class WorkerChat {
  int workerLongPollTick = 200;
  int workerLongPollMaxWait = 1000*30;
  long lastWorkerRequested; // timestamp for notification sound
  S mainAdminLink = "/";

  O html(DynNewBot2.Req req) null {
    SS params = req.params;
    S uri = req.uri, uri2 = appendSlash(uri);
    bool requestAuthed = req.auth != null;
    Conversation conv = req.conv;
  
    if (startsWith(uri2, "/worker/")) {
      if (!req.webRequest.isHttps())
        ret subBot_serveRedirect("https://" + req.webRequest.domain() + req.uri + htmlQuery(req.params));
  
      if (!requestAuthed) ret serveAuthForm(params.get('uri));
      
      if (nempty(params.get("turnBotOn")))
        conv.turnBotOn();
      
      ret serveWorkerPage(req);
    }
  }
  
  // auth is tested before we get here
  S serveWorkerPage(DynNewBot2.Req req) {
    AuthedDialogID auth = req.auth;
    Conversation conv = req.conv;
    S uri = req.uri;
    SS params = req.params;
    S cookie = conv.cookie;
    S uri2 = afterLastSlash(uri);

    if (eq(uri2, "availableWorkers"))
      ret "Available workers: " + or2(joinWithComma(map(workersAvailable(), w -> w.renderAsHTML())), "-");
    
    if (nempty(params.get('workerLogOut)))
      cset(auth, loggedIn := null);
      
    if (auth.loggedIn != null && nempty(params.get('workerAvailableBox)))
      if (cset_trueIfChanged(auth.loggedIn, available := nempty(params.get('workerAvailable))))
        noteConversationChange(); // update list of available workers

    if (nempty(params.get("acceptConversation"))) {
      if (conv.worker == null) { // only if not accepted by anyone
        cset(conv, worker := auth.loggedIn);
        conv.turnBotOff();
      }
    }
      
    S loginID = params.get('workerLogIn);
    if (nempty(loginID))
      cset(auth, loggedIn := getConcept Worker(parseLong(loginID)));
  
    Map map = prependEmptyOptionForHSelect(mapToOrderedMap(conceptsSortedByFieldCI(Worker, 'loginName),
      w -> pair(w.id, w.loginName)));
    if (auth.loggedIn == null)
      ret hsansserif() + p("You are not logged in as a worker")
        + hpostform(
          "Log in as: " + hselect("workerLogIn", map, conceptID(auth.loggedIn)) + " " + hsubmit("OK"), action := botMod().baseLink + "/worker");
          
    // We are logged in
    
    if (eq(uri2, "conversation")) {
      if (conv == null) ret "Conversation not found";
      // Serve the checkbox & the JavaScript
      S onOffURL = botMod().baseLink + "/worker/botOnOff" + hquery(+cookie) + "&on=";
      ret
         hsansserif() + loadJQuery()
       + hhidden(+cookie) // for other frame
       + hpostform(
         hhidden(+cookie) +
         p(renderBotStatus(conv))
          + p(conv.botOn
            ? hsubmit("Accept conversation", name := "acceptConversation")
            : hsubmit("Turn bot back on", name := "turnBotOn"))
          , action := botMod().baseLink + "/worker/innerFrameSet", target := "innerFrameSet")

       // include bot
       + hscriptsrc(botMod().baseLink + "/script" + hquery(workerMode := 1, cookie := conv.cookie));
    }
    
    if (eq(uri2, "conversations")) {
      cset(auth.loggedIn, lastOnline := now());
      bool poll = eq("1", params.get("poll")); // poll mode?
      S content = "";
      
      if (poll) {
        long seenChange = parseLong(params.get("lastChange"));
        vmBus_send chatBot_startingWorkerPoll(mc(), conv);
      
        long start = sysNow();
        L msgs;
        bool first = true;
        while (licensed() && sysNow() < start+workerLongPollMaxWait
          && lastConversationChange == seenChange)
          sleep(workerLongPollTick);
          
        printVars_str(+lastWorkerRequested, +seenChange);
        if (lastWorkerRequested > seenChange)
          content = hscript([[
            window.parent.parent.frames[0].sendDesktopNotification("A worker is requested!", { action: function() { window.focus(); } });
            window.parent.parent.frames[0].playWorkerRequestedSound();
          ]]);
          
        // if poll times out, send update anyway to update time calculations
      }
  
      long pingThreshold = now()-activeConversationTimeout();
      L<Conversation> convos = sortByCalculatedFieldDesc(c -> c.lastMsgTime(),
        conceptsWithFieldGreaterThan Conversation(lastPing := pingThreshold));
        
      content +=
          hhiddenWithID(+lastConversationChange) + tag table(
          hsimpletableheader("IP", "Country", "Bot/worker status", "Last change", "Last messages")
          + mapToLines(convos, c -> {
            L<Msg> lastMsgs = lastTwo(c.msgs);
            S style = c == conv ? "background: #90EE90" : null;
            S convLink = botMod().baseLink + "/worker/innerFrameSet" + hquery(cookie := c.cookie);
            ret tag tr(
              td(ahref(convLink, c.ip, target := "innerFrameSet")) +
              td(getCountry(c)) +
              td(renderBotStatus(c)) +
              td(renderHowLongAgo(c.lastMsgTime())) +
              td(ahref(convLink, hparagraphs(lambdaMap renderMsgForWorkerChat(lastMsgs)), target := "innerFrameSet", style := "text-decoration: none")), +style, /*class := "clickable-row", "data-href" := convLink*/);
          }), class := "responstable");
  
      if (poll) ret content;
  
