/*
    * Portions of this software was developed by employees of the National Institute
    * of Standards and Technology (NIST), an agency of the Federal Government and is
    * being made available as a public service. Pursuant to title 17 United States
    * Code Section 105, works of NIST employees are not subject to copyright
    * protection in the United States. This software may be subject to foreign
    * copyright. Permission in the United States and in foreign countries, to the
    * extent that NIST may hold copyright, to use, copy, modify, create derivative
    * works, and distribute this software and its documentation without fee is hereby
   * granted on a non-exclusive basis, provided that this notice and disclaimer
   * of warranty appears in all copies.
   *
   * THE SOFTWARE IS PROVIDED 'AS IS' WITHOUT ANY WARRANTY OF ANY KIND, EITHER
   * EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, ANY WARRANTY
   * THAT THE SOFTWARE WILL CONFORM TO SPECIFICATIONS, ANY IMPLIED WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND FREEDOM FROM
   * INFRINGEMENT, AND ANY WARRANTY THAT THE DOCUMENTATION WILL CONFORM TO THE
   * SOFTWARE, OR ANY WARRANTY THAT THE SOFTWARE WILL BE ERROR FREE.  IN NO EVENT
   * SHALL NIST BE LIABLE FOR ANY DAMAGES, INCLUDING, BUT NOT LIMITED TO, DIRECT,
   * INDIRECT, SPECIAL OR CONSEQUENTIAL DAMAGES, ARISING OUT OF, RESULTING FROM,
   * OR IN ANY WAY CONNECTED WITH THIS SOFTWARE, WHETHER OR NOT BASED UPON WARRANTY,
   * CONTRACT, TORT, OR OTHERWISE, WHETHER OR NOT INJURY WAS SUSTAINED BY PERSONS OR
   * PROPERTY OR OTHERWISE, AND WHETHER OR NOT LOSS WAS SUSTAINED FROM, OR AROSE OUT
   * OF THE RESULTS OF, OR USE OF, THE SOFTWARE OR SERVICES PROVIDED HEREUNDER.
   */
  
  package gov.nist.secauto.metaschema.schemagen.xml.datatype;
  
  import gov.nist.secauto.metaschema.schemagen.datatype.IDatatypeContent;
  import gov.nist.secauto.metaschema.schemagen.datatype.IDatatypeProvider;
  
  import org.codehaus.stax2.XMLStreamWriter2;
  import org.jdom2.Element;
  import org.jdom2.JDOMException;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.Collections;
  import java.util.LinkedHashSet;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  
  import javax.xml.stream.XMLStreamException;
  
  import edu.umd.cs.findbugs.annotations.NonNull;
  import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
  
  public abstract class AbstractXmlDatatypeProvider implements IDatatypeProvider {
    private Map<String, IDatatypeContent> datatypes;
  
    protected abstract InputStream getSchemaResource();
  
    private void initSchema() {
      synchronized (this) {
        if (datatypes == null) {
          try (InputStream is = getSchemaResource()) {
            assert is != null;
            JDom2XmlSchemaLoader loader = new JDom2XmlSchemaLoader(is);
  
            List<Element> elements = queryElements(loader);
  
            datatypes = Collections.unmodifiableMap(handleResults(elements));
          } catch (JDOMException | IOException ex) {
            throw new IllegalStateException(ex);
          }
        }
      }
    }
  
    @NonNull
    protected abstract List<Element> queryElements(JDom2XmlSchemaLoader loader);
  
    @NonNull
    protected abstract Map<String, IDatatypeContent> handleResults(@NonNull List<Element> items);
  
    @Override
    @SuppressFBWarnings({ "IS2_INCONSISTENT_SYNC", "MT_CORRECTNESS", "EI_EXPOSE_REP" })
    public Map<String, IDatatypeContent> getDatatypes() {
      initSchema();
      assert datatypes != null;
      return datatypes;
    }
  
    @Override
    public Set<String> generateDatatypes(Set<String> requiredTypes, @NonNull XMLStreamWriter2 writer)
        throws XMLStreamException {
      Map<String, IDatatypeContent> datatypes = getDatatypes();
  
      Set<String> providedDatatypes = new LinkedHashSet<>();
      for (IDatatypeContent datatype : datatypes.values()) {
        String type = datatype.getTypeName();
        if (requiredTypes.contains(type)) {
          providedDatatypes.add(type);
          providedDatatypes.addAll(datatype.getDependencies());
        }
      }
  
      for (IDatatypeContent datatype : datatypes.values()) {
       String type = datatype.getTypeName();
       if (providedDatatypes.contains(type)) {
         datatype.write(writer);
       }
     }
     return providedDatatypes;
   }
 
 }