/*
 * 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 java.util.concurrent.atomic.AtomicLong

import scala.jdk.CollectionConverters._

import org.apache.spark.internal.Logging
import org.apache.spark.sql.catalyst.expressions._
import org.apache.spark.sql.catalyst.expressions.aggregate._
import org.apache.spark.sql.catalyst.expressions.objects.StaticInvoke
import org.apache.spark.sql.comet.DecimalPrecision
import org.apache.spark.sql.execution.{ScalarSubquery, SparkPlan}
import org.apache.spark.sql.internal.SQLConf
import org.apache.spark.sql.types._

import org.apache.comet.CometConf
import org.apache.comet.CometSparkSessionExtensions.withInfo
import org.apache.comet.expressions._
import org.apache.comet.serde.ExprOuterClass.{AggExpr, Expr, ScalarFunc}
import org.apache.comet.serde.Types.{DataType => ProtoDataType}
import org.apache.comet.serde.Types.DataType._
import org.apache.comet.serde.literals.CometLiteral
import org.apache.comet.shims.CometExprShim

/**
 * An utility object for query plan and expression serialization.
 */
object QueryPlanSerde extends Logging with CometExprShim {

  private val arrayExpressions: Map[Class[_ <: Expression], CometExpressionSerde[_]] = Map(
    classOf[ArrayAppend] -> CometArrayAppend,
    classOf[ArrayCompact] -> CometArrayCompact,
    classOf[ArrayContains] -> CometArrayContains,
    classOf[ArrayDistinct] -> CometArrayDistinct,
    classOf[ArrayExcept] -> CometArrayExcept,
    classOf[ArrayFilter] -> CometArrayFilter,
    classOf[ArrayInsert] -> CometArrayInsert,
    classOf[ArrayIntersect] -> CometArrayIntersect,
    classOf[ArrayJoin] -> CometArrayJoin,
    classOf[ArrayMax] -> CometArrayMax,
    classOf[ArrayMin] -> CometArrayMin,
    classOf[ArrayRemove] -> CometArrayRemove,
    classOf[ArrayRepeat] -> CometArrayRepeat,
    classOf[SortArray] -> CometSortArray,
    classOf[ArraysOverlap] -> CometArraysOverlap,
    classOf[ArrayUnion] -> CometArrayUnion,
    classOf[CreateArray] -> CometCreateArray,
    classOf[ElementAt] -> CometElementAt,
    classOf[Flatten] -> CometFlatten,
    classOf[GetArrayItem] -> CometGetArrayItem,
    classOf[Size] -> CometSize)

  private val conditionalExpressions: Map[Class[_ <: Expression], CometExpressionSerde[_]] =
    Map(classOf[CaseWhen] -> CometCaseWhen, classOf[If] -> CometIf)

  private val predicateExpressions: Map[Class[_ <: Expression], CometExpressionSerde[_]] = Map(
    classOf[And] -> CometAnd,
    classOf[EqualTo] -> CometEqualTo,
    classOf[EqualNullSafe] -> CometEqualNullSafe,
    classOf[GreaterThan] -> CometGreaterThan,
    classOf[GreaterThanOrEqual] -> CometGreaterThanOrEqual,
    classOf[LessThan] -> CometLessThan,
    classOf[LessThanOrEqual] -> CometLessThanOrEqual,
    classOf[In] -> CometIn,
    classOf[IsNotNull] -> CometIsNotNull,
    classOf[IsNull] -> CometIsNull,
    classOf[InSet] -> CometInSet,
    classOf[Not] -> CometNot,
    classOf[Or] -> CometOr)

