content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  package org.apache.asterix.column.assembler;
  
  import static org.apache.asterix.om.dictionary.AbstractFieldNamesDictionary.DUMMY_FIELD_NAME_INDEX;
  
  import java.util.ArrayList;
  import java.util.BitSet;
  import java.util.Collection;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  import org.apache.asterix.column.assembler.value.IValueGetter;
  import org.apache.asterix.column.assembler.value.IValueGetterFactory;
  import org.apache.asterix.column.metadata.schema.AbstractSchemaNode;
  import org.apache.asterix.column.metadata.schema.ISchemaNodeVisitor;
  import org.apache.asterix.column.metadata.schema.ObjectSchemaNode;
  import org.apache.asterix.column.metadata.schema.UnionSchemaNode;
  import org.apache.asterix.column.metadata.schema.collection.AbstractCollectionSchemaNode;
  import org.apache.asterix.column.metadata.schema.primitive.PrimitiveSchemaNode;
  import org.apache.asterix.column.operation.query.QueryColumnMetadata;
  import org.apache.asterix.column.values.IColumnValuesReader;
  import org.apache.asterix.column.values.IColumnValuesReaderFactory;
  import org.apache.asterix.om.pointables.base.DefaultOpenFieldType;
  import org.apache.asterix.om.types.ARecordType;
  import org.apache.asterix.om.types.ATypeTag;
  import org.apache.asterix.om.types.AbstractCollectionType;
  import org.apache.asterix.om.types.BuiltinType;
  import org.apache.asterix.om.types.IAType;
  import org.apache.hyracks.api.exceptions.HyracksDataException;
  import org.apache.hyracks.data.std.api.IValueReference;
  
  import it.unimi.dsi.fastutil.ints.IntArrayList;
  import it.unimi.dsi.fastutil.ints.IntList;
  
  public class AssemblerBuilderVisitor implements ISchemaNodeVisitor<AbstractValueAssembler, AssemblerInfo> {
      private static final BitSet NO_DECLARED_FIELDS = new BitSet(0);
      private final QueryColumnMetadata columnMetadata;
      private final IColumnValuesReaderFactory readerFactory;
      private final List<AbstractPrimitiveValueAssembler> valueAssemblers;
      private final IValueGetterFactory valueGetterFactory;
      private final Map<Integer, IColumnValuesReader> primaryKeyReaders;
      private AbstractValueAssembler rootAssembler;
  
      //Recursion info
      private final IntList delimiters;
      private RepeatedPrimitiveValueAssembler delegateAssembler;
      private int level;
  
      public AssemblerBuilderVisitor(QueryColumnMetadata columnMetadata, IColumnValuesReaderFactory readerFactory,
              IValueGetterFactory valueGetterFactory) {
          this.columnMetadata = columnMetadata;
          this.readerFactory = readerFactory;
          this.valueGetterFactory = valueGetterFactory;
          valueAssemblers = new ArrayList<>();
          delimiters = new IntArrayList();
          primaryKeyReaders = new HashMap<>();
          for (IColumnValuesReader reader : columnMetadata.getPrimaryKeyReaders()) {
              primaryKeyReaders.put(reader.getColumnIndex(), reader);
          }
      }
  
      public AbstractPrimitiveValueAssembler[] createValueAssemblers(AbstractSchemaNode requestedSchema,
              ARecordType declaredType) throws HyracksDataException {
          EmptyAssembler root = new EmptyAssembler();
          AssemblerInfo info = new AssemblerInfo(declaredType, root);
          level = 0;
          rootAssembler = requestedSchema.accept(this, info);
          return valueAssemblers.toArray(new AbstractPrimitiveValueAssembler[0]);
      }
  
      public AbstractValueAssembler getRootAssembler() {
          return rootAssembler;
      }
  
      @Override
      public AbstractValueAssembler visit(ObjectSchemaNode objectNode, AssemblerInfo info) throws HyracksDataException {
          ObjectValueAssembler objectAssembler = new ObjectValueAssembler(level, info);
          level++;
  
