package net.i2p.router.web.helpers;

import java.io.IOException;
import java.io.Serializable;
import java.io.Writer;
import java.math.RoundingMode;
import java.util.Comparator;
import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.util.Collections;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.SortedMap;
import java.util.TreeMap;
import java.util.TreeSet;

import net.i2p.data.DataHelper;
import net.i2p.data.router.RouterAddress;
import net.i2p.router.transport.Transport;
import net.i2p.router.transport.TransportManager;
import net.i2p.router.transport.TransportUtil;
import net.i2p.router.transport.ntcp.NTCPConnection;
import net.i2p.router.transport.ntcp.NTCPTransport;
import net.i2p.router.transport.udp.PeerState;
import net.i2p.router.transport.udp.UDPTransport;
import net.i2p.router.web.HelperBase;
import static net.i2p.router.web.helpers.UDPSorters.*;
import net.i2p.util.Addresses;
import net.i2p.util.AddressType;
import net.i2p.util.SystemVersion;



public class PeerHelper extends HelperBase {
    private int _sortFlags;
    private String _urlBase;
    private String _transport;
    private boolean _graphical;

    private static final String titles[] = {
                                            _x("Status"),
                                            _x("Addresses"),
                                             "NTCP",
                                             "SSU",
                                             _x("Banned"),
                                             _x("UPnP Status")
                                           };

    private static final String links[] = {
                                            "",
                                             "?tx=addresses",
                                             "?tx=ntcp",
                                             "?tx=ssu",
                                             "?tx=banned",
                                             "?tx=upnp"
                                           };

    // Opera doesn't have the char, TODO check UA
    //private static final String THINSP = "&thinsp;/&thinsp;";
    private static final String THINSP = " / ";

    public PeerHelper() {}

    public void setSort(String flags) {
        if (flags != null) {
            try {
                _sortFlags = Integer.parseInt(flags);
            } catch (NumberFormatException nfe) {
                _sortFlags = 0;
            }
        } else {
            _sortFlags = 0;
        }
    }

    public void setUrlBase(String base) { _urlBase = base; }

    /** @since 0.9.38 */
    public void setTransport(String t) { _transport = t; }

    /**
     *  call for non-text-mode browsers
     *  @since 0.9.38
     */
    public void allowGraphical() {
        _graphical = true;
    }

    public String getPeerSummary() {
        try {
            renderStatusHTML(_out, _urlBase, _sortFlags);
            // boring and not worth translating
            //_context.bandwidthLimiter().renderStatusHTML(_out);
        } catch (IOException ioe) {
            ioe.printStackTrace();
        }
        return "";
    }

    /**
     *  Warning - blocking, very slow, queries the active UPnP router,
     *  will take many seconds if it has vanished.
     *
     *  @since 0.9.31 moved from TransportManager
     */
    private void renderStatusHTML(Writer out, String urlBase, int sortFlags) throws IOException {
        if (_context.commSystem().isDummy()) {
            out.write("<p>No peers, no transports, no UPnP: i2p.vmCommSystem=true</p>");
            return;
        }
        renderNavBar(out);
        if (_transport == null) {
            out.write("<p id=\"upnpstatus\"><b>");
            out.write(_t("Status"));
            out.write(": ");
            out.write(_context.commSystem().getLocalizedStatusString());
            out.write("</b></p>");
        }

