DMDirc-Plugins/logging/src/com/dmdirc/addons/logging/LoggingManager.java

/*
 * Copyright (c) 2006-2014 DMDirc Developers
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

package com.dmdirc.addons.logging;

import com.dmdirc.Channel;
import com.dmdirc.ClientModule.GlobalConfig;
import com.dmdirc.DMDircMBassador;
import com.dmdirc.FrameContainer;
import com.dmdirc.Query;
import com.dmdirc.commandline.CommandLineOptionsModule.Directory;
import com.dmdirc.events.BaseChannelActionEvent;
import com.dmdirc.events.BaseChannelMessageEvent;
import com.dmdirc.events.BaseQueryActionEvent;
import com.dmdirc.events.BaseQueryMessageEvent;
import com.dmdirc.events.ChannelClosedEvent;
import com.dmdirc.events.ChannelGottopicEvent;
import com.dmdirc.events.ChannelJoinEvent;
import com.dmdirc.events.ChannelKickEvent;
import com.dmdirc.events.ChannelModechangeEvent;
import com.dmdirc.events.ChannelNickchangeEvent;
import com.dmdirc.events.ChannelOpenedEvent;
import com.dmdirc.events.ChannelPartEvent;
import com.dmdirc.events.ChannelQuitEvent;
import com.dmdirc.events.ChannelTopicChangeEvent;
import com.dmdirc.events.QueryClosedEvent;
import com.dmdirc.events.QueryOpenedEvent;
import com.dmdirc.events.UserErrorEvent;
import com.dmdirc.interfaces.PrivateChat;
import com.dmdirc.interfaces.config.AggregateConfigProvider;
import com.dmdirc.interfaces.config.ConfigChangeListener;
import com.dmdirc.logger.ErrorLevel;
import com.dmdirc.parser.interfaces.ChannelClientInfo;
import com.dmdirc.parser.interfaces.ChannelInfo;
import com.dmdirc.parser.interfaces.ClientInfo;
import com.dmdirc.parser.interfaces.Parser;
import com.dmdirc.plugins.PluginDomain;
import com.dmdirc.ui.WindowManager;
import com.dmdirc.ui.messages.ColourManagerFactory;
import com.dmdirc.ui.messages.Styliser;
import com.dmdirc.util.URLBuilder;
import com.dmdirc.util.io.ReverseFileReader;
import com.dmdirc.util.io.StreamUtils;

import java.awt.Color;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.Stack;
import java.util.Timer;
import java.util.TimerTask;

import javax.annotation.Nullable;
import javax.inject.Inject;
import javax.inject.Provider;
import javax.inject.Singleton;

import net.engio.mbassy.listener.Handler;

/**
 * Manages logging activities.
 */
@Singleton
public class LoggingManager implements ConfigChangeListener {

    /** Date format used for "File Opened At" log. */
    private static final DateFormat OPENED_AT_FORMAT = new SimpleDateFormat(
            "EEEE MMMM dd, yyyy - HH:mm:ss");
    /** Object for synchronising access to the date forma.t */
    private static final Object FORMAT_LOCK = new Object();
    /** This plugin's plugin info. */
    private final String domain;
    /** Global config. */
    private final AggregateConfigProvider config;
    /** The manager to add history windows to. */
    private final WindowManager windowManager;
    /** Map of open files. */
    private final Map<String, OpenFile> openFiles = Collections.synchronizedMap(
            new HashMap<String, OpenFile>());
    private final URLBuilder urlBuilder;
    private final DMDircMBassador eventBus;
    private final Provider<String> directoryProvider;
    private final ColourManagerFactory colourManagerFactory;
    /** Timer used to close idle files. */
    private Timer idleFileTimer;
    /** Cached boolean settings. */
    private boolean networkfolders;
    private boolean filenamehash;
    private boolean addtime;
    private boolean stripcodes;
    private boolean channelmodeprefix;
    private boolean autobackbuffer;
    private boolean backbufferTimestamp;
    private boolean usedate;
    /** Cached string settings. */
    private String timestamp;
    private String usedateformat;
    private String colour;
    /** Cached int settings. */
    private int historyLines;
    private int backbufferLines;

