/*
    * 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.merge;
  
  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.ObjectUtils;
  import gov.nist.secauto.oscal.lib.model.BackMatter.Resource;
  import gov.nist.secauto.oscal.lib.model.CatalogGroup;
  import gov.nist.secauto.oscal.lib.model.Control;
  import gov.nist.secauto.oscal.lib.model.ControlPart;
  import gov.nist.secauto.oscal.lib.model.Metadata.Location;
  import gov.nist.secauto.oscal.lib.model.Metadata.Party;
  import gov.nist.secauto.oscal.lib.model.Metadata.Role;
  import gov.nist.secauto.oscal.lib.model.Parameter;
  import gov.nist.secauto.oscal.lib.profile.resolver.policy.ReferenceCountingVisitor;
  import gov.nist.secauto.oscal.lib.profile.resolver.selection.DefaultResult;
  import gov.nist.secauto.oscal.lib.profile.resolver.selection.FilterNonSelectedVisitor;
  import gov.nist.secauto.oscal.lib.profile.resolver.support.AbstractCatalogEntityVisitor;
  import gov.nist.secauto.oscal.lib.profile.resolver.support.IEntityItem;
  import gov.nist.secauto.oscal.lib.profile.resolver.support.IEntityItem.ItemType;
  import gov.nist.secauto.oscal.lib.profile.resolver.support.IIndexer;
  import gov.nist.secauto.oscal.lib.profile.resolver.support.IIndexer.SelectionStatus;
  
  import java.util.EnumSet;
  import java.util.UUID;
  
  import edu.umd.cs.findbugs.annotations.NonNull;
  
  public class FlatteningStructuringVisitor
      extends AbstractCatalogEntityVisitor<IIndexer, Void> {
    private static final FlatteningStructuringVisitor SINGLETON = new FlatteningStructuringVisitor();
  
    public static FlatteningStructuringVisitor instance() {
      return SINGLETON;
    }
  
    public FlatteningStructuringVisitor() {
      super(ObjectUtils.notNull(EnumSet.of(ItemType.GROUP, ItemType.CONTROL)));
    }
  
    @Override
    protected Void newDefaultResult(IIndexer state) {
      // do nothing
      return null;
    }
  
    @Override
    protected Void aggregateResults(Void first, Void second, IIndexer state) {
      // do nothing
      return null;
    }
  
    @Override
    public Void visitCatalog(@NonNull IDocumentNodeItem catalogItem, IIndexer index) {
      index.resetSelectionStatus();
  
      index.setSelectionStatus(catalogItem, SelectionStatus.SELECTED);
      super.visitCatalog(catalogItem, index);
  
      for (ItemType itemType : ItemType.values()) {
        assert itemType != null;
        for (IEntityItem item : index.getEntitiesByItemType(itemType)) {
          item.resetReferenceCount();
        }
      }
  
      // process references, looking for orphaned links to groups
      ReferenceCountingVisitor.instance().visitCatalog(catalogItem, index, catalogItem.getDocumentUri());
  
      FlatteningFilterNonSelectedVisitor.instance().visitCatalog(catalogItem, index);
      return null;
    }
  
   @Override
   public Void visitGroup(IRequiredValueModelNodeItem item, Void childResult, IIndexer index) {
     CatalogGroup group = (CatalogGroup) item.getValue();
     String id = group.getId();
     if (id != null) {
       IEntityItem entity = index.getEntity(ItemType.GROUP, id);
       assert entity != null;
       // refresh the instance
       entity.setInstance(item);
     }
 
     index.setSelectionStatus(item, SelectionStatus.UNSELECTED);
     handlePartSelection(item, index, SelectionStatus.UNSELECTED);
     return super.visitGroup(item, childResult, index);
   }
 
   @Override
   public Void visitControl(IRequiredValueModelNodeItem item, Void childResult, IIndexer index) {
     Control control = (Control) item.getValue();
     String id = ObjectUtils.requireNonNull(control.getId());
     IEntityItem entity = index.getEntity(ItemType.CONTROL, id);
     assert entity != null;
     // refresh the instance
     entity.setInstance(item);
 
     index.setSelectionStatus(item, SelectionStatus.SELECTED);
     handlePartSelection(item, index, SelectionStatus.SELECTED);
     return null;
   }
 