          BitSet declaredFields = handleDeclaredFields(objectNode, info, objectAssembler);
          IntList childrenFieldNameIndexes = objectNode.getChildrenFieldNameIndexes();
          int numberOfAddedChildren = declaredFields.cardinality();
          if (numberOfAddedChildren < childrenFieldNameIndexes.size()) {
              // Now handle any open fields
              for (int i = 0; i < childrenFieldNameIndexes.size(); i++) {
                  int fieldNameIdx = childrenFieldNameIndexes.getInt(i);
                  AbstractSchemaNode childNode = objectNode.getChild(fieldNameIdx);
                  if (fieldNameIdx == DUMMY_FIELD_NAME_INDEX || !declaredFields.get(fieldNameIdx)) {
                      numberOfAddedChildren++;
                      IAType childType = getChildType(childNode, BuiltinType.ANY);
                      IValueReference fieldName = columnMetadata.getFieldNamesDictionary().getFieldName(fieldNameIdx);
                      //The last child should be a delegate
                      boolean delegate = numberOfAddedChildren == childrenFieldNameIndexes.size();
                      AssemblerInfo childInfo = new AssemblerInfo(childType, objectAssembler, delegate, fieldName);
                      childNode.accept(this, childInfo);
                  }
              }
          }
  
          level--;
          return objectAssembler;
      }
  
      private BitSet handleDeclaredFields(ObjectSchemaNode objectNode, AssemblerInfo info,
              ObjectValueAssembler objectAssembler) throws HyracksDataException {
          ARecordType declaredType = (ARecordType) info.getDeclaredType();
          if (declaredType == DefaultOpenFieldType.NESTED_OPEN_RECORD_TYPE) {
              return NO_DECLARED_FIELDS;
          }
          BitSet processedFields = new BitSet();
          String[] declaredFieldNames = declaredType.getFieldNames();
          IAType[] declaredFieldTypes = declaredType.getFieldTypes();
  
          int addedChildren = 0;
          int requestedChildren = objectNode.getChildren().size();
          for (int i = 0; i < declaredFieldTypes.length; i++) {
              String fieldName = declaredFieldNames[i];
              int fieldNameIndex = columnMetadata.getFieldNamesDictionary().getFieldNameIndex(fieldName);
              //Check if the declared field was requested
              AbstractSchemaNode childNode = objectNode.getChild(fieldNameIndex);
              if (childNode.getTypeTag() != ATypeTag.MISSING) {
                  addedChildren++;
                  IAType childType = getChildType(childNode, declaredFieldTypes[i]);
                  processedFields.set(fieldNameIndex);
                  boolean delegate = addedChildren == requestedChildren;
                  AssemblerInfo childInfo = new AssemblerInfo(childType, objectAssembler, delegate, i);
                  childNode.accept(this, childInfo);
              }
          }
          return processedFields;
      }
  
      @Override
      public AbstractValueAssembler visit(AbstractCollectionSchemaNode collectionNode, AssemblerInfo info)
              throws HyracksDataException {
          AbstractCollectionType declaredType = (AbstractCollectionType) info.getDeclaredType();
          AbstractSchemaNode itemNode = collectionNode.getItemNode();
  
          ArrayValueAssembler arrayAssembler = itemNode.getTypeTag() == ATypeTag.UNION
                  ? new ArrayWithUnionValueAssembler(level, info, valueAssemblers.size(), itemNode)
                  : new ArrayValueAssembler(level, info, valueAssemblers.size());
          delimiters.add(level - 1);
          level++;
  
          RepeatedPrimitiveValueAssembler previousDelegate = delegateAssembler;
          delegateAssembler = null;
  
          IAType itemDeclaredType = getChildType(itemNode, declaredType.getItemType());
          AssemblerInfo itemInfo = new AssemblerInfo(itemDeclaredType, arrayAssembler, false);
          itemNode.accept(this, itemInfo);
  
          // if delegateAssembler is null, that means no column will be accessed
          if (delegateAssembler != null) {
              // Set repeated assembler as a delegate (responsible for writing null values)
              delegateAssembler.setAsDelegate(level - 1);
              IColumnValuesReader reader = delegateAssembler.getReader();
              int numberOfDelimiters = reader.getNumberOfDelimiters();
              // End of group assembler is responsible to finalize array/multiset builders
              EndOfRepeatedGroupAssembler endOfGroupAssembler =
                      new EndOfRepeatedGroupAssembler(reader, arrayAssembler, numberOfDelimiters - delimiters.size());
              valueAssemblers.add(endOfGroupAssembler);
          }
  
          level--;
          delimiters.removeInt(delimiters.size() - 1);
          if (previousDelegate != null && !delimiters.isEmpty()) {
              // Return the delegate assembler to the previous one
              delegateAssembler = previousDelegate;
          }
          return arrayAssembler;
      }
  