    @Inject
    public LoggingManager(@PluginDomain(LoggingPlugin.class) final String domain,
            @GlobalConfig final AggregateConfigProvider globalConfig,
            final WindowManager windowManager, final URLBuilder urlBuilder, final DMDircMBassador eventBus,
            @Directory(LoggingModule.LOGS_DIRECTORY) final Provider<String> directoryProvider,
            final ColourManagerFactory colourManagerFactory) {
        this.domain = domain;
        this.config = globalConfig;
        this.windowManager = windowManager;
        this.urlBuilder = urlBuilder;
        this.eventBus = eventBus;
        this.directoryProvider = directoryProvider;
        this.colourManagerFactory = colourManagerFactory;
    }

    public void load() {
        setCachedSettings();

        final File dir = new File(directoryProvider.get());
        if (dir.exists()) {
            if (!dir.isDirectory()) {
                eventBus.publishAsync(new UserErrorEvent(ErrorLevel.LOW, null,
                        "Unable to create logging dir (file exists instead)", ""));
            }
        } else {
            if (!dir.mkdirs()) {
                eventBus.publishAsync(new UserErrorEvent(ErrorLevel.LOW, null,
                        "Unable to create logging dir", ""));
            }
        }

        config.addChangeListener(domain, this);

        // Close idle files every hour.
        idleFileTimer = new Timer("LoggingPlugin Timer");
        idleFileTimer.schedule(new TimerTask() {

            @Override
            public void run() {
                timerTask();
            }
        }, 3600000);

        eventBus.subscribe(this);
    }

    public void unload() {
        if (idleFileTimer != null) {
            idleFileTimer.cancel();
            idleFileTimer.purge();
        }

        synchronized (openFiles) {
            for (OpenFile file : openFiles.values()) {
                StreamUtils.close(file.writer);
            }
            openFiles.clear();
        }

        eventBus.unsubscribe(this);
    }

    /**
     * What to do every hour when the timer fires.
     */
    protected void timerTask() {
        // Oldest time to allow
        final long oldestTime = System.currentTimeMillis() - 3480000;

        synchronized (openFiles) {
            final Collection<String> old = new ArrayList<>(openFiles.size());
            for (Map.Entry<String, OpenFile> entry : openFiles.entrySet()) {
                if (entry.getValue().lastUsedTime < oldestTime) {
                    StreamUtils.close(entry.getValue().writer);
                    old.add(entry.getKey());
                }
            }

            openFiles.keySet().removeAll(old);
        }
    }

    @Handler
    public void handleQueryOpened(final QueryOpenedEvent event) {
        final Parser parser = event.getQuery().getConnection().getParser();
        final ClientInfo client = parser.getClient(event.getQuery().getHost());
        final String filename = getLogFile(client);
        if (autobackbuffer) {
            showBackBuffer(event.getQuery(), filename);
        }

        synchronized (FORMAT_LOCK) {
            appendLine(filename, "*** Query opened at: %s", OPENED_AT_FORMAT.format(new Date()));
            appendLine(filename, "*** Query with User: %s", event.getQuery().getHost());
            appendLine(filename, "");
        }
    }

    @Handler
    public void handleQueryClosed(final QueryClosedEvent event) {
        final Parser parser = event.getQuery().getConnection().getParser();
        final ClientInfo client = parser.getClient(event.getQuery().getHost());
        final String filename = getLogFile(client);

        synchronized (FORMAT_LOCK) {
            appendLine(filename, "*** Query closed at: %s", OPENED_AT_FORMAT.format(new Date()));
        }

        if (openFiles.containsKey(filename)) {
            StreamUtils.close(openFiles.get(filename).writer);
            openFiles.remove(filename);
        }
    }

