/*
    *  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.mina.integration.beans;
  
  import java.beans.PropertyEditor;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  /**
   * A {@link PropertyEditor} which converts a {@link String} into
   * a {@link Collection} and vice versa.
   *
   * @author <a href="http://mina.apache.org">Apache MINA Project</a>
   */
  public class CollectionEditor extends AbstractPropertyEditor {
      static final Pattern ELEMENT = Pattern.compile("([,\\s]+)|"
              + // Delimiter
              "(?<=\")((?:\\\\\"|\\\\'|\\\\\\\\|\\\\ |[^\"])*)(?=\")|"
              + "(?<=')((?:\\\\\"|\\\\'|\\\\\\\\|\\\\ |[^'])*)(?=')|" + "((?:[^\\\\\\s'\",]|\\\\ |\\\\\"|\\\\')+)");
  
      private final Class<?> elementType;
  
      /**
       * Creates a new CollectionEditor instance
       * 
       * @param elementType The Element type
       */
      public CollectionEditor(Class<?> elementType) {
          if (elementType == null) {
              throw new IllegalArgumentException("elementType");
          }
  
          this.elementType = elementType;
          getElementEditor();
          setTrimText(false);
      }
  
      private PropertyEditor getElementEditor() {
          PropertyEditor e = PropertyEditorFactory.getInstance(elementType);
          if (e == null) {
              throw new IllegalArgumentException("No " + PropertyEditor.class.getSimpleName() + " found for "
                      + elementType.getSimpleName() + '.');
          }
          return e;
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      protected final String toText(Object value) {
          StringBuilder buf = new StringBuilder();
          
          for (Object v : (Collection<?>) value) {
              if (v == null) {
                  v = defaultElement();
              }
  
              PropertyEditor e = PropertyEditorFactory.getInstance(v);
              
              if (e == null) {
                  throw new IllegalArgumentException("No " + PropertyEditor.class.getSimpleName() + " found for "
                          + v.getClass().getSimpleName() + '.');
              }
              
              e.setValue(v);
              // TODO normalize.
              String s = e.getAsText();
              buf.append(s);
              buf.append(", ");
          }
  
          // Remove the last delimiter.
          if (buf.length() >= 2) {
              buf.setLength(buf.length() - 2);
          }
          
          return buf.toString();
      }
  
     /**
      * {@inheritDoc}
      */
     @Override
     protected final Object toValue(String text) throws IllegalArgumentException {
         PropertyEditor e = getElementEditor();
         Collection<Object> answer = newCollection();
         Matcher m = ELEMENT.matcher(text);
         boolean matchedDelimiter = true;
 
         while (m.find()) {
             if (m.group(1) != null) {
                 matchedDelimiter = true;
                 continue;
             }
 
             if (!matchedDelimiter) {
                 throw new IllegalArgumentException("No delimiter between elements: " + text);
             }
 
             // TODO escape here.
             e.setAsText(m.group());
             answer.add(e.getValue());
 
             matchedDelimiter = false;
             
             if (m.group(2) != null || m.group(3) != null) {
                 // Skip the last '"'.
                 m.region(m.end() + 1, m.regionEnd());
             }
         }
 
         return answer;
     }
 
     protected Collection<Object> newCollection() {
         return new ArrayList<>();
     }
 
     protected Object defaultElement() {
         PropertyEditor e = PropertyEditorFactory.getInstance(elementType);
         
         if (e == null) {
             return null;
         }
 
         if (e instanceof AbstractPropertyEditor) {
             return ((AbstractPropertyEditor) e).defaultValue();
         }
 
         return null;
     }
 }