   @Override
   protected Void visitParameter(IRequiredValueModelNodeItem item,
       IRequiredValueModelNodeItem catalogOrGroupOrControl, IIndexer index) {
     Parameter parameter = (Parameter) item.getValue();
     String id = ObjectUtils.requireNonNull(parameter.getId());
     IEntityItem entity = index.getEntity(ItemType.PARAMETER, id);
     assert entity != null;
     // refresh the instance
     entity.setInstance(item);
 
     return null;
   }
 
   @Override
   protected void visitRole(IRequiredValueModelNodeItem item, IRequiredValueModelNodeItem metadataItem,
       IIndexer index) {
     Role role = (Role) item.getValue();
     String id = ObjectUtils.requireNonNull(role.getId());
     IEntityItem entity = index.getEntity(ItemType.ROLE, id);
     assert entity != null;
     // refresh the instance
     entity.setInstance(item);
   }
 
   @Override
   protected void visitLocation(IRequiredValueModelNodeItem item, IRequiredValueModelNodeItem metadataItem,
       IIndexer index) {
     Location location = (Location) item.getValue();
     UUID uuid = ObjectUtils.requireNonNull(location.getUuid());
     IEntityItem entity = index.getEntity(ItemType.LOCATION, uuid);
     assert entity != null;
     // refresh the instance
     entity.setInstance(item);
   }
 
   @Override
   protected void visitParty(IRequiredValueModelNodeItem item, IRequiredValueModelNodeItem metadataItem,
       IIndexer index) {
     Party location = (Party) item.getValue();
     UUID uuid = ObjectUtils.requireNonNull(location.getUuid());
     IEntityItem entity = index.getEntity(ItemType.PARTY, uuid);
     assert entity != null;
     // refresh the instance
     entity.setInstance(item);
   }
 
   @Override
   protected void visitResource(IRequiredValueModelNodeItem item, IRootAssemblyNodeItem rootItem,
       IIndexer index) {
     Resource location = (Resource) item.getValue();
     UUID uuid = ObjectUtils.requireNonNull(location.getUuid());
     IEntityItem entity = index.getEntity(ItemType.RESOURCE, uuid);
     assert entity != null;
     // refresh the instance
     entity.setInstance(item);
   }
 
   private static void handlePartSelection(
       @NonNull IRequiredValueModelNodeItem groupOrControlItem,
       @NonNull IIndexer index,
       @NonNull SelectionStatus selectionStatus) {
     CHILD_PART_METAPATH.evaluate(groupOrControlItem).asStream()
         .map(item -> (IRequiredValueModelNodeItem) item)
         .forEachOrdered(partItem -> {
           index.setSelectionStatus(ObjectUtils.requireNonNull(partItem), selectionStatus);
 
           ControlPart part = (ControlPart) partItem.getValue();
           String id = part.getId();
           if (id != null) {
             IEntityItem entity = index.getEntity(ItemType.PART, id);
             assert entity != null;
             // refresh the instance
             entity.setInstance(partItem);
           }
         });
   }
 
   private static final class FlatteningFilterNonSelectedVisitor
       extends FilterNonSelectedVisitor {
     private static final FlatteningFilterNonSelectedVisitor SINGLETON = new FlatteningFilterNonSelectedVisitor();
 
     public static FlatteningFilterNonSelectedVisitor instance() {
       return SINGLETON;
     }
 
     @Override
     public DefaultResult visitControl(IRequiredValueModelNodeItem item, DefaultResult childResult,
         Context context) {
       assert childResult != null;
 
       Control control = (Control) item.getValue();
       IIndexer index = context.getIndexer();
       // this control should always be found in the index
       IEntityItem entity = ObjectUtils.requireNonNull(
           index.getEntity(ItemType.CONTROL, ObjectUtils.requireNonNull(control.getId()), false));
 
       IRequiredValueModelNodeItem parent = ObjectUtils.notNull(item.getParentContentNodeItem());
       DefaultResult retval = new DefaultResult();
       if (SelectionStatus.SELECTED.equals(index.getSelectionStatus(item))) {
         // keep this control
 
         // always promote the control and any children
         retval.promoteControl(control);
 
         retval.appendPromoted(childResult);
         childResult.applyRemovesTo(control);
 
         if (parent.getValue() instanceof Control && SelectionStatus.SELECTED.equals(index.getSelectionStatus(parent))) {
           retval.removeControl(control);
         }
       } else {
         // remove this control and promote any needed children
 
         if (SelectionStatus.SELECTED.equals(index.getSelectionStatus(parent))) {
           retval.removeControl(control);
         }
         retval.appendPromoted(ObjectUtils.notNull(childResult));
         index.removeItem(entity);
 
         // remove any associated parts from the index
         removePartsFromIndex(item, index);
       }
       return retval;
     }
   }
 }