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.adapter.druid;
  
  import org.apache.calcite.avatica.util.DateTimeUtils;
  import org.apache.calcite.avatica.util.TimeUnitRange;
  import org.apache.calcite.rel.type.RelDataType;
  import org.apache.calcite.rex.RexCall;
  import org.apache.calcite.rex.RexLiteral;
  import org.apache.calcite.rex.RexNode;
  import org.apache.calcite.sql.SqlOperator;
  import org.apache.calcite.sql.fun.SqlStdOperatorTable;
  import org.apache.calcite.sql.type.SqlTypeName;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.util.TimeZone;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * DruidSqlOperatorConverter implementation that handles Ceil operations
   * conversions.
   */
  public class CeilOperatorConversion implements DruidSqlOperatorConverter {
    @Override public SqlOperator calciteOperator() {
      return SqlStdOperatorTable.CEIL;
    }
  
    @Override public @Nullable String toDruidExpression(RexNode rexNode, RelDataType rowType,
        DruidQuery query) {
      final RexCall call = (RexCall) rexNode;
      final RexNode arg = call.getOperands().get(0);
      final String druidExpression =
          DruidExpressions.toDruidExpression(arg, rowType, query);
      if (druidExpression == null) {
        return null;
      } else if (call.getOperands().size() == 1) {
        // case CEIL(expr)
        return  DruidQuery.format("ceil(%s)", druidExpression);
      } else if (call.getOperands().size() == 2) {
        // CEIL(expr TO timeUnit)
        final RexLiteral flag = (RexLiteral) call.getOperands().get(1);
        final TimeUnitRange timeUnit =
            requireNonNull((TimeUnitRange) flag.getValue());
        final Granularity.Type type = DruidDateTimeUtils.toDruidGranularity(timeUnit);
        if (type == null) {
          // Unknown Granularity bail out
          return null;
        }
        String isoPeriodFormat = DruidDateTimeUtils.toISOPeriodFormat(type);
        if (isoPeriodFormat == null) {
          return null;
        }
        final TimeZone tz;
        if (arg.getType().getSqlTypeName() == SqlTypeName.TIMESTAMP_WITH_LOCAL_TIME_ZONE) {
          tz = TimeZone.getTimeZone(query.getConnectionConfig().timeZone());
        } else {
          tz = DateTimeUtils.UTC_ZONE;
        }
        return DruidExpressions.applyTimestampCeil(
            druidExpression, isoPeriodFormat, "", tz);
      } else {
        return null;
      }
    }
  }
  