/*
    * 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.commons.text.lookup;
  
  import java.io.InputStream;
  import java.nio.file.Files;
  import java.nio.file.Path;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Map.Entry;
  import java.util.Objects;
  
  import javax.xml.XMLConstants;
  import javax.xml.xpath.XPathFactory;
  
  import org.apache.commons.lang3.StringUtils;
  import org.xml.sax.InputSource;
  
  /**
   * Looks up keys from an XML document.
   * <p>
   * Looks up the value for a given key in the format "Document:XPath".
   * </p>
   * <p>
   * For example: "com/domain/document.xml:/path/to/node".
   * </p>
   *
   * @since 1.5
   */
  final class XmlStringLookup extends AbstractPathFencedLookup {
  
      /**
       * Defines default XPath factory features.
       */
      static final Map<String, Boolean> DEFAULT_FEATURES;
  
      static {
          DEFAULT_FEATURES = new HashMap<>(1);
          DEFAULT_FEATURES.put(XMLConstants.FEATURE_SECURE_PROCESSING, Boolean.TRUE);
      }
  
      /**
       * Defines the singleton for this class.
       */
      static final XmlStringLookup INSTANCE = new XmlStringLookup(DEFAULT_FEATURES, (Path[]) null);
  
      /**
       * Defines XPath factory features.
       */
      private final Map<String, Boolean> xPathFactoryFeatures;
  
      /**
       * No need to build instances for now.
       *
       * @param xPathFactoryFeatures XPathFactory features to set.
       * @see XPathFactory#setFeature(String, boolean)
       */
      XmlStringLookup(final Map<String, Boolean> xPathFactoryFeatures, final Path... fences) {
          super(fences);
          this.xPathFactoryFeatures = Objects.requireNonNull(xPathFactoryFeatures, "xPathFfactoryFeatures");
      }
  
      /**
       * Looks up the value for the key in the format "DocumentPath:XPath".
       * <p>
       * For example: "com/domain/document.xml:/path/to/node".
       * </p>
       *
       * @param key the key to be looked up, may be null
       * @return The value associated with the key.
       */
      @Override
      public String lookup(final String key) {
          if (key == null) {
              return null;
          }
          final String[] keys = key.split(SPLIT_STR);
          final int keyLen = keys.length;
          if (keyLen != 2) {
              throw IllegalArgumentExceptions.format("Bad XML key format [%s]; expected format is DocumentPath:XPath.",
                      key);
          }
          final String documentPath = keys[0];
          final String xpath = StringUtils.substringAfter(key, SPLIT_CH);
         try (InputStream inputStream = Files.newInputStream(getPath(documentPath))) {
             final XPathFactory factory = XPathFactory.newInstance();
             for (final Entry<String, Boolean> p : xPathFactoryFeatures.entrySet()) {
                 factory.setFeature(p.getKey(), p.getValue());
             }
             return factory.newXPath().evaluate(xpath, new InputSource(inputStream));
         } catch (final Exception e) {
             throw IllegalArgumentExceptions.format(e, "Error looking up XML document [%s] and XPath [%s].",
                     documentPath, xpath);
         }
     }
 
 }