/*
    * SPDX-FileCopyrightText: none
    * SPDX-License-Identifier: CC0-1.0
    */
   
   package gov.nist.secauto.metaschema.schemagen.json.impl;
   
   import com.fasterxml.jackson.databind.node.ArrayNode;
   import com.fasterxml.jackson.databind.node.JsonNodeFactory;
  import com.fasterxml.jackson.databind.node.ObjectNode;
  
  import gov.nist.secauto.metaschema.core.model.IAssemblyDefinition;
  import gov.nist.secauto.metaschema.core.model.IChoiceGroupInstance;
  import gov.nist.secauto.metaschema.core.model.IChoiceInstance;
  import gov.nist.secauto.metaschema.core.model.INamedModelInstanceAbsolute;
  import gov.nist.secauto.metaschema.core.model.ModelType;
  import gov.nist.secauto.metaschema.core.util.CollectionUtil;
  import gov.nist.secauto.metaschema.core.util.ObjectUtils;
  import gov.nist.secauto.metaschema.schemagen.json.IDefinitionJsonSchema;
  import gov.nist.secauto.metaschema.schemagen.json.IJsonGenerationState;
  import gov.nist.secauto.metaschema.schemagen.json.impl.IJsonProperty.PropertyCollection;
  
  import java.io.IOException;
  import java.util.Collection;
  import java.util.LinkedList;
  import java.util.List;
  import java.util.Map;
  import java.util.function.Function;
  import java.util.stream.Collectors;
  import java.util.stream.Stream;
  
  import edu.umd.cs.findbugs.annotations.NonNull;
  import edu.umd.cs.findbugs.annotations.Nullable;
  import nl.talsmasoftware.lazy4j.Lazy;
  
  public class AssemblyDefinitionJsonSchema
      extends AbstractModelDefinitionJsonSchema<IAssemblyDefinition> {
  
    private final Lazy<List<IGroupableModelInstanceJsonProperty<?>>> groupableModelInstances;
  
    private final Map<INamedModelInstanceAbsolute, IGroupableModelInstanceJsonProperty<?>> choiceInstances;
  
    public AssemblyDefinitionJsonSchema(
        @NonNull IAssemblyDefinition definition,
        @Nullable String jsonKeyFlagName,
        @Nullable String discriminatorProperty,
        @Nullable String discriminatorValue,
        @NonNull IJsonGenerationState state) {
      super(definition, jsonKeyFlagName, discriminatorProperty, discriminatorValue);
      this.groupableModelInstances = Lazy.lazy(() -> ObjectUtils.notNull(definition.getModelInstances().stream()
          .filter(instance -> !(instance instanceof IChoiceInstance))
          .map(instance -> {
            IGroupableModelInstanceJsonProperty<?> property;
            if (instance instanceof INamedModelInstanceAbsolute) {
              INamedModelInstanceAbsolute named = (INamedModelInstanceAbsolute) instance;
              property = new NamedModelInstanceJsonProperty(named, state);
            } else if (instance instanceof IChoiceGroupInstance) {
              IChoiceGroupInstance choice = (IChoiceGroupInstance) instance;
              property = new ChoiceGroupInstanceJsonProperty(choice, state);
            } else {
              throw new UnsupportedOperationException(
                  "model instance class not supported: " + instance.getClass().getName());
            }
            return property;
          })
          .collect(Collectors.toUnmodifiableList())));
  
      this.choiceInstances = definition.getChoiceInstances().stream()
          .flatMap(choice -> explodeChoice(ObjectUtils.requireNonNull(choice)))
          .collect(Collectors.toUnmodifiableMap(
              Function.identity(),
              instance -> new NamedModelInstanceJsonProperty(ObjectUtils.requireNonNull(instance), state)));
    }
  
    private static Stream<? extends INamedModelInstanceAbsolute> explodeChoice(@NonNull IChoiceInstance choice) {
      return choice.getNamedModelInstances().stream();
    }
  
    @NonNull
    protected List<IGroupableModelInstanceJsonProperty<?>> getGroupableModelInstances() {
      return groupableModelInstances.get();
    }
  
