feat: NCS-37 game lifecycle endpoints (createGame, getGame)

Add domain model (GameResult, GameSession, GameId, GameStore, GameMapper),
DTOs, JacksonConfig, and GameResource REST endpoints with QuarkusTest coverage.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

modules/backcore/src/main/scala/de/nowchess/backcore/config/JacksonConfig.scala

@@ -0,0 +1,11 @@
+package de.nowchess.backcore.config
+
+import com.fasterxml.jackson.databind.ObjectMapper
+import com.fasterxml.jackson.module.scala.DefaultScalaModule
+import io.quarkus.jackson.ObjectMapperCustomizer
+import jakarta.inject.Singleton
+
+@Singleton
+class JacksonConfig extends ObjectMapperCustomizer:
+  def customize(mapper: ObjectMapper): Unit =
+    mapper.registerModule(DefaultScalaModule)

modules/backcore/src/main/scala/de/nowchess/backcore/dto/Dtos.scala

@@ -0,0 +1,57 @@
+package de.nowchess.backcore.dto
+
+import com.fasterxml.jackson.annotation.JsonInclude
+import com.fasterxml.jackson.annotation.JsonInclude.Include
+
+case class PlayerInfoDto(id: String, displayName: String)
+
+case class GameStateResponse(
+  fen: String,
+  pgn: String,
+  turn: String,
+  status: String,
+  @JsonInclude(Include.NON_ABSENT) winner: Option[String],
+  moves: List[String],
+  undoAvailable: Boolean,
+  redoAvailable: Boolean,
+)
+
+case class GameFullResponse(
+  gameId: String,
+  white: PlayerInfoDto,
+  black: PlayerInfoDto,
+  state: GameStateResponse,
+)
+
+case class OkResponse(ok: Boolean = true)
+
+@JsonInclude(Include.NON_ABSENT)
+case class ApiErrorResponse(
+  code: String,
+  message: String,
+  field: Option[String] = None,
+)
+
+// Requests
+case class CreateGameRequest(
+  white: Option[PlayerInfoDto] = None,
+  black: Option[PlayerInfoDto] = None,
+)
+
+case class ImportFenRequest(
+  fen: String = "",
+  white: Option[PlayerInfoDto] = None,
+  black: Option[PlayerInfoDto] = None,
+)
+
+case class ImportPgnRequest(pgn: String = "")
+
+case class LegalMoveDto(
+  from: String,
+  to: String,
+  uci: String,
+  moveType: String,
+  @JsonInclude(Include.NON_ABSENT) promotion: Option[String] = None,
+)
+
+case class LegalMovesResponse(moves: List[LegalMoveDto])

modules/backcore/src/main/scala/de/nowchess/backcore/game/GameId.scala

@@ -0,0 +1,10 @@
+package de.nowchess.backcore.game
+
+import java.security.SecureRandom
+
+object GameId:
+  private val chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
+  private val random = SecureRandom()
+
+  def generate(): String =
+    (1 to 8).map(_ => chars(random.nextInt(chars.length))).mkString

modules/backcore/src/main/scala/de/nowchess/backcore/game/GameMapper.scala

@@ -0,0 +1,75 @@
+package de.nowchess.backcore.game
+
+import de.nowchess.api.board.Color
+import de.nowchess.api.move.{Move, MoveType, PromotionPiece}
+import de.nowchess.backcore.dto.*
+import de.nowchess.io.fen.FenExporter
+import de.nowchess.rules.sets.DefaultRules
+
+object GameMapper:
+
+  def toGameFull(session: GameSession): GameFullResponse =
+    GameFullResponse(
+      gameId = session.gameId,
+      white = toPlayerInfo(session.white),
+      black = toPlayerInfo(session.black),
+      state = toGameState(session),
+    )
+
+  def toGameState(session: GameSession): GameStateResponse =
+    val (status, winner) = computeStatus(session)
+    GameStateResponse(
+      fen = FenExporter.exportGameContext(session.context),
+      pgn = buildPgn(session.context.moves),
+      turn = if session.context.turn == Color.White then "white" else "black",
+      status = status,
+      winner = winner,
+      moves = session.context.moves.map(moveToUci),
+      undoAvailable = session.invoker.canUndo,
+      redoAvailable = session.invoker.canRedo,
+    )
+
+  private def toPlayerInfo(p: de.nowchess.api.player.PlayerInfo): PlayerInfoDto =
+    PlayerInfoDto(id = p.id.value, displayName = p.displayName)
+
+  private def computeStatus(session: GameSession): (String, Option[String]) =
+    session.result match
+      case Some(GameResult.Checkmate(winner)) =>
+        val w = if winner == Color.White then "white" else "black"
+        ("checkmate", Some(w))
+      case Some(GameResult.Stalemate) =>
+        ("stalemate", None)
+      case Some(GameResult.Resign(winner)) =>
+        val w = if winner == Color.White then "white" else "black"
+        ("resign", Some(w))
+      case Some(GameResult.AgreedDraw) | Some(GameResult.FiftyMoveDraw) =>
+        ("draw", None)
+      case Some(GameResult.InsufficientMaterial) =>
+        ("insufficientMaterial", None)
+      case None =>
+        computeLiveStatus(session)
+
+  private def computeLiveStatus(session: GameSession): (String, Option[String]) =
+    val ctx = session.context
+    if session.drawOfferedBy.isDefined then ("drawOffered", None)
+    else if DefaultRules.isFiftyMoveRule(ctx) then ("fiftyMoveAvailable", None)
+    else if DefaultRules.isCheck(ctx) then ("check", None)
+    else ("started", None)
+
+  def moveToUci(move: Move): String =
+    val base = s"${move.from}${move.to}"
+    move.moveType match
+      case MoveType.Promotion(piece) =>
+        val suffix = piece match
+          case PromotionPiece.Queen  => "q"
+          case PromotionPiece.Rook   => "r"
+          case PromotionPiece.Bishop => "b"
+          case PromotionPiece.Knight => "n"
+        base + suffix
+      case _ => base
+
+  private def buildPgn(moves: List[Move]): String =
+    moves.zipWithIndex.map { (move, i) =>
+      val prefix = if i % 2 == 0 then s"${i / 2 + 1}. " else ""
+      prefix + moveToUci(move)
+    }.mkString(" ")

