package com.aurea.maven.plugins.sonic.sdm;

 import java.io.File;

 import java.io.IOException;

 import java.util.HashSet;

 import java.util.Properties;

 import java.util.Set;

 import javax.xml.parsers.DocumentBuilder;

 import javax.xml.parsers.DocumentBuilderFactory;

 import javax.xml.parsers.ParserConfigurationException;

 import org.apache.maven.plugin.MojoExecutionException;

 import org.codehaus.plexus.util.xml.XmlStreamReader;

 import org.codehaus.plexus.util.xml.Xpp3Dom;

 import org.codehaus.plexus.util.xml.Xpp3DomBuilder;

 import org.w3c.dom.Document;

 import org.w3c.dom.Element;

 import org.w3c.dom.NodeList;

 import org.xml.sax.SAXException;

 import com.aurea.maven.plugins.sonic.AbstractSonicMojo;

 public abstract class AbstractSdmMojo extends AbstractSonicMojo {

     private static final String TOPOLOGY_XSD = "/SDM/schema/2015/Topology.xsd";

         //indicates mandatory elements in topology.xsd - the elements that have minOccurs > 0

     private Set<String> mandatoryElements;

   /**

    * @return location of the SDM directory

    */

   protected File getTargetSDMDir() {

     return new File(getOutputDirectory(), "sonicesb/sdm");

   }

   /**

    * @return the generated tailoring properties file

    */

   protected File getGeneratedPropertiesFile() {

     return new File(getTargetSDMDir(), "/generated.tailoring.properties");

   }

   /**

    * @return the generated Topology file

    */

   protected File getGeneratedTopologyFile() {

     return new File(getTargetSDMDir(), "/generated.Topology.xml");

   }

   /**

    * @return the generated Topology file

    */

   protected File getMasterTopologyFile() {

     return new File(getTargetSDMDir(), "/Topology.xml");

   }

   protected Properties buildPropertiesFromTopology(File topoFile) throws MojoExecutionException {

     try {

       Properties generated = new Properties();

       XmlStreamReader topoReader = new XmlStreamReader(topoFile);

       Xpp3Dom topology = Xpp3DomBuilder.build(topoReader);

       Xpp3Dom parameters = topology.getChild("Parameters");

       for (Xpp3Dom parameter : parameters.getChildren()) {

             String id = getChildElementValue(parameter, "Id");

         String value = getChildElementValue(parameter, "Value");

         value = !value.isEmpty() ? value : getChildElementValue(parameter,"EncryptedValue");

         if(value.isEmpty())

             continue;

                 getLog().debug("Adding Property: " + id + " -- " + value);

                 generated.put(id, value);

       }

       return generated;

     } catch (Exception e) {

       throw new MojoExecutionException("Exception while reading topology file: " + topoFile.getName(), e);

     }

   }

   protected String getChildElementValue(Xpp3Dom parent, String name) 

                   throws ParserConfigurationException, SAXException, IOException, IllegalArgumentException {

           Xpp3Dom childElement = parent.getChild(name);

           if(childElement != null)

                   return childElement.getValue();

           else if (!getMandatoryElements().contains(name))

               return "";

           throw new IllegalArgumentException("Child element " + name + " does not exist in element " + parent.getName());

   }

   /*

    * parsing Toplogy.xsd and loading the elements which have the minOccurs > 0

    * the access to mandatoryElements through this method ensures a proper and 

    * lazy loading of the required elements

    */

   private Set<String> getMandatoryElements() 

                   throws ParserConfigurationException, SAXException, IOException {

       if(mandatoryElements == null) {

           mandatoryElements = new HashSet<>();

           DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();

           dbf.setNamespaceAware(true);

           DocumentBuilder docBuilder = dbf.newDocumentBuilder();

           Document document = docBuilder.parse(getClass().getResourceAsStream(TOPOLOGY_XSD));

           document.getDocumentElement().normalize();

           NodeList nodes = document.getElementsByTagName("xsd:element");

           for(int i = 0; i < nodes.getLength(); i++) {

               Element item = (Element)nodes.item(i);

               String itemMinOccurrence = item.getAttribute("minOccurs");

               if(itemMinOccurrence == null || itemMinOccurrence.isEmpty()) {

                   continue;

               }

               if(Integer.parseInt(itemMinOccurrence) > 0) {

                   mandatoryElements.add(item.getAttribute("name"));

               }

           }

       }

       return this.mandatoryElements;

   }

 }