    @Handler
    public void handleQueryActions(final BaseQueryActionEvent event) {
        final ClientInfo client = event.getClient();
        final String filename = getLogFile(client);
        appendLine(filename, "* %s %s", client.getNickname(), event.getMessage());
    }

    @Handler
    public void handleQueryMessages(final BaseQueryMessageEvent event) {
        final ClientInfo client = event.getClient();
        final String filename = getLogFile(client);
        appendLine(filename, "<%s> %s", client.getNickname(), event.getMessage());
    }

    @Handler
    public void handleChannelMessage(final BaseChannelMessageEvent event) {
        final String filename = getLogFile(event.getChannel().getChannelInfo());
        appendLine(filename, "<%s> %s", getDisplayName(event.getClient()), event.getMessage());
    }

    @Handler
    public void handleChannelAction(final BaseChannelActionEvent event) {
        final String filename = getLogFile(event.getChannel().getChannelInfo());
        appendLine(filename, "* %s %s", getDisplayName(event.getClient()), event.getMessage());
    }

    @Handler
    public void handleChannelGotTopic(final ChannelGottopicEvent event) {
        final String filename = getLogFile(event.getChannel().getChannelInfo());
        final ChannelInfo channel = event.getChannel().getChannelInfo();
        final DateFormat timeFormat = new SimpleDateFormat("HH:mm:ss");
        final DateFormat dateFormat = new SimpleDateFormat("dd/MM/yyyy");

        appendLine(filename, "*** Topic is: %s", channel.getTopic());
        appendLine(filename, "*** Set at: %s on %s by %s", timeFormat.format(1000 * channel.
                getTopicTime()), dateFormat.format(1000 * channel.getTopicTime()), channel.
                getTopicSetter());
    }

    @Handler
    public void handleChannelTopicChange(final ChannelTopicChangeEvent event) {
        final String filename = getLogFile(event.getChannel().getChannelInfo());
        final ChannelClientInfo channelClient = event.getClient();
        appendLine(filename, "*** %s Changed the topic to: %s",
                getDisplayName(channelClient), event.getTopic());
    }

    @Handler
    public void handleChannelJoin(final ChannelJoinEvent event) {
        final String filename = getLogFile(event.getChannel().getChannelInfo());
        final ChannelClientInfo channelClient = event.getClient();
        final ClientInfo client = channelClient.getClient();
        appendLine(filename, "*** %s (%s) joined the channel",
                getDisplayName(channelClient), client.toString());
    }

    @Handler
    public void handleChannelPart(final ChannelPartEvent event) {
        final String filename = getLogFile(event.getChannel().getChannelInfo());
        final String message = event.getMessage();
        final ChannelClientInfo channelClient = event.getClient();
        final ClientInfo client = channelClient.getClient();
        if (message.isEmpty()) {
            appendLine(filename, "*** %s (%s) left the channel",
                    getDisplayName(channelClient), client.toString());
        } else {
            appendLine(filename, "*** %s (%s) left the channel (%s)",
                    getDisplayName(channelClient), client.toString(), message);
        }
    }

    @Handler
    public void handleChannelQuit(final ChannelQuitEvent event) {
        final String filename = getLogFile(event.getChannel().getChannelInfo());
        final String reason = event.getMessage();
        final ChannelClientInfo channelClient = event.getClient();
        final ClientInfo client = channelClient.getClient();
        if (reason.isEmpty()) {
            appendLine(filename, "*** %s (%s) Quit IRC",
                    getDisplayName(channelClient), client.toString());
        } else {
            appendLine(filename, "*** %s (%s) Quit IRC (%s)",
                    getDisplayName(channelClient), client.toString(), reason);
        }
    }

