/*
    *  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.Collection;
  import java.util.LinkedHashMap;
  import java.util.Map;
  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 The Apache MINA Project (dev@mina.apache.org)
   */
  public class MapEditor extends AbstractPropertyEditor {
      static final Pattern ELEMENT = Pattern.compile(
              "([,\\s]+)|" + // Entry delimiter
              "(\\s*=\\s*)|" + // Key-Value delimiter
              "(?<=\")((?:\\\\\"|\\\\'|\\\\\\\\|\\\\ |[^\"])*)(?=\")|" +
              "(?<=')((?:\\\\\"|\\\\'|\\\\\\\\|\\\\ |[^'])*)(?=')|" +
              "((?:[^\\\\\\s'\",]|\\\\ |\\\\\"|\\\\')+)");
      
      private final Class<?> keyType;
      private final Class<?> valueType;
      
      public MapEditor(Class<?> keyType, Class<?> valueType) {
          if (keyType == null) {
              throw new NullPointerException("keyType");
          }
          if (valueType == null) {
              throw new NullPointerException("valueType");
          }
          this.keyType = keyType;
          this.valueType = valueType;
          getKeyEditor();
          getValueEditor();
          setTrimText(false);
      }
  
      private PropertyEditor getKeyEditor() {
          PropertyEditor e = PropertyEditorFactory.getInstance(keyType);
          if (e == null) {
              throw new IllegalArgumentException(
                      "No key " + PropertyEditor.class.getSimpleName() + 
                      " found for " + keyType.getSimpleName() + '.');
          }
          return e;
      }
  
      private PropertyEditor getValueEditor() {
          PropertyEditor e = PropertyEditorFactory.getInstance(valueType);
          if (e == null) {
              throw new IllegalArgumentException(
                      "No value " + PropertyEditor.class.getSimpleName() + 
                      " found for " + valueType.getSimpleName() + '.');
          }
          return e;
      }
  
      @Override
      @SuppressWarnings("unchecked")
      protected final String toText(Object value) {
          StringBuilder buf = new StringBuilder();
          for (Object o: ((Map) value).entrySet()) {
              Map.Entry entry = (Map.Entry) o;
              Object ekey = entry.getKey();
              Object evalue = entry.getValue();
              
              PropertyEditor ekeyEditor = PropertyEditorFactory.getInstance(ekey);
              if (ekeyEditor == null) {
                  throw new IllegalArgumentException(
                          "No key " + PropertyEditor.class.getSimpleName() + 
                          " found for " + ekey.getClass().getSimpleName() + '.');
              }
              ekeyEditor.setValue(ekey);
              
              PropertyEditor evalueEditor = PropertyEditorFactory.getInstance(evalue);
              if (evalueEditor == null) {
                  throw new IllegalArgumentException(
                         "No value " + PropertyEditor.class.getSimpleName() + 
                         " found for " + evalue.getClass().getSimpleName() + '.');
             }
             ekeyEditor.setValue(ekey);
             evalueEditor.setValue(evalue);
             
             // TODO normalize.
             String keyString = ekeyEditor.getAsText();
             String valueString = evalueEditor.getAsText();
             buf.append(keyString);
             buf.append(" = ");
             buf.append(valueString);
             buf.append(", ");
         }
         
         // Remove the last delimiter.
         if (buf.length() >= 2) {
             buf.setLength(buf.length() - 2);
         }
         return buf.toString();
     }
 
     @Override
     protected final Object toValue(String text) throws IllegalArgumentException {
         PropertyEditor keyEditor = getKeyEditor();
         PropertyEditor valueEditor = getValueEditor();
         Map<Object, Object> answer = newMap();
         Matcher m = ELEMENT.matcher(text);
         TokenType lastTokenType = TokenType.ENTRY_DELIM;
         Object key = null;
         Object value = null;
 
         while (m.find()) {
             if (m.group(1) != null) {
                 switch (lastTokenType) {
                 case VALUE: case ENTRY_DELIM:
                     break;
                 default:
                     throw new IllegalArgumentException(
                             "Unexpected entry delimiter: " + text);
                 }
                 
                 lastTokenType = TokenType.ENTRY_DELIM;
                 continue;
             }
             
             if (m.group(2) != null) {
                 if (lastTokenType != TokenType.KEY) {
                     throw new IllegalArgumentException(
                             "Unexpected key-value delimiter: " + text);
                 }
                 
                 lastTokenType = TokenType.KEY_VALUE_DELIM;
                 continue;
             }
             
             
             // TODO escape here.
             String region = m.group();
 
             if (m.group(3) != null || m.group(4) != null) {
                 // Skip the last '"'.
                 m.region(m.end() + 1, m.regionEnd());
             }
             
             switch (lastTokenType) {
             case ENTRY_DELIM:
                 keyEditor.setAsText(region);
                 key = keyEditor.getValue();
                 lastTokenType = TokenType.KEY;
                 break;
             case KEY_VALUE_DELIM:
                 valueEditor.setAsText(region);
                 value = valueEditor.getValue();
                 lastTokenType = TokenType.VALUE;
                 answer.put(key, value);
                 break;
             case KEY: case VALUE:
                 throw new IllegalArgumentException(
                         "Unexpected key or value: " + text);
             }
         }
         
         return answer;
     }
     
     protected Map<Object, Object> newMap() {
         return new LinkedHashMap<Object, Object>();
     }
     
     private static enum TokenType {
         ENTRY_DELIM,
         KEY_VALUE_DELIM,
         KEY,
         VALUE,
     }
 }