/*
    * Copyright 2004-2025 the original author or authors.
    *
    * Licensed 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
    *
    *    https://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 com.ibatis.sqlmap.engine.builder.xml;
  
  import com.ibatis.common.resources.Resources;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.HashMap;
  import java.util.Locale;
  import java.util.Map;
  
  import org.xml.sax.EntityResolver;
  import org.xml.sax.InputSource;
  import org.xml.sax.SAXException;
  
  /**
   * Offline entity resolver for the iBATIS DTDs.
   */
  public class SqlMapClasspathEntityResolver implements EntityResolver {
  
    /** The Constant SQL_MAP_CONFIG_DTD. */
    private static final String SQL_MAP_CONFIG_DTD = "com/ibatis/sqlmap/engine/builder/xml/sql-map-config-2.dtd";
  
    /** The Constant SQL_MAP_DTD. */
    private static final String SQL_MAP_DTD = "com/ibatis/sqlmap/engine/builder/xml/sql-map-2.dtd";
  
    /** The Constant doctypeMap. */
    private static final Map doctypeMap = new HashMap<>();
  
    static {
      doctypeMap.put("https://ibatis.apache.org/dtd/sql-map-config-2.dtd".toUpperCase(Locale.ROOT), SQL_MAP_CONFIG_DTD);
      doctypeMap.put("-//ibatis.apache.org//DTD SQL Map Config 2.0//EN".toUpperCase(Locale.ROOT), SQL_MAP_CONFIG_DTD);
  
      doctypeMap.put("https://ibatis.apache.org/dtd/sql-map-2.dtd".toUpperCase(Locale.ROOT), SQL_MAP_DTD);
      doctypeMap.put("-//ibatis.apache.org//DTD SQL Map 2.0//EN".toUpperCase(Locale.ROOT), SQL_MAP_DTD);
    }
  
    /**
     * Converts a public DTD into a local one
     *
     * @param publicId
     *          Unused but required by EntityResolver interface
     * @param systemId
     *          The DTD that is being requested
     *
     * @return The InputSource for the DTD
     *
     * @throws SAXException
     *           If anything goes wrong
     */
    @Override
    public InputSource resolveEntity(String publicId, String systemId) throws SAXException {
  
      if (publicId != null) {
        publicId = publicId.toUpperCase(Locale.ROOT);
      }
      if (systemId != null) {
        systemId = systemId.toUpperCase(Locale.ROOT);
      }
  
      InputSource source = null;
      try {
        String path = (String) doctypeMap.get(publicId);
        source = getInputSource(path, source);
        if (source == null) {
          path = (String) doctypeMap.get(systemId);
          source = getInputSource(path, source);
        }
      } catch (Exception e) {
        throw new SAXException(e.toString());
      }
      return source;
    }
  
    /**
     * Gets the input source.
     *
     * @param path
     *          the path
     * @param source
     *          the source
     *
     * @return the input source
     */
    private InputSource getInputSource(String path, InputSource source) {
     if (path != null) {
       InputStream in = null;
       try {
         in = Resources.getResourceAsStream(path);
         source = new InputSource(in);
       } catch (IOException e) {
         // ignore, null is ok
       }
     }
     return source;
   }
 
 }