/*
 * 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.comet.serde

import org.apache.spark.sql.catalyst.expressions.{Attribute, Reverse}
import org.apache.spark.sql.types.ArrayType

import org.apache.comet.serde.ExprOuterClass.Expr
import org.apache.comet.shims.CometTypeShim

object CometReverse
    extends CometScalarFunction[Reverse]("reverse")
    with CometTypeShim
    with CodegenDispatchFallback {

  // Spark 4.0 widens the string branch of Reverse to accept collated strings and propagates the
  // collation through dataType. The native reverse UDF reverses code units and produces UTF8
  // (UTF8_BINARY semantics), so a non-default collation diverges from Spark.
  private val collationReason =
    "reverse does not support non-UTF8_BINARY collations " +
      "(https://github.com/apache/datafusion-comet/issues/2190)"

  override def getIncompatibleReasons(): Seq[String] =
    CometArrayReverse.getIncompatibleReasons() :+ collationReason

  override def getSupportLevel(expr: Reverse): SupportLevel = {
    if (expr.child.dataType.isInstanceOf[ArrayType]) {
      CometArrayReverse.getSupportLevel(expr)
    } else if (hasNonDefaultStringCollation(expr.child.dataType)) {
      Incompatible(Some(collationReason))
    } else {
      Compatible()
    }
  }

  override def convert(expr: Reverse, inputs: Seq[Attribute], binding: Boolean): Option[Expr] = {
    if (expr.child.dataType.isInstanceOf[ArrayType]) {
      CometArrayReverse.convert(expr, inputs, binding)
    } else {
      super.convert(expr, inputs, binding)
    }
  }
}