        SortedMap<String, Transport> transports = _context.commSystem().getTransports();
        if ("addresses".equals(_transport)) {
            StringBuilder buf = new StringBuilder(4*1024);
            buf.append("<h3 id=\"transports\">").append(_t("Router Transport Addresses")).append("</h3><pre id=\"transports\">\n");
            if (!transports.isEmpty()) {
                for (Transport t : transports.values()) {
                    if (t.hasCurrentAddress()) {
                        for (RouterAddress ra : t.getCurrentAddresses()) {
                            buf.append(ra.toString());
                            buf.append("\n\n");
                        }
                    } else {
                        buf.append(_t("{0} is used for outbound connections only", t.getStyle()));
                        buf.append("\n\n");
                    }
                }
            } else {
                buf.append(_t("none"));
            }
            buf.append("</pre>\n");
            out.write(buf.toString());
        } else if ("upnp".equals(_transport)) {
            // UPnP Status
            StringBuilder buf = new StringBuilder(512);
            buf.append("<h3>").append(_t("UPnP Overview"))
               .append("</h3><div id=\"upnpoverview\"><p>")
               .append(_t("UPnP is used to communicate with Internet Gateway Devices (IGDs) to detect the external IP address and forward ports."))
               .append(' ')
               .append(_t("If UPnP is not working, it may be for one of the following reasons:"))
               .append("</p><ul id=\"upnphelp\"><li>").append(_t("No UPnP-compatible device present"))
               .append("</li>\n<li>").append(_t("UPnP disabled on the device"))
               .append("</li>\n<li>").append(_t("Software firewall interference with UPnP"))
               .append("</li>\n<li>").append(_t("Bugs in the device's UPnP implementation"))
               .append("</li>\n<li>").append(_t("Multiple firewall/routers in the internet connection path"))
               .append("</li>\n<li>").append(_t("UPnP device change, reset, or address change"))
               .append("</li>\n</ul><p>")
               .append(_t("UPnP may be enabled or disabled on the Network Configuration page, but a change requires a router restart to take effect."))
               .append("</p></div>");
            out.write(buf.toString());
            _context.commSystem().renderStatusHTML(_out, _urlBase, _sortFlags);
        } else if ("banned".equals(_transport)) {
            BanlistRenderer br = new BanlistRenderer(_context);
            br.renderStatusHTML(_out);
        } else if (_transport != null) {
            boolean rendered = false;
            for (Map.Entry<String, Transport> e : transports.entrySet()) {
                String style = e.getKey();
                Transport t = e.getValue();
                if (style.equals("NTCP") && "ntcp".equals(_transport)) {
                    NTCPTransport nt = (NTCPTransport) t;
                    render(nt, out, urlBase, sortFlags);
                    rendered = true;
                    break;
                } else if (style.equals("SSU") && "ssu".equals(_transport)) {
                    UDPTransport ut = (UDPTransport) t;
                    render(ut, out, urlBase, sortFlags);
                    rendered = true;
                    break;
                } else if (style.equals(_transport)) {
                    // pluggable (none yet)
                    t.renderStatusHTML(out, urlBase, sortFlags);
                    rendered = true;
                    break;
                }
            }
            if (rendered) {
                out.write(getTransportsLegend());
            } else {
                out.write("<p class=\"infohelp\">" +
                          "Transport not enabled: " +
                          DataHelper.escapeHTML(_transport) +
                          "</p>");
            }
        } else {
            // summary
            Set<AddressType> connected = Addresses.getConnectedAddressTypes();
            TransportUtil.IPv6Config ntcpConfig = TransportUtil.getIPv6Config(_context, "NTCP");
            TransportUtil.IPv6Config ssuConfig = TransportUtil.getIPv6Config(_context, "SSU");
            boolean showIPv4 = connected.contains(AddressType.IPV4) &&
                               (ntcpConfig != TransportUtil.IPv6Config.IPV6_ONLY ||
                                ssuConfig != TransportUtil.IPv6Config.IPV6_ONLY);
            boolean showIPv6 = connected.contains(AddressType.IPV6) &&
                               (ntcpConfig != TransportUtil.IPv6Config.IPV6_DISABLED ||
                                ssuConfig != TransportUtil.IPv6Config.IPV6_DISABLED);
            StringBuilder buf = new StringBuilder(512);
            buf.append("<h3 id=\"transports\">").append(_t("Peer Connections")).append("</h3><table><tr><th>")
               .append(_t("Transport")).append("</th><th>")
               .append(_t("Total")).append("</th>");
            if (showIPv4) {
                buf.append("<th>")
                   .append(_t("IPv4")).append(" <img src=\"/themes/console/images/inbound.png\" alt=\"").append(_t("Inbound")).append("\" title=\"").append(_t("Inbound")).append("\"/></th><th>")
                   .append(_t("IPv4")).append(" <img src=\"/themes/console/images/outbound.png\" alt=\"").append(_t("Outbound")).append("\" title=\"").append(_t("Outbound")).append("\"/></th>");
            }
            if (showIPv6) {
                buf.append("<th>")
                   .append(_t("IPv6")).append(" <img src=\"/themes/console/images/inbound.png\" alt=\"").append(_t("Inbound")).append("\" title=\"").append(_t("Inbound")).append("\"/></th><th>")
                   .append(_t("IPv6")).append(" <img src=\"/themes/console/images/outbound.png\" alt=\"").append(_t("Outbound")).append("\" title=\"").append(_t("Outbound")).append("\"/></th>");
            }
            buf.append("</tr>\n");
            boolean warnInbound = !_context.router().isHidden() && _context.router().getUptime() > 15*60*1000;
            int[] totals = new int[5];
            int rows = 0;
            for (Map.Entry<String, Transport> e : transports.entrySet()) {
                String style = e.getKey();
                Transport t = e.getValue();
                int[] counts = t.getPeerCounts();
                for (int idx = 0; idx < 8; idx += 4) {
                    if (style.equals("NTCP") && idx == 0)
                        continue;
                    if (style.equals("SSU") && idx == 0) // && !_context.getBooleanProperty(TransportManager.PROP_ENABLE_SSU1))
                        continue;
                    rows++;
                    buf.append("<tr><td align=\"center\"><b>")
                       .append(style)
                       .append(1 + (idx / 4))
                       .append("</b></td><td align=\"center\">");
                    int total = 0;
                    for (int i = 0; i < 4; i++) {
                        total += counts[idx + i];
                    }
                    if (total <= 0)
                        buf.append("<b>**</b> ");
                    else
                        totals[0] += total;
                    buf.append(total);
                    for (int i = 0; i < 4; i++) {
                        if (!showIPv4 && i < 2)
                            continue;
                        if (!showIPv6 && i >= 2)
                            break;
                        int cnt = counts[idx + i];
                        buf.append("</td><td align=\"center\">");
                        if (cnt <= 0) {
                            if ((i & 0x01) != 0 || warnInbound)
                                buf.append("<b>**</b> ");
                        } else {
                            totals[i + 1] += cnt;
                        }
                        buf.append(cnt);
                    }
                    buf.append("</td></tr>\n");
                }
            }
            if (rows > 1) {
                buf.append("<tr><th align=\"center\"><b>").append(_t("Total")).append("</b>");
                for (int i = 0; i < 5; i++) {
                    if (!showIPv4 && i > 0 && i < 3)
                        continue;
                    if (!showIPv6 && i >= 3)
                        break;
                    int cnt = totals[i];
                    buf.append("</th><th align=\"center\">");
                    if (cnt <= 0) {
                        if ((i & 0x01) == 0 || warnInbound)
                            buf.append("<b>**</b> ");
                    }
                    buf.append("<b>").append(cnt).append("</b");
                }
                buf.append("</th></tr>");
            }
            buf.append("</table>\n");
            out.write(buf.toString());
        }
        out.flush();
    }

