/*
    * SPDX-FileCopyrightText: none
    * SPDX-License-Identifier: CC0-1.0
    */
   
   package gov.nist.secauto.oscal.lib.profile.resolver.support;
   
   import gov.nist.secauto.metaschema.core.datatype.adapter.UuidAdapter;
   import gov.nist.secauto.metaschema.core.metapath.MetapathExpression;
  import gov.nist.secauto.metaschema.core.metapath.MetapathExpression.ResultType;
  import gov.nist.secauto.metaschema.core.metapath.item.node.IModelNodeItem;
  import gov.nist.secauto.metaschema.core.metapath.item.node.INodeItem;
  import gov.nist.secauto.metaschema.core.util.CollectionUtil;
  import gov.nist.secauto.metaschema.core.util.ObjectUtils;
  import gov.nist.secauto.oscal.lib.OscalBindingContext;
  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.ProfileResolver;
  import gov.nist.secauto.oscal.lib.profile.resolver.support.IEntityItem.ItemType;
  
  import org.apache.logging.log4j.LogManager;
  import org.apache.logging.log4j.Logger;
  
  import java.util.Collection;
  import java.util.Collections;
  import java.util.EnumMap;
  import java.util.LinkedHashMap;
  import java.util.Locale;
  import java.util.Map;
  import java.util.UUID;
  import java.util.concurrent.ConcurrentHashMap;
  import java.util.stream.Collectors;
  
  import edu.umd.cs.findbugs.annotations.NonNull;
  
  public class BasicIndexer implements IIndexer {
    private static final Logger LOGGER = LogManager.getLogger(ProfileResolver.class);
    private static final MetapathExpression CONTAINER_METAPATH
        = MetapathExpression.compile("(ancestor::control|ancestor::group)[1]",
            OscalBindingContext.OSCAL_STATIC_METAPATH_CONTEXT);
  
    @NonNull
    private final Map<IEntityItem.ItemType, Map<String, IEntityItem>> entityTypeToIdentifierToEntityMap;
    @NonNull
    private Map<INodeItem, SelectionStatus> nodeItemToSelectionStatusMap;
  
    @Override
    public void append(@NonNull IIndexer other) {
      for (ItemType itemType : ItemType.values()) {
        assert itemType != null;
        for (IEntityItem entity : other.getEntitiesByItemType(itemType)) {
          assert entity != null;
          addItem(entity);
        }
      }
  
      this.nodeItemToSelectionStatusMap.putAll(other.getSelectionStatusMap());
    }
  
    public BasicIndexer() {
      this.entityTypeToIdentifierToEntityMap = new EnumMap<>(IEntityItem.ItemType.class);
      this.nodeItemToSelectionStatusMap = new ConcurrentHashMap<>();
    }
  
    @SuppressWarnings("PMD.AvoidInstantiatingObjectsInLoops") // needed
    public BasicIndexer(IIndexer other) {
      // copy entity map
      this.entityTypeToIdentifierToEntityMap = other.getEntities();
  
      // copy selection map
      this.nodeItemToSelectionStatusMap = new ConcurrentHashMap<>(other.getSelectionStatusMap());
    }
  
    @Override
    public void setSelectionStatus(@NonNull INodeItem item, @NonNull SelectionStatus selectionStatus) {
      nodeItemToSelectionStatusMap.put(item, selectionStatus);
    }
  
    @Override
    public Map<INodeItem, SelectionStatus> getSelectionStatusMap() {
      return CollectionUtil.unmodifiableMap(nodeItemToSelectionStatusMap);
    }
  
    @Override
    public SelectionStatus getSelectionStatus(@NonNull INodeItem item) {
      SelectionStatus retval = nodeItemToSelectionStatusMap.get(item);
      return retval == null ? SelectionStatus.UNKNOWN : retval;
    }
  
    @Override
    public void resetSelectionStatus() {
      nodeItemToSelectionStatusMap = new ConcurrentHashMap<>();
    }
 
   @Override
   public boolean isSelected(@NonNull IEntityItem entity) {
     boolean retval;
     switch (entity.getItemType()) {
     case CONTROL:
     case GROUP:
       retval = IIndexer.SelectionStatus.SELECTED.equals(getSelectionStatus(entity.getInstance()));
       break;
     case PART: {
       IModelNodeItem<?, ?> instance = entity.getInstance();
       IIndexer.SelectionStatus status = getSelectionStatus(instance);
       if (IIndexer.SelectionStatus.UNKNOWN.equals(status)) {
         // lookup the status if not known
         IModelNodeItem<?, ?> containerItem = CONTAINER_METAPATH.evaluateAs(instance, ResultType.ITEM);
         assert containerItem != null;
         status = getSelectionStatus(containerItem);
 
