// Note: renderUIUrl etc are called in Swing thread

srecord noeq UIURLSystem(Enterable owner, SimpleLiveValue<S> uiURL) {
  // key:   ui URL
  transient Map<S, Entry> uiMap = syncCIMap();
  
  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;
  JComboBox comboBox;
  
  JComponent urlBar() {
    comboBox = autoComboBox(url(), cloneKeys(uiMap));
    centerComboBox(comboBox);
    comboBoxDynamicToolTip(comboBox, entry -> entry.toolTip);
    
    ret withLabel("Show",
      comboBoxAndButton(
        onSelectedItem(
          bindComboBoxToLiveValue(comboBox, uiURL),
          url -> showUIURL(url)
        ),
        "Go", url -> showUIURL(url)));
  }
  
  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);
    }
  }
  
  void showUIURL(S url) {
    temp tempEnter(owner);
    setURL(trim(url));
    go();
  }
  
  void go {
    setComponent(scp, renderUIUrl(url()));
  }
  
  S url() { ret uiURL!; }
  void setURL(S url) { uiURL.set(url); }
  
  selfType put(S url, S toolTip default null, IF0<? extends JComponent> maker) {
    uiMap.put(url, new Entry(url, toolTip, maker));
    this;
  }
}