/*
    * 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.maven.internal.xml;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.Reader;
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  import org.apache.maven.api.xml.XmlNode;
  import org.codehaus.plexus.util.xml.pull.MXParser;
  import org.codehaus.plexus.util.xml.pull.XmlPullParser;
  import org.codehaus.plexus.util.xml.pull.XmlPullParserException;
  
  /**
   * All methods in this class attempt to fully parse the XML.
   * The caller is responsible for closing {@code InputStream} and {@code Reader} arguments.
   */
  public class XmlNodeBuilder {
      private static final boolean DEFAULT_TRIM = true;
  
      public static XmlNodeImpl build(Reader reader) throws XmlPullParserException, IOException {
          return build(reader, null);
      }
  
      /**
       * @param reader the reader
       * @param locationBuilder the builder
       * @since 3.2.0
       * @return DOM
       * @throws XmlPullParserException xml exception
       * @throws IOException io
       */
      public static XmlNodeImpl build(Reader reader, InputLocationBuilder locationBuilder)
              throws XmlPullParserException, IOException {
          return build(reader, DEFAULT_TRIM, locationBuilder);
      }
  
      public static XmlNodeImpl build(InputStream is, String encoding) throws XmlPullParserException, IOException {
          return build(is, encoding, DEFAULT_TRIM);
      }
  
      public static XmlNodeImpl build(InputStream is, String encoding, boolean trim)
              throws XmlPullParserException, IOException {
          XmlPullParser parser = new MXParser();
          parser.setInput(is, encoding);
          return build(parser, trim);
      }
  
      public static XmlNodeImpl build(Reader reader, boolean trim) throws XmlPullParserException, IOException {
          return build(reader, trim, null);
      }
  
      /**
       * @param reader the reader
       * @param trim to trim
       * @param locationBuilder the builder
       * @since 3.2.0
       * @return DOM
       * @throws XmlPullParserException xml exception
       * @throws IOException io
       */
      public static XmlNodeImpl build(Reader reader, boolean trim, InputLocationBuilder locationBuilder)
              throws XmlPullParserException, IOException {
          XmlPullParser parser = new MXParser();
          parser.setInput(reader);
          return build(parser, trim, locationBuilder);
      }
  
      public static XmlNodeImpl build(XmlPullParser parser) throws XmlPullParserException, IOException {
          return build(parser, DEFAULT_TRIM);
      }
  
      public static XmlNodeImpl build(XmlPullParser parser, boolean trim) throws XmlPullParserException, IOException {
          return build(parser, trim, null);
      }
  
      /**
       * @since 3.2.0
       * @param locationBuilder builder
      * @param parser the parser
      * @param trim do trim
      * @return DOM
      * @throws XmlPullParserException xml exception
      * @throws IOException io
      */
     public static XmlNodeImpl build(XmlPullParser parser, boolean trim, InputLocationBuilder locationBuilder)
             throws XmlPullParserException, IOException {
         boolean spacePreserve = false;
         String name = null;
         String value = null;
         Object location = null;
         Map<String, String> attrs = null;
         List<XmlNode> children = null;
         int eventType = parser.getEventType();
         boolean emptyTag = false;
         while (eventType != XmlPullParser.END_DOCUMENT) {
             if (eventType == XmlPullParser.START_TAG) {
                 emptyTag = parser.isEmptyElementTag();
                 if (name == null) {
                     name = parser.getName();
                     location = locationBuilder != null ? locationBuilder.toInputLocation(parser) : null;
                     int attributesSize = parser.getAttributeCount();
                     if (attributesSize > 0) {
                         attrs = new HashMap<>();
                         for (int i = 0; i < attributesSize; i++) {
                             String aname = parser.getAttributeName(i);
                             String avalue = parser.getAttributeValue(i);
                             attrs.put(aname, avalue);
                             spacePreserve = spacePreserve || ("xml:space".equals(aname) && "preserve".equals(avalue));
                         }
                     }
                 } else {
                     if (children == null) {
                         children = new ArrayList<>();
                     }
                     XmlNode child = build(parser, trim, locationBuilder);
                     children.add(child);
                 }
             } else if (eventType == XmlPullParser.TEXT) {
                 String text = parser.getText();
                 if (trim && !spacePreserve) {
                     text = text.trim();
                 }
                 value = value != null ? value + text : text;
             } else if (eventType == XmlPullParser.END_TAG) {
                 return new XmlNodeImpl(
                         name,
                         children == null ? (value != null ? value : emptyTag ? null : "") : null,
                         attrs,
                         children,
                         location);
             }
             eventType = parser.next();
         }
         throw new IllegalStateException("End of document found before returning to 0 depth");
     }
 
     /**
      * Input location builder interface, to be implemented to choose how to store data.
      *
      * @since 3.2.0
      */
     public interface InputLocationBuilder {
         Object toInputLocation(XmlPullParser parser);
     }
 }