Network/IRC/IrcChannelWidget.py

# -*- coding: utf-8 -*-

# Copyright (c) 2012 - 2018 Detlev Offenbach <detlev@die-offenbachs.de>
#

"""
Module implementing the IRC channel widget.
"""

from __future__ import unicode_literals

try:
    from itertools import izip_longest as zip_longest   # __IGNORE_EXCEPTION__
except ImportError:
    from itertools import zip_longest

import re

from PyQt5.QtCore import pyqtSlot, pyqtSignal, QDateTime, QPoint, QFileInfo, \
    QTimer, QUrl, QCoreApplication
from PyQt5.QtGui import QIcon, QPainter, QTextCursor, QDesktopServices
from PyQt5.QtWidgets import QWidget, QListWidgetItem, QMenu, QApplication, \
    QInputDialog, QLineEdit

from E5Gui import E5MessageBox, E5FileDialog
from E5Gui.E5Application import e5App

from .Ui_IrcChannelWidget import Ui_IrcChannelWidget

from .IrcUtilities import ircFilter, ircTimestamp, getChannelModesDict

import Utilities
import UI.PixmapCache
import Preferences

from UI.Info import Version, Copyright


class IrcUserItem(QListWidgetItem):
    """
    Class implementing a list widget item containing an IRC channel user.
    """
    Normal = 0x00       # no privileges
    Operator = 0x01     # channel operator
    Voice = 0x02        # voice operator
    Admin = 0x04        # administrator
    Halfop = 0x08       # half operator
    Owner = 0x10        # channel owner
    Away = 0x80         # user away
    
    PrivilegeMapping = {
        "a": Away,
        "o": Operator,
        "O": Owner,
        "v": Voice,
        
    }
    
    def __init__(self, name, parent=None):
        """
        Constructor
        
        @param name string with user name and privilege prefix (string)
        @param parent reference to the parent widget (QListWidget or
            QListWidgetItem)
        """
        super(IrcUserItem, self).__init__(name, parent)
        
        self.__privilege = IrcUserItem.Normal
        self.__name = name
        self.__ignored = False
        
        self.__setText()
        self.__setIcon()
    
    def name(self):
        """
        Public method to get the user name.
        
        @return user name (string)
        """
        return self.__name
    
    def setName(self, name):
        """
        Public method to set a new nick name.
        
        @param name new nick name for the user (string)
        """
        self.__name = name
        self.__setText()
    
    def changePrivilege(self, privilege):
        """
        Public method to set or unset a user privilege.
        
        @param privilege privilege to set or unset (string)
        """
        oper = privilege[0]
        priv = privilege[1]
        if oper == "+":
            if priv in IrcUserItem.PrivilegeMapping:
                self.__privilege |= IrcUserItem.PrivilegeMapping[priv]
        elif oper == "-":
            if priv in IrcUserItem.PrivilegeMapping:
                self.__privilege &= ~IrcUserItem.PrivilegeMapping[priv]
        self.__setIcon()
    
    def clearPrivileges(self):
        """
        Public method to clear the user privileges.
        """
        self.__privilege = IrcUserItem.Normal
        self.__setIcon()
    
    def __setText(self):
        """
        Private method to set the user item text.
        """
        if self.__ignored:
            self.setText(QCoreApplication.translate(
                "IrcUserItem",
                "{0} (ignored)").format(self.__name))
        else:
            self.setText(self.__name)
    
    def __setIcon(self):
        """
        Private method to set the icon dependent on user privileges.
        """
        # step 1: determine the icon
        if self.__privilege & IrcUserItem.Voice:
            icon = UI.PixmapCache.getIcon("ircVoice.png")
        elif self.__privilege & IrcUserItem.Owner:
            icon = UI.PixmapCache.getIcon("ircOwner.png")
        elif self.__privilege & IrcUserItem.Operator:
            icon = UI.PixmapCache.getIcon("ircOp.png")
        elif self.__privilege & IrcUserItem.Halfop:
            icon = UI.PixmapCache.getIcon("ircHalfop.png")
        elif self.__privilege & IrcUserItem.Admin:
            icon = UI.PixmapCache.getIcon("ircAdmin.png")
        else:
            icon = UI.PixmapCache.getIcon("ircNormal.png")
        if self.__privilege & IrcUserItem.Away:
            icon = self.__awayIcon(icon)
        
        # step 2: set the icon
        self.setIcon(icon)
    
    def __awayIcon(self, icon):
        """
        Private method to convert an icon to an away icon.
        
        @param icon icon to be converted (QIcon)
        @return away icon (QIcon)
        """
        pix1 = icon.pixmap(16, 16)
        pix2 = UI.PixmapCache.getPixmap("ircAway.png")
        painter = QPainter(pix1)
        painter.drawPixmap(0, 0, pix2)
        painter.end()
        return QIcon(pix1)
    
    def parseWhoFlags(self, flags):
        """
        Public method to parse the user flags reported by a WHO command.
        
        @param flags user flags as reported by WHO (string)
        """
        # H The user is not away.
        # G The user is set away.
        # * The user is an IRC operator.
        # @ The user is a channel op in the channel listed in the first field.
        # + The user is voiced in the channel listed.
        if flags.endswith("@"):
            privilege = IrcUserItem.Operator
        elif flags.endswith("+"):
            privilege = IrcUserItem.Voice
        else:
            privilege = IrcUserItem.Normal
        if "*" in flags:
            privilege = IrcUserItem.Admin
        if flags.startswith("G"):
            privilege |= IrcUserItem.Away
        self.__privilege = privilege
        self.__setIcon()
    
    def canChangeTopic(self):
        """
        Public method to check, if the user is allowed to change the topic.
        
        @return flag indicating that the topic can be changed (boolean)
        """
        return(bool(self.__privilege & IrcUserItem.Operator) or
               bool(self.__privilege & IrcUserItem.Admin) or
               bool(self.__privilege & IrcUserItem.Owner))
    
    def setIgnored(self, ignored):
        """
        Public method to set the user status to ignored.
        
        @param ignored flag indicating the new ignored status
        @type bool
        """
        self.__ignored = ignored
        self.__setText()
    
    def isIgnored(self):
        """
        Public method to check, if this user is ignored.
        
        @return flag indicating the ignored status
        @rtype bool
        """
        return self.__ignored


class IrcChannelWidget(QWidget, Ui_IrcChannelWidget):
    """
    Class implementing the IRC channel widget.
    
    @signal sendData(str) emitted to send a message to the channel
    @signal sendCtcpRequest(str, str, str) emitted to send a CTCP request
    @signal sendCtcpReply(str, str) emitted to send a CTCP reply
    @signal channelClosed(str) emitted after the user has left the channel
    @signal openPrivateChat(str) emitted to open a "channel" for private
        messages
    @signal awayCommand(str) emitted to set the away status via the /away
        command
    @signal leaveChannels(list) emitted to leave a list of channels
    @signal leaveAllChannels() emitted to leave all channels
    """
    sendData = pyqtSignal(str)
    sendCtcpRequest = pyqtSignal(str, str, str)
    sendCtcpReply = pyqtSignal(str, str)
    channelClosed = pyqtSignal(str)
    openPrivateChat = pyqtSignal(str)
    awayCommand = pyqtSignal(str)
    leaveChannels = pyqtSignal(list)
    leaveAllChannels = pyqtSignal()
    
    UrlRe = re.compile(
        r"""((?:http|ftp|https):\/\/[\w\-_]+(?:\.[\w\-_]+)+"""
        r"""(?:[\w\-\.,@?^=%&amp;:/~\+#]*[\w\-\@?^=%&amp;/~\+#])?)""")
    
