/* ======================================================================
   Parts Copyright 2006 University of Leeds, Oxford University, University of the Highlands and Islands.

   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 org.bodington.xml;

import java.net.URL;
import java.io.Writer;
import java.io.FileOutputStream;
import java.io.OutputStream;
import java.io.InputStream;
import java.io.IOException;
import java.util.Properties;
import java.util.Map;

import javax.xml.transform.OutputKeys;
import javax.xml.transform.Result;
import javax.xml.transform.Transformer;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.apache.log4j.Logger;

//import org.apache.xalan.templates.OutputProperties;
import org.apache.xml.serializer.OutputPropertiesFactory;
import org.bodington.server.BuildingServerException;

import org.w3c.dom.Node;

/**
 * Provides methods for serializing XML to a File, OutputStream or Writer.
 * Can also transform the xml prior to serialization using transformOutput methods.
 * <p>NB use OutputStreams instead of Writers to preserve the required output character encoding</p>
 * @author Antony Corfield; Colin Tatham
 */
public class XMLSerializer {

  private static Logger log = Logger.getLogger(XMLSerializer.class);
 
  /*
   * out() methods here call transformation methods in org.bodington.xml.XMLTransformer
   *  in order to do the serialisation (Identity transform).
   */
  
  public static void out(Node node, boolean omitXMLDeclaration, String filePath) throws BuildingServerException {

      Transformer transformer = XMLTransformer.getTransformer();
      transformer.setOutputProperties( getModifiedProperties( omitXMLDeclaration) );
      serialise(node, transformer, filePath);
    }
  
  public static void out(Node node, boolean omitXMLDeclaration, OutputStream stream) throws BuildingServerException {

      Transformer transformer = XMLTransformer.getTransformer();
      transformer.setOutputProperties( getModifiedProperties( omitXMLDeclaration) );
      serialise(node, transformer, stream);
  }

  public static void out(Node node, boolean omitXMLDeclaration, Writer writer) throws BuildingServerException {

      Transformer transformer = XMLTransformer.getTransformer();
      transformer.setOutputProperties( getModifiedProperties( omitXMLDeclaration) );
      serialise(node, transformer, writer);
  }


  public static void out(Node node, String method, String filePath) throws BuildingServerException {

      Transformer transformer = XMLTransformer.getTransformer();
      transformer.setOutputProperties( getDefaultProperties(method) );
      serialise(node, transformer, filePath);
    }
  
  public static void out(Node node, String method, OutputStream stream) throws BuildingServerException {

      Transformer transformer = XMLTransformer.getTransformer();
      transformer.setOutputProperties( getDefaultProperties(method) );
      serialise(node, transformer, stream);
  }

  public static void out(Node node, String method, Writer writer) throws BuildingServerException {

      Transformer transformer = XMLTransformer.getTransformer();
      transformer.setOutputProperties( getDefaultProperties(method) );
      serialise(node, transformer, writer);
  }

  /*
   * transformOutput() methods here call transformation methods in org.bodington.xml.XMLTransformer
   *  in order to do combined transformation and serialisation.
   */

  public static void transformOutput(Node sourceNode, URL stylesheet, String filePath) throws BuildingServerException {

      Transformer transformer = XMLTransformer.getTransformer( stylesheet.getPath() );
      serialise(sourceNode, transformer, filePath );
    }
  
  public static void transformOutput(Node sourceNode, URL stylesheet, Map parameters, String filePath) throws BuildingServerException {

      Transformer transformer = XMLTransformer.getTransformer( stylesheet.getPath(), parameters );
      serialise(sourceNode, transformer, filePath );
    }
  
  public static void transformOutput(Node sourceNode, URL stylesheet, OutputStream stream) throws BuildingServerException {

      Transformer transformer = XMLTransformer.getTransformer( stylesheet.getPath() );
      serialise(sourceNode, transformer, stream);
  }
  
  public static void transformOutput(Node sourceNode, URL stylesheet, Map parameters, OutputStream stream) throws BuildingServerException {

      Transformer transformer = XMLTransformer.getTransformer( stylesheet.getPath(), parameters );
      serialise(sourceNode, transformer, stream);
    }
  
  public static void transformOutput(Node sourceNode, URL stylesheet, Writer writer) throws BuildingServerException {

