Effective Programming in Scala - Week 1 challenge: Generic checkProperty function

game_base_generic_properties.worksheet.sc

enum Shape:
  case Diamond, Squiggle, Oval

enum Color:
  case Red, Green, Purple

enum Shading:
  case Open, Striped, Solid

enum NumberType:
  case One, Two, Three

case class Card(shape: Shape, number: NumberType, color: Color, shading: Shading)

type PropertyType = Shape | Color | Shading | NumberType

enum Property(value: Card => PropertyType):
  def apply(card: Card): PropertyType = value(card)

  case Shape extends Property(_.shape)
  case Color extends Property(_.color)
  case Shading extends Property(_.shading)
  case Number extends Property(_.number)

def checkProperty(property: Property, card1: Card, card2: Card, card3: Card): Boolean =
  def allSame =
    property(card1) == property(card2) && property(card1)== property(card3)
  def allDifferent =
    property(card1) != property(card2) &&
      property(card1) != property(card3) &&
      property(card2) != property(card3)
  allSame || allDifferent

def isValidSet(card1: Card, card2: Card, card3: Card): Boolean =
  Property.values.forall(property => checkProperty(property, card1, card2, card3))

isValidSet(
  Card(Shape.Diamond,  NumberType.One,   Color.Purple, Shading.Striped),
  Card(Shape.Squiggle, NumberType.Two,   Color.Purple, Shading.Open),
  Card(Shape.Oval,     NumberType.Three, Color.Purple, Shading.Solid)
)

isValidSet(
  Card(Shape.Diamond,  NumberType.Two,   Color.Purple, Shading.Striped),
  Card(Shape.Squiggle, NumberType.Two,   Color.Purple, Shading.Open),
  Card(Shape.Oval,     NumberType.Three, Color.Purple, Shading.Solid)
)