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.cassandra.cql3;
  
  import java.nio.ByteBuffer;
  import java.util.List;
  import java.util.Objects;
  
  import org.apache.cassandra.cql3.functions.Function;
  import org.apache.cassandra.cql3.terms.Constants;
  import org.apache.cassandra.cql3.terms.Lists;
  import org.apache.cassandra.cql3.terms.Maps;
  import org.apache.cassandra.cql3.terms.Term;
  import org.apache.cassandra.db.marshal.AbstractType;
  import org.apache.cassandra.db.marshal.CollectionType;
  import org.apache.cassandra.db.marshal.Int32Type;
  import org.apache.cassandra.db.marshal.MapType;
  import org.apache.cassandra.db.marshal.UTF8Type;
  import org.apache.cassandra.db.marshal.UserType;
  import org.apache.cassandra.schema.ColumnMetadata;
  
  import static org.apache.cassandra.cql3.statements.RequestValidations.invalidRequest;
  
  /**
   * An element expression representation in case of element column expression.
   *
   * <p>This class can be modified to add support for more element expressions like range of elements, for example. </p>
   */
  
  public final class ElementExpression
  {
      /**
       * Represent the expression kind
       */
      public enum Kind
      {
          /**
           * UDT field expression (e.g. {@code columnA.fieldA})
           */
          UDT_FIELD
          {
              @Override
              public String toCQLString(String element)
              {
                  return '.' + element;
              }
  
              @Override
              public String toString()
              {
                  return "UDT field";
              }
          },
          /**
           * Collection element expression (e.g. {@code columnA[?]})
           */
          COLLECTION_ELEMENT
          {
              @Override
              public String toCQLString(String element)
              {
                  return '[' + element + ']';
              }
  
              @Override
              public String toString()
              {
                  return "collection element";
              }
          };
  
          public abstract String toCQLString(String element);
      }
  
      /**
       * The kind of element expression - udt field or collection element.
       */
      private final ElementExpression.Kind kind;
  
      /**
       * The type of the key, index or udt field.
       */
      private final AbstractType<?> keyOrIndexType;
  
      /**
       * The term representing the key, index or udt field.
       */
      private final Term keyOrIndex;
  
      /**
       * The element type.
       */
      private final AbstractType<?> type;
  
      private ElementExpression(ElementExpression.Kind kind, AbstractType<?> type, AbstractType<?> keyOrIndexType, Term keyOrIndex)
      {
          this.kind = kind;
          this.type = type;
          this.keyOrIndexType = keyOrIndexType;
          this.keyOrIndex = keyOrIndex;
      }
  
      /**
       * Returns the expression kind.
       * @return the expression kind.
       */
      public ElementExpression.Kind kind()
      {
          return kind;
      }
  
      /**
       * Returns the element type.
       * @return the element type.
       */
      public AbstractType<?> type()
      {
          return type;
      }
  
      /**
       * Collects the column specifications for the bind variables.
       *
       * @param boundNames the variables specification where to collect the
       * bind variables of the map key/collection element in.
       */
      public void collectMarkerSpecification(VariableSpecifications boundNames)
      {
          keyOrIndex.collectMarkerSpecification(boundNames);
      }
  
      /**
       * Adds all functions (native and user-defined) used by any component of the restriction
       * to the specified list.
       * @param functions the list to add to
       */
      public void addFunctionsTo(List<Function> functions)
      {
          keyOrIndex.addFunctionsTo(functions);
      }
  
      /**
       * Returns the ByteBuffer representation of the key or index.
       *
       * @param options the query options
       * @return the ByteBuffer representation of the key or index.
       */
      public ByteBuffer bindAndGet(QueryOptions options)
      {
          return keyOrIndex.bindAndGet(options);
      }
  
      public String toCQLString()
      {
          // If a Term is not terminal it can be a row marker or a function.
          // We ignore the fact that it could be a function for now.
  