    /**
     *  @since 0.9.38
     */
    private int getTab() {
        if ("addresses".equals(_transport))
            return 1;
        if ("ntcp".equals(_transport))
            return 2;
        if ("ssu".equals(_transport))
            return 3;
        if ("banned".equals(_transport))
            return 4;
        if ("upnp".equals(_transport))
            return 5;
        return 0;
    }

    /**
     *  @since 0.9.38
     */
    private void renderNavBar(Writer out) throws IOException {
        StringBuilder buf = new StringBuilder(1024);
        buf.append("<div class=\"confignav\" id=\"confignav\">");
        boolean span = _graphical;
        if (!span)
            buf.append("<center>");
        int tab = getTab();
        for (int i = 0; i < titles.length; i++) {
            if (i == tab) {
                // we are there
                if (span)
                    buf.append("<span class=\"tab2\">");
                buf.append(_t(titles[i]));
            } else {
                if (i == 2) {
                    if (!_context.getBooleanPropertyDefaultTrue(TransportManager.PROP_ENABLE_NTCP))
                        continue;
                } else if (i == 3) {
                    if (!_context.getBooleanPropertyDefaultTrue(TransportManager.PROP_ENABLE_UDP))
                        continue;
                }
                // we are not there, make a link
                if (span)
                    buf.append("<span class=\"tab\">");
                buf.append("<a href=\"peers").append(links[i]).append("\">").append(_t(titles[i])).append("</a>");
            }
            if (span)
                buf.append("</span>\n");
            else if (i != titles.length - 1)
                buf.append("&nbsp;&nbsp;\n");
        }
        if (!span)
            buf.append("</center>");
        buf.append("</div>");
        out.write(buf.toString());
    }

    /**
     *  @since 0.9.31 moved from TransportManager
     */
    private final String getTransportsLegend() {
        StringBuilder buf = new StringBuilder(1024);
        buf.append("<p class=\"infohelp\">")
           .append(_t("Your transport connection limits are automatically set based on your configured bandwidth."))
           .append('\n')
           .append(_t("To override these limits, add the settings i2np.ntcp.maxConnections=nnn and i2np.udp.maxConnections=nnn on the advanced configuration page."))
           .append("</p>\n");
        buf.append("<h3 class=\"tabletitle\">").append(_t("Definitions")).append("</h3>")
           .append("<table id=\"peerdefs\">\n")
           .append("<tr><td><b id=\"def.peer\">").append(_t("Peer")).append("</b></td><td>").append(_t("The remote peer, identified by router hash")).append("</td></tr>\n")
           .append("<tr><td><b id=\"def.dir\">").append(_t("Dir")).append("</b></td><td><span class=\"peer_arrow\"><img alt=\"Inbound\" src=\"/themes/console/images/inbound.png\"></span> ").append(_t("Inbound connection")).append("<br>\n")
           .append("<span class=\"peer_arrow\"><img alt=\"Outbound\" src=\"/themes/console/images/outbound.png\"></span> ").append(_t("Outbound connection")).append("<br>\n")
           .append("<span class=\"peer_arrow\"><img src=\"/themes/console/images/inbound.png\" alt=\"V\" height=\"8\" width=\"12\"></span> ").append(_t("They offered to introduce us (help other peers traverse our firewall)")).append("<br>\n")
           .append("<span class=\"peer_arrow\"><img src=\"/themes/console/images/outbound.png\" alt=\"^\" height=\"8\" width=\"12\"></span> ").append(_t("We offered to introduce them (help other peers traverse their firewall)")).append("</td></tr>\n")
           .append("<tr><td><b id=\"def.idle\">").append(_t("Idle")).append("</b></td><td>").append(_t("How long since a packet has been received / sent")).append("</td></tr>\n")
           .append("<tr><td><b id=\"def.rate\">").append(_t("In/Out")).append("</b></td><td>").append(_t("The smoothed inbound / outbound transfer rate (KBytes per second)")).append("</td></tr>\n")
           .append("<tr><td><b id=\"def.up\">").append(_t("Up")).append("</b></td><td>").append(_t("How long ago this connection was established")).append("</td></tr>\n")
           .append("<tr><td><b id=\"def.skew\">").append(_t("Skew")).append("</b></td><td>").append(_t("The difference between the peer's clock and your own")).append("</td></tr>\n");
        if (isAdvanced()) {
           buf.append("<tr><td><b id=\"def.cwnd\">CWND</b></td><td>").append(_t("The congestion window, which is how many bytes can be sent without an acknowledgment")).append(" /<br>\n")
           .append(_t("The number of sent messages awaiting acknowledgment")).append(" /<br>\n")
           .append(_t("The maximum number of concurrent messages to send")).append(" /<br>\n")
           .append(_t("The number of pending sends which exceed congestion window")).append("</td></tr>\n")
           .append("<tr><td><b id=\"def.ssthresh\">SST</b></td><td>").append(_t("The slow start threshold")).append("</td></tr>\n")
           .append("<tr><td><b id=\"def.rtt\">RTT</b></td><td>").append(_t("The round trip time in milliseconds")).append("</td></tr>\n")
           //.append("<tr><td><b id=\"def.dev\">").append(_t("Dev")).append("</b></td><td>").append(_t("The standard deviation of the round trip time in milliseconds")).append("</td></tr>\n")
           .append("<tr><td><b id=\"def.rto\">RTO</b></td><td>").append(_t("The retransmit timeout in milliseconds")).append("</td></tr>\n")
           .append("<tr><td><b id=\"def.mtu\">MTU</b></td><td>").append(_t("Maximum receive / send packet size (bytes)")).append("</td></tr>\n");
        }
        buf.append("<tr><td><b id=\"def.recv\">").append(_t("RX")).append("</b></td><td>").append(_t("The total number of messages received from the peer")).append("</td></tr>\n")
           .append("<tr><td><b id=\"def.send\">").append(_t("TX")).append("</b></td><td>").append(_t("The total number of messages sent to the peer")).append("</td></tr>\n")
           .append("<tr><td><b id=\"def.dupRecv\">").append(_t("Dup RX")).append("</b></td><td>").append(_t("The total number of duplicate packets received from the peer")).append("</td></tr>\n")
           .append("<tr><td><b id=\"def.resent\">").append(_t("Dup TX")).append("</b></td><td>").append(_t("The total number of packets retransmitted to the peer")).append("</td></tr>\n")
           .append("</table>");
        return buf.toString();
    }

