selection.scala

case class Metric(id: String, aggregationOperation: AggregationOperation)

case class Dimension(id: String)

object AggregationOperation extends Enumeration {
  type AggregationOperation = Value
  val Sum, Average, Min, Max, Count = Value
}

/**
 * Think of a RowSelection as a typed SQL table. We use this selection to
 * modelize OLAP cubes.
 * 
 * Headers are the names of each column, with an additionnal information about
 * wether we are dealing with a dimension or a metric.
 * 
 * Rows are double dimensions arrays. 
 * Each row is viewed as 2 concatened sequence: one of strings for dimension values, the others of numerics.
 * 
 * Ex:
 * ["ga:origin", "ga:browser"] ["ga:visits", "ga:timeOnSite"]
 * ["France", "Chrome"] [20.0, 345.5]
 * 
 */
case class RowSelection(
    metricHeaders: Seq[Metric],
    dimensionHeaders: Seq[Dimension],
    metricRows: Seq[IndexedSeq[Double]],
    dimensionRows: Seq[IndexedSeq[String]]) {
    
  def take(n: Int): RowSelection = {
    /// To be implemented
  }  
  
  def ++(other: Selection): RowSelection = {
    /// To be implemented
  }

  def filter(col: Dimension, f: (String) => Boolean): RowSelection = {
    /// To be implemented
  }
  
  def groupByColumns(cols: Seq[Dimension]): RowSelection = {
    ///To be implemented
  }
}
  
  
  
class RowSelectionSpec extends FunSpec with ShouldMatchers {
  
  val metric1 = Metric("m1", AggregationOperation.Sum)
  val metric2 = Metric("m2", AggregationOperation.Average)
  val dimension1 = Dimension("d1")
  val dimension2 = Dimension("d2")
  
  val selection = RowSelection(
    Seq(metric1, metric2),
    Seq(dimension1, dimension2),
    Seq(IndexedSeq(1.0, 3.0), IndexedSeq(2.0, 9.0)),
    Seq(IndexedSeq("dimVal11", "dimVal12"), IndexedSeq("dimVal21", "dimVal22"))
  )
  
    
  describe("RowSelection") {
  
    it should "take the n first rows" in {
      val taken = selection.take(1)
      taken.metricRows should have size(1)
      taken.dimensionRows should have size(1)
    } 
    
    it should "add a selection to another selection" in {
      val other = selection
      val added = selection ++ other 
      added.metricHeaders should equal(selection.metricHeaders)
      added.dimensionHeaders should equal(selection.dimensionHeaders)
      added.metricRows should equal(Seq(IndexedSeq(1.0, 3.0), IndexedSeq(2.0, 9.0), IndexedSeq(1.0, 3.0), IndexedSeq(2.0, 9.0)))
      added.dimensionRows should equal(Seq(IndexedSeq("dimVal11", "dimVal12"), IndexedSeq("dimVal21", "dimVal22"), IndexedSeq("dimVal11", "dimVal12"), IndexedSeq("dimVal21", "dimVal22")))
    }
    
    it should "filter the selection" in {
      val f: (String => Boolean) = dimVal => (dimVal == "dimVal11")
      val filtered = selection.filter(dimension1, f)
      filtered.metricRows should equal(Seq(IndexedSeq(1.0, 3.0))))
      filtered.dimensionRows should equal(Seq(IndexedSeq("dimVal11", "dimVal12")))
    }
    
    it should "group by columns" in {
      val s = selection.copy(dimensionRows = Seq(IndexedSeq("dimVal1", "dimVal2"), IndexedSeq("dimVal1", "dimVal2")))
      val grouped = s.groupByColumns(Seq(dimension1, dimension2))
      grouped.dimensionRows should equal(Seq(IndexedSeq("dimVal1", "dimVal2")))
      grouped.metricRows should equal(Seq(IndexedSeq(3.0, 6.0)))
    }
    
  }

}