/*
    * 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.oscal.lib.profile.resolver.support;
  
  import gov.nist.secauto.metaschema.model.common.metapath.MetapathExpression;
  import gov.nist.secauto.metaschema.model.common.metapath.item.IDocumentNodeItem;
  import gov.nist.secauto.metaschema.model.common.metapath.item.IRequiredValueModelNodeItem;
  import gov.nist.secauto.metaschema.model.common.metapath.item.IRootAssemblyNodeItem;
  import gov.nist.secauto.metaschema.model.common.util.CollectionUtil;
  import gov.nist.secauto.metaschema.model.common.util.ObjectUtils;
  
  import java.util.Collections;
  import java.util.EnumSet;
  import java.util.Set;
  
  import edu.umd.cs.findbugs.annotations.NonNull;
  
  /**
   * Visits a catalog document and its children as designated.
   * <p>
   * This implementation is stateless. The {@code T} parameter can be used to
   * convey state as needed.
   *
   * @param <T>
   *          the state type
   * @param <R>
   *          the result type
   */
  public abstract class AbstractCatalogEntityVisitor<T, R>
      extends AbstractCatalogVisitor<T, R> {
    @NonNull
    public static final MetapathExpression CHILD_PART_METAPATH
        = MetapathExpression.compile("part|part//part");
    @NonNull
    private static final MetapathExpression BACK_MATTER_RESOURCES_METAPATH
        = MetapathExpression.compile("back-matter/resource");
    @NonNull
    private static final Set<IEntityItem.ItemType> GROUP_CONTAINER_TYPES
        = ObjectUtils.notNull(EnumSet.of(
            IEntityItem.ItemType.GROUP,
            IEntityItem.ItemType.CONTROL,
            IEntityItem.ItemType.PARAMETER,
            IEntityItem.ItemType.PART));
    @NonNull
    private static final Set<IEntityItem.ItemType> CONTROL_CONTAINER_TYPES
        = ObjectUtils.notNull(EnumSet.of(
            IEntityItem.ItemType.CONTROL,
            IEntityItem.ItemType.PARAMETER,
            IEntityItem.ItemType.PART));
    @NonNull
    private final Set<IEntityItem.ItemType> itemTypesToVisit;
  
    /**
     * Create a new visitor that will visit the item types identified by
     * {@code itemTypesToVisit}.
     *
     * @param itemTypesToVisit
     *          the item type the visitor will visit
     */
    public AbstractCatalogEntityVisitor(@NonNull Set<IEntityItem.ItemType> itemTypesToVisit) {
      this.itemTypesToVisit = CollectionUtil.unmodifiableSet(itemTypesToVisit);
    }
  
    public Set<IEntityItem.ItemType> getItemTypesToVisit() {
      return CollectionUtil.unmodifiableSet(itemTypesToVisit);
    }
  
    protected boolean isVisitedItemType(@NonNull IEntityItem.ItemType type) {
      return itemTypesToVisit.contains(type);
    }
  
    @Override
    public R visitCatalog(IDocumentNodeItem catalogDocument, T state) {
      R result = super.visitCatalog(catalogDocument, state);
  
     IRootAssemblyNodeItem root = catalogDocument.getRootAssemblyNodeItem();
     visitMetadata(root, state);
     visitBackMatter(root, state);
     return result;
   }
 
   @Override
   protected R visitGroupContainer(IRequiredValueModelNodeItem catalogOrGroup, R initialResult, T state) {
     R retval;
     if (Collections.disjoint(getItemTypesToVisit(), GROUP_CONTAINER_TYPES)) {
       retval = initialResult;
     } else {
       retval = super.visitGroupContainer(catalogOrGroup, initialResult, state);
     }
     return retval;
   }
 
   @Override
   protected R visitControlContainer(IRequiredValueModelNodeItem catalogOrGroupOrControl, R initialResult, T state) {
     R retval;
     if (Collections.disjoint(getItemTypesToVisit(), CONTROL_CONTAINER_TYPES)) {
       retval = initialResult;
     } else {
       // first descend to all control container children
       retval = super.visitControlContainer(catalogOrGroupOrControl, initialResult, state);
 
       // handle parameters
       if (isVisitedItemType(IEntityItem.ItemType.PARAMETER)) {
         retval = catalogOrGroupOrControl.getModelItemsByName("param").stream()
             .map(paramItem -> {
               return visitParameter(ObjectUtils.requireNonNull(paramItem), catalogOrGroupOrControl, state);
             })
             .reduce(retval, (first, second) -> aggregateResults(first, second, state));
       } // TODO Auto-generated method stub
     }
     return retval;
   }
 
   protected void visitParts(@NonNull IRequiredValueModelNodeItem groupOrControlItem, T state) {
     // handle parts
     if (isVisitedItemType(IEntityItem.ItemType.PART)) {
       CHILD_PART_METAPATH.evaluate(groupOrControlItem).asStream()
           .map(item -> (IRequiredValueModelNodeItem) item)
           .forEachOrdered(partItem -> {
             visitPart(ObjectUtils.requireNonNull(partItem), groupOrControlItem, state);
           });
     }
   }
 
   @Override
   protected R visitGroupInternal(@NonNull IRequiredValueModelNodeItem item, R childResult, T state) {
     if (isVisitedItemType(IEntityItem.ItemType.PART)) {
       visitParts(item, state);
     }
 
     R retval = childResult;
     if (isVisitedItemType(IEntityItem.ItemType.GROUP)) {
       retval = visitGroup(item, retval, state);
     }
     return retval;
   }
 
   @Override
   protected R visitControlInternal(IRequiredValueModelNodeItem item, R childResult, T state) {
     if (isVisitedItemType(IEntityItem.ItemType.PART)) {
       visitParts(item, state);
     }
 
