feat: NCS-41 Bot Platform (#33)

Co-authored-by: Janis <janis@nowchess.de>
Reviewed-on: #33
Co-authored-by: Janis <janis.e.20@gmx.de>
Co-committed-by: Janis <janis.e.20@gmx.de>

modules/api/src/main/scala/de/nowchess/api/bot/Bot.scala

@@ -0,0 +1,11 @@
+package de.nowchess.api.bot
+
+import de.nowchess.api.game.GameContext
+import de.nowchess.api.move.Move
+
+trait Bot {
+
+  def name: String
+  def nextMove(context: GameContext): Option[Move]
+
+}

modules/api/src/main/scala/de/nowchess/api/game/GameContext.scala

@@ -1,6 +1,6 @@
 package de.nowchess.api.game
 
-import de.nowchess.api.board.{Board, CastlingRights, Color, Square}
+import de.nowchess.api.board.{Board, CastlingRights, Color, PieceType, Square}
 import de.nowchess.api.move.Move
 
 /** Immutable bundle of complete game state. All state changes produce new GameContext instances.
@@ -15,6 +15,13 @@ case class GameContext(
     result: Option[GameResult] = None,
     initialBoard: Board = Board.initial,
 ):
+  private lazy val whiteKingSquare: Option[Square] =
+    board.pieces.find((_, p) => p.color == Color.White && p.pieceType == PieceType.King).map(_._1)
+  private lazy val blackKingSquare: Option[Square] =
+    board.pieces.find((_, p) => p.color == Color.Black && p.pieceType == PieceType.King).map(_._1)
+  def kingSquare(color: Color): Option[Square] =
+    if color == Color.White then whiteKingSquare else blackKingSquare
+
   /** Create new context with updated board. */
   def withBoard(newBoard: Board): GameContext = copy(board = newBoard)
 

modules/api/src/main/scala/de/nowchess/api/game/Participant.scala

@@ -0,0 +1,8 @@
+package de.nowchess.api.game
+
+import de.nowchess.api.bot.Bot
+import de.nowchess.api.player.PlayerInfo
+
+sealed trait Participant
+final case class Human(playerInfo: PlayerInfo) extends Participant
+final case class BotParticipant(bot: Bot)      extends Participant

modules/api/src/test/scala/de/nowchess/api/game/GameContextTest.scala

@@ -71,3 +71,9 @@ class GameContextTest extends AnyFunSuite with Matchers:
   test("withResult clears result"):
     val ctx = GameContext.initial.withResult(Some(GameResult.Win(Color.Black)))
     ctx.withResult(None).result shouldBe None
+
+  test("kingSquare returns white king position"):
+    GameContext.initial.kingSquare(Color.White) shouldBe Some(Square(File.E, Rank.R1))
+
+  test("kingSquare returns black king position"):
+    GameContext.initial.kingSquare(Color.Black) shouldBe Some(Square(File.E, Rank.R8))