    JoinIndicator = "--&gt;"
    LeaveIndicator = "&lt;--"
    MessageIndicator = "***"
    
    def __init__(self, parent=None):
        """
        Constructor
        
        @param parent reference to the parent widget (QWidget)
        """
        super(IrcChannelWidget, self).__init__(parent)
        self.setupUi(self)
        
        self.__ui = e5App().getObject("UserInterface")
        self.__ircWidget = parent
        
        self.editTopicButton.setIcon(
            UI.PixmapCache.getIcon("ircEditTopic.png"))
        self.editTopicButton.hide()
        
        height = self.usersList.height() + self.messages.height()
        self.splitter.setSizes([height * 0.3, height * 0.7])
        
        self.__initMessagesMenu()
        self.__initUsersMenu()
        
        self.__name = ""
        self.__userName = ""
        self.__partMessage = ""
        self.__prefixToPrivilege = {}
        self.__private = False
        self.__privatePartner = ""
        self.__whoIsNick = ""
        
        self.__markerLine = ""
        self.__hidden = True
        
        self.__serviceNamesLower = ["nickserv", "chanserv", "memoserv"]
        
        self.__patterns = [
            # :foo_!n=foo@foohost.bar.net PRIVMSG #eric-ide :some long message
            # :foo_!n=foo@foohost.bar.net PRIVMSG bar_ :some long message
            (re.compile(r":([^!]+)!([^ ]+)\sPRIVMSG\s([^ ]+)\s:(.*)"),
             self.__message),
            # :foo_!n=foo@foohost.bar.net JOIN :#eric-ide
            (re.compile(r":([^!]+)!([^ ]+)\sJOIN\s:?([^ ]+)"),
             self.__userJoin),
            # :foo_!n=foo@foohost.bar.net PART #eric-ide :part message
            (re.compile(r":([^!]+).*\sPART\s([^ ]+)\s:(.*)"), self.__userPart),
            # :foo_!n=foo@foohost.bar.net PART #eric-ide
            (re.compile(r":([^!]+).*\sPART\s([^ ]+)\s*"), self.__userPart),
            # :foo_!n=foo@foohost.bar.net QUIT :quit message
            (re.compile(r":([^!]+).*\sQUIT\s:(.*)"), self.__userQuit),
            # :foo_!n=foo@foohost.bar.net QUIT
            (re.compile(r":([^!]+).*\sQUIT\s*"), self.__userQuit),
            # :foo_!n=foo@foohost.bar.net NICK :newnick
            (re.compile(r":([^!]+).*\sNICK\s:(.*)"), self.__userNickChange),
            # :foo_!n=foo@foohost.bar.net MODE #eric-ide +o foo_
            (re.compile(r":([^!]+).*\sMODE\s([^ ]+)\s([+-][ovO]+)\s([^ ]+).*"),
                self.__setUserPrivilege),
            # :cameron.freenode.net MODE #eric-ide +ns
            (re.compile(r":([^ ]+)\sMODE\s([^ ]+)\s(.+)"),
             self.__updateChannelModes),
            # :foo_!n=foo@foohost.bar.net TOPIC #eric-ide :eric - Python IDE
            (re.compile(r":.*\sTOPIC\s([^ ]+)\s:(.*)"), self.__setTopic),
            # :sturgeon.freenode.net 301 foo_ bar :Gone away for now
            (re.compile(r":.*\s301\s([^ ]+)\s([^ ]+)\s:(.+)"),
             self.__userAway),
            # :sturgeon.freenode.net 315 foo_ #eric-ide :End of /WHO list.
            (re.compile(r":.*\s315\s[^ ]+\s([^ ]+)\s:(.*)"), self.__whoEnd),
            # :zelazny.freenode.net 324 foo_ #eric-ide +cnt
            (re.compile(r":.*\s324\s.*\s([^ ]+)\s(.+)"), self.__channelModes),
            # :zelazny.freenode.net 328 foo_ #eric-ide :http://www.bugger.com/
            (re.compile(r":.*\s328\s.*\s([^ ]+)\s:(.+)"), self.__channelUrl),
            # :zelazny.freenode.net 329 foo_ #eric-ide 1353001005
            (re.compile(r":.*\s329\s.*\s([^ ]+)\s(.+)"),
             self.__channelCreated),
            # :zelazny.freenode.net 332 foo_ #eric-ide :eric support channel
            (re.compile(r":.*\s332\s.*\s([^ ]+)\s:(.*)"), self.__setTopic),
            # :zelazny.freenode.net foo_ 333 #eric-ide foo 1353089020
            (re.compile(r":.*\s333\s.*\s([^ ]+)\s([^ ]+)\s(\d+)"),
             self.__topicCreated),
            # :cameron.freenode.net 352 detlev_ #eric-ide ~foo foohost.bar.net
            # cameron.freenode.net foo_ H :0 Foo Bar
            (re.compile(
                r":.*\s352\s[^ ]+\s([^ ]+)\s([^ ]+)\s([^ ]+)\s[^ ]+\s([^ ]+)"
                r"\s([^ ]+)\s:\d+\s(.*)"), self.__whoEntry),
            # :zelazny.freenode.net 353 foo_ @ #eric-ide :@user1 +user2 user3
            (re.compile(r":.*\s353\s.*\s.\s([^ ]+)\s:(.*)"), self.__userList),
            # :sturgeon.freenode.net 354 foo_ 42 ChanServ H@
            (re.compile(r":.*\s354\s[^ ]+\s42\s([^ ]+)\s(.*)"),
             self.__autoWhoEntry),
            # :zelazny.freenode.net 366 foo_ #eric-ide :End of /NAMES list.
            (re.compile(r":.*\s366\s.*\s([^ ]+)\s:(.*)"), self.__ignore),
            # :sturgeon.freenode.net 704 foo_ index :Help topics available:
            (re.compile(r":.*\s70[456]\s[^ ]+\s([^ ]+)\s:(.*)"), self.__help),
            
            # WHOIS replies
            # :sturgeon.freenode.net 311 foo_ bar ~bar barhost.foo.net * :Bar
            (re.compile(
                r":.*\s311\s[^ ]+\s([^ ]+)\s([^ ]+)\s([^ ]+)\s\*\s:(.*)"),
             self.__whoIsUser),
            # :sturgeon.freenode.net 319 foo_ bar :@#eric-ide
            (re.compile(r":.*\s319\s[^ ]+\s([^ ]+)\s:(.*)"),
             self.__whoIsChannels),
            # :sturgeon.freenode.net 312 foo_ bar sturgeon.freenode.net :London
            (re.compile(r":.*\s312\s[^ ]+\s([^ ]+)\s([^ ]+)\s:(.*)"),
             self.__whoIsServer),
            # :sturgeon.freenode.net 671 foo_ bar :is using a secure connection
            (re.compile(r":.*\s671\s[^ ]+\s([^ ]+)\s:.*"), self.__whoIsSecure),
            # :sturgeon.freenode.net 317 foo_ bar 3758 1355046912 :seconds
            # idle, signon time
            (re.compile(r":.*\s317\s[^ ]+\s([^ ]+)\s(\d+)\s(\d+)\s:.*"),
                self.__whoIsIdle),
            # :sturgeon.freenode.net 330 foo_ bar bar :is logged in as
            (re.compile(r":.*\s330\s[^ ]+\s([^ ]+)\s([^ ]+)\s:.*"),
             self.__whoIsAccount),
            # :sturgeon.freenode.net 318 foo_ bar :End of /WHOIS list.
            (re.compile(r":.*\s318\s[^ ]+\s([^ ]+)\s:(.*)"), self.__whoIsEnd),
            # :sturgeon.freenode.net 307 foo_ bar :is an identified user
            (re.compile(r":.*\s307\s[^ ]+\s([^ ]+)\s:(.*)"),
             self.__whoIsIdentify),
            # :sturgeon.freenode.net 320 foo_ bar :is an identified user
            (re.compile(r":.*\s320\s[^ ]+\s([^ ]+)\s:(.*)"),
             self.__whoIsIdentify),
            # :sturgeon.freenode.net 310 foo_ bar :is available for help
            (re.compile(r":.*\s310\s[^ ]+\s([^ ]+)\s:(.*)"),
             self.__whoIsHelper),
            # :sturgeon.freenode.net 338 foo_ bar real.ident@real.host
            # 12.34.56.78 :Actual user@host, Actual IP
            (re.compile(r":.*\s338\s[^ ]+\s([^ ]+)\s([^ ]+)\s([^ ]+)\s:.*"),
             self.__whoIsActually),
            # :sturgeon.freenode.net 313 foo_ bar :is an IRC Operator
            (re.compile(r":.*\s313\s[^ ]+\s([^ ]+)\s:(.*)"),
             self.__whoIsOperator),
            # :sturgeon.freenode.net 378 foo_ bar :is connecting from
            # *@mnch-4d044d5a.pool.mediaWays.net 77.4.77.90
            (re.compile(r":.*\s378\s[^ ]+\s([^ ]+)\s:.*\s([^ ]+)\s([^ ]+)"),
             self.__whoIsConnection),
        ]
        
        self.__autoWhoTemplate = "WHO {0} %tnf,42"
        self.__autoWhoTimer = QTimer()
        self.__autoWhoTimer.setSingleShot(True)
        self.__autoWhoTimer.timeout.connect(self.__sendAutoWhoCommand)
        self.__autoWhoRequested = False
    