      S incrementalURL = botMod().baseLink + "/worker/conversations?poll=1&lastChange=";
      
      ret hhtml(
          hhead(hsansserif() + loadJQuery()
        + hscript_clickableRows())
        + hbody(h3(botName)
        + hpostform(
            "Logged in as "
          + htmlEncode2(auth.loggedIn.loginName)
          + " (display name: " + htmlEncode2(auth.loggedIn.displayName) + ")"
          + hhidden(workerAvailableBox := 1)
          + " &nbsp; "
          + hcheckboxWithText("workerAvailable", "I am available", auth.loggedIn.available, onclick := "form.submit()")
          + " &nbsp; "
          + hsubmit("Log out", name := "workerLogOut"),
          target := "innerFrameSet", action := botMod().baseLink + "/worker/innerFrameSet")
        + p("Available workers: " + b(or2(joinWithComma(
          map(workersAvailable(), w -> w.displayName)), "none")))
        + h3("Active conversations")
        + hcss_responstable()
        + hdivWithID("contentArea", content)
        + hscript([[
          function poll_start() {
            var lastChange = $("#lastConversationChange").val();
            if (!lastChange)
              setTimeout(poll_start, 1000);
            else {
              var url = "#INCREMENTALURL#" + lastChange;
              console.log("Loading " + url);
              $.get(url, function(src) {
                if (src.match(/^ERROR/)) console.log(src);
                else {
                  console.log("Loaded " + src.length + " chars");
                  $("#contentArea").html(src);
                }
                setTimeout(poll_start, 1000);
              }, 'text')
                .fail(function() {
                  console.log("Rescheduling after fail");
                  setTimeout(poll_start, 1000);
                });
            }
          }
          poll_start();
        ]].replace("#INCREMENTALURL#", incrementalURL)
        ));
    } // end of worker/conversations part
    
    if (eq(uri2, "notificationArea"))
      ret hhtml(
          hhead(hsansserif() + loadJQuery())
        + hbody(hdesktopNotifications()
        + div(small(
            span(hbutton("CLICK HERE to enable notification sounds!"), id := "enableSoundsBtn")
          + " | "
          + span("", id := "notiStatus")), style := "float: right")
        + hscript([[
          function enableSounds() {
            document.removeEventListener('click', enableSounds);
            $("#enableSoundsBtn").html("Notification sounds enabled");
          }
          document.addEventListener('click', enableSounds);
          
          if (window.workerRequestedSound == null) {
            console.log("Loading worker requested sound");
            window.workerRequestedSound = new Audio("https://botcompany.de/files/1400404/worker-requested.mp3");
          }
          
          function playWorkerRequestedSound() {
            console.log("Playing worker requested sound");
            window.workerRequestedSound.play();
          }
          window.playWorkerRequestedSound = playWorkerRequestedSound;

        ]])));
    
    if (eq(uri2, "innerFrameSet"))
      // serve frame set 2
      ret hhtml(hhead_title("Worker Chat [" + auth.loggedIn.loginName + "]")
        + hframeset_cols("*,*", 
          tag frame("", name := "conversations", src := botMod().baseLink + "/worker/conversations" + hquery(+cookie)) +
          tag frame("", name := "conversation", src := conv == null ? null : botMod().baseLink + "/worker/conversation" + hquery(+cookie))));
          
    // serve frame set 1
    ret hhtml(hhead_title("Worker Chat [" + auth.loggedIn.loginName + "]")
      + hframeset_rows("50,*", 
        tag frame("", name := "notificationArea", src := botMod().baseLink + "/worker/notificationArea") +
        tag frame("", name := "innerFrameSet", src := conv == null ? null : botMod().baseLink + "/worker/innerFrameSet" + hquery(+cookie))));
        
  }
  
  S renderMsgForWorkerChat(Msg msg) {
    ret (msg.fromWorker != null ? htmlEncode2(msg.fromWorker.displayName) : msg.fromUser ? "User" : "Bot") + ": " + b(htmlEncode2If(shouldHtmlEncodeMsg(msg), msg.text));
  }
  
  Cl<Worker> workersAvailable() {
    long timestamp = now()-workerLongPollMaxWait-10000;
    ret filter(list(Worker), w -> w.available && w.lastOnline >= timestamp);
  }

  bool anyWorkersAvailable() {
    ret nempty(workersAvailable());
  }
  
  S renderBotStatus(Conversation conv) {
   ret "Bot is " + b(conv.botOn ? "on" : "off") + "<br>"
     + "Assigned worker: " + b(conv.worker == null ? "none" : conv.worker.displayName);
  }
}

Began life as a copy of #1028434