/*
    * SPDX-FileCopyrightText: none
    * SPDX-License-Identifier: CC0-1.0
    */
   
   package gov.nist.secauto.metaschema.schemagen;
   
   import gov.nist.secauto.metaschema.core.model.IAssemblyDefinition;
   import gov.nist.secauto.metaschema.core.model.IAssemblyInstance;
  import gov.nist.secauto.metaschema.core.model.IChoiceInstance;
  import gov.nist.secauto.metaschema.core.model.IDefinition;
  import gov.nist.secauto.metaschema.core.model.IFieldDefinition;
  import gov.nist.secauto.metaschema.core.model.IFieldInstance;
  import gov.nist.secauto.metaschema.core.model.IFlagDefinition;
  import gov.nist.secauto.metaschema.core.model.IFlagInstance;
  import gov.nist.secauto.metaschema.core.model.IModule;
  import gov.nist.secauto.metaschema.core.model.INamedInstance;
  import gov.nist.secauto.metaschema.core.model.INamedModelInstance;
  import gov.nist.secauto.metaschema.core.model.INamedModelInstanceGrouped;
  import gov.nist.secauto.metaschema.core.model.ModelWalker;
  import gov.nist.secauto.metaschema.core.util.ObjectUtils;
  
  import java.util.Collection;
  import java.util.HashSet;
  import java.util.LinkedHashMap;
  import java.util.Map;
  import java.util.Set;
  import java.util.concurrent.atomic.AtomicBoolean;
  
  import edu.umd.cs.findbugs.annotations.NonNull;
  
  public class ModuleIndex {
    private final Map<IDefinition, DefinitionEntry> index = new LinkedHashMap<>();// new ConcurrentHashMap<>();
  
    @NonNull
    public static ModuleIndex indexDefinitions(@NonNull IModule module, @NonNull IInlineStrategy inlineStrategy) {
      Collection<? extends IAssemblyDefinition> definitions = module.getExportedRootAssemblyDefinitions();
      ModuleIndex index = new ModuleIndex();
      if (!definitions.isEmpty()) {
        IndexVisitor visitor = new IndexVisitor(index, inlineStrategy);
        for (IAssemblyDefinition definition : definitions) {
          assert definition != null;
  
          // // add the root definition to the index
          // index.getEntry(definition).incrementReferenceCount();
  
          // walk the definition
          visitor.walk(ObjectUtils.requireNonNull(definition));
        }
      }
      return index;
    }
  
    public boolean hasEntry(@NonNull IDefinition definition) {
      return index.containsKey(definition);
    }
  
    @NonNull
    public DefinitionEntry getEntry(@NonNull IDefinition definition) {
      return ObjectUtils.notNull(index.computeIfAbsent(
          definition,
          k -> new ModuleIndex.DefinitionEntry(ObjectUtils.notNull(k))));
    }
  
    @NonNull
    public Collection<DefinitionEntry> getDefinitions() {
      return ObjectUtils.notNull(index.values());
    }
  
    private static class IndexVisitor
        extends ModelWalker<ModuleIndex> {
      @NonNull
      private final IInlineStrategy inlineStrategy;
      @NonNull
      private final ModuleIndex index;
  
      public IndexVisitor(@NonNull ModuleIndex index, @NonNull IInlineStrategy inlineStrategy) {
        this.index = index;
        this.inlineStrategy = inlineStrategy;
      }
  
      @Override
      protected ModuleIndex getDefaultData() {
        return index;
      }
  
      @Override
      protected boolean visit(IFlagInstance instance, ModuleIndex index) {
        handleInstance(instance);
        return true;
      }
  
      @Override
      protected boolean visit(IFieldInstance instance, ModuleIndex index) {
        handleInstance(instance);
        return true;
      }
  
      @Override
     protected boolean visit(IAssemblyInstance instance, ModuleIndex index) {
       handleInstance(instance);
       return true;
     }
 
     @Override
     protected void visit(IFlagDefinition def, ModuleIndex data) {
       handleDefinition(def);
     }
 
     // @Override
     // protected boolean visit(IAssemblyDefinition def, ModuleIndex data) {
     // // only walk if the definition hasn't already been visited
     // return !index.hasEntry(def);
     // }
 