    @pyqtSlot()
    def on_messageEdit_returnPressed(self):
        """
        Private slot to send a message to the channel.
        """
        msg = self.messageEdit.text()
        if msg:
            self.messages.append(
                '<font color="{0}">{2} <b>&lt;</b><font color="{1}">{3}</font>'
                '<b>&gt;</b> {4}</font>'.format(
                    Preferences.getIrc("ChannelMessageColour"),
                    Preferences.getIrc("OwnNickColour"),
                    ircTimestamp(), self.__userName,
                    Utilities.html_encode(msg)))
            
            if msg.startswith("/"):
                if self.__private:
                    E5MessageBox.information(
                        self,
                        self.tr("Send Message"),
                        self.tr(
                            """Messages starting with a '/' are not allowed"""
                            """ in private chats."""))
                else:
                    sendData = True
                    # flag set to False, if command was handled
                    
                    msgList = msg.split()
                    cmd = msgList[0][1:].upper()
                    if cmd in ["MSG", "QUERY"]:
                        cmd = "PRIVMSG"
                        if len(msgList) > 1:
                            if msgList[1].strip().lower() in \
                                    self.__serviceNamesLower:
                                msg = "PRIVMSG " + \
                                    msgList[1].strip().lower() + \
                                    " :" + " ".join(msgList[2:])
                            else:
                                msg = "PRIVMSG {0} :{1}".format(
                                    msgList[1], " ".join(msgList[2:]))
                        else:
                            msgList[0] = cmd
                            msg = " ".join(msgList)
                    elif cmd == "NOTICE":
                        if len(msgList) > 2:
                            msg = "NOTICE {0} :{1}".format(
                                msgList[1], " ".join(msgList[2:]))
                        else:
                            msg = "NOTICE {0}".format(" ".join(msgList[1:]))
                    elif cmd == "PING":
                        receiver = msgList[1]
                        msg = "PING {0} "
                        self.sendCtcpRequest.emit(receiver, "PING", "")
                        sendData = False
                    elif cmd == "IGNORE":
                        sendData = False
                        if len(msgList) > 1:
                            if msgList[1] == "-r":
                                ignored = False
                                userNamesList = msgList[2:]
                            else:
                                ignored = True
                                userNamesList = msgList[1:]
                        else:
                            userNamesList = []
                        userNames = ",".join(
                            u.rstrip(",") for u in userNamesList).split(",")
                        for userName in userNames:
                            itm = self.__findUser(userName)
                            if itm:
                                itm.setIgnored(ignored)
                    elif cmd == "UNIGNORE":
                        sendData = False
                        if len(msgList) > 1:
                            userNamesList = msgList[1:]
                        else:
                            userNamesList = []
                        userNames = ",".join(
                            u.rstrip(",") for u in userNamesList).split(",")
                        for userName in userNames:
                            itm = self.__findUser(userName)
                            if itm:
                                itm.setIgnored(False)
                    elif cmd == "AWAY":
                        sendData = False
                        if len(msgList) > 1:
                            msg = " ".join(msgList[1:])
                        else:
                            msg = ""
                        self.awayCommand.emit(msg)
                    elif cmd == "JOIN":
                        sendData = False
                        if len(msgList) > 1:
                            channels = msgList[1].split(",")
                            if len(msgList) > 2:
                                keys = msgList[2].split(",")
                            else:
                                keys = []
                            for channel, key in zip_longest(
                                    channels, keys, fillvalue=""):
                                self.__ircWidget.joinChannel(channel, key)
                    elif cmd == "PART":
                        sendData = False
                        if len(msgList) == 1:
                            self.leaveChannel()
                        else:
                            self.leaveChannels.emit(msgList[1:])
                    elif cmd == "PARTALL":
                        sendData = False
                        self.leaveAllChannels.emit()
                    else:
                        msg = msg[1:]
                    if sendData:
                        self.sendData.emit(msg)
            else:
                if self.__private:
                    self.sendData.emit(
                        "PRIVMSG " + self.__privatePartner + " :" + msg)
                else:
                    self.sendData.emit(
                        "PRIVMSG " + self.__name + " :" + msg)
            
            self.messageEdit.clear()
            self.unsetMarkerLine()
    
    def requestLeave(self):
        """
        Public method to leave the channel.
        """
        ok = E5MessageBox.yesNo(
            self,
            self.tr("Leave IRC channel"),
            self.tr(
                """Do you really want to leave the IRC channel"""
                """ <b>{0}</b>?""").format(self.__name))
        if ok:
            self.leaveChannel()

    def leaveChannel(self):
        """
        Public slot to leave the channel.
        """
        if not self.__private:
            self.sendData.emit(
                "PART " + self.__name + " :" + self.__partMessage)
        self.channelClosed.emit(self.__name)
    
    def name(self):
        """
        Public method to get the name of the channel.
        
        @return name of the channel (string)
        """
        return self.__name
    
    def setName(self, name):
        """
        Public method to set the name of the channel.
        
        @param name of the channel (string)
        """
        self.__name = name
    
    def getUsersCount(self):
        """
        Public method to get the users count of the channel.
        
        @return users count of the channel (integer)
        """
        return self.usersList.count()
    
    def userName(self):
        """
        Public method to get the nick name of the user.
        
        @return nick name of the user (string)
        """
        return self.__userName
    
    def setUserName(self, name):
        """
        Public method to set the user name for the channel.
        
        @param name user name for the channel (string)
        """
        self.__userName = name
    
    def partMessage(self):
        """
        Public method to get the part message.
        
        @return part message (string)
        """
        return self.__partMessage
    
    def setPartMessage(self, message):
        """
        Public method to set the part message.
        
        @param message message to be used for PART messages (string)
        """
        self.__partMessage = message
    
    def setPrivate(self, private, partner=""):
        """
        Public method to set the private chat mode.
        
        @param private flag indicating private chat mode (boolean)
        @param partner name of the partner user (string)
        """
        self.__private = private
        self.__privatePartner = partner
        self.editTopicButton.setEnabled(private)
    
    def setPrivateInfo(self, infoText):
        """
        Public method to set some info text for private chat mode.
        
        @param infoText info text to be shown (string)
        """
        if self.__private:
            self.topicLabel.setText(infoText)
    
    def handleMessage(self, line):
        """
        Public method to handle the message sent by the server.
        
        @param line server message (string)
        @return flag indicating, if the message was handled (boolean)
        """
        for patternRe, patternFunc in self.__patterns:
            match = patternRe.match(line)
            if match is not None:
                if patternFunc(match):
                    return True
        
        return False
    
    def __message(self, match):
        """
        Private method to handle messages to the channel.
        
        @param match match object that matched the pattern
        @return flag indicating whether the message was handled (boolean)
        """
        # group(1)   sender user name
        # group(2)   sender user@host
        # group(3)   target nick
        # group(4)   message
        if match.group(3).lower() == self.__name.lower():
            senderName = match.group(1)
            itm = self.__findUser(senderName)
            if itm and itm.isIgnored():
                # user should be ignored
                return True
            
            if match.group(4).startswith("\x01"):
                return self.__handleCtcp(match)
            
            self.addMessage(senderName, match.group(4))
            if self.__private and not self.topicLabel.text():
                self.setPrivateInfo(
                    "{0} - {1}".format(match.group(1), match.group(2)))
            return True
        
        return False
    
    def addMessage(self, sender, msg):
        """
        Public method to add a message from external.
        