    @Handler
    public void handleChannelKick(final ChannelKickEvent event) {
        final ChannelClientInfo victim = event.getVictim();
        final ChannelClientInfo perpetrator = event.getClient();
        final String reason = event.getReason();
        final String filename = getLogFile(event.getChannel().getChannelInfo());

        if (reason.isEmpty()) {
            appendLine(filename, "*** %s was kicked by %s",
                    getDisplayName(victim), getDisplayName(perpetrator));
        } else {
            appendLine(filename, "*** %s was kicked by %s (%s)",
                    getDisplayName(victim), getDisplayName(perpetrator), reason);
        }
    }

    @Handler
    public void handleNickChange(final ChannelNickchangeEvent event) {
        final String filename = getLogFile(event.getChannel().getChannelInfo());
        appendLine(filename, "*** %s is now %s", getDisplayName(event.getClient(),
                event.getOldNick()), getDisplayName(event.getClient()));
    }

    @Handler
    public void handleModeChange(final ChannelModechangeEvent event) {
        final String filename = getLogFile(event.getChannel().getChannelInfo());
        if (event.getClient().getClient().getNickname().isEmpty()) {
            appendLine(filename, "*** Channel modes are: %s", event.getModes());
        } else {
            appendLine(filename, "*** %s set modes: %s",
                    getDisplayName(event.getClient()), event.getModes());
        }
    }

    @Override
    public void configChanged(final String domain, final String key) {
        setCachedSettings();
    }

    @Handler
    public void handleChannelOpened(final ChannelOpenedEvent event) {
        final String filename = getLogFile(event.getChannel().getName());

        if (autobackbuffer) {
            showBackBuffer(event.getChannel(), filename);
        }

        synchronized (FORMAT_LOCK) {
            appendLine(filename, "*** Channel opened at: %s", OPENED_AT_FORMAT.format(new Date()));
            appendLine(filename, "");
        }
    }

    @Handler
    public void handleChannelClosed(final ChannelClosedEvent event) {
        final String filename = getLogFile(event.getChannel().getName());

        synchronized (FORMAT_LOCK) {
            appendLine(filename, "*** Channel closed at: %s", OPENED_AT_FORMAT.format(new Date()));
        }

        if (openFiles.containsKey(filename)) {
            StreamUtils.close(openFiles.get(filename).writer);
            openFiles.remove(filename);
        }
    }

    /**
     * Add a backbuffer to a frame.
     *
     * @param frame    The frame to add the backbuffer lines to
     * @param filename File to get backbuffer from
     */
    protected void showBackBuffer(final FrameContainer frame, final String filename) {
        if (frame == null) {
            eventBus.publishAsync(new UserErrorEvent(ErrorLevel.LOW, null, "Given a null frame", ""));
            return;
        }

        final File testFile = new File(filename);
        if (testFile.exists()) {
            try {
                final ReverseFileReader file = new ReverseFileReader(testFile);
                // Because the file includes a newline char at the end, an empty line
                // is returned by getLines. To counter this, we call getLines(1) and do
                // nothing with the output.
                file.getLines(1);
                final Stack<String> lines = file.getLines(backbufferLines);
                while (!lines.empty()) {
                    frame.addLine(getColouredString(colour, lines.pop()), backbufferTimestamp);
                }
                file.close();
                frame.addLine(getColouredString(colour, "--- End of backbuffer\n"),
                        backbufferTimestamp);
            } catch (IOException | SecurityException e) {
                eventBus.publishAsync(new UserErrorEvent(ErrorLevel.LOW, e,
                        "Unable to show backbuffer (Filename: " + filename + "): " + e.getMessage(),
                        ""));
            }
        }
    }

