/*
    * 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.selection;
  
  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;
  import gov.nist.secauto.oscal.lib.model.BackMatter.Resource;
  import gov.nist.secauto.oscal.lib.model.Catalog;
  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;
  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.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 org.apache.logging.log4j.LogManager;
  import org.apache.logging.log4j.Logger;
  
  import java.util.EnumSet;
  import java.util.stream.Collectors;
  
  import edu.umd.cs.findbugs.annotations.NonNull;
  import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
  
  public class FilterNonSelectedVisitor
      extends AbstractCatalogEntityVisitor<FilterNonSelectedVisitor.Context, DefaultResult> {
    private static final Logger LOGGER = LogManager.getLogger(FilterNonSelectedVisitor.class);
    private static final FilterNonSelectedVisitor SINGLETON = new FilterNonSelectedVisitor();
  
    public static FilterNonSelectedVisitor instance() {
      return SINGLETON;
    }
  
    @SuppressWarnings("null")
    protected FilterNonSelectedVisitor() {
      // all other entity types are handled in a special way by this visitor
      super(EnumSet.of(IEntityItem.ItemType.GROUP, IEntityItem.ItemType.CONTROL, IEntityItem.ItemType.PARAMETER));
    }
  
    public void visitCatalog(@NonNull IDocumentNodeItem catalogItem, @NonNull IIndexer indexer) {
      Context context = new Context(indexer);
      IResult result = visitCatalog(catalogItem, context);
  
      IRootAssemblyNodeItem root = catalogItem.getRootAssemblyNodeItem();
  
      Catalog catalog = (Catalog) catalogItem.getValue();
      result.applyTo(catalog);
  
      root.getModelItemsByName("metadata").forEach(child -> {
        assert child != null;
        visitMetadata(child, context);
      });
  
      root.getModelItemsByName("back-matter").forEach(child -> {
        assert child != null;
        visitBackMatter(child, context);
      });
    }
  
    @Override
    protected DefaultResult newDefaultResult(Context state) {
      return new DefaultResult();
    }
  
    @Override
   protected DefaultResult aggregateResults(DefaultResult first, DefaultResult second, Context state) {
     return first.append(ObjectUtils.notNull(second));
   }
 
   protected void visitMetadata(@NonNull IRequiredValueModelNodeItem metadataItem, Context context) {
     Metadata metadata = (Metadata) metadataItem.getValue();
 
     IIndexer index = context.getIndexer();
     // prune roles, parties, and locations
     // keep entries with prop name:keep and any referenced
     for (IEntityItem entity : IIndexer.getUnreferencedEntitiesAsStream(index.getEntitiesByItemType(ItemType.ROLE))
         .collect(Collectors.toList())) {
       Role role = entity.getInstanceValue();
       if (LOGGER.isDebugEnabled()) {
         LOGGER.atDebug().log("Removing role '{}'", role.getId());
       }
       metadata.removeRole(role);
       index.removeItem(entity);
     }
 
     for (IEntityItem entity : IIndexer.getUnreferencedEntitiesAsStream(index.getEntitiesByItemType(ItemType.PARTY))
         .collect(Collectors.toList())) {
       Party party = entity.getInstanceValue();
       if (LOGGER.isDebugEnabled()) {
         LOGGER.atDebug().log("Removing party '{}'", party.getUuid());
       }
       metadata.removeParty(party);
       index.removeItem(entity);
     }
 
     for (IEntityItem entity : IIndexer.getUnreferencedEntitiesAsStream(index.getEntitiesByItemType(ItemType.LOCATION))
         .collect(Collectors.toList())) {
       Location location = entity.getInstanceValue();
       if (LOGGER.isDebugEnabled()) {
         LOGGER.atDebug().log("Removing location '{}'", location.getUuid());
       }
       metadata.removeLocation(location);
       index.removeItem(entity);
     }
   }
 
   @SuppressWarnings("static-method")
   private void visitBackMatter(@NonNull IRequiredValueModelNodeItem backMatterItem, Context context) {
     BackMatter backMatter = (BackMatter) backMatterItem.getValue();
 
