/*
    * #%L
    * wcm.io
    * %%
    * Copyright (C) 2014 wcm.io
    * %%
    * 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
   *
   *      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.
   * #L%
   */
  package io.wcm.handler.commons.dom;
  
  import java.util.Collection;
  import java.util.regex.Pattern;
  
  import org.apache.commons.lang3.StringUtils;
  import org.jdom2.Attribute;
  import org.jdom2.Content;
  import org.jdom2.DataConversionException;
  import org.jdom2.Namespace;
  import org.jdom2.output.XMLOutputter;
  import org.osgi.annotation.versioning.ConsumerType;
  
  /**
   * Generic DOM element.
   * This element implementation is derived from JDOM element implementation.
   */
  @SuppressWarnings("unchecked")
  @ConsumerType
  public abstract class AbstractElement extends org.jdom2.Element {
  
    private static final long serialVersionUID = 1L;
  
    // matches all control chars ([\x00-\x1F\x7F]), that are invalid inside XML
    private static final Pattern CONTROL_CHARS = Pattern.compile("[\\p{Cntrl}]");
  
    /**
     * Initializes DOM element.
     * @param name Element name
     */
    protected AbstractElement(String name) {
      super(name);
    }
  
    /**
     * Gets attribute value as integer.
     * @param attributeName Attribute name
     * @return Attribute value as integer or 0 if not set.
     */
    public final int getAttributeValueAsInteger(String attributeName) {
      Attribute attribute = getAttribute(attributeName);
      if (attribute == null) {
        return 0;
      }
      else {
        try {
          return attribute.getIntValue();
        }
        catch (DataConversionException ex) {
          return 0;
        }
      }
    }
  
    /**
     * Sets attribute value as long.
     * @param name Attribute name
     * @param value Attribute value as long
     * @return Self reference
     */
    public AbstractElement setAttributeValueAsLong(String name, long value) {
      setAttribute(name, Long.toString(value));
      return this;
    }
  
    /**
     * Gets attribute value as long.
     * @param attributeName Attribute name
     * @return Attribute value as long or 0 if not set.
     */
    public final long getAttributeValueAsLong(String attributeName) {
      Attribute attribute = getAttribute(attributeName);
      if (attribute == null) {
        return 0;
      }
      else {
        try {
          return attribute.getLongValue();
        }
        catch (DataConversionException ex) {
         return 0;
       }
     }
   }
 
   /**
    * Sets attribute value as integer.
    * @param name Attribute name
    * @param value Attribute value as integer
    * @return Self reference
    */
   public final AbstractElement setAttributeValueAsInteger(String name, int value) {
     setAttribute(name, Integer.toString(value));
     return this;
   }
 
   /**
    * Appends the child to the end of the element's content list
    * @param content Child to append to end of content list. Null values are ignored.
    * @return The element on which the method was called.
    */
   @Override
   public final org.jdom2.Element addContent(Content content) {
     // ignore empty elements
     if (content == null) {
       return null;
     }
     return super.addContent(content);
   }
 
   /**
    * Inserts the child into the content list at the given index
    * @param index Location for adding the collection
    * @param content Child to append to end of content list. Null values are ignored.
    * @return The element on which the method was called.
    */
   @Override
   public final org.jdom2.Element addContent(int index, Content content) {
     // ignore empty elements
     if (content == null) {
       return null;
     }
     return super.addContent(index, content);
   }
 
   /**
    * This adds text content to this element. It does not replace the existing content as does setText().
    * @param text String to add. Null values are ignored.
    * @return This element modified
    */
   @Override
   public final org.jdom2.Element addContent(String text) {
     // ignore empty elements
     if (text == null) {
       return null;
     }
     return super.addContent(cleanUpString(text));
   }
 
   /**
    * Appends all children in the given collection to the end of the content list. In event of an exception
    * during add the original content will be unchanged and the objects in the supplied collection will be unaltered.
    * @param collection Collection to append. Null values are ignored.
    * @return the element on which the method was called
    */
   @Override
   public final org.jdom2.Element addContent(Collection collection) {
     // ignore empty elements
     if (collection == null) {
       return null;
     }
     return super.addContent(collection);
   }
 