    /// begin NTCP

    /**
     *  @since 0.9.31 moved from NTCPTransport
     */
    private void render(NTCPTransport nt, Writer out, String urlBase, int sortFlags) throws IOException {
        TreeSet<NTCPConnection> peers = new TreeSet<NTCPConnection>(getNTCPComparator(sortFlags));
        peers.addAll(nt.getPeers());

        long offsetTotal = 0;
        float bpsSend = 0;
        float bpsRecv = 0;
        long totalUptime = 0;
        long totalSend = 0;
        long totalRecv = 0;

        if (!isAdvanced()) {
            for (Iterator<NTCPConnection> iter = peers.iterator(); iter.hasNext(); ) {
                 // outbound conns get put in the map before they are established
                 if (!iter.next().isEstablished())
                     iter.remove();
            }
        }

        StringBuilder buf = new StringBuilder(1024);
        buf.append("<h3 id=\"ntcpcon\">").append(_t("NTCP connections")).append(": ").append(peers.size());
        buf.append(". ").append(_t("Limit")).append(": ").append(nt.getMaxConnections());
        //buf.append(". ").append(_t("Timeout")).append(": ").append(DataHelper.formatDuration2(_pumper.getIdleTimeout()));
        if (isAdvanced()) {
            buf.append(". ").append(_t("Status")).append(": ").append(nt.getReachabilityStatus().toLocalizedStatusString(_context));
        }
        buf.append(".</h3>\n" +
                   "<div class=\"widescroll\"><table id=\"ntcpconnections\">\n" +
                   "<tr><th><a href=\"#def.peer\">").append(_t("Peer")).append("</a></th>" +
                   "<th><a href=\"#def.dir\" title=\"").append(_t("Direction/Introduction"))
                   .append("\">").append(_t("Dir")).append("</a></th>" +
                   "<th>").append(_t("IPv6")).append("</th>" +
                   "<th>").append(_t("Version")).append("</th>" +
                   "<th><a href=\"#def.idle\">").append(_t("Idle")).append("</a></th>" +
                   "<th><a href=\"#def.rate\">").append(_t("In/Out")).append("</a></th>" +
                   "<th align=\"right\"><a href=\"#def.up\">").append(_t("Up")).append("</a></th>" +
                   "<th align=\"right\"><a href=\"#def.skew\">").append(_t("Skew")).append("</a></th>" +
                   "<th align=\"right\"><a href=\"#def.recv\">").append(_t("RX")).append("</a></th>" +
                   "<th align=\"right\"><a href=\"#def.send\">").append(_t("TX")).append("</a></th>" +
                   "<th>").append(_t("Out Queue")).append("</th>" +
                   "<th title=\"").append(_t("Is peer backlogged?")).append("\">").append(_t("Backlogged?")).append("</th>" +
                   //"<th>").append(_t("Reading?")).append("</th>" +
                   " </tr>\n");
        out.write(buf.toString());
        buf.setLength(0);
        long now = _context.clock().now();
        for (NTCPConnection con : peers) {
            buf.append("<tr><td class=\"cells\" align=\"left\" nowrap>");
            buf.append(_context.commSystem().renderPeerHTML(con.getRemotePeer().calculateHash()));
            //byte[] ip = getIP(con.getRemotePeer().calculateHash());
            //if (ip != null)
            //    buf.append(' ').append(_context.blocklist().toStr(ip));
            buf.append("</td><td class=\"cells\" align=\"center\">");
            if (con.isInbound()) {
                buf.append("<img src=\"/themes/console/images/inbound.png\" alt=\"Inbound\" title=\"").append(_t("Inbound"));
                if (isAdvanced())
                    buf.append(' ').append(Addresses.toString(con.getRemoteIP(), con.getChannel().socket().getPort()));
            } else {
                buf.append("<img src=\"/themes/console/images/outbound.png\" alt=\"Outbound\" title=\"").append(_t("Outbound"));
                if (isAdvanced())
                    buf.append(' ').append(Addresses.toString(con.getRemoteIP(), con.getRemoteAddress().getPort()));
            }
            buf.append("\"/>" +
                       "</td><td class=\"cells peeripv6\" align=\"center\">");
            if (con.isIPv6())
                buf.append("<span class=\"backlogged\">&#x2713;</span>");
            else
                buf.append("");
            buf.append("</td><td class=\"cells peeripv6\" align=\"center\">").append(con.getVersion());
            buf.append("</td><td class=\"cells\" align=\"center\"><span class=\"right\">");
            buf.append(DataHelper.formatDuration2(con.getTimeSinceReceive(now)));
            buf.append("</span>").append(THINSP).append("<span class=\"left\">").append(DataHelper.formatDuration2(con.getTimeSinceSend(now)));
            buf.append("</span></td><td class=\"cells\" align=\"center\"><span class=\"right\">");
            if (con.getTimeSinceReceive(now) < 2*60*1000) {
                float r = con.getRecvRate();
                buf.append(formatRate(r / 1000));
                bpsRecv += r;
            } else {
                buf.append(formatRate(0));
            }
            buf.append("</span>").append(THINSP).append("<span class=\"left\">");
            if (con.getTimeSinceSend(now) < 2*60*1000) {
                float r = con.getSendRate();
                buf.append(formatRate(r / 1000));
                bpsSend += r;
            } else {
                buf.append(formatRate(0));
            }
            //buf.append(" K/s");
            buf.append("</span></td><td class=\"cells\" align=\"right\">").append(DataHelper.formatDuration2(con.getUptime()));
            totalUptime += con.getUptime();
            offsetTotal = offsetTotal + con.getClockSkew();
            buf.append("</td><td class=\"cells\" align=\"right\">").append(DataHelper.formatDuration2(1000 * con.getClockSkew()));
            buf.append("</td><td class=\"cells\" align=\"right\">").append(con.getMessagesReceived());
            totalRecv += con.getMessagesReceived();
            buf.append("</td><td class=\"cells\" align=\"right\">").append(con.getMessagesSent());
            totalSend += con.getMessagesSent();
            long outQueue = con.getOutboundQueueSize();
            buf.append("</td><td class=\"cells\" align=\"center\">").append(outQueue);
            buf.append("</td><td class=\"cells\" align=\"center\">");
            if (con.isBacklogged())
                buf.append("<span class=\"backlogged\">&#x2713;</span>");
            else
                buf.append("&nbsp;");
            //long readTime = con.getReadTime();
            //if (readTime <= 0) {
            //    buf.append("</td> <td class=\"cells\" align=\"center\">0");
            //} else {
            //    buf.append("</td> <td class=\"cells\" align=\"center\">").append(DataHelper.formatDuration(readTime));
            //}
            buf.append("</td></tr>\n");
            out.write(buf.toString());
            buf.setLength(0);
        }

