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 * (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
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package org.apache.spark.sql.catalyst.optimizer

import org.apache.spark.sql.catalyst.analysis.EliminateSubqueryAliases
import org.apache.spark.sql.catalyst.dsl.expressions._
import org.apache.spark.sql.catalyst.dsl.plans._
import org.apache.spark.sql.catalyst.expressions.{Alias, CreateArray, Expression, GetArrayItem, PythonUDF, Rand, UpdateFields}
import org.apache.spark.sql.catalyst.plans.PlanTest
import org.apache.spark.sql.catalyst.plans.logical._
import org.apache.spark.sql.catalyst.rules.RuleExecutor
import org.apache.spark.sql.internal.SQLConf
import org.apache.spark.sql.types.{ArrayType, IntegerType, MetadataBuilder}

class CollapseProjectSuite extends PlanTest {
  object Optimize extends RuleExecutor[LogicalPlan] {
    val batches =
      Batch("Subqueries", FixedPoint(10), EliminateSubqueryAliases) ::
      Batch("CollapseProject", Once, CollapseProject) ::
      Batch("SimplifyExtractValueOps", Once, SimplifyExtractValueOps) ::
      Batch("ReplaceUpdateFieldsExpression", Once, ReplaceUpdateFieldsExpression) :: Nil
  }

  val testRelation = LocalRelation($"a".int, $"b".int)

  test("collapse two deterministic, independent projects into one") {
    val query = testRelation
      .select(($"a" + 1).as("a_plus_1"), $"b")
      .select($"a_plus_1", ($"b" + 1).as("b_plus_1"))

    val optimized = Optimize.execute(query.analyze)
    val correctAnswer = testRelation.select(($"a" + 1).as("a_plus_1"),
      ($"b" + 1).as("b_plus_1")).analyze

    comparePlans(optimized, correctAnswer)
  }

  test("collapse two deterministic, dependent projects into one") {
    val query = testRelation
      .select(($"a" + 1).as("a_plus_1"), $"b")
      .select(($"a_plus_1" + 1).as("a_plus_2"), $"b")

    val optimized = Optimize.execute(query.analyze)

    val correctAnswer = testRelation.select(
      (($"a" + 1).as("a_plus_1") + 1).as("a_plus_2"),
      $"b").analyze

    comparePlans(optimized, correctAnswer)
  }

  test("do not collapse nondeterministic projects") {
    val query = testRelation
      .select(Rand(10).as("rand"))
      .select(($"rand" + 1).as("rand1"), ($"rand" + 2).as("rand2"))

    val optimized = Optimize.execute(query.analyze)
    val correctAnswer = query.analyze

    comparePlans(optimized, correctAnswer)
  }

  test("collapse two nondeterministic, independent projects into one") {
    val query = testRelation
      .select(Rand(10).as("rand"))
      .select(Rand(20).as("rand2"))

    val optimized = Optimize.execute(query.analyze)

    val correctAnswer = testRelation
      .select(Rand(20).as("rand2")).analyze

    comparePlans(optimized, correctAnswer)
  }

  test("collapse one nondeterministic, one deterministic, independent projects into one") {
    val query = testRelation
      .select(Rand(10).as("rand"), $"a")
      .select(($"a" + 1).as("a_plus_1"))

    val optimized = Optimize.execute(query.analyze)

    val correctAnswer = testRelation
      .select(($"a" + 1).as("a_plus_1")).analyze

    comparePlans(optimized, correctAnswer)
  }

  test("collapse project into aggregate") {
    val query = testRelation
      .groupBy($"a", $"b")(($"a" + 1).as("a_plus_1"), $"b")
      .select($"a_plus_1", ($"b" + 1).as("b_plus_1"))

    val optimized = Optimize.execute(query.analyze)

    val correctAnswer = testRelation
      .groupBy($"a", $"b")(($"a" + 1).as("a_plus_1"), ($"b" + 1).as("b_plus_1"))
      .analyze