        @param sender nick name of the sender (string)
        @param msg message received from sender (string)
        """
        self.__appendMessage(
            '<font color="{0}">{2} <b>&lt;</b><font color="{1}">{3}</font>'
            '<b>&gt;</b> {4}</font>'.format(
                Preferences.getIrc("ChannelMessageColour"),
                Preferences.getIrc("NickColour"),
                ircTimestamp(), sender, ircFilter(msg)))
        if Preferences.getIrc("ShowNotifications"):
            if Preferences.getIrc("NotifyMessage"):
                self.__ui.showNotification(
                    UI.PixmapCache.getPixmap("irc48.png"),
                    self.tr("Channel Message"), msg)
            elif Preferences.getIrc("NotifyNick") and \
                    self.__userName.lower() in msg.lower():
                self.__ui.showNotification(
                    UI.PixmapCache.getPixmap("irc48.png"),
                    self.tr("Nick mentioned"), msg)
    
    def addUsers(self, users):
        """
        Public method to add users to the channel.
        
        @param users list of user names to add (list of string)
        """
        for user in users:
            itm = self.__findUser(user)
            if itm is None:
                IrcUserItem(user, self.usersList)
    
    def __userJoin(self, match):
        """
        Private method to handle a user joining the channel.
        
        @param match match object that matched the pattern
        @return flag indicating whether the message was handled (boolean)
        """
        if match.group(3).lower() == self.__name.lower():
            if self.__userName != match.group(1):
                IrcUserItem(match.group(1), self.usersList)
                msg = self.tr(
                    "{0} has joined the channel {1} ({2}).").format(
                    match.group(1), self.__name, match.group(2))
                self.__addManagementMessage(
                    IrcChannelWidget.JoinIndicator, msg)
            else:
                msg = self.tr(
                    "You have joined the channel {0} ({1}).").format(
                    self.__name, match.group(2))
                self.__addManagementMessage(
                    IrcChannelWidget.JoinIndicator, msg)
            if Preferences.getIrc("ShowNotifications") and \
               Preferences.getIrc("NotifyJoinPart"):
                self.__ui.showNotification(
                    UI.PixmapCache.getPixmap("irc48.png"),
                    self.tr("Join Channel"), msg)
            return True
        
        return False
    
    def __userPart(self, match):
        """
        Private method to handle a user leaving the channel.
        
        @param match match object that matched the pattern
        @return flag indicating whether the message was handled (boolean)
        """
        if match.group(2).lower() == self.__name.lower():
            itm = self.__findUser(match.group(1))
            self.usersList.takeItem(self.usersList.row(itm))
            del itm
            if match.lastindex == 2:
                msg = self.tr("{0} has left {1}.").format(
                    match.group(1), self.__name)
                nmsg = msg
                self.__addManagementMessage(
                    IrcChannelWidget.LeaveIndicator, msg)
            else:
                msg = self.tr("{0} has left {1}: {2}.").format(
                    match.group(1), self.__name, ircFilter(match.group(3)))
                nmsg = self.tr("{0} has left {1}: {2}.").format(
                    match.group(1), self.__name, match.group(3))
                self.__addManagementMessage(
                    IrcChannelWidget.LeaveIndicator, msg)
            if Preferences.getIrc("ShowNotifications") and \
               Preferences.getIrc("NotifyJoinPart"):
                self.__ui.showNotification(
                    UI.PixmapCache.getPixmap("irc48.png"),
                    self.tr("Leave Channel"), nmsg)
            return True
        
        return False
    
    def __userQuit(self, match):
        """
        Private method to handle a user logging off the server.
        
        @param match match object that matched the pattern
        @return flag indicating whether the message was handled (boolean)
        """
        itm = self.__findUser(match.group(1))
        if itm:
            self.usersList.takeItem(self.usersList.row(itm))
            del itm
            if match.lastindex == 1:
                msg = self.tr("{0} has quit {1}.").format(
                    match.group(1), self.__name)
                self.__addManagementMessage(
                    IrcChannelWidget.MessageIndicator, msg)
            else:
                msg = self.tr("{0} has quit {1}: {2}.").format(
                    match.group(1), self.__name, ircFilter(match.group(2)))
                self.__addManagementMessage(
                    IrcChannelWidget.MessageIndicator, msg)
            if Preferences.getIrc("ShowNotifications") and \
               Preferences.getIrc("NotifyJoinPart"):
                self.__ui.showNotification(
                    UI.PixmapCache.getPixmap("irc48.png"),
                    self.tr("Quit"), msg)
        
        # always return False for other channels and server to process
        return False
    
    def __userNickChange(self, match):
        """
        Private method to handle a nickname change of a user.
        
        @param match match object that matched the pattern
        @return flag indicating whether the message was handled (boolean)
        """
        itm = self.__findUser(match.group(1))
        if itm:
            itm.setName(match.group(2))
            if match.group(1) == self.__userName:
                self.__addManagementMessage(
                    IrcChannelWidget.MessageIndicator,
                    self.tr("You are now known as {0}.").format(
                        match.group(2)))
                self.__userName = match.group(2)
            else:
                self.__addManagementMessage(
                    IrcChannelWidget.MessageIndicator,
                    self.tr("User {0} is now known as {1}.").format(
                        match.group(1), match.group(2)))
        
        # always return False for other channels and server to process
        return False
    
    def __userList(self, match):
        """
        Private method to handle the receipt of a list of users of the channel.
        
        @param match match object that matched the pattern
        @return flag indicating whether the message was handled (boolean)
        """
        if match.group(1).lower() == self.__name.lower():
            users = match.group(2).split()
            for user in users:
                userPrivileges, userName = self.__extractPrivilege(user)
                itm = self.__findUser(userName)
                if itm is None:
                    itm = IrcUserItem(userName, self.usersList)
                for privilege in userPrivileges:
                    itm.changePrivilege(privilege)
            
            self.__setEditTopicButton()
            return True
        
        return False

    def __userAway(self, match):
        """
        Private method to handle a topic change of the channel.
        
        @param match match object that matched the pattern
        @return flag indicating whether the message was handled (boolean)
        """
        if match.group(1).lower() == self.__name.lower():
            self.__addManagementMessage(
                self.tr("Away"),
                self.tr("{0} is away: {1}").format(
                    match.group(2), match.group(3)))
            return True
        
        return False
    
    def __setTopic(self, match):
        """
        Private method to handle a topic change of the channel.
        
        @param match match object that matched the pattern
        @return flag indicating whether the message was handled (boolean)
        """
        if match.group(1).lower() == self.__name.lower():
            self.topicLabel.setText(match.group(2))
            self.__addManagementMessage(
                IrcChannelWidget.MessageIndicator,
                ircFilter(self.tr('The channel topic is: "{0}".').format(
                    match.group(2))))
            return True
        
        return False
    
    def __topicCreated(self, match):
        """
        Private method to handle a topic created message.
        
        @param match match object that matched the pattern
        @return flag indicating whether the message was handled (boolean)
        """
        if match.group(1).lower() == self.__name.lower():
            self.__addManagementMessage(
                IrcChannelWidget.MessageIndicator,
                self.tr("The topic was set by {0} on {1}.").format(
                    match.group(2), QDateTime.fromTime_t(int(match.group(3)))
                    .toString("yyyy-MM-dd hh:mm")))
            return True
        
        return False
    
    def __channelUrl(self, match):
        """
        Private method to handle a channel URL message.
        
        @param match match object that matched the pattern
        @return flag indicating whether the message was handled (boolean)
        """
        if match.group(1).lower() == self.__name.lower():
            self.__addManagementMessage(
                IrcChannelWidget.MessageIndicator,
                ircFilter(self.tr("Channel URL: {0}").format(
                    match.group(2))))
            return True
        
        return False
    
    def __channelModes(self, match):
        """
        Private method to handle a message reporting the channel modes.
        