        if (!peers.isEmpty()) {
//            buf.append("<tr> <td colspan=\"11\"><hr></td></tr>\n");
            buf.append("<tr class=\"tablefooter\"><td colspan=\"5\" align=\"left\"><b>")
               .append(ngettext("{0} peer", "{0} peers", peers.size()));
            buf.append("</b></td><td align=\"center\" nowrap><span class=\"right\"><b>").append(formatRate(bpsRecv/1000)).append("</b></span>");
            buf.append(THINSP).append("<span class=\"left\"><b>").append(formatRate(bpsSend/1000)).append("</b></span>");
            buf.append("</td><td align=\"right\"><b>").append(DataHelper.formatDuration2(totalUptime/peers.size()));
            buf.append("</b></td><td align=\"right\"><b>").append(DataHelper.formatDuration2(offsetTotal*1000/peers.size()));
            buf.append("</b></td><td align=\"right\"><b>").append(totalRecv).append("</b></td><td align=\"right\"><b>").append(totalSend);
            buf.append("</b></td><td>&nbsp;</td><td>&nbsp;</td></tr>\n");
        }

        buf.append("</table></div>\n");
        out.write(buf.toString());
        buf.setLength(0);
    }

    private static final NumberFormat _rateFmt = new DecimalFormat("#,##0.00");
    static {
        _rateFmt.setRoundingMode(RoundingMode.HALF_UP);
    }

    private static String formatRate(float rate) {
        if (rate < 0.005f)
            return "0";
        synchronized (_rateFmt) { return _rateFmt.format(rate); }
    }

    private Comparator<NTCPConnection> getNTCPComparator(int sortFlags) {
        Comparator<NTCPConnection> rv = null;
        switch (Math.abs(sortFlags)) {
            default:
                rv = AlphaComparator.instance();
        }
        if (sortFlags < 0)
            rv = Collections.reverseOrder(rv);
        return rv;
    }

    private static class AlphaComparator extends PeerComparator {
        private static final AlphaComparator _instance = new AlphaComparator();
        public static final AlphaComparator instance() { return _instance; }
    }

    private static class PeerComparator implements Comparator<NTCPConnection>, Serializable {
        public int compare(NTCPConnection l, NTCPConnection r) {
            if (l == null || r == null)
                throw new IllegalArgumentException();
            return HashComparator.comp(l.getRemotePeer().calculateHash(), r.getRemotePeer().calculateHash());
        }
    }

    /// end NTCP
    /// begin SSU

    /**
     *  @since 0.9.31 moved from UDPTransport
     */
    private void render(UDPTransport ut, Writer out, String urlBase, int sortFlags) throws IOException {
        TreeSet<PeerState> peers = new TreeSet<PeerState>(getComparator(sortFlags));
        peers.addAll(ut.getPeers());
        long offsetTotal = 0;

        int bpsIn = 0;
        int bpsOut = 0;
        long uptimeMsTotal = 0;
        long cwinTotal = 0;
        long rttTotal = 0;
        long rtoTotal = 0;
        long sendTotal = 0;
        long recvTotal = 0;
        long resentTotal = 0;
        long dupRecvTotal = 0;
        int numPeers = 0;
        int numRTTPeers = 0;

