/*
    * SPDX-FileCopyrightText: none
    * SPDX-License-Identifier: CC0-1.0
    */
   
   package gov.nist.secauto.oscal.lib.profile.resolver.selection;
   
   import gov.nist.secauto.metaschema.core.metapath.item.node.IAssemblyNodeItem;
   import gov.nist.secauto.metaschema.core.metapath.item.node.IDocumentNodeItem;
  import gov.nist.secauto.metaschema.core.metapath.item.node.INodeItem;
  import gov.nist.secauto.metaschema.core.util.ObjectUtils;
  import gov.nist.secauto.oscal.lib.OscalModelConstants;
  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);
    @NonNull
    private static final FilterNonSelectedVisitor SINGLETON = new FilterNonSelectedVisitor();
  
    @NonNull
    @SuppressFBWarnings(value = "SING_SINGLETON_GETTER_NOT_SYNCHRONIZED", justification = "class initialization")
    public static FilterNonSelectedVisitor instance() {
      return SINGLETON;
    }
  
    @SuppressWarnings("null")
  
    @SuppressFBWarnings(value = "SING_SINGLETON_HAS_NONPRIVATE_CONSTRUCTOR", justification = "allows for extension")
    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);
  
      Catalog catalog = (Catalog) INodeItem.toValue(catalogItem);
      result.applyTo(catalog);
  
      catalogItem.modelItems().forEachOrdered(root -> {
        root.getModelItemsByName(OscalModelConstants.QNAME_METADATA).stream()
            .map(child -> (IAssemblyNodeItem) child)
            .forEachOrdered(child -> {
              assert child != null;
              visitMetadata(child, context);
            });
  
        root.getModelItemsByName(OscalModelConstants.QNAME_BACK_MATTER).stream()
            .map(child -> (IAssemblyNodeItem) child)
            .forEachOrdered(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 IAssemblyNodeItem metadataItem, Context context) {
      Metadata metadata = ObjectUtils.requireNonNull((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 IAssemblyNodeItem backMatterItem, Context context) {
     BackMatter backMatter = ObjectUtils.requireNonNull((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(
       IAssemblyNodeItem item,
       DefaultResult childResult,
       Context context) {
     CatalogGroup group = ObjectUtils.requireNonNull((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(
       IAssemblyNodeItem item,
       DefaultResult childResult,
       Context context) {
     Control control = ObjectUtils.requireNonNull((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));
 
     IAssemblyNodeItem 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 IAssemblyNodeItem groupOrControlItem,
       @NonNull IIndexer index) {
     CHILD_PART_METAPATH.evaluate(groupOrControlItem).stream()
         .map(item -> (IAssemblyNodeItem) item)
         .forEachOrdered(partItem -> {
           ControlPart part = ObjectUtils.requireNonNull((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(IAssemblyNodeItem item, IAssemblyNodeItem parent,
       Context context) {
     Parameter param = ObjectUtils.requireNonNull((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) {
       this.indexer = indexer;
     }
 
     @NonNull
     @SuppressFBWarnings(value = "EI_EXPOSE_REP", justification = "provides intentional access to index state")
     public IIndexer getIndexer() {
       return indexer;
     }
   }
 }