    comparePlans(optimized, correctAnswer)
  }

  test("do not collapse common nondeterministic project and aggregate") {
    val query = testRelation
      .groupBy($"a")($"a", Rand(10).as("rand"))
      .select(($"rand" + 1).as("rand1"), ($"rand" + 2).as("rand2"))

    val optimized = Optimize.execute(query.analyze)
    val correctAnswer = query.analyze

    comparePlans(optimized, correctAnswer)
  }

  test("SPARK-36718: do not collapse project if non-cheap expressions will be repeated") {
    val query = testRelation
      .select(($"a" + 1).as("a_plus_1"))
      .select(($"a_plus_1" + $"a_plus_1").as("a_2_plus_2"))
      .analyze

    val optimized = Optimize.execute(query)
    comparePlans(optimized, query)
  }

  test("SPARK-39699: collapse project with collection creation expressions") {
    val struct = namedStruct(
      "a", $"a",
      "a_plus_1", $"a" + 1,
      "a_plus_2", $"a" + 2,
      "nested", namedStruct("inner1", $"a" + 3, "inner2", $"a" + 4)
    ).as("struct")
    val baseQuery = testRelation.select(struct)

    // Can collapse as there is only one non-cheap access: `struct.a_plus_1`
    val query1 = baseQuery
      .select(($"struct".getField("a") + $"struct".getField("a_plus_1")).as("add"))
      .analyze
    val optimized1 = Optimize.execute(query1)
    val expected1 = testRelation
      .select(($"a" + ($"a" + 1)).as("add"))
      .analyze
    comparePlans(optimized1, expected1)

    // Cannot collapse as there are two non-cheap accesses: `struct.a_plus_1` and `struct.a_plus_1`
    val query2 = baseQuery
      .select(($"struct".getField("a_plus_1") + $"struct".getField("a_plus_1")).as("add"))
      .analyze
    val optimized2 = Optimize.execute(query2)
    comparePlans(optimized2, query2)

    // Cannot collapse as there are two non-cheap accesses: `struct.a_plus_1` and `struct`
    val query3 = baseQuery
      .select($"struct".getField("a_plus_1"), $"struct")
      .analyze
    val optimized3 = Optimize.execute(query3)
    comparePlans(optimized3, query3)

    // Can collapse as there is only one non-cheap access: `struct`
    val query4 = baseQuery
      .select($"struct".getField("a"), $"struct")
      .analyze
    val optimized4 = Optimize.execute(query4)
    val expected4 = testRelation
      .select($"a".as("struct.a"), struct)
      .analyze
    comparePlans(optimized4, expected4)

    // Referenced by WithFields.
    val query5 = testRelation.select(namedStruct("a", $"a", "b", $"a" + 1).as("struct"))
      .select(UpdateFields($"struct", "c", $"struct".getField("a")).as("u"))
      .analyze
    val optimized5 = Optimize.execute(query5)
    val expected5 = testRelation
      .select(namedStruct("a", $"a", "b", $"a" + 1, "c", $"a").as("struct").as("u"))
      .analyze
    comparePlans(optimized5, expected5)

    // TODO: should collapse as the non-cheap accesses are distinct:
    //  `struct.a_plus_1` and `struct.a_plus_2`
    val query6 = baseQuery
      .select(($"struct".getField("a_plus_1") + $"struct".getField("a_plus_2")).as("add"))
      .analyze
    val optimized6 = Optimize.execute(query6)
    comparePlans(optimized6, query6)