        StringBuilder buf = new StringBuilder(4096);
        buf.append("<h3 id=\"udpcon\">").append(_t("UDP connections")).append(": ").append(peers.size());
        buf.append(". ").append(_t("Limit")).append(": ").append(ut.getMaxConnections());
        //buf.append(". ").append(_t("Timeout")).append(": ").append(DataHelper.formatDuration2(_expireTimeout));
        final boolean isAdvanced = isAdvanced();
        if (isAdvanced) {
            buf.append(". ").append(_t("Status")).append(": ").append(ut.getReachabilityStatus().toLocalizedStatusString(_context));
        }
        buf.append(".</h3>\n");
        buf.append("<div class=\"widescroll\"><table id=\"udpconnections\">\n");
        buf.append("<tr class=\"smallhead\"><th nowrap><a href=\"#def.peer\">").append(_t("Peer")).append("</a><br>");
        if (sortFlags != FLAG_ALPHA)
            appendSortLinks(buf, urlBase, sortFlags, _t("Sort by peer hash"), FLAG_ALPHA);
        buf.append("</th><th nowrap><a href=\"#def.dir\" title=\"")
           .append(_t("Direction/Introduction")).append("\">").append(_t("Dir"))
           .append("</a></th><th nowrap>").append(_t("IPv6"))
           .append("</th><th nowrap>").append(_t("Version"))
           .append("</th><th nowrap><a href=\"#def.idle\">").append(_t("Idle")).append("</a><br>");
        appendSortLinks(buf, urlBase, sortFlags, _t("Sort by idle inbound"), FLAG_IDLE_IN);
        buf.append(" / ");
        appendSortLinks(buf, urlBase, sortFlags, _t("Sort by idle outbound"), FLAG_IDLE_OUT);
        buf.append("</th>");
        buf.append("<th nowrap><a href=\"#def.rate\">").append(_t("In/Out")).append("</a><br>");
        appendSortLinks(buf, urlBase, sortFlags, _t("Sort by inbound rate"), FLAG_RATE_IN);
        buf.append(" / ");
        appendSortLinks(buf, urlBase, sortFlags, _t("Sort by outbound rate"), FLAG_RATE_OUT);
        buf.append("</th>\n");
        buf.append("<th nowrap><span class=\"peersort\"><a href=\"#def.up\">").append(_t("Up")).append("</a><br>");
        appendSortLinks(buf, urlBase, sortFlags, _t("Sort by connection uptime"), FLAG_UPTIME);
        buf.append("</span></th><th nowrap><span class=\"peersort\"><a href=\"#def.skew\">").append(_t("Skew")).append("</a><br>");
        appendSortLinks(buf, urlBase, sortFlags, _t("Sort by clock skew"), FLAG_SKEW);
        buf.append("</span></th>\n");
        if (isAdvanced) {
            buf.append("<th nowrap><a href=\"#def.cwnd\">CWND</a><br>");
            appendSortLinks(buf, urlBase, sortFlags, _t("Sort by congestion window"), FLAG_CWND);
            buf.append("</th><th nowrap><span class=\"peersort\"><a href=\"#def.ssthresh\">SST</a><br>");
            appendSortLinks(buf, urlBase, sortFlags, _t("Sort by slow start threshold"), FLAG_SSTHRESH);
            buf.append("</span></th>\n");
            buf.append("<th nowrap><span class=\"peersort\"><a href=\"#def.rtt\">RTT</a><br>");
            appendSortLinks(buf, urlBase, sortFlags, _t("Sort by round trip time"), FLAG_RTT);
            //buf.append("</th><th nowrap><a href=\"#def.dev\">").append(_t("Dev")).append("</a><br>");
            //appendSortLinks(buf, urlBase, sortFlags, _t("Sort by round trip time deviation"), FLAG_DEV);
            buf.append("</span></th><th nowrap><span class=\"peersort\"><a href=\"#def.rto\">RTO</a><br>");
            appendSortLinks(buf, urlBase, sortFlags, _t("Sort by retransmission timeout"), FLAG_RTO);
            buf.append("</span></th>\n");
            buf.append("<th nowrap><a href=\"#def.mtu\">MTU</a><br>");
            appendSortLinks(buf, urlBase, sortFlags, _t("Sort by outbound maximum transmit unit"), FLAG_MTU);
            buf.append("</th>");
        }
        buf.append("</span></th><th nowrap><span class=\"peersort\"><a href=\"#def.recv\">").append(_t("RX")).append("</a><br>");
        appendSortLinks(buf, urlBase, sortFlags, _t("Sort by packets received"), FLAG_RECV);
        buf.append("<th nowrap><span class=\"peersort\"><a href=\"#def.send\">").append(_t("TX")).append("</a><br>");
        appendSortLinks(buf, urlBase, sortFlags, _t("Sort by packets sent"), FLAG_SEND);
        buf.append("</span></th>\n");
        buf.append("</span></th><th nowrap><span class=\"peersort\"><a href=\"#def.dupRecv\">").append(_t("Dup RX")).append("</a><br>");
        appendSortLinks(buf, urlBase, sortFlags, _t("Sort by packets received more than once"), FLAG_DUP);
        buf.append("<th nowrap><span class=\"peersort\"><a href=\"#def.resent\">").append(_t("Dup TX")).append("</a><br>");
        appendSortLinks(buf, urlBase, sortFlags, _t("Sort by packets retransmitted"), FLAG_RESEND);
        buf.append("</span></th></tr>\n");
        out.write(buf.toString());
        buf.setLength(0);
        long now = _context.clock().now();
        for (PeerState peer : peers) {
            if (now-peer.getLastReceiveTime() > 60*60*1000)
                continue; // don't include old peers