          String value = keyOrIndex.isTerminal() ? keyOrIndexType.asCQL3Type().toCQLLiteral(((Term.Terminal) keyOrIndex).get()) : "?";
          return kind.toCQLString(value);
      }
  
      @Override
      public String toString()
      {
          return this.kind.toString();
      }
  
      public static final class Raw
      {
          private final Kind kind;
          private final Term.Raw rawCollectionElement;
  
          private final FieldIdentifier udtField;
  
          Raw(Term.Raw collectionElement, FieldIdentifier udtField, Kind kind)
          {
              this.rawCollectionElement = collectionElement;
              this.udtField = udtField;
              this.kind = kind;
          }
  
          /**
           * Returns the expression kind.
           * @return the expression kind.
           */
          public Kind kind()
          {
              return kind;
          }
  
          /**
           * Bind this {@link Raw} instance to the schema and return the resulting {@link ElementExpression}.
           *
           * @param column     the column
           * @return the {@link ElementExpression} resulting from the schema binding
           */
          ElementExpression prepare(ColumnMetadata column)
          {
              if (kind == Kind.COLLECTION_ELEMENT)
              {
                  AbstractType<?> baseType = column.type.unwrap();
  
                  if (!(baseType.isCollection()))
                      throw invalidRequest("Invalid element access syntax for non-collection column %s", column.name);
  
                  Term term = prepareCollectionElement(column);
                  CollectionType<?> collectionType = (CollectionType<?>) baseType;
                  AbstractType<?> elementType = collectionType.valueComparator();
                  AbstractType<?> keyOrIndexType = collectionType.isMap() ? ((MapType<?, ?>) collectionType).getKeysType() : Int32Type.instance;
                  return new ElementExpression(kind, elementType, keyOrIndexType, term);
              }
  
              UserType userType = (UserType) column.type;
              int fieldPosition = userType.fieldPosition(udtField);
              if (fieldPosition == -1)
                  throw invalidRequest("Unknown field %s for column %s", udtField, column.name);
  
              return new ElementExpression(kind,
                                           userType.type(fieldPosition),
                                           UTF8Type.instance,
                                           new Constants.Value(udtField.bytes));
          }
  
          private Term prepareCollectionElement(ColumnMetadata receiver)
          {
              ColumnSpecification elementSpec;
              switch ((((CollectionType<?>) receiver.type.unwrap()).kind))
              {
                  case LIST:
                      elementSpec = Lists.indexSpecOf(receiver);
                      break;
                  case MAP:
                      elementSpec = Maps.keySpecOf(receiver);
                      break;
                  case SET:
                      throw invalidRequest("Invalid element access syntax for set column %s", receiver.name);
                  default:
                      throw new AssertionError();
              }
  
              return rawCollectionElement.prepare(receiver.ksName, elementSpec);
          }
  
  
          /**
           * Checks if this raw expression contains bind markers.
           * @return {@code true} if this raw expression contains bind markers, {@code false} otherwise.
           */
          public boolean containsBindMarkers()
          {
              return rawCollectionElement != null && rawCollectionElement.containsBindMarker();
          }
  
          @Override
          public int hashCode()
          {
              return Objects.hash(kind, rawCollectionElement, udtField);
          }
  
          @Override
          public boolean equals(Object o)
          {
              if (this == o)
                  return true;
  
              if (!(o instanceof ElementExpression.Raw))
                  return false;
  
              ElementExpression.Raw r = (ElementExpression.Raw) o;
              return kind == r.kind && Objects.equals(rawCollectionElement, r.rawCollectionElement) && Objects.equals(udtField, r.udtField);
          }
  
          public String toCQLString()
          {
              String element = rawCollectionElement == null ? udtField.toString() : rawCollectionElement.getText();
              return kind.toCQLString(element);
          }
  
          @Override
          public String toString()
          {
              return this.kind.toString();
          }
      }
  }
  