/*
    * 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.syncope.client.console.wicket.markup.html.form;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Iterator;
  import java.util.List;
  import org.apache.wicket.WicketRuntimeException;
  import org.apache.wicket.extensions.markup.html.form.palette.Palette;
  import org.apache.wicket.extensions.markup.html.form.palette.component.Recorder;
  import org.apache.wicket.markup.html.form.IChoiceRenderer;
  import org.apache.wicket.model.Model;
  import org.apache.wicket.util.string.Strings;
  
  /**
   * A variant of Recorder, supporting single element selection (for editing purpose, for example). <b>Note</b>: this
   * class extends Recorder&lt;T&gt; but in fact it is a bare copy of most source code; this was done because the original
   * class is keeping everything private.
   *
   * @param <T> Type of the palette
   */
  public class SelectableRecorder<T> extends Recorder<T> {
  
      private static final long serialVersionUID = -3009044376132921879L;
  
      private boolean attached = false;
  
      private static final String[] EMPTY_IDS = new String[0];
  
      /**
       * Conveniently maintained array of selected ids.
       */
      private String[] ids;
  
      private String selectedId;
  
      public SelectableRecorder(final String id, final Palette<T> palette) {
          super(id, palette);
      }
  
      @Override
      protected void onBeforeRender() {
          super.onBeforeRender();
  
          if (!getForm().hasError()) {
              initIds();
          } else if (ids == null) {
              ids = EMPTY_IDS;
          }
          attached = true;
      }
  
      /**
       * Synchronize ids collection from the palette's model
       */
      private void initIds() {
          // construct the model string based on selection collection
          IChoiceRenderer<? super T> renderer = getPalette().getChoiceRenderer();
          StringBuilder modelStringBuffer = new StringBuilder();
          Collection<T> modelCollection = getPalette().getModelCollection();
          if (modelCollection == null) {
              throw new WicketRuntimeException("Expected getPalette().getModelCollection() to return a non-null value."
                      + " Please make sure you have model object assigned to the palette");
          }
          Iterator<T> selection = modelCollection.iterator();
  
          int i = 0;
          while (selection.hasNext()) {
              modelStringBuffer.append(renderer.getIdValue(selection.next(), i++));
              if (selection.hasNext()) {
                  modelStringBuffer.append(',');
              }
          }
  
          // set model and update ids array
          String modelString = modelStringBuffer.toString();
          setDefaultModel(new Model<>(modelString));
          updateIds(modelString);
      }
  
      public T getSelectedItem() {
          if (selectedId == null) {
             return null;
         }
 
         IChoiceRenderer<? super T> renderer = getPalette().getChoiceRenderer();
 
         T selected = null;
         for (T choice : getPalette().getChoices()) {
             if (renderer.getIdValue(choice, 0).equals(selectedId)) {
                 selected = choice;
                 break;
             }
         }
 
         return selected;
     }
 
     @Override
     public List<T> getSelectedList() {
         IChoiceRenderer<? super T> renderer = getPalette().getChoiceRenderer();
         if (ids.length == 0) {
             return List.of();
         }
 
         List<T> selected = new ArrayList<>(ids.length);
         for (String id : ids) {
             for (T choice : getPalette().getChoices()) {
                 if (renderer.getIdValue(choice, 0).equals(id)) {
                     selected.add(choice);
                     break;
                 }
             }
         }
         return selected;
     }
 
     @Override
     public List<T> getUnselectedList() {
         IChoiceRenderer<? super T> renderer = getPalette().getChoiceRenderer();
         Collection<? extends T> choices = getPalette().getChoices();
 
         if (choices.size() - ids.length == 0) {
             return List.of();
         }
 
         List<T> unselected = new ArrayList<>(Math.max(1, choices.size() - ids.length));
         for (T choice : choices) {
             final String choiceId = renderer.getIdValue(choice, 0);
             boolean selected = false;
             for (String id : ids) {
                 if (id.equals(choiceId)) {
                     selected = true;
                     break;
                 }
             }
             if (!selected) {
                 unselected.add(choice);
             }
         }
         return unselected;
     }
 
     @Override
     protected void onValid() {
         super.onValid();
         if (attached) {
             updateIds();
         }
     }
 
     @Override
     protected void onInvalid() {
         super.onInvalid();
         if (attached) {
             updateIds();
         }
     }
 
     private void updateIds() {
         updateIds(getValue());
     }
 
     private void updateIds(final String value) {
         if (Strings.isEmpty(value)) {
             ids = EMPTY_IDS;
         } else if (value.indexOf('|') == -1) {
             ids = value.split(",");
             selectedId = null;
         } else {
             String[] splitted = value.split("\\|");
             selectedId = splitted[0];
             ids = splitted[1].split(",");
         }
     }
 }