            buf.append("<tr><td class=\"cells\" align=\"left\" nowrap>");
            buf.append(_context.commSystem().renderPeerHTML(peer.getRemotePeer()));
            //byte ip[] = peer.getRemoteIP();
            //if (ip != null)
            //    buf.append(' ').append(_context.blocklist().toStr(ip));
            buf.append("</td><td class=\"cells\" nowrap align=\"left\">");
            if (peer.isInbound()) {
                buf.append("<img src=\"/themes/console/images/inbound.png\" alt=\"Inbound\" title=\"").append(_t("Inbound"));
                if (isAdvanced())
                    buf.append(' ').append(Addresses.toString(peer.getRemoteIP(), peer.getRemotePort()));
            } else {
                buf.append("<img src=\"/themes/console/images/outbound.png\" alt=\"Outbound\" title=\"").append(_t("Outbound"));
                if (isAdvanced())
                    buf.append(' ').append(Addresses.toString(peer.getRemoteIP(), peer.getRemotePort()));
            }
            buf.append("\"/>");
            if (peer.getWeRelayToThemAs() > 0)
                buf.append("&nbsp;&nbsp;<img src=\"/themes/console/images/outbound.png\" height=\"8\" width=\"12\" alt=\"^\" title=\"").append(_t("We offered to introduce them")).append("\">");
            if (peer.getTheyRelayToUsAs() > 0)
                buf.append("&nbsp;&nbsp;<img src=\"/themes/console/images/inbound.png\" height=\"8\" width=\"12\" alt=\"V\" title=\"").append(_t("They offered to introduce us")).append("\">");

            if (isAdvanced) {
                boolean appended = false;
                //if (_activeThrottle.isChoked(peer.getRemotePeer())) {
                //    buf.append("<br><i>").append(_t("Choked")).append("</i>");
                //    appended = true;
                //}
                int cfs = peer.getConsecutiveFailedSends();
                if (cfs > 0) {
                    if (!appended) buf.append("<br>");
                    buf.append(" <i>");
                    buf.append(ngettext("{0} fail", "{0} fails", cfs));
                    buf.append("</i>");
                    appended = true;
                }
                if (_context.banlist().isBanlisted(peer.getRemotePeer(), "SSU")) {
                    if (!appended) buf.append("<br>");
                    buf.append(" <i>").append(_t("Banned")).append("</i>");
                }
                //byte[] ip = getIP(peer.getRemotePeer());
                //if (ip != null)
                //    buf.append(' ').append(_context.blocklist().toStr(ip));
            }
            buf.append("</td>");

            buf.append("<td class=\"cells peeripv6\" align=\"center\">");
            if (peer.isIPv6())
                buf.append("&#x2713;");
            else
                buf.append("");
            buf.append("</td>");

            buf.append("<td class=\"cells peeripv6\" align=\"center\">");
            buf.append(peer.getVersion());
            buf.append("</td>");

            long idleIn = Math.max(now-peer.getLastReceiveTime(), 0);
            long idleOut = Math.max(now-peer.getLastSendTime(), 0);

            buf.append("<td class=\"cells\" align=\"center\"><span class=\"right\">");
            buf.append(DataHelper.formatDuration2(idleIn));
            buf.append("</span>").append(THINSP);
            buf.append("<span class=\"left\">").append(DataHelper.formatDuration2(idleOut));
            buf.append("</span></td>");
 
            int recvBps = peer.getReceiveBps(now);
            int sendBps = peer.getSendBps(now);

            buf.append("<td class=\"cells\" align=\"center\" nowrap><span class=\"right\">");
            buf.append(formatKBps(recvBps));
            buf.append("</span>").append(THINSP);
            buf.append("<span class=\"left\">").append(formatKBps(sendBps));
            //buf.append(" K/s");
            //buf.append(formatKBps(peer.getReceiveACKBps()));
            //buf.append("K/s/");
            //buf.append(formatKBps(peer.getSendACKBps()));
            //buf.append("K/s ");
            buf.append("</span></td>");

            long uptime = now - peer.getKeyEstablishedTime();

            buf.append("<td class=\"cells\" align=\"right\">");
            buf.append(DataHelper.formatDuration2(uptime));
            buf.append("</td>");

            buf.append("<td class=\"cells\" align=\"right\">");
            long skew = peer.getClockSkew();
            buf.append(DataHelper.formatDuration2(skew));
            buf.append("</td>");
            offsetTotal = offsetTotal + skew;

            int rtt = 0;
            int rto = 0;
            if (isAdvanced) {
                int sendWindow = peer.getSendWindowBytes();
                cwinTotal += sendWindow;
                buf.append("<td class=\"cells cwnd\" align=\"center\"><span class=\"right\">");
                buf.append(DataHelper.formatSize2(sendWindow));
                buf.append("B");
                buf.append("</span>").append(THINSP).append("<span class=\"right\">").append(peer.getConcurrentSends());
                buf.append("</span>").append(THINSP).append("<span class=\"right\">").append(peer.getConcurrentSendWindow());
                buf.append("</span>").append(THINSP).append("<span class=\"left\">").append(peer.getConsecutiveSendRejections());
                buf.append("</span>");
                if (peer.isBacklogged())
                    buf.append("<br><i>").append(_t("backlogged")).append("</i>");
                buf.append("</td>");

                buf.append("<td class=\"cells\" align=\"right\">");
                buf.append(DataHelper.formatSize2(peer.getSlowStartThreshold()));
                buf.append("B</td>");

                rtt = peer.getRTT();
                rto = peer.getRTO();

                buf.append("<td class=\"cells\" align=\"right\">");
                if (rtt > 0)
                    buf.append(DataHelper.formatDuration2(rtt));
                else
                    buf.append("n/a");
                buf.append("</td>");