  private val mathExpressions: Map[Class[_ <: Expression], CometExpressionSerde[_]] = Map(
    classOf[Acos] -> CometScalarFunction("acos"),
    classOf[Add] -> CometAdd,
    classOf[Asin] -> CometScalarFunction("asin"),
    classOf[Atan] -> CometScalarFunction("atan"),
    classOf[Atan2] -> CometAtan2,
    classOf[Ceil] -> CometCeil,
    classOf[Cos] -> CometScalarFunction("cos"),
    classOf[Cosh] -> CometScalarFunction("cosh"),
    classOf[Divide] -> CometDivide,
    classOf[Exp] -> CometScalarFunction("exp"),
    classOf[Expm1] -> CometScalarFunction("expm1"),
    classOf[Floor] -> CometFloor,
    classOf[Hex] -> CometHex,
    classOf[IntegralDivide] -> CometIntegralDivide,
    classOf[IsNaN] -> CometIsNaN,
    classOf[Log] -> CometLog,
    classOf[Log2] -> CometLog2,
    classOf[Log10] -> CometLog10,
    classOf[Logarithm] -> CometLogarithm,
    classOf[Multiply] -> CometMultiply,
    classOf[Pow] -> CometScalarFunction("pow"),
    classOf[Rand] -> CometRand,
    classOf[Randn] -> CometRandn,
    classOf[Remainder] -> CometRemainder,
    classOf[Round] -> CometRound,
    classOf[Signum] -> CometScalarFunction("signum"),
    classOf[Sin] -> CometScalarFunction("sin"),
    classOf[Sinh] -> CometScalarFunction("sinh"),
    classOf[Sqrt] -> CometScalarFunction("sqrt"),
    classOf[Subtract] -> CometSubtract,
    classOf[Tan] -> CometScalarFunction("tan"),
    classOf[Tanh] -> CometScalarFunction("tanh"),
    classOf[Cot] -> CometScalarFunction("cot"),
    classOf[UnaryMinus] -> CometUnaryMinus,
    classOf[Unhex] -> CometUnhex,
    classOf[Abs] -> CometAbs,
    classOf[Bin] -> CometScalarFunction("bin"))

  private val mapExpressions: Map[Class[_ <: Expression], CometExpressionSerde[_]] = Map(
    classOf[GetMapValue] -> CometMapExtract,
    classOf[MapKeys] -> CometMapKeys,
    classOf[MapEntries] -> CometMapEntries,
    classOf[MapValues] -> CometMapValues,
    classOf[MapFromArrays] -> CometMapFromArrays,
    classOf[MapContainsKey] -> CometMapContainsKey,
    classOf[MapFromEntries] -> CometMapFromEntries)

  private val structExpressions: Map[Class[_ <: Expression], CometExpressionSerde[_]] = Map(
    classOf[CreateNamedStruct] -> CometCreateNamedStruct,
    classOf[GetArrayStructFields] -> CometGetArrayStructFields,
    classOf[GetStructField] -> CometGetStructField,
    classOf[JsonToStructs] -> CometJsonToStructs,
    classOf[StructsToJson] -> CometStructsToJson,
    classOf[StructsToCsv] -> CometStructsToCsv)

  private val hashExpressions: Map[Class[_ <: Expression], CometExpressionSerde[_]] = Map(
    classOf[Crc32] -> CometScalarFunction("crc32"),
    classOf[Md5] -> CometScalarFunction("md5"),
    classOf[Murmur3Hash] -> CometMurmur3Hash,
    classOf[Sha2] -> CometSha2,
    classOf[XxHash64] -> CometXxHash64,
    classOf[Sha1] -> CometSha1)

  private val stringExpressions: Map[Class[_ <: Expression], CometExpressionSerde[_]] = Map(
    classOf[Ascii] -> CometScalarFunction("ascii"),
    classOf[BitLength] -> CometScalarFunction("bit_length"),
    classOf[Chr] -> CometScalarFunction("char"),
    classOf[ConcatWs] -> CometConcatWs,
    classOf[Concat] -> CometConcat,
    classOf[Contains] -> CometScalarFunction("contains"),
    classOf[EndsWith] -> CometScalarFunction("ends_with"),
    classOf[GetJsonObject] -> CometGetJsonObject,
    classOf[InitCap] -> CometInitCap,
    classOf[Length] -> CometLength,
    classOf[Like] -> CometLike,
    classOf[Lower] -> CometLower,
    classOf[OctetLength] -> CometScalarFunction("octet_length"),
    classOf[RegExpReplace] -> CometRegExpReplace,
    classOf[Reverse] -> CometReverse,
    classOf[RLike] -> CometRLike,
    classOf[StartsWith] -> CometScalarFunction("starts_with"),
    classOf[StringInstr] -> CometScalarFunction("instr"),
    classOf[StringRepeat] -> CometStringRepeat,
    classOf[StringReplace] -> CometScalarFunction("replace"),
    classOf[StringRPad] -> CometStringRPad,
    classOf[StringLPad] -> CometStringLPad,
    classOf[StringSpace] -> CometScalarFunction("space"),
    classOf[StringSplit] -> CometStringSplit,
    classOf[StringTranslate] -> CometScalarFunction("translate"),
    classOf[StringTrim] -> CometScalarFunction("trim"),
    classOf[StringTrimBoth] -> CometScalarFunction("btrim"),
    classOf[StringTrimLeft] -> CometScalarFunction("ltrim"),
    classOf[StringTrimRight] -> CometScalarFunction("rtrim"),
    classOf[Left] -> CometLeft,
    classOf[Right] -> CometRight,
    classOf[Substring] -> CometSubstring,
    classOf[Upper] -> CometUpper)