      @Override
      public AbstractValueAssembler visit(UnionSchemaNode unionNode, AssemblerInfo info) throws HyracksDataException {
          /*
           * UnionSchemaNode does not actually exist. We know the parent of the union could have items of multiple types.
           * Thus, the union's parent is the actual parent for all the union types
           */
          Collection<AbstractSchemaNode> children = unionNode.getChildren().values();
          int index = 0;
          for (AbstractSchemaNode node : children) {
              IAType unionDeclaredType = getChildType(node, info.getDeclaredType());
              boolean delegate = info.isDelegate() && index++ == children.size() - 1;
              AssemblerInfo unionInfo = new AssemblerInfo(unionDeclaredType, info.getParent(), delegate,
                      info.getFieldName(), info.getFieldIndex(), true);
              node.accept(this, unionInfo);
          }
          return info.getParent();
      }
  
      @Override
      public AbstractValueAssembler visit(PrimitiveSchemaNode primitiveNode, AssemblerInfo info) {
          AbstractPrimitiveValueAssembler assembler;
          IValueGetter valueGetter = valueGetterFactory.createValueGetter(getTypeTag(info, primitiveNode));
          if (!delimiters.isEmpty()) {
              IColumnValuesReader reader = readerFactory.createValueReader(primitiveNode.getTypeTag(),
                      primitiveNode.getColumnIndex(), level, getDelimiters());
  
              assembler = new RepeatedPrimitiveValueAssembler(level, info, reader, valueGetter);
              setDelegate(reader, (RepeatedPrimitiveValueAssembler) assembler);
  
          } else {
              IColumnValuesReader reader;
              boolean primaryKey = primitiveNode.isPrimaryKey();
              if (primaryKey) {
                  reader = primaryKeyReaders.get(primitiveNode.getColumnIndex());
              } else {
                  reader = readerFactory.createValueReader(primitiveNode.getTypeTag(), primitiveNode.getColumnIndex(),
                          level, false);
              }
              assembler = new PrimitiveValueAssembler(level, info, reader, valueGetter, primaryKey);
          }
          valueAssemblers.add(assembler);
          return assembler;
      }
  
      private ATypeTag getTypeTag(AssemblerInfo info, PrimitiveSchemaNode primitiveNode) {
          IAType declaredType = info.getDeclaredType();
  
          if (declaredType.getTypeTag() == ATypeTag.ANY) {
              return primitiveNode.getTypeTag();
          }
  
          // Declared types are not (and cannot be) normalized
          return declaredType.getTypeTag();
      }
  
      private int[] getDelimiters() {
          int numOfDelimiters = delimiters.size();
          int[] reversed = new int[numOfDelimiters];
          for (int i = 0; i < numOfDelimiters; i++) {
              reversed[i] = delimiters.getInt(numOfDelimiters - i - 1);
          }
          return reversed;
      }
  
      private IAType getChildType(AbstractSchemaNode childNode, IAType childType) {
          if (childType.getTypeTag() != ATypeTag.ANY) {
              return childType;
          }
          ATypeTag childTypeTag = childNode.getTypeTag();
          if (childTypeTag == ATypeTag.UNION) {
              //Union type could return any type
              return BuiltinType.ANY;
          } else if (childTypeTag.isDerivedType()) {
              return DefaultOpenFieldType.getDefaultOpenFieldType(childTypeTag);
          } else {
              return BuiltinType.getBuiltinType(childTypeTag);
          }
      }
  
      private void setDelegate(IColumnValuesReader reader, RepeatedPrimitiveValueAssembler assembler) {
          int delegateIndex =
                  delegateAssembler == null ? Integer.MAX_VALUE : delegateAssembler.getReader().getColumnIndex();
          if (delegateIndex > reader.getColumnIndex()) {
              delegateAssembler = assembler;
          }
      }
  }
  