    // Cannot collapse as the two non-cheap accesses have a lineage:
    // `struct.nested` and `struct.nested.inner1`
    val query7 = baseQuery
      .select($"struct".getField("nested"), $"struct".getField("nested").getField("inner1"))
      .analyze
    val optimized7 = Optimize.execute(query7)
    comparePlans(optimized7, query7)
  }

  test("preserve top-level alias metadata while collapsing projects") {
    def hasMetadata(logicalPlan: LogicalPlan): Boolean = {
      logicalPlan.asInstanceOf[Project].projectList.exists(_.metadata.contains("key"))
    }

    val metadata = new MetadataBuilder().putLong("key", 1).build()
    val analyzed =
      Project(Seq(Alias($"a_with_metadata", "b")()),
        Project(Seq(Alias($"a", "a_with_metadata")(explicitMetadata = Some(metadata))),
          testRelation.logicalPlan)).analyze
    require(hasMetadata(analyzed))

    val optimized = Optimize.execute(analyzed)
    val projects = optimized.collect { case p: Project => p }
    assert(projects.size === 1)
    assert(hasMetadata(optimized))
  }

  test("collapse redundant alias through limit") {
    val relation = LocalRelation($"a".int, $"b".int)
    val query = relation.select($"a" as "b").limit(1).select($"b" as "c").analyze
    val optimized = Optimize.execute(query)
    val expected = relation.select($"a" as "c").limit(1).analyze
    comparePlans(optimized, expected)
  }

  test("collapse redundant alias through local limit") {
    val relation = LocalRelation($"a".int, $"b".int)
    val query = LocalLimit(1, relation.select($"a" as "b"))
      .select($"b" as "c").analyze
    val optimized = Optimize.execute(query)
    val expected = LocalLimit(1, relation.select($"a" as "c")).analyze
    comparePlans(optimized, expected)
  }

  test("collapse redundant alias through repartition") {
    val relation = LocalRelation($"a".int, $"b".int)
    val query = relation.select($"a" as "b").repartition(1)
      .select($"b" as "c").analyze
    val optimized = Optimize.execute(query)
    val expected = relation.select($"a" as "c").repartition(1).analyze
    comparePlans(optimized, expected)
  }

  test("collapse redundant alias through sample") {
    val relation = LocalRelation($"a".int, $"b".int)
    val query = Sample(0.0, 0.6, false, 11L, relation.select($"a" as "b"))
      .select($"b" as "c").analyze
    val optimized = Optimize.execute(query)
    val expected = Sample(0.0, 0.6, false, 11L, relation.select($"a" as "c")).analyze
    comparePlans(optimized, expected)
  }

  test("SPARK-36086: CollapseProject should keep output schema name") {
    val relation = LocalRelation($"a".int, $"b".int)
    val select = relation.select(($"a" + $"b").as("c")).analyze
    val query = Project(Seq(select.output.head.withName("C")), select)
    val optimized = Optimize.execute(query)
    val expected = relation.select(($"a" + $"b").as("C")).analyze
    comparePlans(optimized, expected)
  }

  test("ES-1102888: collapse project duplicating aggregate expressions in UDF") {
    withSQLConf(SQLConf.AVOID_COLLAPSE_UDF_WITH_EXPENSIVE_EXPR.key -> "true") {
      val pythonUdf = (e: Expression) => {
        PythonUDF("udf", null, ArrayType(IntegerType), Seq(e), 0, udfDeterministic = true)
      }

      val query = testRelation
        .groupBy($"a")(collectList($"b").as("l1"))
        .select(pythonUdf($"l1").as("l2"))
        .select(CreateArray(Seq(
          GetArrayItem($"l2", 0),
          GetArrayItem($"l2", 1),
          GetArrayItem($"l2", 2),
          GetArrayItem($"l2", 3)
        )))
        .analyze

      val optimized = Optimize.execute(query)
      val expected = testRelation
        .groupBy($"a")(pythonUdf(collectList($"b")).as("l2"))
        .select(CreateArray(Seq(
          GetArrayItem($"l2", 0),
          GetArrayItem($"l2", 1),
          GetArrayItem($"l2", 2),
          GetArrayItem($"l2", 3)
        )))
        .analyze
      comparePlans(optimized, expected)
    }
  }
}