  private val bitwiseExpressions: Map[Class[_ <: Expression], CometExpressionSerde[_]] = Map(
    classOf[BitwiseAnd] -> CometBitwiseAnd,
    classOf[BitwiseCount] -> CometBitwiseCount,
    classOf[BitwiseGet] -> CometBitwiseGet,
    classOf[BitwiseOr] -> CometBitwiseOr,
    classOf[BitwiseNot] -> CometBitwiseNot,
    classOf[BitwiseXor] -> CometBitwiseXor,
    classOf[ShiftLeft] -> CometShiftLeft,
    classOf[ShiftRight] -> CometShiftRight)

  private val temporalExpressions: Map[Class[_ <: Expression], CometExpressionSerde[_]] = Map(
    classOf[DateAdd] -> CometDateAdd,
    classOf[DateDiff] -> CometDateDiff,
    classOf[DateFormatClass] -> CometDateFormat,
    classOf[DateFromUnixDate] -> CometDateFromUnixDate,
    classOf[Days] -> CometDays,
    classOf[Hours] -> CometHours,
    classOf[DateSub] -> CometDateSub,
    classOf[UnixDate] -> CometUnixDate,
    classOf[FromUnixTime] -> CometFromUnixTime,
    classOf[LastDay] -> CometLastDay,
    classOf[Hour] -> CometHour,
    classOf[MakeDate] -> CometMakeDate,
    classOf[Minute] -> CometMinute,
    classOf[NextDay] -> CometNextDay,
    classOf[Second] -> CometSecond,
    classOf[TruncDate] -> CometTruncDate,
    classOf[TruncTimestamp] -> CometTruncTimestamp,
    classOf[UnixTimestamp] -> CometUnixTimestamp,
    classOf[Year] -> CometYear,
    classOf[Month] -> CometMonth,
    classOf[DayOfMonth] -> CometDayOfMonth,
    classOf[DayOfWeek] -> CometDayOfWeek,
    classOf[WeekDay] -> CometWeekDay,
    classOf[DayOfYear] -> CometDayOfYear,
    classOf[WeekOfYear] -> CometWeekOfYear,
    classOf[Quarter] -> CometQuarter)

  private val conversionExpressions: Map[Class[_ <: Expression], CometExpressionSerde[_]] = Map(
    classOf[Cast] -> CometCast)

  private val miscExpressions: Map[Class[_ <: Expression], CometExpressionSerde[_]] = Map(
    // TODO PromotePrecision
    classOf[Alias] -> CometAlias,
    classOf[AttributeReference] -> CometAttributeReference,
    classOf[BloomFilterMightContain] -> CometBloomFilterMightContain,
    classOf[CheckOverflow] -> CometCheckOverflow,
    classOf[Coalesce] -> CometCoalesce,
    classOf[KnownFloatingPointNormalized] -> CometKnownFloatingPointNormalized,
    classOf[Literal] -> CometLiteral,
    classOf[MakeDecimal] -> CometMakeDecimal,
    classOf[MonotonicallyIncreasingID] -> CometMonotonicallyIncreasingId,
    classOf[ScalarSubquery] -> CometScalarSubquery,
    classOf[SparkPartitionID] -> CometSparkPartitionId,
    classOf[SortOrder] -> CometSortOrder,
    classOf[StaticInvoke] -> CometStaticInvoke,
    classOf[UnscaledValue] -> CometUnscaledValue)

