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.calcite.sql.dialect;
  
  import org.apache.calcite.avatica.util.Casing;
  import org.apache.calcite.rel.type.RelDataType;
  import org.apache.calcite.sql.SqlBasicCall;
  import org.apache.calcite.sql.SqlCall;
  import org.apache.calcite.sql.SqlDialect;
  import org.apache.calcite.sql.SqlKind;
  import org.apache.calcite.sql.SqlNode;
  import org.apache.calcite.sql.SqlOperator;
  import org.apache.calcite.sql.SqlWriter;
  import org.apache.calcite.sql.fun.SqlLibraryOperators;
  import org.apache.calcite.sql.parser.SqlParserPos;
  import org.apache.calcite.sql.type.SqlTypeName;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  /**
   * A <code>SqlDialect</code> implementation for the Snowflake database.
   */
  public class SnowflakeSqlDialect extends SqlDialect {
    public static final SqlDialect.Context DEFAULT_CONTEXT = SqlDialect.EMPTY_CONTEXT
        .withDatabaseProduct(SqlDialect.DatabaseProduct.SNOWFLAKE)
        .withIdentifierQuoteString("\"")
        .withUnquotedCasing(Casing.TO_UPPER);
  
    public static final SqlDialect DEFAULT =
        new SnowflakeSqlDialect(DEFAULT_CONTEXT);
  
    /** Creates a SnowflakeSqlDialect. */
    public SnowflakeSqlDialect(Context context) {
      super(context);
    }
  
    @Override public void unparseCall(final SqlWriter writer, final SqlCall call, final int leftPrec,
        final int rightPrec) {
      switch (call.getKind()) {
      case BIT_AND:
        SqlCall bitAndCall = SqlLibraryOperators.BITAND_AGG
            .createCall(SqlParserPos.ZERO, call.getOperandList());
        super.unparseCall(writer, bitAndCall, leftPrec, rightPrec);
        break;
      case BIT_OR:
        SqlCall bitOrCall = SqlLibraryOperators.BITOR_AGG
            .createCall(SqlParserPos.ZERO, call.getOperandList());
        super.unparseCall(writer, bitOrCall, leftPrec, rightPrec);
        break;
      case CHAR_LENGTH:
        SqlCall lengthCall = SqlLibraryOperators.LENGTH
            .createCall(SqlParserPos.ZERO, call.getOperandList());
        super.unparseCall(writer, lengthCall, leftPrec, rightPrec);
        break;
      case ENDS_WITH:
        SqlCall endsWithCall = SqlLibraryOperators.ENDSWITH
            .createCall(SqlParserPos.ZERO, call.getOperandList());
        super.unparseCall(writer, endsWithCall, leftPrec, rightPrec);
        break;
      case STARTS_WITH:
        SqlCall startsWithCall = SqlLibraryOperators.STARTSWITH
            .createCall(SqlParserPos.ZERO, call.getOperandList());
        super.unparseCall(writer, startsWithCall, leftPrec, rightPrec);
        break;
      default:
        super.unparseCall(writer, call, leftPrec, rightPrec);
      }
    }
  
    @Override public SqlNode rewriteMaxMinExpr(SqlNode aggCall, RelDataType relDataType) {
      return rewriteMaxMin(aggCall, relDataType);
    }
  
    /**
     * Helper for rewrites of MAX/MIN.
     * Snowflake, rewrite as
     * BOOLOR_AGG/BOOLAND_AGG if the return type is BOOLEAN.
     */
    public static SqlNode rewriteMaxMin(SqlNode aggCall, RelDataType relDataType) {
      // The behavior of this method depends on the argument type,
      // and whether it is MIN/MAX
      final SqlTypeName type = relDataType.getSqlTypeName();
      final boolean isMax = aggCall.getKind() == SqlKind.MAX;
      // If the type is BOOLEAN, create a new call to the correct operator
      if (type == SqlTypeName.BOOLEAN) {
        final SqlOperator op =
            isMax ? SqlLibraryOperators.BOOLOR_AGG
                : SqlLibraryOperators.BOOLAND_AGG;
        final SqlNode operand = ((SqlBasicCall) aggCall).operand(0);
        return op.createCall(SqlParserPos.ZERO, operand);
      }
      // Otherwise, just return as it arrived
      return aggCall;
    }
  
    @Override public void unparseOffsetFetch(SqlWriter writer, @Nullable SqlNode offset,
        @Nullable SqlNode fetch) {
      unparseFetchUsingLimit(writer, offset, fetch);
    }
  
    @Override public boolean supportsApproxCountDistinct() {
      return true;
    }
  }
  