package org.kuali.ole.ingest;
   
   import org.apache.commons.io.IOUtils;
   import org.kuali.ole.exception.ParseException;
   import org.kuali.ole.exception.XmlErrorHandler;
   import org.xml.sax.SAXException;
   
   import javax.xml.XMLConstants;
   import javax.xml.transform.Source;
  import javax.xml.transform.stream.StreamSource;
  import javax.xml.validation.Schema;
  import javax.xml.validation.SchemaFactory;
  import javax.xml.validation.Validator;
  import java.io.ByteArrayInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  
  /**
   * This class provides schema validation for uploaded location xml
   */
  public class OleLocationXMLSchemaValidator {
      //TODO: refactor the validateContentsAgainstSchema method to take only 1 parameter which is the file content.
      private static final String LOCATION_SCHEMA_FILE = "locations.xsd";
  
      /**
       *  This method returns True/False.
       *  This method  validate the inputStream content with W3C Xml Schema standard,if it matches it return True else return False.
       * @param inputStream
       * @return   boolean
       * @throws ParseException
       * @throws IOException
       * @throws SAXException
       */
      public boolean validateContentsAgainstSchema(InputStream inputStream)
              throws ParseException, IOException, SAXException {
          try {
              SchemaFactory factory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
              Source schemaSource = null;
              schemaSource = new StreamSource(getFileContents());
              Schema schema = null;
              schema = factory.newSchema(schemaSource);
              Validator validator = schema.newValidator();
              validator.setErrorHandler(new XmlErrorHandler());
              validator.validate(new StreamSource(inputStream));
              return true;
          }
          catch(Exception ex){
              //TODO: logging required
          }
          return false;
      }
  
      /**
       *  This method returns fileContent as InputStream.
       *  This method get the fileContent based on Location file schema.
       * @return locationXmlFile.
       */
      private InputStream getFileContents(){
          byte[] locationByteArray;
          ByteArrayInputStream locationXmlFile=null;
          try{
              locationByteArray = IOUtils.toByteArray(getClass().getResourceAsStream(LOCATION_SCHEMA_FILE));
              locationXmlFile = new ByteArrayInputStream(locationByteArray);
          }
          catch(Exception e){
              //TODO: logging required
          }
          return locationXmlFile;
      }
  
  }