  /**
   * Mapping of Spark expression class to Comet expression handler.
   */
  val exprSerdeMap: Map[Class[_ <: Expression], CometExpressionSerde[_]] =
    mathExpressions ++ hashExpressions ++ stringExpressions ++
      conditionalExpressions ++ mapExpressions ++ predicateExpressions ++
      structExpressions ++ bitwiseExpressions ++ miscExpressions ++ arrayExpressions ++
      temporalExpressions ++ conversionExpressions

  /**
   * Mapping of Spark aggregate expression class to Comet expression handler.
   */
  val aggrSerdeMap: Map[Class[_], CometAggregateExpressionSerde[_]] = Map(
    classOf[Average] -> CometAverage,
    classOf[BitAndAgg] -> CometBitAndAgg,
    classOf[BitOrAgg] -> CometBitOrAgg,
    classOf[BitXorAgg] -> CometBitXOrAgg,
    classOf[BloomFilterAggregate] -> CometBloomFilterAggregate,
    classOf[Corr] -> CometCorr,
    classOf[Count] -> CometCount,
    classOf[CovPopulation] -> CometCovPopulation,
    classOf[CovSample] -> CometCovSample,
    classOf[First] -> CometFirst,
    classOf[Last] -> CometLast,
    classOf[Max] -> CometMax,
    classOf[Min] -> CometMin,
    classOf[StddevPop] -> CometStddevPop,
    classOf[StddevSamp] -> CometStddevSamp,
    classOf[Sum] -> CometSum,
    classOf[VariancePop] -> CometVariancePop,
    classOf[VarianceSamp] -> CometVarianceSamp)

  //  A unique id for each expression. ~used to look up QueryContext during error creation.
  private val exprIdCounter = new AtomicLong(0)

  private def nextExprId(): Long = exprIdCounter.incrementAndGet()

  /**
   * Extract SQL context information (query text, line/position, object name) from the
   * expression's origin.
   *
   * @param expr
   *   The Spark expression to extract context from
   * @return
   *   Some(QueryContext) if origin is present, None otherwise
   */
  private def extractQueryContext(expr: Expression): Option[ExprOuterClass.QueryContext] = {
    val contexts = expr.origin.getQueryContext
    if (contexts != null && contexts.length > 0) {
      try {
        val ctx = contexts(0)
        // Check if this is a SQLQueryContext with additional fields
        ctx match {
          case sqlCtx: org.apache.spark.sql.catalyst.trees.SQLQueryContext =>
            val builder = ExprOuterClass.QueryContext
              .newBuilder()
              .setSqlText(sqlCtx.sqlText.getOrElse(""))
              .setStartIndex(sqlCtx.originStartIndex.getOrElse(ctx.startIndex))
              .setStopIndex(sqlCtx.originStopIndex.getOrElse(ctx.stopIndex))
              .setLine(sqlCtx.line.getOrElse(0))
              .setStartPosition(sqlCtx.startPosition.getOrElse(0))

            // Add optional fields if present
            sqlCtx.originObjectType.foreach(builder.setObjectType)
            sqlCtx.originObjectName.foreach(builder.setObjectName)

            Some(builder.build())
          case _ =>
            // Fallback: use only QueryContext interface methods
            val builder = ExprOuterClass.QueryContext
              .newBuilder()
              .setSqlText(ctx.fragment())
              .setStartIndex(ctx.startIndex())
              .setStopIndex(ctx.stopIndex())
              .setLine(0)
              .setStartPosition(0)

            if (ctx.objectType() != null && !ctx.objectType().isEmpty) {
              builder.setObjectType(ctx.objectType())
            }
            if (ctx.objectName() != null && !ctx.objectName().isEmpty) {
              builder.setObjectName(ctx.objectName())
            }

            Some(builder.build())
        }
      } catch {
        case _: Exception => None
      }
    } else {
      None
    }
  }

  def supportedDataType(dt: DataType, allowComplex: Boolean = false): Boolean = dt match {
    case _: ByteType | _: ShortType | _: IntegerType | _: LongType | _: FloatType |
        _: DoubleType | _: StringType | _: BinaryType | _: TimestampType | _: TimestampNTZType |
        _: DecimalType | _: DateType | _: BooleanType | _: NullType =>
      true
    case s: StructType if allowComplex =>
      s.fields.nonEmpty && s.fields.map(_.dataType).forall(supportedDataType(_, allowComplex))
    case a: ArrayType if allowComplex =>
      supportedDataType(a.elementType, allowComplex)
    case m: MapType if allowComplex =>
      supportedDataType(m.keyType, allowComplex) && supportedDataType(m.valueType, allowComplex)
    case _ =>
      false
  }