        @param match match object that matched the pattern
        @return flag indicating whether the message was handled (boolean)
        """
        if match.group(1).lower() == self.__name.lower():
            modesDict = getChannelModesDict()
            modesParameters = match.group(2).split()
            modeString = modesParameters.pop(0)
            modes = []
            for modeChar in modeString:
                if modeChar == "+":
                    continue
                elif modeChar == "k":
                    parameter = modesParameters.pop(0)
                    modes.append(self.tr(
                        "password protected ({0})").format(parameter))
                elif modeChar == "l":
                    parameter = modesParameters.pop(0)
                    modes.append(self.tr(
                        "limited to %n user(s)", "", int(parameter)))
                elif modeChar in modesDict:
                    modes.append(modesDict[modeChar])
                else:
                    modes.append(modeChar)
            
            self.__addManagementMessage(
                IrcChannelWidget.MessageIndicator,
                self.tr("Channel modes: {0}.").format(", ".join(modes)))
            
            return True
        
        return False
    
    def __channelCreated(self, match):
        """
        Private method to handle a channel created message.
        
        @param match match object that matched the pattern
        @return flag indicating whether the message was handled (boolean)
        """
        if match.group(1).lower() == self.__name.lower():
            self.__addManagementMessage(
                IrcChannelWidget.MessageIndicator,
                self.tr("This channel was created on {0}.").format(
                    QDateTime.fromTime_t(int(match.group(2)))
                    .toString("yyyy-MM-dd hh:mm")))
            return True
        
        return False
    
    def __updateChannelModes(self, match):
        """
        Private method to handle a message reporting the channel modes.
        
        @param match match object that matched the pattern
        @return flag indicating whether the message was handled (boolean)
        """
        # group(1)  user or server
        # group(2)  channel
        # group(3)  modes and parameter list
        if match.group(2).lower() == self.__name.lower():
            nick = match.group(1)
            modesParameters = match.group(3).split()
            modeString = modesParameters.pop(0)
            isPlus = True
            message = ""
            for mode in modeString:
                if mode == "+":
                    isPlus = True
                    continue
                elif mode == "-":
                    isPlus = False
                    continue
                elif mode == "a":
                    if isPlus:
                        message = self.tr(
                            "{0} sets the channel mode to 'anonymous'.")\
                            .format(nick)
                    else:
                        message = self.tr(
                            "{0} removes the 'anonymous' mode from the"
                            " channel.").format(nick)
                elif mode == "b":
                    if isPlus:
                        message = self.tr(
                            "{0} sets a ban on {1}.").format(
                            nick, modesParameters.pop(0))
                    else:
                        message = self.tr(
                            "{0} removes the ban on {1}.").format(
                            nick, modesParameters.pop(0))
                elif mode == "c":
                    if isPlus:
                        message = self.tr(
                            "{0} sets the channel mode to 'no colors"
                            " allowed'.").format(nick)
                    else:
                        message = self.tr(
                            "{0} sets the channel mode to 'allow color"
                            " codes'.").format(nick)
                elif mode == "e":
                    if isPlus:
                        message = self.tr(
                            "{0} sets a ban exception on {1}.").format(
                            nick, modesParameters.pop(0))
                    else:
                        message = self.tr(
                            "{0} removes the ban exception on {1}.").format(
                            nick, modesParameters.pop(0))
                elif mode == "i":
                    if isPlus:
                        message = self.tr(
                            "{0} sets the channel mode to 'invite only'.")\
                            .format(nick)
                    else:
                        message = self.tr(
                            "{0} removes the 'invite only' mode from the"
                            " channel.").format(nick)
                elif mode == "k":
                    if isPlus:
                        message = self.tr(
                            "{0} sets the channel key to '{1}'.").format(
                            nick, modesParameters.pop(0))
                    else:
                        message = self.tr(
                            "{0} removes the channel key.").format(nick)
                elif mode == "l":
                    if isPlus:
                        message = self.tr(
                            "{0} sets the channel limit to %n nick(s).", "",
                            int(modesParameters.pop(0))).format(nick)
                    else:
                        message = self.tr(
                            "{0} removes the channel limit.").format(nick)
                elif mode == "m":
                    if isPlus:
                        message = self.tr(
                            "{0} sets the channel mode to 'moderated'.")\
                            .format(nick)
                    else:
                        message = self.tr(
                            "{0} sets the channel mode to 'unmoderated'.")\
                            .format(nick)
                elif mode == "n":
                    if isPlus:
                        message = self.tr(
                            "{0} sets the channel mode to 'no messages from"
                            " outside'.").format(nick)
                    else:
                        message = self.tr(
                            "{0} sets the channel mode to 'allow messages"
                            " from outside'.").format(nick)
                elif mode == "p":
                    if isPlus:
                        message = self.tr(
                            "{0} sets the channel mode to 'private'.")\
                            .format(nick)
                    else:
                        message = self.tr(
                            "{0} sets the channel mode to 'public'.")\
                            .format(nick)
                elif mode == "q":
                    if isPlus:
                        message = self.tr(
                            "{0} sets the channel mode to 'quiet'.")\
                            .format(nick)
                    else:
                        message = self.tr(
                            "{0} removes the 'quiet' mode from the channel.")\
                            .format(nick)
                elif mode == "r":
                    continue
                elif mode == "s":
                    if isPlus:
                        message = self.tr(
                            "{0} sets the channel mode to 'secret'.")\
                            .format(nick)
                    else:
                        message = self.tr(
                            "{0} sets the channel mode to 'visible'.")\
                            .format(nick)
                elif mode == "t":
                    if isPlus:
                        message = self.tr(
                            "{0} switches on 'topic protection'.").format(nick)
                    else:
                        message = self.tr(
                            "{0} switches off 'topic protection'.")\
                            .format(nick)
                elif mode == "I":
                    if isPlus:
                        message = self.tr(
                            "{0} sets invitation mask {1}.").format(
                            nick, modesParameters.pop(0))
                    else:
                        message = self.tr(
                            "{0} removes the invitation mask {1}.").format(
                            nick, modesParameters.pop(0))
                
                self.__addManagementMessage(self.tr("Mode"), message)
            
            return True
        
        return False
    
    def __setUserPrivilege(self, match):
        """
        Private method to handle a change of user privileges for the channel.
        
        @param match match object that matched the pattern
        @return flag indicating whether the message was handled (boolean)
        """
        if match.group(2).lower() == self.__name.lower():
            itm = self.__findUser(match.group(4))
            if itm:
                itm.changePrivilege(match.group(3))
                self.__setEditTopicButton()
            self.__addManagementMessage(
                IrcChannelWidget.MessageIndicator,
                self.tr("{0} sets mode for {1}: {2}.").format(
                    match.group(1), match.group(4), match.group(3)))
            return True
        
        return False
    
    def __ignore(self, match):
        """
        Private method to handle a channel message we are not interested in.
        
        @param match match object that matched the pattern
        @return flag indicating whether the message was handled (boolean)
        """
        if match.group(1).lower() == self.__name.lower():
            return True
        
        return False
    
    def __help(self, match):
        """
        Private method to handle a help message.
        
        @param match match object that matched the pattern
        @return flag indicating whether the message was handled (boolean)
        """
        self.__addManagementMessage(
            self.tr("Help"),
            "{0} {1}".format(match.group(1), ircFilter(match.group(2))))
        return True
    
    def __handleCtcp(self, match):
        """
        Private method to handle a CTCP channel command.
        
        @param match reference to the match object
        @return flag indicating, if the message was handled (boolean)
        """
        # group(1)   sender user name
        # group(2)   sender user@host
        # group(3)   target nick
        # group(4)   message
        if match.group(4).startswith("\x01"):
            ctcpCommand = match.group(4)[1:].split("\x01", 1)[0]
            if " " in ctcpCommand:
                ctcpRequest, ctcpArg = ctcpCommand.split(" ", 1)
            else:
                ctcpRequest, ctcpArg = ctcpCommand, ""
            ctcpRequest = ctcpRequest.lower()
            if ctcpRequest == "version":
                msg = "Eric IRC client {0}, {1}".format(Version, Copyright)
                self.__addManagementMessage(
                    self.tr("CTCP"),
                    self.tr("Received Version request from {0}.").format(
                        match.group(1)))
                self.sendCtcpReply.emit(match.group(1), "VERSION " + msg)
            elif ctcpRequest == "ping":
                self.__addManagementMessage(
                    self.tr("CTCP"),
                    self.tr(
                        "Received CTCP-PING request from {0},"
                        " sending answer.").format(match.group(1)))
                self.sendCtcpReply.emit(
                    match.group(1), "PING {0}".format(ctcpArg))
            elif ctcpRequest == "clientinfo":
                self.__addManagementMessage(
                    self.tr("CTCP"),
                    self.tr(
                        "Received CTCP-CLIENTINFO request from {0},"
                        " sending answer.").format(match.group(1)))
                self.sendCtcpReply.emit(
                    match.group(1), "CLIENTINFO CLIENTINFO PING VERSION")
            else:
                self.__addManagementMessage(
                    self.tr("CTCP"),
                    self.tr("Received unknown CTCP-{0} request from {1}.")
                    .format(ctcpRequest, match.group(1)))
            return True
        
        return False
    
    def setUserPrivilegePrefix(self, prefixes):
        """
        Public method to set the user privilege to prefix mapping.
        