    /**
     * Get a coloured String. If colour is invalid, IRC Colour 14 will be used.
     *
     * @param colour The colour the string should be (IRC Colour or 6-digit hex colour)
     * @param line   the line to colour
     *
     * @return The given line with the appropriate irc codes appended/prepended to colour it.
     */
    protected static String getColouredString(final String colour, final String line) {
        String res = null;
        if (colour.length() < 3) {
            int num;

            try {
                num = Integer.parseInt(colour);
            } catch (NumberFormatException ex) {
                num = -1;
            }

            if (num >= 0 && num <= 15) {
                res = String.format("%c%02d%s%1$c", Styliser.CODE_COLOUR, num, line);
            }
        } else if (colour.length() == 6) {
            try {
                Color.decode('#' + colour);
                res = String.format("%c%s%s%1$c", Styliser.CODE_HEXCOLOUR, colour, line);
            } catch (NumberFormatException ex) { /* Do Nothing */ }
        }

        if (res == null) {
            res = String.format("%c%02d%s%1$c", Styliser.CODE_COLOUR, 14, line);
        }
        return res;
    }

    /**
     * Add a line to a file.
     *
     * @param filename Name of file to write to
     * @param format   Format of line to add. (NewLine will be added Automatically)
     * @param args     Arguments for format
     *
     * @return true on success, else false.
     */
    protected boolean appendLine(final String filename, final String format, final Object... args) {
        return appendLine(filename, String.format(format, args));
    }

    /**
     * Add a line to a file.
     *
     * @param filename Name of file to write to
     * @param line     Line to add. (NewLine will be added Automatically)
     *
     * @return true on success, else false.
     */
    protected boolean appendLine(final String filename, final String line) {
        final StringBuilder finalLine = new StringBuilder();

        if (addtime) {
            String dateString;
            try {
                final DateFormat dateFormat = new SimpleDateFormat(timestamp);
                dateString = dateFormat.format(new Date()).trim();
            } catch (IllegalArgumentException iae) {
                // Default to known good format
                final DateFormat dateFormat = new SimpleDateFormat("[dd/MM/yyyy HH:mm:ss]");
                dateString = dateFormat.format(new Date()).trim();

                eventBus.publishAsync(new UserErrorEvent(ErrorLevel.LOW, iae,
                        "Dateformat String '" + timestamp + "' is invalid. For more information: "
                        + "http://java.sun.com/javase/6/docs/api/java/text/SimpleDateFormat.html",
                        ""));
            }
            finalLine.append(dateString);
            finalLine.append(' ');
        }

        if (stripcodes) {
            finalLine.append(Styliser.stipControlCodes(line));
        } else {
            finalLine.append(line);
        }

        try {
            final BufferedWriter out;
            if (openFiles.containsKey(filename)) {
                final OpenFile of = openFiles.get(filename);
                of.lastUsedTime = System.currentTimeMillis();
                out = of.writer;
            } else {
                out = new BufferedWriter(new FileWriter(filename, true));
                openFiles.put(filename, new OpenFile(out));
            }
            out.write(finalLine.toString());
            out.newLine();
            out.flush();
            return true;
        } catch (IOException e) {
            /*
             * Do Nothing
             *
             * Makes no sense to keep adding errors to the logger when we can't write to the file,
             * as chances are it will happen on every incomming line.
             */
        }
        return false;
    }

    /**
     * Get the name of the log file for a specific object.
     *
     * @param channel Channel to get the name for
     *
     * @return the name of the log file to use for this object.
     */
    protected String getLogFile(final ChannelInfo channel) {
        final StringBuffer directory = getLogDirectory();
        final StringBuffer file = new StringBuffer();
        if (channel.getParser() != null) {
            addNetworkDir(directory, file, channel.getParser().getNetworkName());
        }
        file.append(sanitise(channel.getName().toLowerCase()));
        return getPath(directory, file, channel.getName());
    }

    /**
     * Get the name of the log file for a specific object.
     *
     * @param client Client to get the name for
     *
     * @return the name of the log file to use for this object.
     */
    protected String getLogFile(final ClientInfo client) {
        final StringBuffer directory = getLogDirectory();
        final StringBuffer file = new StringBuffer();
        if (client.getParser() != null) {
            addNetworkDir(directory, file, client.getParser().getNetworkName());
        }
        file.append(sanitise(client.getNickname().toLowerCase()));
        return getPath(directory, file, client.getNickname());
    }