  /**
   * Serializes Spark datatype to protobuf. Note that, a datatype can be serialized by this method
   * doesn't mean it is supported by Comet native execution, i.e., `supportedDataType` may return
   * false for it.
   */
  def serializeDataType(dt: org.apache.spark.sql.types.DataType): Option[Types.DataType] = {
    val typeId = dt match {
      case _: BooleanType => 0
      case _: ByteType => 1
      case _: ShortType => 2
      case _: IntegerType => 3
      case _: LongType => 4
      case _: FloatType => 5
      case _: DoubleType => 6
      case _: StringType => 7
      case _: BinaryType => 8
      case _: TimestampType => 9
      case _: DecimalType => 10
      case _: TimestampNTZType => 11
      case _: DateType => 12
      case _: NullType => 13
      case _: ArrayType => 14
      case _: MapType => 15
      case _: StructType => 16
      case dt =>
        logWarning(s"Cannot serialize Spark data type: $dt")
        return None
    }

    val builder = ProtoDataType.newBuilder()
    builder.setTypeIdValue(typeId)

    // Decimal
    val dataType = dt match {
      case t: DecimalType =>
        val info = DataTypeInfo.newBuilder()
        val decimal = DecimalInfo.newBuilder()
        decimal.setPrecision(t.precision)
        decimal.setScale(t.scale)
        info.setDecimal(decimal)
        builder.setTypeInfo(info.build()).build()

      case a: ArrayType =>
        val elementType = serializeDataType(a.elementType)

        if (elementType.isEmpty) {
          return None
        }

        val info = DataTypeInfo.newBuilder()
        val list = ListInfo.newBuilder()
        list.setElementType(elementType.get)
        list.setContainsNull(a.containsNull)

        info.setList(list)
        builder.setTypeInfo(info.build()).build()

      case m: MapType =>
        val keyType = serializeDataType(m.keyType)
        if (keyType.isEmpty) {
          return None
        }

        val valueType = serializeDataType(m.valueType)
        if (valueType.isEmpty) {
          return None
        }

        val info = DataTypeInfo.newBuilder()
        val map = MapInfo.newBuilder()
        map.setKeyType(keyType.get)
        map.setValueType(valueType.get)
        map.setValueContainsNull(m.valueContainsNull)

        info.setMap(map)
        builder.setTypeInfo(info.build()).build()

      case s: StructType =>
        val info = DataTypeInfo.newBuilder()
        val struct = StructInfo.newBuilder()

        val fieldNames = s.fields.map(_.name).toIterable.asJava
        val fieldDatatypes = s.fields.map(f => serializeDataType(f.dataType)).toSeq
        val fieldNullable = s.fields.map(f => Boolean.box(f.nullable)).toIterable.asJava

        if (fieldDatatypes.exists(_.isEmpty)) {
          return None
        }

        struct.addAllFieldNames(fieldNames)
        struct.addAllFieldDatatypes(fieldDatatypes.map(_.get).asJava)
        struct.addAllFieldNullable(fieldNullable)

        info.setStruct(struct)
        builder.setTypeInfo(info.build()).build()
      case _ => builder.build()
    }

    Some(dataType)
  }

  def aggExprToProto(
      aggExpr: AggregateExpression,
      inputs: Seq[Attribute],
      binding: Boolean,
      conf: SQLConf): Option[AggExpr] = {

    // Support Count(distinct single_value)
    // COUNT(DISTINCT x) - supported
    // COUNT(DISTINCT x, x) - supported through transition to COUNT(DISTINCT x)
    // COUNT(DISTINCT x, y) - not supported
    if (aggExpr.isDistinct
      &&
      !(aggExpr.aggregateFunction.prettyName == "count" &&
        aggExpr.aggregateFunction.children.length == 1)) {
      withInfo(aggExpr, s"Distinct aggregate not supported for: $aggExpr")
      return None
    }