         // cache the status
         setSelectionStatus(instance, status);
       }
       retval = IIndexer.SelectionStatus.SELECTED.equals(status);
       break;
     }
     case PARAMETER:
     case LOCATION:
     case PARTY:
     case RESOURCE:
     case ROLE:
       // always "selected"
       retval = true;
       break;
     default:
       throw new UnsupportedOperationException(entity.getItemType().name());
     }
     return retval;
   }
 
   @Override
   public Map<ItemType, Map<String, IEntityItem>> getEntities() {
     // make a copy
     Map<ItemType, Map<String, IEntityItem>> copy = entityTypeToIdentifierToEntityMap.entrySet().stream()
         .map(entry -> {
           ItemType key = entry.getKey();
           Map<String, IEntityItem> oldMap = entry.getValue();
 
           Map<String, IEntityItem> newMap = oldMap.entrySet().stream()
               .collect(Collectors.toMap(
                   Map.Entry::getKey,
                   Map.Entry::getValue,
                   (key1, key2) -> key1,
                   LinkedHashMap::new)); // need ordering
           assert newMap != null;
           // use a synchronized map to ensure thread safety
           return Map.entry(key, Collections.synchronizedMap(newMap));
         })
         .collect(Collectors.toMap(
             Map.Entry::getKey,
             Map.Entry::getValue,
             (key1, key2) -> key1,
             ConcurrentHashMap::new));
 
     assert copy != null;
     return copy;
   }
 
   @Override
   @NonNull
   // TODO: rename to getEntitiesForItemType
   public Collection<IEntityItem> getEntitiesByItemType(@NonNull IEntityItem.ItemType itemType) {
     Map<String, IEntityItem> entityGroup = entityTypeToIdentifierToEntityMap.get(itemType);
     return entityGroup == null ? CollectionUtil.emptyList() : ObjectUtils.notNull(entityGroup.values());
   }
   //
   // public EntityItem getEntity(@NonNull ItemType itemType, @NonNull UUID
   // identifier) {
   // return getEntity(itemType, ObjectUtils.notNull(identifier.toString()),
   // false);
   // }
   //
   // public EntityItem getEntity(@NonNull ItemType itemType, @NonNull String
   // identifier) {
   // return getEntity(itemType, identifier, itemType.isUuid());
   // }
 
   @Override
   public IEntityItem getEntity(@NonNull ItemType itemType, @NonNull String identifier, boolean normalize) {
     Map<String, IEntityItem> entityGroup = entityTypeToIdentifierToEntityMap.get(itemType);
     String normalizedIdentifier = normalize ? normalizeIdentifier(identifier) : identifier;
     return entityGroup == null ? null : entityGroup.get(normalizedIdentifier);
   }
 
   protected IEntityItem addItem(@NonNull IEntityItem item) {
     IEntityItem.ItemType type = item.getItemType();
 
     @SuppressWarnings("PMD.UseConcurrentHashMap") // need ordering
     Map<String, IEntityItem> entityGroup = entityTypeToIdentifierToEntityMap.computeIfAbsent(
         type,
         key -> Collections.synchronizedMap(new LinkedHashMap<>()));
     IEntityItem oldEntity = entityGroup.put(item.getIdentifier(), item);
 
     if (oldEntity != null && LOGGER.isWarnEnabled()) {
       LOGGER.atWarn().log("Duplicate {} found with identifier {} in index.",
           oldEntity.getItemType().name().toLowerCase(Locale.ROOT),
           oldEntity.getIdentifier());
     }
     return oldEntity;
   }
 
   @NonNull
   protected IEntityItem addItem(@NonNull AbstractEntityItem.Builder builder) {
     IEntityItem retval = builder.build();
     addItem(retval);
     return retval;
   }
 
   @Override
   public boolean removeItem(@NonNull IEntityItem entity) {
     IEntityItem.ItemType type = entity.getItemType();
     Map<String, IEntityItem> entityGroup = entityTypeToIdentifierToEntityMap.get(type);
 
     boolean retval = false;
     if (entityGroup != null) {
       retval = entityGroup.remove(entity.getIdentifier(), entity);
 
       // remove if present
       nodeItemToSelectionStatusMap.remove(entity.getInstance());
 
       if (retval) {
         if (LOGGER.isDebugEnabled()) {
           LOGGER.atDebug().log("Removing {} '{}' from index.", type.name(), entity.getIdentifier());
         }
       } else if (LOGGER.isDebugEnabled()) {
         LOGGER.atDebug().log("The {} entity '{}' was not found in the index to remove.",
             type.name(),
             entity.getIdentifier());
       }
     }
     return retval;
   }
 
