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.runtime.evaluators.functions;
  
  import java.io.IOException;
  
  import org.apache.asterix.builders.IAsterixListBuilder;
  import org.apache.asterix.formats.nontagged.BinaryComparatorFactoryProvider;
  import org.apache.asterix.om.functions.BuiltinFunctions;
  import org.apache.asterix.om.functions.IFunctionDescriptorFactory;
  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.asterix.runtime.evaluators.base.AbstractScalarFunctionDynamicDescriptor;
  import org.apache.asterix.runtime.evaluators.common.ListAccessor;
  import org.apache.asterix.runtime.functions.FunctionTypeInferers;
  import org.apache.asterix.runtime.utils.DescriptorFactoryUtil;
  import org.apache.hyracks.algebricks.common.exceptions.AlgebricksException;
  import org.apache.hyracks.algebricks.core.algebra.functions.FunctionIdentifier;
  import org.apache.hyracks.algebricks.runtime.base.IScalarEvaluator;
  import org.apache.hyracks.algebricks.runtime.base.IScalarEvaluatorFactory;
  import org.apache.hyracks.api.context.IEvaluatorContext;
  import org.apache.hyracks.api.dataflow.value.IBinaryComparator;
  import org.apache.hyracks.api.exceptions.HyracksDataException;
  import org.apache.hyracks.data.std.api.IPointable;
  import org.apache.hyracks.data.std.primitive.VoidPointable;
  import org.apache.hyracks.data.std.util.ArrayBackedValueStorage;
  import org.apache.hyracks.dataflow.common.data.accessors.IFrameTupleReference;
  
  /**
   * <pre>
   * array_remove(list, val1, val2, ...) returns a new list with all the values removed from the input
   * list. Values cannot be null (i.e., one cannot remove nulls). It's case-sensitive to string value arguments.
   *
   * It throws an error at compile time if the number of arguments < 2
   *
   * It returns (or throws an error at runtime) in order:
   * 1. missing, if any argument is missing.
   * 2. null, if any argument is null.
   * 3. otherwise, a new list that has the same type as the input list.
   *
   * </pre>
   */
  public class ArrayRemoveDescriptor extends AbstractScalarFunctionDynamicDescriptor {
      private static final long serialVersionUID = 1L;
      private IAType[] argTypes;
  
      public static final IFunctionDescriptorFactory FACTORY =
              DescriptorFactoryUtil.createFactory(ArrayRemoveDescriptor::new, FunctionTypeInferers.SET_ARGUMENTS_TYPE);
  
      @Override
      public FunctionIdentifier getIdentifier() {
          return BuiltinFunctions.ARRAY_REMOVE;
      }
  
      @Override
      public IScalarEvaluatorFactory createEvaluatorFactory(final IScalarEvaluatorFactory[] args)
              throws AlgebricksException {
          return new IScalarEvaluatorFactory() {
              private static final long serialVersionUID = 1L;
  
              @Override
              public IScalarEvaluator createScalarEvaluator(final IEvaluatorContext ctx) throws HyracksDataException {
                  return new ArrayRemoveEval(args, ctx, argTypes);
              }
          };
      }
  
      @Override
      public void setImmutableStates(Object... states) {
          argTypes = (IAType[]) states;
      }
  
      public static class ArrayRemoveEval extends AbstractArrayAddRemoveEval {
          private final ArrayBackedValueStorage storage;
          private final IPointable item;
          private final IBinaryComparator[] comp;
  
          ArrayRemoveEval(IScalarEvaluatorFactory[] args, IEvaluatorContext ctx, IAType[] argTypes)
                  throws HyracksDataException {
              super(args, ctx, 0, 1, args.length - 1, argTypes, false, false);
              storage = new ArrayBackedValueStorage();
              item = new VoidPointable();
              comp = createValuesComparators(argTypes);
          }
  
          @Override
          protected int getPosition(IFrameTupleReference tuple, IPointable listArg, ATypeTag listTag) {
              return 0;
          }
  
          @Override
          protected void processList(ListAccessor listAccessor, IAsterixListBuilder listBuilder, IPointable[] removed,
                  int position) throws IOException {
              // get the list items one by one and append to the new list only if the list item is not in removed list
              boolean addItem;
              for (int i = 0; i < listAccessor.size(); i++) {
                  listAccessor.getOrWriteItem(i, item, storage);
                  addItem = true;
                  for (int j = 0; j < removed.length; j++) {
                      if (comp[j].compare(item.getByteArray(), item.getStartOffset(), item.getLength(),
                              removed[j].getByteArray(), removed[j].getStartOffset(), removed[j].getLength()) == 0) {
                          addItem = false;
                          break;
                      }
                  }
                  if (addItem) {
                      listBuilder.addItem(item);
                  }
              }
          }
  
          private static IBinaryComparator[] createValuesComparators(IAType[] argTypes) {
              // one comparator for each value since the values will not be opened (they won't be added to a list).
              // for the list item, it's either the item type if input list is determined to be a list or ANY if not.
              IAType itemType = argTypes[0].getTypeTag().isListType()
                      ? ((AbstractCollectionType) argTypes[0]).getItemType() : BuiltinType.ANY;
              IBinaryComparator[] comparators = new IBinaryComparator[argTypes.length - 1];
              for (int i = 1; i < argTypes.length; i++) {
                  comparators[i - 1] = BinaryComparatorFactoryProvider.INSTANCE
                          .getBinaryComparatorFactory(itemType, argTypes[i], true).createBinaryComparator();
              }
              return comparators;
          }
      }
  }
  