     R retval = childResult;
     if (isVisitedItemType(IEntityItem.ItemType.CONTROL)) {
       retval = visitControl(item, retval, state);
     }
     return retval;
   }
 
   /**
    * Called when visiting a parameter.
    * <p>
    * Can be overridden by classes extending this interface to support processing
    * of the visited object.
    *
    * @param item
    *          the Metapath item for the parameter
    * @param catalogOrGroupOrControl
    *          the parameter's parent Metapath item
    * @param state
    *          the calling context information
    * @return a meaningful result of the given type
    */
   protected R visitParameter(
       @NonNull IRequiredValueModelNodeItem item,
       @NonNull IRequiredValueModelNodeItem catalogOrGroupOrControl,
       T state) {
     // do nothing
     return newDefaultResult(state);
   }
 
   /**
    * Called when visiting a part.
    * <p>
    * Can be overridden by classes extending this interface to support processing
    * of the visited object.
    *
    * @param item
    *          the Metapath item for the part
    * @param groupOrControl
    *          the part's parent Metapath item
    * @param state
    *          the calling context information
    */
   protected void visitPart( // NOPMD noop default
       @NonNull IRequiredValueModelNodeItem item,
       @NonNull IRequiredValueModelNodeItem groupOrControl,
       T state) {
     // do nothing
   }
 
   /**
    * Called when visiting the "metadata" section of an OSCAL document.
    * <p>
    * Visits each contained role, location, and party.
    *
    * @param rootItem
    *          the root Metaschema node item containing the "metadata" node
    * @param state
    *          the calling context information
    */
   protected void visitMetadata(@NonNull IRootAssemblyNodeItem rootItem, T state) {
     rootItem.getModelItemsByName("metadata").forEach(metadataItem -> {
       if (isVisitedItemType(IEntityItem.ItemType.ROLE)) {
         metadataItem.getModelItemsByName("role").forEach(roleItem -> {
           visitRole(ObjectUtils.requireNonNull(roleItem), metadataItem, state);
         });
       }
 
       if (isVisitedItemType(IEntityItem.ItemType.LOCATION)) {
         metadataItem.getModelItemsByName("location").forEach(locationItem -> {
           visitLocation(ObjectUtils.requireNonNull(locationItem), metadataItem, state);
         });
       }
 
       if (isVisitedItemType(IEntityItem.ItemType.PARTY)) {
         metadataItem.getModelItemsByName("party").forEach(partyItem -> {
           visitParty(ObjectUtils.requireNonNull(partyItem), metadataItem, state);
         });
       }
     });
   }
 
   /**
    * Called when visiting a role in the "metadata" section of an OSCAL document.
    * <p>
    * Can be overridden by classes extending this interface to support processing
    * of the visited object.
    *
    * @param item
    *          the role Metaschema node item which is a child of the "metadata"
    *          node
    * @param metadataItem
    *          the "metadata" Metaschema node item containing the role
    * @param state
    *          the calling context information
    */
   protected void visitRole( // NOPMD noop default
       @NonNull IRequiredValueModelNodeItem item,
       @NonNull IRequiredValueModelNodeItem metadataItem,
       T state) {
     // do nothing
   }
 
   /**
    * Called when visiting a location in the "metadata" section of an OSCAL
    * document.
    * <p>
    * Can be overridden by classes extending this interface to support processing
    * of the visited object.
    *
    * @param item
    *          the location Metaschema node item which is a child of the "metadata"
    *          node
    * @param metadataItem
    *          the "metadata" Metaschema node item containing the location
    * @param state
    *          the calling context information
    */
   protected void visitLocation( // NOPMD noop default
       @NonNull IRequiredValueModelNodeItem item,
       @NonNull IRequiredValueModelNodeItem metadataItem,
       T state) {
     // do nothing
   }
 
   /**
    * Called when visiting a party in the "metadata" section of an OSCAL document.
    * <p>
    * Can be overridden by classes extending this interface to support processing
    * of the visited object.
    *
    * @param item
    *          the party Metaschema node item which is a child of the "metadata"
    *          node
    * @param metadataItem
    *          the "metadata" Metaschema node item containing the party
    * @param state
    *          the calling context information
    */
   protected void visitParty( // NOPMD noop default
       @NonNull IRequiredValueModelNodeItem item,
       @NonNull IRequiredValueModelNodeItem metadataItem,
       T state) {
     // do nothing
   }
 
   /**
    * Called when visiting the "back-matter" section of an OSCAL document.
    * <p>
    * Visits each contained resource.
    *
    * @param rootItem
    *          the root Metaschema node item containing the "back-matter" node
    * @param state
    *          the calling context information
    */
   protected void visitBackMatter(@NonNull IRootAssemblyNodeItem rootItem, T state) {
     if (isVisitedItemType(IEntityItem.ItemType.RESOURCE)) {
       BACK_MATTER_RESOURCES_METAPATH.evaluate(rootItem).asStream()
           .map(item -> (IRequiredValueModelNodeItem) item)
           .forEachOrdered(resourceItem -> {
             visitResource(ObjectUtils.requireNonNull(resourceItem), rootItem, state);
           });
     }
   }
 
   /**
    * Called when visiting a resource in the "back-matter" section of an OSCAL
    * document.
    * <p>
    * Can be overridden by classes extending this interface to support processing
    * of the visited object.
    *
    * @param item
    *          the resource Metaschema node item which is a child of the "metadata"
    *          node
    * @param backMatterItem
    *          the resource Metaschema node item containing the party
    * @param state
    *          the calling context information
    */
   protected void visitResource( // NOPMD noop default
       @NonNull IRequiredValueModelNodeItem item,
       @NonNull IRootAssemblyNodeItem backMatterItem,
       T state) {
     // do nothing
   }
 }