     @Override
     protected boolean visit(IFieldDefinition def, ModuleIndex data) {
       return handleDefinition(def);
     }
 
     @Override
     protected boolean visit(IAssemblyDefinition def, ModuleIndex data) {
       return handleDefinition(def);
     }
 
     private boolean handleDefinition(@NonNull IDefinition definition) {
       DefinitionEntry entry = getDefaultData().getEntry(definition);
       boolean visited = entry.isVisited();
       if (!visited) {
         entry.markVisited();
 
         if (inlineStrategy.isInline(definition, index)) {
           entry.markInline();
         }
       }
       return !visited;
     }
 
     /**
      * Updates the index entry for the definition associated with the reference.
      *
      * @param instance
      *          the instance to process
      */
     @NonNull
     private DefinitionEntry handleInstance(INamedInstance instance) {
       IDefinition definition = instance.getDefinition();
       // check if this will be a new entry, which needs to be called before getEntry,
       // which will create it
       DefinitionEntry entry = getDefaultData().getEntry(definition);
       entry.addReference(instance);
 
       if (isChoice(instance)) {
         entry.markUsedAsChoice();
       }
 
       if (isChoiceSibling(instance)) {
         entry.markAsChoiceSibling();
       }
       return entry;
     }
 
     private static boolean isChoice(@NonNull INamedInstance instance) {
       return instance.getParentContainer() instanceof IChoiceInstance;
     }
 
     private static boolean isChoiceSibling(@NonNull INamedInstance instance) {
       IDefinition containingDefinition = instance.getContainingDefinition();
       return containingDefinition instanceof IAssemblyDefinition
           && !((IAssemblyDefinition) containingDefinition).getChoiceInstances().isEmpty();
     }
   }
 
   public static class DefinitionEntry {
     @NonNull
     private final IDefinition definition;
     private final Set<INamedInstance> references = new HashSet<>();
     private final AtomicBoolean inline = new AtomicBoolean(); // false
     private final AtomicBoolean visited = new AtomicBoolean(); // false
     private final AtomicBoolean usedAsChoice = new AtomicBoolean(); // false
     private final AtomicBoolean choiceSibling = new AtomicBoolean(); // false
 
     public DefinitionEntry(@NonNull IDefinition definition) {
       this.definition = definition;
     }
 
     @NonNull
     public IDefinition getDefinition() {
       return definition;
     }
 
     public boolean isRoot() {
       return definition instanceof IAssemblyDefinition
           && ((IAssemblyDefinition) definition).isRoot();
     }
 
     public boolean isReferenced() {
       return !references.isEmpty()
           || isRoot();
     }
 
     public Set<INamedInstance> getReferences() {
       return references;
     }
 
     public boolean addReference(@NonNull INamedInstance reference) {
       return references.add(reference);
     }
 
     public void markVisited() {
       visited.compareAndSet(false, true);
     }
 
     public boolean isVisited() {
       return visited.get();
     }
 
     public void markInline() {
       inline.compareAndSet(false, true);
     }
 
     public boolean isInline() {
       return inline.get();
     }
 
     public void markUsedAsChoice() {
       usedAsChoice.compareAndSet(false, true);
     }
 
     public boolean isUsedAsChoice() {
       return usedAsChoice.get();
     }
 
     public void markAsChoiceSibling() {
       choiceSibling.compareAndSet(false, true);
     }
 
     public boolean isChoiceSibling() {
       return choiceSibling.get();
     }
 
     public boolean isUsedAsJsonKey() {
       return references.stream()
           .anyMatch(ref -> ref instanceof INamedModelInstance
               && ((INamedModelInstance) ref).hasJsonKey());
     }
 
     public boolean isUsedWithoutJsonKey() {
       return definition instanceof IFlagDefinition
           || references.isEmpty()
           || references.stream()
               .anyMatch(ref -> ref instanceof INamedModelInstance
                   && !((INamedModelInstance) ref).hasJsonKey());
     }
 
     public boolean isChoiceGroupMember() {
       return references.stream()
           .anyMatch(INamedModelInstanceGrouped.class::isInstance);
     }
   }
 }