    val fn = aggExpr.aggregateFunction
    val cometExpr = aggrSerdeMap.get(fn.getClass)
    val protoAggExprOpt = cometExpr match {
      case Some(handler) =>
        val aggHandler = handler.asInstanceOf[CometAggregateExpressionSerde[AggregateFunction]]
        val exprConfName = aggHandler.getExprConfigName(fn)
        if (!CometConf.isExprEnabled(exprConfName)) {
          withInfo(
            aggExpr,
            "Expression support is disabled. Set " +
              s"${CometConf.getExprEnabledConfigKey(exprConfName)}=true to enable it.")
          return None
        }
        aggHandler.getSupportLevel(fn) match {
          case Unsupported(notes) =>
            withInfo(fn, notes.getOrElse(""))
            None
          case Incompatible(notes) =>
            val exprAllowIncompat = CometConf.isExprAllowIncompat(exprConfName)
            if (exprAllowIncompat) {
              if (notes.isDefined) {
                logWarning(
                  s"Comet supports $fn when " +
                    s"${CometConf.getExprAllowIncompatConfigKey(exprConfName)}=true " +
                    s"but has notes: ${notes.get}")
              }
              aggHandler.convert(aggExpr, fn, inputs, binding, conf)
            } else {
              val optionalNotes = notes.map(str => s" ($str)").getOrElse("")
              withInfo(
                fn,
                s"$fn is not fully compatible with Spark$optionalNotes. To enable it anyway, " +
                  s"set ${CometConf.getExprAllowIncompatConfigKey(exprConfName)}=true. " +
                  s"${CometConf.COMPAT_GUIDE}.")
              None
            }
          case Compatible(notes) =>
            if (notes.isDefined) {
              logWarning(s"Comet supports $fn but has notes: ${notes.get}")
            }
            aggHandler.convert(aggExpr, fn, inputs, binding, conf)
        }
      case _ =>
        withInfo(
          aggExpr,
          s"unsupported Spark aggregate function: ${fn.prettyName}",
          fn.children: _*)
        None
    }

    // Attach QueryContext and expr_id to the aggregate expression
    protoAggExprOpt.flatMap { protoAggExpr =>
      val builder = protoAggExpr.toBuilder
      builder.setExprId(nextExprId())

      // Serialize FILTER (WHERE ...) clause if present.
      // The filter is only meaningful in Partial mode; Final/PartialMerge never set it.
      if (aggExpr.filter.isDefined && aggExpr.mode == Partial) {
        val filterProto = exprToProto(aggExpr.filter.get, inputs, binding)
        if (filterProto.isEmpty) {
          withInfo(aggExpr, aggExpr.filter.get)
          return None
        }
        builder.setFilter(filterProto.get)
      }

      extractQueryContext(fn).foreach { ctx =>
        builder.setQueryContext(ctx)
      }
      Some(builder.build())
    }
  }

  def evalModeToProto(evalMode: CometEvalMode.Value): ExprOuterClass.EvalMode = {
    evalMode match {
      case CometEvalMode.LEGACY => ExprOuterClass.EvalMode.LEGACY
      case CometEvalMode.TRY => ExprOuterClass.EvalMode.TRY
      case CometEvalMode.ANSI => ExprOuterClass.EvalMode.ANSI
      case _ => throw new IllegalStateException(s"Invalid evalMode $evalMode")
    }
  }

  /**
   * Convert a Spark expression to a protocol-buffer representation of a native Comet/DataFusion
   * expression.
   *
   * This method performs a transformation on the plan to handle decimal promotion and then calls
   * into the recursive method [[exprToProtoInternal]].
   *
   * @param expr
   *   The input expression
   * @param inputs
   *   The input attributes
   * @param binding
   *   Whether to bind the expression to the input attributes
   * @return
   *   The protobuf representation of the expression, or None if the expression is not supported.
   *   In the case where None is returned, the expression will be tagged with the reason(s) why it
   *   is not supported.
   */
  def exprToProto(
      expr: Expression,
      inputs: Seq[Attribute],
      binding: Boolean = true): Option[Expr] = {

    val conf = SQLConf.get
    val newExpr =
      DecimalPrecision.promote(conf.decimalOperationsAllowPrecisionLoss, expr, !conf.ansiEnabled)
    exprToProtoInternal(newExpr, inputs, binding)
  }