        @param prefixes dictionary with privilege as key and prefix as value
        """
        self.__prefixToPrivilege = {}
        for privilege, prefix in prefixes.items():
            if prefix:
                self.__prefixToPrivilege[prefix] = privilege
    
    def __findUser(self, name):
        """
        Private method to find the user in the list of users.
        
        @param name user name to search for (string)
        @return reference to the list entry (QListWidgetItem)
        """
        for row in range(self.usersList.count()):
            itm = self.usersList.item(row)
            if itm.name() == name:
                return itm
        
        return None
    
    def __extractPrivilege(self, name):
        """
        Private method to extract the user privileges out of the name.
        
        @param name user name and prefixes (string)
        @return list of privileges and user name (list of string, string)
        """
        privileges = []
        while name[0] in self.__prefixToPrivilege:
            prefix = name[0]
            privileges.append(self.__prefixToPrivilege[prefix])
            name = name[1:]
            if name[0] == ",":
                name = name[1:]
        
        return privileges, name
    
    def __addManagementMessage(self, indicator, message):
        """
        Private method to add a channel management message to the list.
        
        @param indicator indicator to be shown (string)
        @param message message to be shown (string)
        """
        if indicator == self.JoinIndicator:
            color = Preferences.getIrc("JoinChannelColour")
        elif indicator == self.LeaveIndicator:
            color = Preferences.getIrc("LeaveChannelColour")
        else:
            color = Preferences.getIrc("ChannelInfoColour")
        self.__appendMessage(
            '<font color="{0}">{1} <b>[</b>{2}<b>]</b> {3}</font>'.format(
                color, ircTimestamp(), indicator, message))
    
    def __appendMessage(self, message):
        """
        Private slot to append a message.
        
        @param message message to be appended (string)
        """
        if self.__hidden and \
           self.__markerLine == "" and \
           Preferences.getIrc("MarkPositionWhenHidden"):
            self.setMarkerLine()
        self.messages.append(message)
    
    def setMarkerLine(self):
        """
        Public method to draw a line to mark the current position.
        """
        self.unsetMarkerLine()
        self.__markerLine = \
            '<span style=" color:{0}; background-color:{1};">{2}</span>'\
            .format(Preferences.getIrc("MarkerLineForegroundColour"),
                    Preferences.getIrc("MarkerLineBackgroundColour"),
                    self.tr('--- New From Here ---'))
        self.messages.append(self.__markerLine)
    
    def unsetMarkerLine(self):
        """
        Public method to remove the marker line.
        """
        if self.__markerLine:
            txt = self.messages.toHtml()
            if txt.endswith(self.__markerLine + "</p></body></html>"):
                # remove empty last paragraph
                pos = txt.rfind("<p")
                txt = txt[:pos] + "</body></html>"
            else:
                txt = txt.replace(self.__markerLine, "")
            self.messages.setHtml(txt)
            self.__markerLine = ""
            self.messages.moveCursor(QTextCursor.End)
    
    def __clearMessages(self):
        """
        Private slot to clear the contents of the messages display.
        """
        self.messages.clear()
    
    def __copyMessages(self):
        """
        Private slot to copy the selection of the messages display to the
        clipboard.
        """
        self.messages.copy()
    
    def __copyAllMessages(self):
        """
        Private slot to copy the contents of the messages display to the
        clipboard.
        """
        txt = self.messages.toPlainText()
        if txt:
            cb = QApplication.clipboard()
            cb.setText(txt)
    
    def __cutAllMessages(self):
        """
        Private slot to cut the contents of the messages display to the
        clipboard.
        """
        txt = self.messages.toPlainText()
        if txt:
            cb = QApplication.clipboard()
            cb.setText(txt)
        self.messages.clear()
    
    def __saveMessages(self):
        """
        Private slot to save the contents of the messages display.
        """
        hasText = not self.messages.document().isEmpty()
        if hasText:
            if Utilities.isWindowsPlatform():
                htmlExtension = "htm"
            else:
                htmlExtension = "html"
            fname, selectedFilter = E5FileDialog.getSaveFileNameAndFilter(
                self,
                self.tr("Save Messages"),
                "",
                self.tr(
                    "HTML Files (*.{0});;Text Files (*.txt);;All Files (*)")
                .format(htmlExtension),
                None,
                E5FileDialog.Options(E5FileDialog.DontConfirmOverwrite))
            if fname:
                ext = QFileInfo(fname).suffix()
                if not ext:
                    ex = selectedFilter.split("(*")[1].split(")")[0]
                    if ex:
                        fname += ex
                    ext = QFileInfo(fname).suffix()
                if QFileInfo(fname).exists():
                    res = E5MessageBox.yesNo(
                        self,
                        self.tr("Save Messages"),
                        self.tr("<p>The file <b>{0}</b> already exists."
                                " Overwrite it?</p>").format(fname),
                        icon=E5MessageBox.Warning)
                    if not res:
                        return
                    fname = Utilities.toNativeSeparators(fname)
                
                try:
                    if ext.lower() in ["htm", "html"]:
                        txt = self.messages.toHtml()
                    else:
                        txt = self.messages.toPlainText()
                    f = open(fname, "w", encoding="utf-8")
                    f.write(txt)
                    f.close()
                except IOError as err:
                    E5MessageBox.critical(
                        self,
                        self.tr("Error saving Messages"),
                        self.tr(
                            """<p>The messages contents could not be written"""
                            """ to <b>{0}</b></p><p>Reason: {1}</p>""")
                        .format(fname, str(err)))
    
    def __initMessagesMenu(self):
        """
        Private slot to initialize the context menu of the messages pane.
        """
        self.__messagesMenu = QMenu(self)
        self.__copyMessagesAct = \
            self.__messagesMenu.addAction(
                UI.PixmapCache.getIcon("editCopy.png"),
                self.tr("Copy"), self.__copyMessages)
        self.__messagesMenu.addSeparator()
        self.__cutAllMessagesAct = \
            self.__messagesMenu.addAction(
                UI.PixmapCache.getIcon("editCut.png"),
                self.tr("Cut all"), self.__cutAllMessages)
        self.__copyAllMessagesAct = \
            self.__messagesMenu.addAction(
                UI.PixmapCache.getIcon("editCopy.png"),
                self.tr("Copy all"), self.__copyAllMessages)
        self.__messagesMenu.addSeparator()
        self.__clearMessagesAct = \
            self.__messagesMenu.addAction(
                UI.PixmapCache.getIcon("editDelete.png"),
                self.tr("Clear"), self.__clearMessages)
        self.__messagesMenu.addSeparator()
        self.__saveMessagesAct = \
            self.__messagesMenu.addAction(
                UI.PixmapCache.getIcon("fileSave.png"),
                self.tr("Save"), self.__saveMessages)
        self.__messagesMenu.addSeparator()
        self.__setMarkerMessagesAct = self.__messagesMenu.addAction(
            self.tr("Mark Current Position"), self.setMarkerLine)
        self.__unsetMarkerMessagesAct = self.__messagesMenu.addAction(
            self.tr("Remove Position Marker"),
            self.unsetMarkerLine)
        
        self.on_messages_copyAvailable(False)
    
    @pyqtSlot(bool)
    def on_messages_copyAvailable(self, yes):
        """
        Private slot to react to text selection/deselection of the messages
        edit.
        
        @param yes flag signaling the availability of selected text (boolean)
        """
        self.__copyMessagesAct.setEnabled(yes)
    
    @pyqtSlot(QPoint)
    def on_messages_customContextMenuRequested(self, pos):
        """
        Private slot to show the context menu of the messages pane.
        