                //buf.append("<td class=\"cells\" align=\"right\">");
                //buf.append(DataHelper.formatDuration2(peer.getRTTDeviation()));
                //buf.append("</td>");

                buf.append("<td class=\"cells\" align=\"right\">");
                buf.append(DataHelper.formatDuration2(rto));
                buf.append("</td>");

                buf.append("<td class=\"cells\" align=\"center\"><span class=\"right\">");
                buf.append(peer.getReceiveMTU()).append("</span>").append(THINSP);
                buf.append("<span class=\"left\">").append(peer.getMTU());

                buf.append("</span></td>");
            }

            long sent = peer.getMessagesSent();
            long recv = peer.getMessagesReceived();

            buf.append("<td class=\"cells\" align=\"right\">");
            buf.append(recv);
            buf.append("</td>");

            buf.append("<td class=\"cells\" align=\"right\">");
            buf.append(sent);
            buf.append("</td>");

            //double sent = (double)peer.getPacketsPeriodTransmitted();
            //double sendLostPct = 0;
            //if (sent > 0)
            //    sendLostPct = (double)peer.getPacketsRetransmitted()/(sent);

            long resent = peer.getPacketsRetransmitted();
            long dupRecv = peer.getPacketsReceivedDuplicate();

            buf.append("<td class=\"cells\" align=\"right\">");
            buf.append(dupRecv);
            buf.append("</td>" +

                       "<td class=\"cells\" align=\"right\">");
            buf.append(resent);
            buf.append("</td>" +

                       "</tr>\n");
            out.write(buf.toString());
            buf.setLength(0);

            bpsIn += recvBps;
            bpsOut += sendBps;

            uptimeMsTotal += uptime;
            if (rtt > 0) {
                rttTotal += rtt;
                numRTTPeers++;
            }
            rtoTotal += rto;

            sendTotal += sent;
            recvTotal += recv;
            resentTotal += resent;
            dupRecvTotal += dupRecv;

            numPeers++;
        }

      if (numPeers > 0) {
//        buf.append("<tr><td colspan=\"16\"><hr></td></tr>\n");
        buf.append("<tr class=\"tablefooter\"><td colspan=\"5\" align=\"left\"><b>")
           .append(ngettext("{0} peer", "{0} peers", peers.size()))
           .append("</b></td>" +
                   "<td align=\"center\" nowrap><span class=\"right\"><b>");
        buf.append(formatKBps(bpsIn)).append("</b></span>").append(THINSP);
        buf.append("<span class=\"left\"><b>").append(formatKBps(bpsOut));
        long x = uptimeMsTotal/numPeers;
        buf.append("</b></span></td>" +
                   "<td align=\"right\"><b>").append(DataHelper.formatDuration2(x));
        x = offsetTotal/numPeers;
        buf.append("</b></td><td align=\"right\"><b>").append(DataHelper.formatDuration2(x)).append("</b></td>\n");
        if (isAdvanced) {
            buf.append("<td align=\"center\"><b>");
            buf.append(cwinTotal/(numPeers*1024) + "K");
            buf.append("</b></td><td>&nbsp;</td>\n" +
                       "<td align=\"right\"><b>");
            if (numRTTPeers > 0)
                buf.append(DataHelper.formatDuration2(rttTotal/numRTTPeers));
            else
                buf.append("n/a");
            //buf.append("</b></td><td>&nbsp;</td><td align=\"center\"><b>");
            buf.append("</b></td><td align=\"right\"><b>");
            buf.append(DataHelper.formatDuration2(rtoTotal/numPeers));
            buf.append("</b></td><td></td>"); // MTU
        }
        buf.append("<td align=\"right\"><b>");
        buf.append(recvTotal).append("</b></td><td align=\"right\"><b>").append(sendTotal).append("</b></td>\n" +
                   "<td align=\"right\"><b>").append(dupRecvTotal);
        buf.append("</b></td><td align=\"right\"><b>").append(resentTotal).append("</b></td></tr>\n");
/****
        if (sortFlags == FLAG_DEBUG) {
            buf.append("<tr><td colspan=\"16\">");
            buf.append("peersByIdent: ").append(_peersByIdent.size());
            buf.append(" peersByRemoteHost: ").append(_peersByRemoteHost.size());
            int dir = 0;
            int indir = 0;
            for (RemoteHostId rhi : _peersByRemoteHost.keySet()) {
                 if (rhi.getIP() != null)
                     dir++;
                 else
                     indir++;
            }
            buf.append(" pBRH direct: ").append(dir).append(" indirect: ").append(indir);
            buf.append("</td></tr>");
        }
****/
     }  // numPeers > 0
        buf.append("</table></div>\n");

      /*****
        long bytesTransmitted = _context.bandwidthLimiter().getTotalAllocatedOutboundBytes();
        // NPE here early
        double averagePacketSize = _context.statManager().getRate("udp.sendPacketSize").getLifetimeAverageValue();
        // lifetime value, not just the retransmitted packets of current connections
        resentTotal = (long)_context.statManager().getRate("udp.packetsRetransmitted").getLifetimeEventCount();
        double nondupSent = ((double)bytesTransmitted - ((double)resentTotal)*averagePacketSize);
        double bwResent = (nondupSent <= 0 ? 0d : ((((double)resentTotal)*averagePacketSize) / nondupSent));
        buf.append("<h3>Percentage of bytes retransmitted (lifetime): ").append(formatPct(bwResent));
        buf.append("</h3><i>(Includes retransmission required by packet loss)</i>\n");
      *****/

        out.write(buf.toString());
        buf.setLength(0);
    }

    private static final DecimalFormat _fmt = new DecimalFormat("#,##0.00");
    static {
        _fmt.setRoundingMode(RoundingMode.HALF_UP);
    }

    private static final String formatKBps(int bps) {
        if (bps < 5)
            return "0";
        synchronized (_fmt) {
            return _fmt.format((float)bps/1000);
        }
    }
}