      Transformer transformer = XMLTransformer.getTransformer( stylesheet.getPath() );
      serialise(sourceNode, transformer, writer);
  }

  public static void transformOutput(Node sourceNode, URL stylesheet, Map parameters, Writer writer) throws BuildingServerException {

      Transformer transformer = XMLTransformer.getTransformer(stylesheet.getPath(), parameters);
      serialise(sourceNode, transformer, writer);
  }  
  
  public static void transformOutput(Node sourceNode, InputStream stylesheet, String filePath) throws BuildingServerException {

      Transformer transformer = XMLTransformer.getTransformer( stylesheet );
      serialise(sourceNode, transformer, filePath);
  }

  public static void transformOutput(Node sourceNode, InputStream stylesheet, Map parameters, String filePath) throws BuildingServerException {

      Transformer transformer = XMLTransformer.getTransformer( stylesheet, parameters );
      serialise(sourceNode, transformer, filePath);
  }
  
  public static void transformOutput(Node sourceNode, InputStream stylesheet, OutputStream stream) throws BuildingServerException {

    Transformer transformer = XMLTransformer.getTransformer( stylesheet );
    serialise(sourceNode, transformer, stream);
  }
  
  public static void transformOutput(Node sourceNode, InputStream stylesheet, Map parameters, OutputStream stream) throws BuildingServerException {

      Transformer transformer = XMLTransformer.getTransformer( stylesheet, parameters );
      serialise(sourceNode, transformer, stream);
  }

  public static void transformOutput(Node sourceNode, InputStream stylesheet, Writer writer) throws BuildingServerException {

    Transformer transformer = XMLTransformer.getTransformer( stylesheet );
    serialise(sourceNode, transformer, writer);
  }
  
  public static void transformOutput(Node sourceNode, InputStream stylesheet, Map parameters, Writer writer) throws BuildingServerException {

      Transformer transformer = XMLTransformer.getTransformer( stylesheet, parameters );
      serialise(sourceNode, transformer, writer);
  }

  
  
  private static Properties getDefaultProperties(String method) throws BuildingServerException {

	  // Java 5 apparently has a bug that means indent amount is always set to zero:
	  // http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6296446
	  // need to set Xalan indent amount to get proper indentation: {http://xml.apache.org/xalan}indent-amount

	  Properties props;
	  method = method.toLowerCase();
	  if (null == method || method.equals(""))
		  method = "xml";

	  props = OutputPropertiesFactory.getDefaultMethodProperties( method );
	  props.setProperty(OutputKeys.INDENT, "yes");
	  props.setProperty(OutputPropertiesFactory.S_KEY_INDENT_AMOUNT, "2");

	  return props;
  }

  private static Properties getModifiedProperties( boolean omitXMLDeclaration ) throws BuildingServerException {
	  
	String value = (omitXMLDeclaration)? "yes":"no";
    return getModifiedProperties("xml", "omit-xml-declaration", value);
  }
  
  private static Properties getModifiedProperties( String method, String property, String value ) throws BuildingServerException {

	  Properties properties = getDefaultProperties( method );
	  properties.setProperty(property, value);
	  return properties;
  }
 
  private static void serialise(Node sourceNode, Transformer transformer, String filePath ) throws BuildingServerException {

      OutputStream stream = getFileOutputStream(filePath);
      serialise( sourceNode, transformer, new StreamResult(stream)  );
    }

  private static void serialise(Node sourceNode, Transformer transformer, OutputStream stream ) throws BuildingServerException {

      serialise( sourceNode, transformer, new StreamResult(stream) );
    }
  
  private static void serialise(Node sourceNode, Transformer transformer, Writer writer ) throws BuildingServerException {

      serialise( sourceNode, transformer, new StreamResult(writer) );
    }
  
  private static void serialise(Node sourceNode, Transformer transformer, Result result) throws BuildingServerException {

      try {
        DOMSource domSource = new DOMSource(sourceNode);
        transformer.transform(domSource, result);
      } catch (Exception e) {
        String message = "Cannot serialise XML node.";
        log.error(message, e);
        throw new BuildingServerException(e.getMessage(), message);
      } 
    }

  private static FileOutputStream getFileOutputStream(String filePath) throws BuildingServerException {

    try {
      return new FileOutputStream(filePath);
    }
    catch (IOException e) {
      String message = "Error in serializing output: (I/O error with path: " + filePath + ")";
      log.error(message);
      throw new BuildingServerException(e.getMessage(), message);
    }
  }
}