        @param pos the position of the mouse pointer (QPoint)
        """
        enable = not self.messages.document().isEmpty()
        self.__cutAllMessagesAct.setEnabled(enable)
        self.__copyAllMessagesAct.setEnabled(enable)
        self.__saveMessagesAct.setEnabled(enable)
        self.__setMarkerMessagesAct.setEnabled(self.__markerLine == "")
        self.__unsetMarkerMessagesAct.setEnabled(self.__markerLine != "")
        self.__messagesMenu.popup(self.messages.mapToGlobal(pos))
    
    def __whoIs(self):
        """
        Private slot to get information about the selected user.
        """
        self.__whoIsNick = self.usersList.selectedItems()[0].text()
        self.sendData.emit("WHOIS " + self.__whoIsNick)
    
    def __openPrivateChat(self):
        """
        Private slot to open a chat with the selected user.
        """
        user = self.usersList.selectedItems()[0].text()
        self.openPrivateChat.emit(user)
    
    def __initUsersMenu(self):
        """
        Private slot to initialize the users list context menu.
        """
        self.__usersMenu = QMenu(self)
        self.__whoIsAct = self.__usersMenu.addAction(
            self.tr("Who Is"), self.__whoIs)
        self.__usersMenu.addSeparator()
        self.__privateChatAct = self.__usersMenu.addAction(
            self.tr("Private Chat"), self.__openPrivateChat)
        self.__usersMenu.addSeparator()
        self.__usersListRefreshAct = self.__usersMenu.addAction(
            self.tr("Refresh"), self.__sendAutoWhoCommand)
    
    @pyqtSlot(QPoint)
    def on_usersList_customContextMenuRequested(self, pos):
        """
        Private slot to show the context menu of the users list.
        
        @param pos the position of the mouse pointer (QPoint)
        """
        enable = len(self.usersList.selectedItems()) > 0
        enablePrivate = enable and not self.__private
        itm = self.usersList.itemAt(pos)
        if itm and enablePrivate:
            enablePrivate = itm.text().lower() not in [
                "chanserv", self.__userName.lower()]
        self.__whoIsAct.setEnabled(enable)
        self.__privateChatAct.setEnabled(enablePrivate)
        self.__usersListRefreshAct.setEnabled(
            self.usersList.count() <= Preferences.getIrc("AutoUserInfoMax"))
        self.__usersMenu.popup(self.usersList.mapToGlobal(pos))
    
    def hideEvent(self, evt):
        """
        Protected method handling hide events.
        
        @param evt reference to the hide event (QHideEvent)
        """
        self.__hidden = True
    
    def showEvent(self, evt):
        """
        Protected method handling show events.
        
        @param evt reference to the show event (QShowEvent)
        """
        self.__hidden = False
    
    def initAutoWho(self):
        """
        Public method to initialize the Auto Who system.
        """
        if Preferences.getIrc("AutoUserInfoLookup"):
            self.__autoWhoTimer.setInterval(
                Preferences.getIrc("AutoUserInfoInterval") * 1000)
            self.__autoWhoTimer.start()
    
    @pyqtSlot()
    def __sendAutoWhoCommand(self):
        """
        Private slot to send the WHO command to update the users list.
        """
        if self.usersList.count() <= Preferences.getIrc("AutoUserInfoMax"):
            self.__autoWhoRequested = True
            self.sendData.emit(self.__autoWhoTemplate.format(self.__name))
    
    def __autoWhoEntry(self, match):
        """
        Private method to handle a WHO entry returned by the server as
        requested automatically.
        
        @param match match object that matched the pattern
        @return flag indicating whether the message was handled (boolean)
        """
        # group(1)  nick
        # group(2)  user flags
        if self.__autoWhoRequested:
            itm = self.__findUser(match.group(1))
            if itm:
                itm.parseWhoFlags(match.group(2))
            return True
        
        return False
    
    def __whoEnd(self, match):
        """
        Private method to handle the end of the WHO list.
        
        @param match match object that matched the pattern
        @return flag indicating whether the message was handled (boolean)
        """
        if match.group(1).lower() == self.__name.lower():
            if self.__autoWhoRequested:
                self.__autoWhoRequested = False
                self.initAutoWho()
            else:
                self.__addManagementMessage(
                    self.tr("Who"),
                    self.tr("End of WHO list for {0}.").format(
                        match.group(1)))
            return True
        
        return False
    
    def __whoEntry(self, match):
        """
        Private method to handle a WHO entry returned by the server as
        requested manually.
        
        @param match match object that matched the pattern
        @return flag indicating whether the message was handled (boolean)
        """
        # group(1)  channel
        # group(2)  user
        # group(3)  host
        # group(4)  nick
        # group(5)  user flags
        # group(6)  real name
        if match.group(1).lower() == self.__name.lower():
            away = self.tr(" (Away)") if match.group(5).startswith("G") \
                else ""
            self.__addManagementMessage(
                self.tr("Who"),
                self.tr("{0} is {1}@{2} ({3}){4}").format(
                    match.group(4), match.group(2), match.group(3),
                    match.group(6), away))
            return True
        
        return False
    
    def __whoIsUser(self, match):
        """
        Private method to handle the WHOIS user reply.
        
        @param match match object that matched the pattern
        @return flag indicating whether the message was handled (boolean)
        """
        # group(1)   nick
        # group(2)   user
        # group(3)   host
        # group(4)   real name
        if match.group(1) == self.__whoIsNick:
            realName = match.group(4).replace("<", "&lt;").replace(">", "&gt;")
            self.__addManagementMessage(
                self.tr("Whois"),
                self.tr("{0} is {1}@{2} ({3}).").format(
                    match.group(1), match.group(2), match.group(3), realName))
            return True
        
        return False
    
    def __whoIsChannels(self, match):
        """
        Private method to handle the WHOIS channels reply.
        
        @param match match object that matched the pattern
        @return flag indicating whether the message was handled (boolean)
        """
        # group(1)   nick
        # group(2)   channels
        if match.group(1) == self.__whoIsNick:
            userChannels = []
            voiceChannels = []
            opChannels = []
            halfopChannels = []
            ownerChannels = []
            adminChannels = []
            
            # generate the list of channels the user is in
            channelList = match.group(2).split()
            for channel in channelList:
                if channel.startswith(("*", "&")):
                    adminChannels.append(channel[1:])
                elif channel.startswith(("!", "~")) and \
                        self.__ircWidget.isChannelName(channel[1:]):
                    ownerChannels.append(channel[1:])
                elif channel.startswith("@+"):
                    opChannels.append(channel[2:])
                elif channel.startswith("@"):
                    opChannels.append(channel[1:])
                elif channel.startswith("%"):
                    halfopChannels.append(channel[1:])
                elif channel.startswith("+"):
                    voiceChannels.append(channel[1:])
                else:
                    userChannels.append(channel)
            
            # show messages
            if userChannels:
                self.__addManagementMessage(
                    self.tr("Whois"),
                    self.tr("{0} is a user on channels: {1}").format(
                        match.group(1), " ".join(userChannels)))
            if voiceChannels:
                self.__addManagementMessage(
                    self.tr("Whois"),
                    self.tr("{0} has voice on channels: {1}").format(
                        match.group(1), " ".join(voiceChannels)))
            if halfopChannels:
                self.__addManagementMessage(
                    self.tr("Whois"),
                    self.tr("{0} is a halfop on channels: {1}").format(
                        match.group(1), " ".join(halfopChannels)))
            if opChannels:
                self.__addManagementMessage(
                    self.tr("Whois"),
                    self.tr("{0} is an operator on channels: {1}").format(
                        match.group(1), " ".join(opChannels)))
            if ownerChannels:
                self.__addManagementMessage(
                    self.tr("Whois"),
                    self.tr("{0} is owner of channels: {1}").format(
                        match.group(1), " ".join(ownerChannels)))
            if adminChannels:
                self.__addManagementMessage(
                    self.tr("Whois"),
                    self.tr("{0} is admin on channels: {1}").format(
                        match.group(1), " ".join(adminChannels)))
            return True
        
        return False
    
    def __whoIsServer(self, match):
        """
        Private method to handle the WHOIS server reply.
        
