/**
 * 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.lucene.analysis;

import java.util.HashMap;
import java.util.Map;

/**
 * Holds a map of String input to String output, to be used
 * with {@link MappingCharFilter}.
 */
public class NormalizeCharMap {

  Map<Character, NormalizeCharMap> submap;
  String normStr;
  int diff;

  /** Records a replacement to be applied to the inputs
   *  stream.  Whenever <code>singleMatch</code> occurs in
   *  the input, it will be replaced with
   *  <code>replacement</code>.
   *
   * @param singleMatch input String to be replaced
   * @param replacement output String
   */
  public void add(String singleMatch, String replacement) {
    NormalizeCharMap currMap = this;
    for(int i = 0; i < singleMatch.length(); i++) {
      char c = singleMatch.charAt(i);
      if (currMap.submap == null) {
        currMap.submap = new HashMap<Character, NormalizeCharMap>(1);
      }
      NormalizeCharMap map = currMap.submap.get(Character.valueOf(c));
      if (map == null) {
        map = new NormalizeCharMap();
        currMap.submap.put(Character.valueOf(c), map);
      }
      currMap = map;
    }
    if (currMap.normStr != null) {
      throw new RuntimeException("MappingCharFilter: there is already a mapping for " + singleMatch);
    }
    currMap.normStr = replacement;
    currMap.diff = singleMatch.length() - replacement.length();
  }
}