    /**
     * Get the name of the log file for a specific object.
     *
     * @param descriptor Description of the object to get a log file for.
     *
     * @return the name of the log file to use for this object.
     */
    protected String getLogFile(@Nullable final String descriptor) {
        final StringBuffer directory = getLogDirectory();
        final StringBuffer file = new StringBuffer();
        final String md5String;
        if (descriptor == null) {
            file.append("null.log");
            md5String = "";
        } else {
            file.append(sanitise(descriptor.toLowerCase()));
            md5String = descriptor;
        }
        return getPath(directory, file, md5String);
    }

    /**
     * Gets the path for the given file and directory. Only intended to be used from getLogFile
     * methods.
     *
     * @param directory Log file directory
     * @param file      Log file path
     * @param md5String Log file object MD5 hash
     *
     * @return Name of the log file
     */
    protected String getPath(final StringBuffer directory, final StringBuffer file,
            final String md5String) {
        if (usedate) {
            final String dateFormat = usedateformat;
            final String dateDir = new SimpleDateFormat(dateFormat).format(new Date());
            directory.append(dateDir);
            if (directory.charAt(directory.length() - 1) != File.separatorChar) {
                directory.append(File.separatorChar);
            }

            if (!new File(directory.toString()).exists()
                    && !new File(directory.toString()).mkdirs()) {
                eventBus.publishAsync(new UserErrorEvent(ErrorLevel.LOW, null,
                        "Unable to create date dirs", ""));
            }
        }

        if (filenamehash) {
            file.append('.');
            file.append(md5(md5String));
        }
        file.append(".log");

        return directory + file.toString();
    }

    /**
     * Sanitises the log file directory.
     *
     * @return Log directory
     */
    private StringBuffer getLogDirectory() {
        final StringBuffer directory = new StringBuffer();
        directory.append(directoryProvider.get());
        if (directory.charAt(directory.length() - 1) != File.separatorChar) {
            directory.append(File.separatorChar);
        }
        return directory;
    }

    /**
     * This function adds the networkName to the log file. It first tries to create a directory for
     * each network, if that fails it will prepend the networkName to the filename instead.
     *
     * @param directory   Current directory name
     * @param file        Current file name
     * @param networkName Name of network
     */
    protected void addNetworkDir(final StringBuffer directory, final StringBuffer file,
            final String networkName) {
        if (!networkfolders) {
            return;
        }

        final String network = sanitise(networkName.toLowerCase());

        boolean prependNetwork = false;

        // Check dir exists
        final File dir = new File(directory + network + System.getProperty(
                "file.separator"));
        if (dir.exists() && !dir.isDirectory()) {
            eventBus.publishAsync(new UserErrorEvent(ErrorLevel.LOW, null,
                    "Unable to create networkfolders dir (file exists instead)", ""));
            // Prepend network name to file instead.
            prependNetwork = true;
        } else if (!dir.exists() && !dir.mkdirs()) {
            eventBus.publishAsync(new UserErrorEvent(ErrorLevel.LOW, null,
                    "Unable to create networkfolders dir", ""));
            prependNetwork = true;
        }

        if (prependNetwork) {
            file.insert(0, " -- ");
            file.insert(0, network);
        } else {
            directory.append(network);
            directory.append(System.getProperty("file.separator"));
        }
    }

    /**
     * Sanitise a string to be used as a filename.
     *
     * @param name String to sanitise
     *
     * @return Sanitised version of name that can be used as a filename.
     */
    protected static String sanitise(final String name) {
        // Replace illegal chars with
        return name.replaceAll("[^\\w\\.\\s\\-#&_]", "_");
    }