   /**
    * Inserts the content in a collection into the content list at the given index. In event of an exception
    * the original content will be unchanged and the objects in the supplied collection will be unaltered.
    * @param index Location for adding the collection
    * @param collection Collection to insert. Null values are ignored.
    * @return The parent on which the method was called
    */
   @Override
   public final org.jdom2.Element addContent(int index, Collection collection) {
     // ignore empty elements
     if (collection == null) {
       return null;
     }
     return super.addContent(index, collection);
   }
 
   /**
    * Appends the child to the end of the element's content list.
    * Returns not the element itself (contrary to addContent), but a reference to the newly added element.
    * @param <T> Type that extends Element
    * @param element Element to add. Null values are ignored.
    * @return The added element.
    */
   public final <T extends AbstractElement> T add(T element) {
     this.addContent(element);
     return element;
   }
 
   /**
    * Sets the content of the element to be the text given. All existing text content and non-text context is removed.
    * If this element should have both textual content and nested elements, use <code>{@link #setContent}</code> instead.
    * Setting a null text value is equivalent to setting an empty string value.
    * @param text new text content for the element
    * @return the target element
    * @throws org.jdom2.IllegalDataException if the assigned text contains an illegal character such as a
    *           vertical tab (as determined by {@link org.jdom2.Verifier#checkCharacterData})
    */
   @Override
   public org.jdom2.Element setText(String text) {
     return super.setText(cleanUpString(StringUtils.defaultString(text)));
   }
 
   /**
    * This sets an attribute value for this element. Any existing attribute with the same name and namespace URI is
    * removed.
    * @param name name of the attribute to set
    * @param value value of the attribute to set
    * @param ns namespace of the attribute to set
    * @return this element modified
    * @throws org.jdom2.IllegalNameException if the given name is illegal as an attribute name, or if the namespace
    *           is an unprefixed default namespace
    * @throws org.jdom2.IllegalDataException if the given attribute value is illegal character data (as determined
    *           by {@link org.jdom2.Verifier#checkCharacterData}).
    * @throws org.jdom2.IllegalAddException if the attribute namespace prefix collides with another namespace
    *           prefix on the element.
    */
   @Override
   public final org.jdom2.Element setAttribute(String name, String value, Namespace ns) {
     // remove attribute if value is set to null
     if (value == null) {
       super.removeAttribute(name, ns);
       return this;
     }
     else {
       return super.setAttribute(name, cleanUpString(value), ns);
     }
   }
 
   /**
    * This sets an attribute value for this element. Any existing attribute with the same name and namespace URI is
    * removed.
    * @param name name of the attribute to set
    * @param value value of the attribute to set
    * @return this element modified
    * @throws org.jdom2.IllegalNameException if the given name is illegal as an attribute name.
    * @throws org.jdom2.IllegalDataException if the given attribute value is illegal character data
    *           (as determined by {@link org.jdom2.Verifier#checkCharacterData}).
    */
   @Override
   public final org.jdom2.Element setAttribute(String name, String value) {
     // remove attribute if value is set to null
     if (value == null) {
       super.removeAttribute(name);
       return this;
     }
     else {
       return super.setAttribute(name, cleanUpString(value));
     }
   }
 
   /**
    * Cleans up the given string and removes all control char characters not valid for XML.
    * These control chars e.g. 0x03 for UTF-8 can by pasted by copy&paste into the CMS RTE.
    * @param text Text
    * @return Cleaned up text
    */
   private String cleanUpString(String text) {
     if (StringUtils.isEmpty(text)) {
       return text;
     }
     else {
       return CONTROL_CHARS.matcher(text).replaceAll("");
     }
   }
 
   @Override
   public final String toString() {
     return new XMLOutputter().outputString(this);
   }
 
   /**
    * @return Content of element serialized as string
    */
   public final String toStringContentOnly() {
     return new XMLOutputter().outputElementContentString(this);
   }
 
 }