/*
 * Jitsi, the OpenSource Java VoIP and Instant Messaging client.
 *
 * Copyright @ 2015 Atlassian Pty Ltd
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package net.java.sip.communicator.plugin.irccommands.command;

import net.java.sip.communicator.impl.protocol.irc.*;

/**
 * Implementation of the /join command. Join a channel from the message input
 * line.
 *
 * @author Danny van Heumen
 */
public class Join implements Command
{
    /**
     * Index of end of command prefix.
     */
    private static final int END_OF_COMMAND_PREFIX = 6;

    /**
     * Instance of the IRC connection.
     */
    private final IrcConnection connection;

    /**
     * Initialization of the /join command. Join a channel.
     *
     * @param provider the provider instance
     * @param connection the IRC connection instance
     */
    public Join(final ProtocolProviderServiceIrcImpl provider,
        final IrcConnection connection)
    {
        if (connection == null)
        {
            throw new IllegalArgumentException("connection cannot be null");
        }
        this.connection = connection;
    }

    /**
     * Execute join command.
     *
     * @param source the source channel/user from which the command was typed.
     * @param line the command message line
     */
    @Override
    public void execute(final String source, final String line)
    {
        if (line.length() < END_OF_COMMAND_PREFIX)
        {
            throw new IllegalArgumentException("Missing channel to join.");
        }
        final String part = line.substring(END_OF_COMMAND_PREFIX);
        final String channel;
        final String password;
        int indexOfSep = part.indexOf(' ');
        if (indexOfSep == -1)
        {
            channel = part;
            password = "";
        }
        else
        {
            channel = part.substring(0, indexOfSep);
            password = part.substring(indexOfSep + 1);
        }
        if (!channel.matches("[^,\\n\\r\\s\\a]+"))
        {
            throw new IllegalArgumentException(
                "Invalid chat room name specified.");
        }
        this.connection.getClient().joinChannel(channel, password);
    }

    /**
     * Command usage instructions.
     */
    @Override
    public String help()
    {
        return "Usage: /join <channel> [password]";
    }
}