/*

  * Copyright 2012-2013 smartics, Kronseder & Reiner GmbH

  *

  * 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.

  */

 package de.smartics.properties.spi.core.metadata.comment;

 import java.io.BufferedInputStream;

 import java.io.IOException;

 import java.io.InputStream;

 import java.util.List;

 import java.util.Locale;

 import org.apache.commons.io.IOUtils;

 import org.jdom.Document;

 import org.jdom.Element;

 import org.jdom.JDOMException;

 import org.jdom.Namespace;

 import org.jdom.input.SAXBuilder;

 import org.slf4j.Logger;

 import org.slf4j.LoggerFactory;

 import de.smartics.properties.api.core.domain.PropertiesContext;

 import de.smartics.properties.api.core.domain.PropertyComment;

 import de.smartics.properties.api.core.domain.PropertyDescriptor;

 import de.smartics.properties.api.core.domain.PropertyValueComment;

 import de.smartics.util.lang.Arg;

 import de.smartics.util.lang.NullArgumentException;

 /**

  * Parses property comments for a property descriptors.

  */

 public final class PropertyCommentParser

 {

   // ********************************* Fields *********************************

   // --- constants ------------------------------------------------------------

   /**

    * Reference to the logger for this class.

    */

   private static final Logger LOG = LoggerFactory

       .getLogger(PropertyCommentParser.class);

   /**

    * The namespace of the XML files this parser can parse.

    */

   private static final Namespace PROPERTY_NS =

       Namespace

           .getNamespace("http://www.smartics.de/schema/projectdoc/doctype/property/1");

   // --- members --------------------------------------------------------------

   /**

    * The properties context to fetch information from the META-INF folder.

    */

   private final PropertiesContext context;

   // ****************************** Initializer *******************************

   // ****************************** Constructors ******************************

   /**

    * Default constructor.

    *

    * @param context the properties context to fetch information from the

    *          META-INF folder.

    * @throws NullArgumentException if {@code context} is <code>null</code>.

    */

   public PropertyCommentParser(final PropertiesContext context)

     throws NullArgumentException

   {

     this.context = Arg.checkNotNull("context", context);

   }

   // ****************************** Inner Classes *****************************

   // ********************************* Methods ********************************

   // --- init -----------------------------------------------------------------

   // --- get&set --------------------------------------------------------------

   // --- business -------------------------------------------------------------

   /**

    * Parses the comments for the given descriptor.

    *

    * @param descriptor the descriptor whose comments are requested to be parsed.

    * @param locale the locale to select the comments.

    * @return the comments for the given locale or the default comments, if the

    *         locale is not supported.

    */

   public PropertyComment parse(final PropertyDescriptor descriptor,

       final Locale locale)

   {

     final String path = context.createMetaInfPath(descriptor, locale);

     final ClassLoader loader = descriptor.getDeclaringType().getClassLoader(); // NOPMD

     InputStream input = null;

     try

     {

       final InputStream resource = loader.getResourceAsStream(path);

       if (resource != null)

       {

         input = new BufferedInputStream(resource);

         final PropertyComment comment = parse(path, input);

         return comment;

       }

       else

       {

         LOG.warn("No comments for property descriptor '{}' found: {}",

             descriptor, path);

       }

     }

     catch (final CommentException e)

     {

       LOG.warn("Cannot parse comments for property descriptor '{}': {}",

           descriptor, e);

     }

     finally

     {

       IOUtils.closeQuietly(input);

     }

     return PropertyComment.EMPTY_COMMENT;

   }

   private PropertyComment parse(final String systemId, final InputStream input)

     throws CommentException

   {

     try

     {

       final SAXBuilder parser = new SAXBuilder();

       final Document document = parser.build(input, systemId);

       final PropertyComment.Builder builder = new PropertyComment.Builder();

       final Element rootNode = document.getRootElement();

       final String comment =

           rootNode.getChildTextNormalize("specification", PROPERTY_NS);

       final PropertyValueComment valueComment = parseValueComment(rootNode);

       builder.withText(comment).with(valueComment);

       return builder.build();

     }

     catch (final JDOMException e)

     {

       throw new CommentException(systemId, e);

     }

     catch (final IOException e)

     {

       throw new CommentException(systemId, e);

     }

   }

   @SuppressWarnings("unchecked")

   private PropertyValueComment parseValueComment(final Element rootNode)

   {

     final Element valueRange = rootNode.getChild("valueRange", PROPERTY_NS);

     if (valueRange == null)

     {

       return null;

     }

     final String summary =

         valueRange.getChildTextNormalize("summary", PROPERTY_NS);

     final PropertyValueComment comment = new PropertyValueComment(summary);

     final List<Element> elements =

         (List<Element>) valueRange.getChildren("element", PROPERTY_NS);

     for (final Element element : elements)

     {

       final String value = element.getChildTextNormalize("value", PROPERTY_NS);

       final String description =

           element.getChildTextNormalize("description", PROPERTY_NS);

       comment.addValueComment(value, description);

     }

     return comment;

   }

   // --- object basics --------------------------------------------------------

 }