   @Override
   public IEntityItem addRole(IModelNodeItem<?, ?> item) {
     Role role = ObjectUtils.requireNonNull((Role) item.getValue());
     String identifier = ObjectUtils.requireNonNull(role.getId());
 
     return addItem(newBuilder(item, ItemType.ROLE, identifier));
   }
 
   @Override
   public IEntityItem addLocation(IModelNodeItem<?, ?> item) {
     Location location = ObjectUtils.requireNonNull((Location) item.getValue());
     UUID identifier = ObjectUtils.requireNonNull(location.getUuid());
 
     return addItem(newBuilder(item, ItemType.LOCATION, identifier));
   }
 
   @Override
   public IEntityItem addParty(IModelNodeItem<?, ?> item) {
     Party party = ObjectUtils.requireNonNull((Party) item.getValue());
     UUID identifier = ObjectUtils.requireNonNull(party.getUuid());
 
     return addItem(newBuilder(item, ItemType.PARTY, identifier));
   }
 
   @Override
   public IEntityItem addGroup(IModelNodeItem<?, ?> item) {
     CatalogGroup group = ObjectUtils.requireNonNull((CatalogGroup) item.getValue());
     String identifier = group.getId();
     return identifier == null ? null : addItem(newBuilder(item, ItemType.GROUP, identifier));
   }
 
   @Override
   public IEntityItem addControl(IModelNodeItem<?, ?> item) {
     Control control = ObjectUtils.requireNonNull((Control) item.getValue());
     String identifier = ObjectUtils.requireNonNull(control.getId());
     return addItem(newBuilder(item, ItemType.CONTROL, identifier));
   }
 
   @Override
   public IEntityItem addParameter(IModelNodeItem<?, ?> item) {
     Parameter parameter = ObjectUtils.requireNonNull((Parameter) item.getValue());
     String identifier = ObjectUtils.requireNonNull(parameter.getId());
 
     return addItem(newBuilder(item, ItemType.PARAMETER, identifier));
   }
 
   @Override
   public IEntityItem addPart(IModelNodeItem<?, ?> item) {
     ControlPart part = ObjectUtils.requireNonNull((ControlPart) item.getValue());
     String identifier = part.getId();
 
     return identifier == null ? null : addItem(newBuilder(item, ItemType.PART, identifier));
   }
 
   @Override
   public IEntityItem addResource(IModelNodeItem<?, ?> item) {
     Resource resource = ObjectUtils.requireNonNull((Resource) item.getValue());
     UUID identifier = ObjectUtils.requireNonNull(resource.getUuid());
 
     return addItem(newBuilder(item, ItemType.RESOURCE, identifier));
   }
 
   @NonNull
   protected final AbstractEntityItem.Builder newBuilder(
       @NonNull IModelNodeItem<?, ?> item,
       @NonNull ItemType itemType,
       @NonNull UUID identifier) {
     return newBuilder(item, itemType, ObjectUtils.notNull(identifier.toString()));
   }
 
   /**
    * Create a new builder with the provided info.
    * <p>
    * This method can be overloaded to support applying additional data to the
    * returned builder.
    * <p>
    * When working with identifiers that are case insensitve, it is important to
    * ensure that the identifiers are normalized to lower case.
    *
    * @param item
    *          the Metapath node to associate with the entity
    * @param itemType
    *          the type of entity
    * @param identifier
    *          the entity's identifier
    * @return the entity builder
    */
   @NonNull
   protected AbstractEntityItem.Builder newBuilder(
       @NonNull IModelNodeItem<?, ?> item,
       @NonNull ItemType itemType,
       @NonNull String identifier) {
     return new AbstractEntityItem.Builder()
         .instance(item, itemType)
         .originalIdentifier(identifier)
         .source(ObjectUtils.requireNonNull(item.getBaseUri(), "item must have an associated URI"));
   }
 
   /**
    * Lower case UUID-based identifiers and leave others unmodified.
    *
    * @param identifier
    *          the identifier
    * @return the resulting normalized identifier
    */
   @NonNull
   public String normalizeIdentifier(@NonNull String identifier) {
     return UuidAdapter.UUID_PATTERN.matcher(identifier).matches()
         ? ObjectUtils.notNull(identifier.toLowerCase(Locale.ROOT))
         : identifier;
   }
   //
   // private static class ItemGroup {
   // @NonNull
   // private final ItemType itemType;
   // Map<String, IEntityItem> idToEntityMap;
   //
   // public ItemGroup(@NonNull ItemType itemType) {
   // this.itemType = itemType;
   // this.idToEntityMap = new LinkedHashMap<>();
   // }
   //
   // public IEntityItem getEntity(@NonNull String identifier) {
   // return idToEntityMap.get(identifier);
   // }
   //
   // @SuppressWarnings("null")
   // @NonNull
   // public Collection<IEntityItem> getEntities() {
   // return idToEntityMap.values();
   // }
   //
   // public IEntityItem add(@NonNull IEntityItem entity) {
   // assert itemType.equals(entity.getItemType());
   // return idToEntityMap.put(entity.getOriginalIdentifier(), entity);
   // }
   // }
 }