  /**
   * Convert a Spark expression to a protocol-buffer representation of a native Comet/DataFusion
   * expression.
   *
   * @param expr
   *   The input expression
   * @param inputs
   *   The input attributes
   * @param binding
   *   Whether to bind the expression to the input attributes
   * @return
   *   The protobuf representation of the expression, or None if the expression is not supported.
   *   In the case where None is returned, the expression will be tagged with the reason(s) why it
   *   is not supported.
   */
  def exprToProtoInternal(
      expr: Expression,
      inputs: Seq[Attribute],
      binding: Boolean): Option[Expr] = {

    def convert[T <: Expression](expr: T, handler: CometExpressionSerde[T]): Option[Expr] = {
      val exprConfName = handler.getExprConfigName(expr)
      if (!CometConf.isExprEnabled(exprConfName)) {
        withInfo(
          expr,
          "Expression support is disabled. Set " +
            s"${CometConf.getExprEnabledConfigKey(exprConfName)}=true to enable it.")
        return None
      }
      handler.getSupportLevel(expr) match {
        case Unsupported(notes) =>
          withInfo(expr, notes.getOrElse(""))
          None
        case Incompatible(notes) =>
          val exprAllowIncompat = CometConf.isExprAllowIncompat(exprConfName)
          if (exprAllowIncompat) {
            if (notes.isDefined) {
              logWarning(
                s"Comet supports $expr when " +
                  s"${CometConf.getExprAllowIncompatConfigKey(exprConfName)}=true " +
                  s"but has notes: ${notes.get}")
            }
            handler.convert(expr, inputs, binding)
          } else {
            val optionalNotes = notes.map(str => s" ($str)").getOrElse("")
            withInfo(
              expr,
              s"$expr is not fully compatible with Spark$optionalNotes. To enable it anyway, " +
                s"set ${CometConf.getExprAllowIncompatConfigKey(exprConfName)}=true. " +
                s"${CometConf.COMPAT_GUIDE}.")
            None
          }
        case Compatible(notes) =>
          if (notes.isDefined) {
            logWarning(s"Comet supports $expr but has notes: ${notes.get}")
          }
          handler.convert(expr, inputs, binding)
      }
    }

    versionSpecificExprToProtoInternal(expr, inputs, binding)
      .orElse(expr match {

        case UnaryExpression(child) if expr.prettyName == "promote_precision" =>
          // `UnaryExpression` includes `PromotePrecision` for Spark 3.3
          // `PromotePrecision` is just a wrapper, don't need to serialize it.
          exprToProtoInternal(child, inputs, binding)

        case expr =>
          QueryPlanSerde.exprSerdeMap.get(expr.getClass) match {
            case Some(handler) =>
              convert(expr, handler.asInstanceOf[CometExpressionSerde[Expression]])
            case _ =>
              withInfo(expr, s"${expr.prettyName} is not supported", expr.children: _*)
              None
          }
      })
      .map { protoExpr =>
        // Attach QueryContext and expr_id to the expression
        val builder = protoExpr.toBuilder
        builder.setExprId(nextExprId())
        extractQueryContext(expr).foreach { ctx =>
          builder.setQueryContext(ctx)
        }
        builder.build()
      }
  }

  /**
   * Creates a UnaryExpr by calling exprToProtoInternal for the provided child expression and then
   * invokes the supplied function to wrap this UnaryExpr in a top-level Expr.
   *
   * @param child
   *   Spark expression
   * @param inputs
   *   Inputs to the expression
   * @param f
   *   Function that accepts an Expr.Builder and a UnaryExpr and builds the specific top-level
   *   Expr
   * @return
   *   Some(Expr) or None if not supported
   */
  def createUnaryExpr(
      expr: Expression,
      child: Expression,
      inputs: Seq[Attribute],
      binding: Boolean,
      f: (ExprOuterClass.Expr.Builder, ExprOuterClass.UnaryExpr) => ExprOuterClass.Expr.Builder)
      : Option[ExprOuterClass.Expr] = {
    val childExpr = exprToProtoInternal(child, inputs, binding) // TODO review
    if (childExpr.isDefined) {
      // create the generic UnaryExpr message
      val inner = ExprOuterClass.UnaryExpr
        .newBuilder()
        .setChild(childExpr.get)
        .build()
      // call the user-supplied function to wrap UnaryExpr in a top-level Expr
      // such as Expr.IsNull or Expr.IsNotNull
      Some(
        f(
          ExprOuterClass.Expr
            .newBuilder(),
          inner).build())
    } else {
      withInfo(expr, child)
      None
    }
  }

