// Note: renderUIUrl etc are called in Swing thread

// TODO: improve AutoComboBox and put it back in

persistable srecord noeq UIURLSystem(transient Enterable owner, transient SimpleLiveValue<S> uiURL) extends MetaWithChangeListeners {

  settable bool showHomeButton = true;

  settable int maxHistoryEntries = 100;

  settable bool showGoButton;

  // key:   ui URL

  transient Map<S, Entry> uiMap = syncCIMap();

  // these are additionally displayed at the top of the list

  // first URL will be shown as "Home" button (if home button is enabled)

  LS preferredURLs = syncList();

  LS history = syncLinkedList();

  LS forwardHistory = syncLinkedList();

  sclass Entry {

    S url;

    S toolTip;

    IF0<? extends JComponent> makeComponent;

    *(S *url, IF0<? extends JComponent> *makeComponent) {}

    *(S *url, S *toolTip, IF0<? extends JComponent> *makeComponent) {}

  }

  settable transient SingleComponentPanel scp;

  transient JComboBox<S> comboBox;

  transient JButton btnHome, btnBack, btnForward;

  transient simplyCached JComponent urlBar() {

    //comboBox = autoComboBox(url(), cloneKeys(uiMap));

    comboBox = jcombobox(urlsForComboBox());

    //centerComboBox(comboBox);

    comboBox.setRenderer(

      new CenteredComboBoxRenderer(

        new ListCellRendererWithToolTip<S>(url -> toolTipForURL(url),

          (ListCellRenderer<S>) comboBox.getRenderer())));

    //comboBoxDynamicToolTip(comboBox, url -> toolTipForURL(url));

    onSelectedItem(

      bindComboBoxToLiveValue(comboBox, uiURL),

      url -> showUIURL(url)

    );

    Runnable cbAction = comboBoxAction(comboBox, url -> showUIURL(url));

    JPanel rightButtons = jlineWithSpacing(5, );

    JPanel leftButtons = jlineWithSpacing(5);

    if (showGoButton)

      rightButtons.add(jbutton("Go", cbAction));

    JComponent panel = withLabel("Show",

      centerAndEastWithMargin(

        comboBox,

        rightButtons));

    btnBack = jimageButtonScaledToWidth(16, #1103102, l0 goBack);

    add(rightButtons, btnBack);

    btnForward = jimageButtonScaledToWidth(16, #1103103, l0 goForward);

    add(rightButtons, btnForward);

    if (showHomeButton) {

      S homeURL = homeURL();

      btnHome = jimageButtonScaledToWidth(16, #1103101,

        homeURL != null ? "Go to " + homeURL : "Go to home URL",

        l0 goHome);

      add(rightButtons, btnHome);

    }

    uiURL.onChangeAndNow(l0 updateButtons);

    if (!emptyContainer(leftButtons))

      panel = westAndCenterWithMargin(leftButtons, panel);

    ret panel;

  }

  void updateButtons {

    swing {

      S homeURL = homeURL();

      setEnabled(btnHome, homeURL != null && !eq(homeURL, url()));

      S backURL = last(history);

      setEnabled(btnBack, backURL != null);

      setToolTip(btnBack, backURL == null ? "Go back" : "Go back to " + backURL);

      S forwardURL = first(forwardHistory);

      printVars("updateButtons", +forwardURL);

      setEnabled(btnForward, forwardURL != null);

      setToolTip(btnForward, forwardURL == null ? "Go forward" : "Go forward to " + forwardURL);

    }

    change();

  }

  JComponent renderUIUrl aka renderUIURL aka uiGet(S url) {

    try {

      temp tempEnter(owner);

      var entry = uiMap.get(url);

      if (entry == null) ret jCenteredLabel("URL not found: " + url);

      var component = entry.makeComponent!;

      ret component;

    } catch print e {

      ret jErrorView(e);

    }

  }

  bool hasURL(S url) { ret uiMap.containsKey(url); }

  void showUIURL(S url) swing {

    if (!eqic(url(), url)) {

      addToHistory(url());

      showUIURL_dontAddToHistory(url);

    }

  }

  void addToHistory(S url) {

    printVars("addToHistory", +url);

    if (empty(url) || eqic(last(history), url)) ret;

    removeAllIC_useIterator(history, url);

    history.add(url);

    if (l(history) > maxHistoryEntries) removeFirst(history);

    forwardHistory.clear();

    updateButtons();

  }

  void showUIURL_dontAddToHistory(S url) {

    temp tempEnter(owner);

    setURL(trim(url));

    go();

  }

  void go {

    setComponent(scp, renderUIUrl(url()));

  }

  S url() { ret uiURL!; }

  void setURL(S url) {

    assertURLValid(url);

    uiURL.set(url);

  }

  swappable void assertURLValid(S url) {

    if (!uiMap.containsKey(url))

      fail("UIURL not found: " + url);

  }

  selfType put(WithToolTip<S> url, IF0<? extends JComponent> maker) {

    ret put(url!, url.toolTip(), maker);

  }

  selfType put(S url, S toolTip default null, IF0<? extends JComponent> maker) {

    uiMap.put(url, new Entry(url, toolTip, maker));

    setComboBoxItems(comboBox, urlsForComboBox());

    this;

  }

  S toolTipForURL(S url) {

    var e = uiMap.get(url);

    ret e?.toolTip;

  }

  LS urlsForComboBox() {

    var sorted = cloneKeys(uiMap);

    ret concatLists(listSetIntersection(preferredURLs, sorted), sorted);

  }

  void addPreferredUIURL(S uiURL) {

    addIfNotContained(preferredURLs, uiURL);

  }

  S homeURL() { ret first(preferredURLs); }

  void goHome { showUIURL(homeURL()); }

  void goBack swing {

    S url = popLast(history);

    if (url != null) {

      S currentURL = url();

      if (nempty(currentURL))

        forwardHistory.add(0, currentURL);

      printVars("goBack", +url, +currentURL, +forwardHistory);

      updateButtons();

      showUIURL_dontAddToHistory(url);

    }

  }

  void goForward swing {

    S url = popFirst(forwardHistory);

    if (url != null) {

      S currentURL = url();

      if (nempty(currentURL))

        history.add(currentURL);

      printVars("goForward", +url, +currentURL, +history);

      updateButtons();

      showUIURL_dontAddToHistory(url);

    }

  }

}