        @param match match object that matched the pattern
        @return flag indicating whether the message was handled (boolean)
        """
        # group(1)   nick
        # group(2)   server
        # group(3)   server info
        if match.group(1) == self.__whoIsNick:
            self.__addManagementMessage(
                self.tr("Whois"),
                self.tr("{0} is online via {1} ({2}).").format(
                    match.group(1), match.group(2), match.group(3)))
            return True
        
        return False
    
    def __whoIsOperator(self, match):
        """
        Private method to handle the WHOIS operator reply.
        
        @param match match object that matched the pattern
        @return flag indicating whether the message was handled (boolean)
        """
        # group(1)   nick
        # group(2)   message
        if match.group(1) == self.__whoIsNick:
            if match.group(2).lower().startswith("is an irc operator"):
                self.__addManagementMessage(
                    self.tr("Whois"),
                    self.tr("{0} is an IRC Operator.").format(
                        match.group(1)))
            else:
                self.__addManagementMessage(
                    self.tr("Whois"),
                    "{0} {1}".format(match.group(1), match.group(2)))
            return True
        
        return False
    
    def __whoIsIdle(self, match):
        """
        Private method to handle the WHOIS idle reply.
        
        @param match match object that matched the pattern
        @return flag indicating whether the message was handled (boolean)
        """
        # group(1)   nick
        # group(2)   idle seconds
        # group(3)   signon time
        if match.group(1) == self.__whoIsNick:
            seconds = int(match.group(2))
            minutes = seconds // 60
            hours = minutes // 60
            days = hours // 24
            
            signonTimestamp = int(match.group(3))
            signonTime = QDateTime()
            signonTime.setTime_t(signonTimestamp)
            
            if days:
                daysString = self.tr("%n day(s)", "", days)
                hoursString = self.tr("%n hour(s)", "", hours)
                minutesString = self.tr("%n minute(s)", "", minutes)
                secondsString = self.tr("%n second(s)", "", seconds)
                self.__addManagementMessage(
                    self.tr("Whois"),
                    self.tr(
                        "{0} has been idle for {1}, {2}, {3}, and {4}.",
                        "{0} = name of person, {1} = (x days),"
                        " {2} = (x hours), {3} = (x minutes),"
                        " {4} = (x seconds)").format(
                        match.group(1), daysString, hoursString, minutesString,
                        secondsString))
            elif hours:
                hoursString = self.tr("%n hour(s)", "", hours)
                minutesString = self.tr("%n minute(s)", "", minutes)
                secondsString = self.tr("%n second(s)", "", seconds)
                self.__addManagementMessage(
                    self.tr("Whois"),
                    self.tr(
                        "{0} has been idle for {1}, {2}, and {3}.",
                        "{0} = name of person, {1} = (x hours), "
                        "{2} = (x minutes), {3} = (x seconds)")
                    .format(match.group(1), hoursString, minutesString,
                            secondsString))
            elif minutes:
                minutesString = self.tr("%n minute(s)", "", minutes)
                secondsString = self.tr("%n second(s)", "", seconds)
                self.__addManagementMessage(
                    self.tr("Whois"),
                    self.tr(
                        "{0} has been idle for {1} and {2}.",
                        "{0} = name of person, {1} = (x minutes), "
                        "{3} = (x seconds)")
                    .format(match.group(1), minutesString, secondsString))
            else:
                self.__addManagementMessage(
                    self.tr("Whois"),
                    self.tr(
                        "{0} has been idle for %n second(s).", "",
                        seconds).format(match.group(1)))
            
            if not signonTime.isNull():
                self.__addManagementMessage(
                    self.tr("Whois"),
                    self.tr("{0} has been online since {1}.").format(
                        match.group(1),
                        signonTime.toString("yyyy-MM-dd, hh:mm:ss")))
            return True
        
        return False
    
    def __whoIsEnd(self, match):
        """
        Private method to handle the end of WHOIS reply.
        
        @param match match object that matched the pattern
        @return flag indicating whether the message was handled (boolean)
        """
        # group(1)   nick
        # group(2)   end message
        if match.group(1) == self.__whoIsNick:
            self.__whoIsNick = ""
            self.__addManagementMessage(
                self.tr("Whois"),
                self.tr("End of WHOIS list for {0}.").format(
                    match.group(1)))
            return True
        
        return False
    
    def __whoIsIdentify(self, match):
        """
        Private method to handle the WHOIS identify and identified replies.
        
        @param match match object that matched the pattern
        @return flag indicating whether the message was handled (boolean)
        """
        # group(1)   nick
        # group(2)   identified message
        if match.group(1) == self.__whoIsNick:
            self.__addManagementMessage(
                self.tr("Whois"),
                self.tr("{0} is an identified user.").format(
                    match.group(1)))
            return True
        
        return False
    
    def __whoIsHelper(self, match):
        """
        Private method to handle the WHOIS helper reply.
        
        @param match match object that matched the pattern
        @return flag indicating whether the message was handled (boolean)
        """
        # group(1)   nick
        # group(2)   helper message
        if match.group(1) == self.__whoIsNick:
            self.__addManagementMessage(
                self.tr("Whois"),
                self.tr("{0} is available for help.").format(
                    match.group(1)))
            return True
        
        return False
    
    def __whoIsAccount(self, match):
        """
        Private method to handle the WHOIS account reply.
        
        @param match match object that matched the pattern
        @return flag indicating whether the message was handled (boolean)
        """
        # group(1)   nick
        # group(2)   login name
        if match.group(1) == self.__whoIsNick:
            self.__addManagementMessage(
                self.tr("Whois"),
                self.tr("{0} is logged in as {1}.").format(
                    match.group(1), match.group(2)))
            return True
        
        return False
    
    def __whoIsActually(self, match):
        """
        Private method to handle the WHOIS actually reply.
        
        @param match match object that matched the pattern
        @return flag indicating whether the message was handled (boolean)
        """
        # group(1)   nick
        # group(2)   actual user@host
        # group(3)   actual IP
        if match.group(1) == self.__whoIsNick:
            self.__addManagementMessage(
                self.tr("Whois"),
                self.tr(
                    "{0} is actually using the host {1} (IP: {2}).").format(
                    match.group(1), match.group(2), match.group(3)))
            return True
        
        return False
    
    def __whoIsSecure(self, match):
        """
        Private method to handle the WHOIS secure reply.
        
        @param match match object that matched the pattern
        @return flag indicating whether the message was handled (boolean)
        """
        # group(1)   nick
        if match.group(1) == self.__whoIsNick:
            self.__addManagementMessage(
                self.tr("Whois"),
                self.tr("{0} is using a secure connection.").format(
                    match.group(1)))
            return True
        
        return False
    
    def __whoIsConnection(self, match):
        """
        Private method to handle the WHOIS connection reply.
        
        @param match match object that matched the pattern
        @return flag indicating whether the message was handled (boolean)
        """
        # group(1)   nick
        # group(2)   host name
        # group(3)   IP
        if match.group(1) == self.__whoIsNick:
            self.__addManagementMessage(
                self.tr("Whois"),
                self.tr("{0} is connecting from {1} (IP: {2}).").format(
                    match.group(1), match.group(2), match.group(3)))
            return True
        
        return False
    
    def __setEditTopicButton(self):
        """
        Private method to set the visibility of the Edit Topic button.
        """
        itm = self.__findUser(self.__userName)
        if itm:
            self.editTopicButton.setVisible(itm.canChangeTopic())
    
    @pyqtSlot()
    def on_editTopicButton_clicked(self):
        """
        Private slot to change the topic of the channel.
        """
        topic, ok = QInputDialog.getText(
            self,
            self.tr("Edit Channel Topic"),
            self.tr("Enter the topic for this channel:"),
            QLineEdit.Normal,
            self.topicLabel.text())
        if ok and topic != "":
            self.sendData.emit("TOPIC {0} :{1}".format(
                self.__name, topic))
    
    @pyqtSlot(QUrl)
    def on_messages_anchorClicked(self, url):
        """
        Private slot to open links in the default browser.
        
        @param url URL to be opened (QUrl)
        """
        QDesktopServices.openUrl(url)