  def createBinaryExpr(
      expr: Expression,
      left: Expression,
      right: Expression,
      inputs: Seq[Attribute],
      binding: Boolean,
      f: (ExprOuterClass.Expr.Builder, ExprOuterClass.BinaryExpr) => ExprOuterClass.Expr.Builder)
      : Option[ExprOuterClass.Expr] = {
    val leftExpr = exprToProtoInternal(left, inputs, binding)
    val rightExpr = exprToProtoInternal(right, inputs, binding)
    if (leftExpr.isDefined && rightExpr.isDefined) {
      // create the generic BinaryExpr message
      val inner = ExprOuterClass.BinaryExpr
        .newBuilder()
        .setLeft(leftExpr.get)
        .setRight(rightExpr.get)
        .build()
      // call the user-supplied function to wrap BinaryExpr in a top-level Expr
      // such as Expr.And or Expr.Or
      Some(
        f(
          ExprOuterClass.Expr
            .newBuilder(),
          inner).build())
    } else {
      withInfo(expr, left, right)
      None
    }
  }

  def scalarFunctionExprToProtoWithReturnType(
      funcName: String,
      returnType: DataType,
      failOnError: Boolean,
      args: Option[Expr]*): Option[Expr] = {
    val builder = ExprOuterClass.ScalarFunc.newBuilder()
    builder.setFunc(funcName)
    builder.setFailOnError(failOnError)
    serializeDataType(returnType).flatMap { t =>
      builder.setReturnType(t)
      scalarFunctionExprToProto0(builder, args: _*)
    }
  }

  def scalarFunctionExprToProto(funcName: String, args: Option[Expr]*): Option[Expr] = {
    val builder = ExprOuterClass.ScalarFunc.newBuilder()
    builder.setFunc(funcName)
    builder.setFailOnError(false)
    scalarFunctionExprToProto0(builder, args: _*)
  }

  private def scalarFunctionExprToProto0(
      builder: ScalarFunc.Builder,
      args: Option[Expr]*): Option[Expr] = {
    args.foreach {
      case Some(a) => builder.addArgs(a)
      case _ =>
        return None
    }
    Some(ExprOuterClass.Expr.newBuilder().setScalarFunc(builder).build())
  }

  // Utility method. Adds explain info if the result of calling exprToProto is None
  def optExprWithInfo(
      optExpr: Option[Expr],
      expr: Expression,
      childExpr: Expression*): Option[Expr] = {
    optExpr match {
      case None =>
        withInfo(expr, childExpr: _*)
        None
      case o => o
    }

  }

  // scalastyle:off
  /**
   * Align w/ Arrow's
   * [[https://github.com/apache/arrow-rs/blob/55.2.0/arrow-ord/src/rank.rs#L30-L40 can_rank]] and
   * [[https://github.com/apache/arrow-rs/blob/55.2.0/arrow-ord/src/sort.rs#L193-L215 can_sort_to_indices]]
   *
   * TODO: Include SparkSQL's [[YearMonthIntervalType]] and [[DayTimeIntervalType]]
   */
  // scalastyle:on
  def supportedScalarSortElementType(dt: DataType): Boolean = {
    dt match {
      case _: ByteType | _: ShortType | _: IntegerType | _: LongType | _: FloatType |
          _: DoubleType | _: DecimalType | _: DateType | _: TimestampType | _: TimestampNTZType |
          _: BooleanType | _: BinaryType | _: StringType =>
        true
      case _ =>
        false
    }
  }

  def supportedSortType(op: SparkPlan, sortOrder: Seq[SortOrder]): Boolean = {
    if (sortOrder.length == 1) {
      val canSort = sortOrder.head.dataType match {
        case ArrayType(elementType, _) => supportedScalarSortElementType(elementType)
        case MapType(_, valueType, _) => supportedScalarSortElementType(valueType)
        case _ => supportedScalarSortElementType(sortOrder.head.dataType)
      }
      if (!canSort) {
        withInfo(op, s"Sort on single column of type ${sortOrder.head.dataType} is not supported")
        false
      } else {
        true
      }
    } else {
      true
    }
  }

}
