content: /*
   *  Licensed to the Apache Software Foundation (ASF) under one
   *  or more contributor license agreements.  See the NOTICE file
   *  distributed with this work for additional information
   *  regarding copyright ownership.  The ASF licenses this file
   *  to you under the Apache License, Version 2.0 (the
   *  "License"); you may not use this file except in compliance
   *  with the License.  You may obtain a copy of the License at
   *
   *        http://www.apache.org/licenses/LICENSE-2.0
   *
   *  Unless required by applicable law or agreed to in writing,
   *  software distributed under the License is distributed on an
   *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   *  KIND, either express or implied.  See the License for the
   *  specific language governing permissions and limitations
   *  under the License.
   */
  package org.apache.causeway.applib.fa;
  
  import java.util.TreeSet;
  import java.util.stream.Collectors;
  
  import org.apache.causeway.commons.collections.Can;
  import org.apache.causeway.commons.internal.base._NullSafe;
  import org.apache.causeway.commons.internal.base._Strings;
  
  import lombok.experimental.UtilityClass;
  
  @UtilityClass
  class FontAwesomeQuickNotationParser {
  
      FontAwesomeLayers parse(final String quickNotation) {
          var iconEntryCssClasses = _Strings.splitThenStream(quickNotation, ",")
              .map(String::trim)
              .map(_Strings::emptyToNull)
              .collect(Can.toCan());
          if(iconEntryCssClasses.isEmpty()) {
              return FontAwesomeLayers.empty();
          }
          if(iconEntryCssClasses.isCardinalityOne()) {
              return FontAwesomeLayers
                  .singleIcon(processPrefixes(iconEntryCssClasses.getFirstElseFail(), "fa-fw"));
          }
          var stackBuilder = FontAwesomeLayers.stackBuilder()
              //.containerCssClasses("fa-fw") ... does not work here, using style instead ...
              .containerCssStyle("width:1.25em")
              ;
          iconEntryCssClasses.stream()
              .map(x->processPrefixes(x, "fa-stack-1x"))
              .forEach(stackBuilder::addIconEntry);
          return stackBuilder.build();
      }
  
      private String processPrefixes(final String cssQuickClasses, final String... mandatory) {
          var elements = _Strings.splitThenStream(cssQuickClasses, " ")
              .map(String::trim)
              .filter(_Strings::isNotEmpty)
              .collect(Collectors.toCollection(TreeSet::new));
          _NullSafe.stream(mandatory)
              .forEach(elements::add);
          return elements.stream()
                  .map(FontAwesomeQuickNotationParser::processPrefix)
                  .collect(Collectors.joining(" "));
      }
  
      private String processPrefix(final String cssQuickClass) {
          if(cssQuickClass.equals("fa")
                  || cssQuickClass.startsWith("fa-")) {
              return cssQuickClass;
          }
          if(cssQuickClass.startsWith(".")) {
              return cssQuickClass.substring(1);
          }
          return "fa-" + cssQuickClass;
      }
  
  }
  