		commands.put("mode", new ModeHandler());
		commands.put("help", new HelpHandler());
		commands.put("away", new AwayHandler());
		commands.put("whois", new WhoisHandler());
		commands.put("msg", new MsgHandler());
		
		aliases = new HashMap<String, String>();
		// Aliases
		aliases.put("j","join");
		aliases.put("q", "query");
		aliases.put("h", "help");
	}
	
	/**
	 * Get the global CommandParser instance
	 * 
	 * @return
	 */
	public static CommandParser getInstance()
	{
		if (instance == null) {
			instance = new CommandParser();
		}
		
		return instance;
	}
	
	/**
	 * Get the commands HashMap
	 * 
	 * @return HashMap - command, commandHandler
	 */
	public HashMap<String, BaseHandler> getCommands()
	{
		return commands;
	}
	
	/**
	 * Get the command aliases HashMap
	 * 
	 * @return HashMap - alias, command the alias belogs to
	 */
	public HashMap<String, String> getAliases()
	{
		return aliases;
	}
	
	
	/**
	 * Is the given command a valid client command?
	 * 
	 * @param command The (client) command to check (/command)
	 * @return true if the command can be handled by the client, false otherwise
	 */
	public boolean isClientCommand(String command)
	{
		return commands.containsKey(command.toLowerCase()) || aliases.containsKey(command.toLowerCase());
	}
	
	/**
	 * Is the given command a valid server command?
	 * 
	 * @param command The (server) command to check (/command)
	 * @return true if the command can be handled by a server, false otherwise
	 */
	public boolean isServerCommand(String command)
	{
		command = command.toLowerCase();
		for (String validCommand : serverCommands) {
			if (validCommand.equals(command)) {
				return true;
			}
		}
		
		return false;
	}
	
	/**
	 * Handle a client command
	 * 
	 * @param type Type of the command (/type param1 param2 ..)
	 * @param params The parameters of the command (0 is the command itself)
	 * @param server The current server
	 * @param conversation The selected conversation
	 * @param service The service handling the connections
	 */
	public void handleClientCommand(String type, String[] params, Server server, Conversation conversation, IRCService service)
	{
		BaseHandler command = null;
		if (commands.containsKey(type.toLowerCase())) {
			command = commands.get(type);
		} else if (aliases.containsKey(type.toLowerCase())) {
			String commandInCommands = aliases.get(type.toLowerCase());
			command = commands.get(commandInCommands);
		}
		try {
			command.execute(params, server, conversation, service);
		} catch(CommandException e) {
			// Command could not be executed
			if (conversation != null) {
				Message errorMessage = new Message(type + ": " + e.getMessage());
				errorMessage.setColor(Message.COLOR_RED);
				conversation.addMessage(errorMessage);
				
				Message usageMessage = new Message("Syntax: " + command.getUsage());
				conversation.addMessage(usageMessage);
				
				Intent intent = Broadcast.createConversationIntent(
					Broadcast.CONVERSATION_MESSAGE,
					server.getId(),
					conversation.getName()
				);

				service.sendBroadcast(intent);
			}
		}
	}
	
	/**
	 * Handle a server command
	 * 
	 * @param type Type of the command (/type param1 param2 ..)
	 * @param params The parameters of the command (0 is the command itself)
	 * @param server The current server
	 * @param conversation The selected conversation
	 * @param service The service handling the connections
	 */
	public void handleServerCommand(String type, String[] params, Server server, Conversation conversation, IRCService service)
	{
		if (params.length > 1) {
			service.getConnection(server.getId()).sendRawLineViaQueue(
				type.toUpperCase() + " " + BaseHandler.mergeParams(params)
			);
		} else {
			service.getConnection(server.getId()).sendRawLineViaQueue(type.toUpperCase());
		}
	}
	
	/**
	 * Handle an unknown command
	 * 
	 * @param type Type of the command (/type param1 param2 ..)
	 * @param server The current server
	 * @param conversation The selected conversation
	 * @param service The service handling the connections
	 */
	public void handleUnknownCommand(String type, Server server, Conversation conversation, IRCService service)
	{
		if (conversation != null) {
			Message message = new Message("Unknown command: " + type);
			message.setColor(Message.COLOR_RED);
			conversation.addMessage(message);
			
			Intent intent = Broadcast.createConversationIntent(
				Broadcast.CONVERSATION_MESSAGE,
				server.getId(),
				conversation.getName()
			);
			
			service.sendBroadcast(intent);
		}
	}
	
	/**
	 * Parse the given line
	 * 
	 * @param line
	 */
	public void parse(String line, Server server, Conversation conversation, IRCService service)
	{
		line = line.trim().substring(1); // cut the slash
		String[] params = line.split(" ");
		String type = params[0];
		
		if (isClientCommand(type)) {
			handleClientCommand(type, params, server, conversation, service);
		} else if (isServerCommand(type)) {
			handleServerCommand(type, params, server, conversation, service);
		} else {
			handleUnknownCommand(type, server, conversation, service);
		}
	}
}