    /**
     * Get the md5 hash of a string.
     *
     * @param string String to hash
     *
     * @return md5 hash of given string
     */
    protected static String md5(final String string) {
        try {
            final MessageDigest m = MessageDigest.getInstance("MD5");
            m.update(string.getBytes(), 0, string.length());
            return new BigInteger(1, m.digest()).toString(16);
        } catch (NoSuchAlgorithmException e) {
            return "";
        }
    }

    /**
     * Get name to display for channelClient (Taking into account the channelmodeprefix setting).
     *
     * @param channelClient The client to get the display name for
     *
     * @return name to display
     */
    protected String getDisplayName(final ChannelClientInfo channelClient) {
        return getDisplayName(channelClient, "");
    }

    /**
     * Get name to display for channelClient (Taking into account the channelmodeprefix setting).
     *
     * @param channelClient The client to get the display name for
     * @param overrideNick  Nickname to display instead of real nickname
     *
     * @return name to display
     */
    protected String getDisplayName(final ChannelClientInfo channelClient, final String overrideNick) {
        if (channelClient == null) {
            return overrideNick.isEmpty() ? "Unknown Client" : overrideNick;
        } else if (overrideNick.isEmpty()) {
            return channelmodeprefix ? channelClient.toString() : channelClient.getClient().
                    getNickname();
        } else {
            return channelmodeprefix ? channelClient.getImportantModePrefix() + overrideNick
                    : overrideNick;
        }
    }

    /**
     * Shows the history window for the specified target, if available.
     *
     * @param target The window whose history we're trying to open
     *
     * @return True if the history is available, false otherwise
     */
    protected boolean showHistory(final FrameContainer target) {
        final String descriptor;

        if (target instanceof Channel) {
            descriptor = target.getName();
        } else if (target instanceof Query) {
            final Parser parser = target.getConnection().getParser();
            descriptor = parser.getClient(((PrivateChat) target).getHost()).getNickname();
        } else {
            // Unknown component
            return false;
        }

        final String log = getLogFile(descriptor);

        if (!new File(log).exists()) {
            // File doesn't exist
            return false;
        }

        final ReverseFileReader reader;

        try {
            reader = new ReverseFileReader(log);
        } catch (IOException | SecurityException ex) {
            return false;
        }

        final HistoryWindow window = new HistoryWindow("History", reader, target, urlBuilder,
                eventBus, colourManagerFactory, historyLines);
        windowManager.addWindow(target, window);

        return true;
    }

    /** Updates cached settings. */
    public void setCachedSettings() {
        networkfolders = config.getOptionBool(domain, "general.networkfolders");
        filenamehash = config.getOptionBool(domain, "advanced.filenamehash");
        addtime = config.getOptionBool(domain, "general.addtime");
        stripcodes = config.getOptionBool(domain, "general.stripcodes");
        channelmodeprefix = config.getOptionBool(domain, "general.channelmodeprefix");
        autobackbuffer = config.getOptionBool(domain, "backbuffer.autobackbuffer");
        backbufferTimestamp = config.getOptionBool(domain, "backbuffer.timestamp");
        usedate = config.getOptionBool(domain, "advanced.usedate");
        timestamp = config.getOption(domain, "general.timestamp");
        usedateformat = config.getOption(domain, "advanced.usedateformat");
        historyLines = config.getOptionInt(domain, "history.lines");
        colour = config.getOption(domain, "backbuffer.colour");
        backbufferLines = config.getOptionInt(domain, "backbuffer.lines");
    }

    /** Open File. */
    private static class OpenFile {

        /** Last used time. */
        public long lastUsedTime = System.currentTimeMillis();
        /** Open file's writer. */
        public final BufferedWriter writer;

        /**
         * Creates a new open file.
         *
         * @param writer Writer that has file open
         */
        protected OpenFile(final BufferedWriter writer) {
            this.writer = writer;
        }

    }

}