PlayersHands class

src/main/kotlin/eventDemo/app/GameState.kt

@@ -15,7 +15,7 @@ data class GameState(
     val lastColor: Card.Color? = null,
     val direction: Direction = Direction.CLOCKWISE,
     val readyPlayers: List<Player> = emptyList(),
-    val deck: Deck = Deck(players.toList()),
+    val deck: Deck = Deck(players),
     val isStarted: Boolean = false,
 ) {
     @Serializable

src/main/kotlin/eventDemo/app/entity/Deck.kt

@@ -6,9 +6,10 @@ import kotlinx.serialization.Serializable
 data class Deck(
     val stack: Stack = Stack(),
     val discard: Discard = Discard(),
-    val playersHands: PlayerHands = emptyMap(),
+    val playersHands: PlayersHands = PlayersHands(),
 ) {
-    constructor(players: List<Player>) : this(playersHands = players.associateWith { emptyList<Card>() })
+    constructor(players: Set<Player>) :
+        this(playersHands = PlayersHands(players))
 
     fun placeFirstCardOnDiscard(): Deck {
         val takenCard = stack.first()
@@ -21,13 +22,14 @@ data class Deck(
     fun takeOneCardFromStackTo(player: Player): Deck =
         takeOne().let { (deck, newPlayerCard) ->
             val newHands =
-                deck.playersHands.mapValues { (p, cards) ->
-                    if (p == player) {
-                        cards + newPlayerCard
-                    } else {
-                        cards
-                    }
-                }
+                deck.playersHands
+                    .mapValues { (p, cards) ->
+                        if (p == player) {
+                            cards + newPlayerCard
+                        } else {
+                            cards
+                        }
+                    }.toPlayersHands()
             deck.copy(playersHands = newHands)
         }
 
@@ -79,7 +81,7 @@ fun Deck.initHands(
     handSize: Int = 7,
 ): Deck {
     // Copy cards from stack to the player hands
-    val deckWithEmptyHands = copy(playersHands = players.associateWith { listOf() })
+    val deckWithEmptyHands = copy(playersHands = PlayersHands(players))
     return players.fold(deckWithEmptyHands) { acc: Deck, player: Player ->
         val hand = acc.stack.take(handSize)
         val newStack = acc.stack.filterNot { card: Card -> hand.contains(card) }.toStack()
@@ -93,11 +95,11 @@ fun Deck.initHands(
 @JvmInline
 @Serializable
 value class Stack(
-    val elems: Set<Card> = emptySet(),
-) : Set<Card> by elems {
-    operator fun plus(card: Card): Stack = elems.plus(card).toStack()
+    private val cards: Set<Card> = emptySet(),
+) : Set<Card> by cards {
+    operator fun plus(card: Card): Stack = cards.plus(card).toStack()
 
-    operator fun minus(card: Card): Stack = elems.minus(card).toStack()
+    operator fun minus(card: Card): Stack = cards.minus(card).toStack()
 }
 
 fun List<Card>.toStack(): Stack = Stack(this.toSet())
@@ -107,11 +109,11 @@ fun Set<Card>.toStack(): Stack = Stack(this)
 @JvmInline
 @Serializable
 value class Discard(
-    val elems: Set<Card> = emptySet(),
-) : Set<Card> by elems {
-    operator fun plus(card: Card): Discard = elems.plus(card).toDiscard()
+    private val cards: Set<Card> = emptySet(),
+) : Set<Card> by cards {
+    operator fun plus(card: Card): Discard = cards.plus(card).toDiscard()
 
-    operator fun minus(card: Card): Discard = elems.minus(card).toDiscard()
+    operator fun minus(card: Card): Discard = cards.minus(card).toDiscard()
 }
 
 fun List<Card>.toDiscard(): Discard = Discard(this.toSet())

src/main/kotlin/eventDemo/app/entity/PlayerHand.kt

@@ -1,27 +0,0 @@
-package eventDemo.app.entity
-
-typealias PlayerHands = Map<Player, List<Card>>
-
-fun PlayerHands.removeCard(
-    player: Player,
-    card: Card,
-): PlayerHands =
-    mapValues { (p, cards) ->
-        if (p == player) {
-            cards - card
-        } else {
-            cards
-        }
-    }
-
-fun PlayerHands.addCards(
-    player: Player,
-    newCards: List<Card>,
-): PlayerHands =
-    mapValues { (p, cards) ->
-        if (p == player) {
-            cards + newCards
-        } else {
-            cards
-        }
-    }

src/main/kotlin/eventDemo/app/entity/PlayersHands.kt

@@ -0,0 +1,37 @@
+package eventDemo.app.entity
+
+import kotlinx.serialization.Serializable
+
+@Serializable
+@JvmInline
+value class PlayersHands(
+    private val map: Map<Player, List<Card>> = emptyMap(),
+) : Map<Player, List<Card>> by map {
+    constructor(players: Set<Player>) : this(players.associateWith { emptyList<Card>() }.toPlayersHands())
+
+    fun removeCard(
+        player: Player,
+        card: Card,
+    ): PlayersHands =
+        mapValues { (p, cards) ->
+            if (p == player) {
+                cards - card
+            } else {
+                cards
+            }
+        }.toPlayersHands()
+
+    fun addCards(
+        player: Player,
+        newCards: List<Card>,
+    ): PlayersHands =
+        mapValues { (p, cards) ->
+            if (p == player) {
+                cards + newCards
+            } else {
+                cards
+            }
+        }.toPlayersHands()
+}
+
+fun Map<Player, List<Card>>.toPlayersHands(): PlayersHands = PlayersHands(this)

src/test/kotlin/eventDemo/app/entity/PlayerHandKtTest.kt

@@ -11,11 +11,11 @@ class PlayerHandKtTest :
             val playerNumbers = 4
             val players = (1..playerNumbers).map { Player(name = "name $it") }.toSet()
             val firstPlayer = players.first()
-            val playersHands: PlayerHands = players.associateWith { emptyList() }
+            val playersHands = PlayersHands(players)
             val card = Card.NumericCard(0, Card.Color.Red)
 
             // When
-            val newHands: PlayerHands = playersHands.addCards(firstPlayer, listOf(card))
+            val newHands: PlayersHands = playersHands.addCards(firstPlayer, listOf(card))
 
             assertNotNull(newHands[firstPlayer]).size shouldBeExactly 1
             assertNotNull(newHands[players.last()]).size shouldBeExactly 0
@@ -28,13 +28,12 @@ class PlayerHandKtTest :
             val firstPlayer = players.first()
             val card1 = Card.NumericCard(1, Card.Color.Red)
             val card2 = Card.NumericCard(2, Card.Color.Red)
-            val playersHands: PlayerHands =
-                players
-                    .associateWith<Player, List<Card>> { emptyList() }
+            val playersHands: PlayersHands =
+                PlayersHands(players)
                     .addCards(firstPlayer, listOf(card1, card2))
 
             // When
-            val newHands: PlayerHands = playersHands.removeCard(firstPlayer, card1)
+            val newHands: PlayersHands = playersHands.removeCard(firstPlayer, card1)
 
             assertNotNull(newHands[firstPlayer]).size shouldBeExactly 1
             assertNotNull(newHands[players.last()]).size shouldBeExactly 0