sclass HMultiCRUD extends HAbstractRenderable {
  Concepts cc = db_mainConcepts();
  L<Class<? extends Concept>> classes;
  bool mutationRights, downloadRights = true;
  S mainTitle = "CRUD";
  
  *(S *baseLink, Class<? extends Concept>... classes) {
    this(classes);
  }
  
  *(Class<? extends Concept>... classes) {
    this.classes = asList(classes);
  }
  
  S renderNavi() {
    ret p(joinWithVBar(naviComponents()));
  }
  
  LS naviComponents() {
    LS l = map(classes, c -> ahref(baseLinkPlus(shortName(c)),
      appendBracketedCountUnlessZero(countConcepts(cc, c),
        shortName(c))));
    if (downloadRights) l.add(ahref(baseLinkPlus("download"), "download"));
    ret l;
  }

  O renderPage(S uri, SS params) {
    LS parts = tok_splitAtSlash_nempties(uri);
    S html = renderNavi() + renderMsgs(params);
    params = mapMinus(params, 'msg);
    Var<S> title = new(mainTitle);
    if (nempty(parts)) {
      if (eq(parts, ll("download"))) {
        if (!downloadRights) ret "No download rights";
        ret serveText(javaTokWordWrap(cc.xfullgrab()));
      }
      
      HCRUD crud = makeCRUD(first(parts));
      if (crud != null) {
        crud.mutationRights = mutationRights;
        crud.baseLink = baseLinkPlus(first(parts));
        crud.makeFrame = (title2, contents) -> {
          title.set(title! + " | " + title2);
          ret h3(title2) + contents;
        };
        html += crud.renderPage(params);
      }
    }
    //ret "parts: " + sfu(parts);
    ret frame(title!, html);
  }
  
  selfType mutationRights(bool mutationRights) {
    this.mutationRights = mutationRights;
    this;
  }
  
  // override me
  HCRUD makeCRUD(S className) {
    null;
  }
  
  selfType mainTitle(S mainTitle) {
    this.mainTitle = mainTitle;
    this;
  }
}