     IIndexer index = context.getIndexer();
     for (IEntityItem entity : IIndexer.getUnreferencedEntitiesAsStream(index.getEntitiesByItemType(ItemType.RESOURCE))
         .collect(Collectors.toList())) {
       Resource resource = entity.getInstanceValue();
       if (LOGGER.isDebugEnabled()) {
         LOGGER.atDebug().log("Removing resource '{}'", resource.getUuid());
       }
       backMatter.removeResource(resource);
       index.removeItem(entity);
     }
   }
 
   @Override
   public DefaultResult visitGroup(
       IRequiredValueModelNodeItem item,
       DefaultResult childResult,
       Context context) {
     CatalogGroup group = (CatalogGroup) item.getValue();
 
     IIndexer index = context.getIndexer();
     String groupId = group.getId();
     DefaultResult retval = new DefaultResult();
     if (SelectionStatus.SELECTED.equals(index.getSelectionStatus(item))) {
       if (groupId != null) {
         // this group should always be found in the index
         IEntityItem entity = ObjectUtils.requireNonNull(index.getEntity(ItemType.GROUP, groupId, false));
         // update the id
         group.setId(entity.getIdentifier());
       }
       childResult.applyTo(group);
     } else {
       retval.removeGroup(group);
       retval.appendPromoted(ObjectUtils.notNull(childResult));
 
       if (groupId != null) {
         // this group should always be found in the index
         IEntityItem entity = ObjectUtils.requireNonNull(index.getEntity(ItemType.GROUP, groupId, false));
         index.removeItem(entity);
       }
 
       // remove any associated parts from the index
       removePartsFromIndex(item, index);
     }
     return retval;
   }
 
   @Override
   public DefaultResult visitControl(
       IRequiredValueModelNodeItem item,
       DefaultResult childResult,
       Context context) {
     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
       // update the id
       control.setId(entity.getIdentifier());
 
       if (!SelectionStatus.SELECTED.equals(index.getSelectionStatus(parent))) {
         // promote this control
         retval.promoteControl(control);
       }
       childResult.applyTo(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;
   }
 
   protected static void removePartsFromIndex(@NonNull IRequiredValueModelNodeItem groupOrControlItem,
       @NonNull IIndexer index) {
     CHILD_PART_METAPATH.evaluate(groupOrControlItem).asStream()
         .map(item -> (IRequiredValueModelNodeItem) item)
         .forEachOrdered(partItem -> {
           ControlPart part = (ControlPart) partItem.getValue();
           String id = part.getId();
           if (id != null) {
             IEntityItem entity = index.getEntity(IEntityItem.ItemType.PART, id);
             if (entity != null) {
               index.removeItem(entity);
             }
           }
         });
   }
 
   @Override
   protected DefaultResult visitParameter(IRequiredValueModelNodeItem item, IRequiredValueModelNodeItem parent,
       Context context) {
     Parameter param = (Parameter) item.getValue();
     IIndexer index = context.getIndexer();
     // this parameter should always be found in the index
     IEntityItem entity = ObjectUtils.requireNonNull(
         index.getEntity(ItemType.PARAMETER, ObjectUtils.requireNonNull(param.getId()), false));
 
     DefaultResult retval = new DefaultResult();
     if (IIndexer.isReferencedEntity(entity)) {
       // keep the parameter
       // update the id
       param.setId(entity.getIdentifier());
 
       // a parameter is selected if it has a reference count greater than 0
       index.setSelectionStatus(item, SelectionStatus.SELECTED);
 
       // promote this parameter
       if (SelectionStatus.UNSELECTED.equals(index.getSelectionStatus(parent))) {
         retval.promoteParameter(param);
       }
     } else {
       // don't keep the parameter
       if (SelectionStatus.SELECTED.equals(index.getSelectionStatus(parent))) {
         retval.removeParameter(param);
       }
       index.removeItem(entity);
     }
     return retval;
   }
 
   protected static final class Context {
 
     @NonNull
     private final IIndexer indexer;
 
     private Context(@NonNull IIndexer indexer) {
       super();
       this.indexer = indexer;
     }
 
     @NonNull
     @SuppressFBWarnings(value = "EI_EXPOSE_REP", justification = "provides intentional access to index state")
     public IIndexer getIndexer() {
       return indexer;
     }
   }
 }