    @Override
    public void gatherDefinitions(
        @NonNull Map<IKey, IDefinitionJsonSchema<?>> gatheredDefinitions,
        @NonNull IJsonGenerationState state) {
      // avoid recursion
      if (!gatheredDefinitions.containsKey(getKey())) {
        super.gatherDefinitions(gatheredDefinitions, state);
  
        // if (isInline(state)) {
        for (IGroupableModelInstanceJsonProperty<?> property : getGroupableModelInstances()) {
          property.gatherDefinitions(gatheredDefinitions, state);
        }
  
        // handle choices
        this.choiceInstances.values().forEach(property -> {
          property.gatherDefinitions(gatheredDefinitions, state);
       });
     }
   }
 
   @Override
   protected void generateBody(
       IJsonGenerationState state,
       ObjectNode obj) throws IOException {
     obj.put("type", "object");
 
     PropertyCollection properties = new PropertyCollection();
 
     // handle possible discriminator
     String discriminatorProperty = getDiscriminatorProperty();
     if (discriminatorProperty != null) {
       ObjectNode discriminatorObj = state.getJsonNodeFactory().objectNode();
       discriminatorObj.put("const", getDiscriminatorValue());
       properties.addProperty(discriminatorProperty, discriminatorObj);
     }
 
     // generate flag properties
     for (FlagInstanceJsonProperty flag : getFlagProperties()) {
       assert flag != null;
       flag.generateProperty(properties, state);
     }
 
     // generate model properties
     for (IGroupableModelInstanceJsonProperty<?> property : getGroupableModelInstances()) {
       assert property != null;
       property.generateProperty(properties, state);
     }
 
     Collection<? extends IChoiceInstance> choices = getDefinition().getChoiceInstances();
     if (choices.isEmpty()) {
       properties.generate(obj);
       obj.put("additionalProperties", false);
     } else {
       List<PropertyCollection> propertyChoices = CollectionUtil.singletonList(properties);
       propertyChoices = explodeChoices(choices, propertyChoices, state);
 
       if (propertyChoices.size() == 1) {
         propertyChoices.iterator().next().generate(obj);
       } else if (propertyChoices.size() > 1) {
         generateChoices(propertyChoices, obj, state);
       }
     }
   }
 
   protected void generateChoices(
       List<PropertyCollection> propertyChoices,
       @NonNull ObjectNode definitionNode,
       @NonNull IJsonGenerationState state) {
     ArrayNode anyOfdNode = ObjectUtils.notNull(JsonNodeFactory.instance.arrayNode());
     for (PropertyCollection propertyChoice : propertyChoices) {
       ObjectNode choiceDefinitionNode = ObjectUtils.notNull(JsonNodeFactory.instance.objectNode());
       propertyChoice.generate(choiceDefinitionNode);
       choiceDefinitionNode.put("additionalProperties", false);
       anyOfdNode.add(choiceDefinitionNode);
     }
     definitionNode.set("anyOf", anyOfdNode);
   }
 
   protected List<PropertyCollection> explodeChoices(
       @NonNull Collection<? extends IChoiceInstance> choices,
       @NonNull List<PropertyCollection> propertyChoices,
       @NonNull IJsonGenerationState state) throws IOException {
 
     List<PropertyCollection> retval = propertyChoices;
 
     for (IChoiceInstance choice : choices) {
       List<PropertyCollection> newRetval = new LinkedList<>(); // NOPMD - intentional
       for (INamedModelInstanceAbsolute optionInstance : choice.getNamedModelInstances()) {
         if (ModelType.CHOICE.equals(optionInstance.getModelType())) {
           // recurse
           newRetval.addAll(explodeChoices(
               CollectionUtil.singleton((IChoiceInstance) optionInstance),
               retval,
               state));
         } else {
           // iterate over the old array of choices and append new choice
           for (PropertyCollection oldInstanceProperties : retval) {
             @SuppressWarnings("null")
             @NonNull PropertyCollection newInstanceProperties = oldInstanceProperties.copy();
 
             // add the choice
             choiceInstances.get(optionInstance)
                 .generateProperty(newInstanceProperties, state);
 
             newRetval.add(newInstanceProperties);
           }
         }
       }
       retval = newRetval;
     }
     return retval;
   }
 }