modules/backcore/src/main/scala/de/nowchess/backcore/game/GameResult.scala

@@ -0,0 +1,12 @@
+package de.nowchess.backcore.game
+
+import de.nowchess.api.board.Color
+
+sealed trait GameResult
+object GameResult:
+  case class Checkmate(winner: Color) extends GameResult
+  case object Stalemate extends GameResult
+  case class Resign(winner: Color) extends GameResult
+  case object AgreedDraw extends GameResult
+  case object FiftyMoveDraw extends GameResult
+  case object InsufficientMaterial extends GameResult

modules/backcore/src/main/scala/de/nowchess/backcore/game/GameSession.scala

@@ -0,0 +1,16 @@
+package de.nowchess.backcore.game
+
+import de.nowchess.api.board.Color
+import de.nowchess.api.game.GameContext
+import de.nowchess.api.player.PlayerInfo
+import de.nowchess.chess.command.CommandInvoker
+
+case class GameSession(
+  gameId: String,
+  white: PlayerInfo,
+  black: PlayerInfo,
+  context: GameContext,
+  invoker: CommandInvoker,
+  drawOfferedBy: Option[Color] = None,
+  result: Option[GameResult] = None,
+)

modules/backcore/src/main/scala/de/nowchess/backcore/game/GameStore.scala

@@ -0,0 +1,33 @@
+package de.nowchess.backcore.game
+
+import de.nowchess.api.game.GameContext
+import de.nowchess.api.player.{PlayerId, PlayerInfo}
+import de.nowchess.backcore.dto.{CreateGameRequest, PlayerInfoDto}
+import de.nowchess.chess.command.CommandInvoker
+import jakarta.enterprise.context.ApplicationScoped
+
+import scala.collection.mutable
+
+@ApplicationScoped
+class GameStore:
+  private val games: mutable.Map[String, GameSession] = mutable.Map.empty
+
+  def create(req: CreateGameRequest): GameSession = synchronized:
+    val id = GameId.generate()
+    val white = toPlayerInfo(req.white, "white", "White")
+    val black = toPlayerInfo(req.black, "black", "Black")
+    val session = GameSession(
+      gameId = id,
+      white = white,
+      black = black,
+      context = GameContext.initial,
+      invoker = new CommandInvoker(),
+    )
+    games(id) = session
+    session
+
+  def get(id: String): Option[GameSession] = synchronized:
+    games.get(id)
+
+  private def toPlayerInfo(dto: Option[PlayerInfoDto], defaultId: String, defaultName: String): PlayerInfo =
+    dto.fold(PlayerInfo(PlayerId(defaultId), defaultName))(d => PlayerInfo(PlayerId(d.id), d.displayName))

modules/backcore/src/main/scala/de/nowchess/backcore/resource/GameResource.scala

@@ -0,0 +1,29 @@
+package de.nowchess.backcore.resource
+
+import de.nowchess.backcore.dto.*
+import de.nowchess.backcore.game.{GameMapper, GameStore}
+import jakarta.enterprise.context.ApplicationScoped
+import jakarta.inject.Inject
+import jakarta.ws.rs.*
+import jakarta.ws.rs.core.{MediaType, Response}
+
+@Path("/api/board/game")
+@Produces(Array(MediaType.APPLICATION_JSON))
+@Consumes(Array(MediaType.APPLICATION_JSON))
+@ApplicationScoped
+class GameResource @Inject() (store: GameStore):
+
+  @POST
+  def createGame(req: CreateGameRequest): Response =
+    val session = store.create(Option(req).getOrElse(CreateGameRequest()))
+    Response.status(201).entity(GameMapper.toGameFull(session)).build()
+
+  @GET
+  @Path("/{gameId}")
+  def getGame(@PathParam("gameId") gameId: String): Response =
+    store.get(gameId) match
+      case Some(session) => Response.ok(GameMapper.toGameFull(session)).build()
+      case None =>
+        Response.status(404)
+          .entity(ApiErrorResponse("GAME_NOT_FOUND", s"Game $gameId not found"))
+          .build()

modules/backcore/src/test/scala/de/nowchess/backcore/resource/GameResourceTest.scala

@@ -0,0 +1,62 @@
+package de.nowchess.backcore.resource
+
+import io.quarkus.test.junit.QuarkusTest
+import io.restassured.RestAssured
+import org.hamcrest.Matchers.{equalTo, matchesPattern, notNullValue}
+import org.junit.jupiter.api.Test
+
+@QuarkusTest
+class GameResourceTest:
+
+  @Test
+  def createGameReturns201WithGameId(): Unit =
+    RestAssured.`given`()
+      .contentType("application/json")
+      .body("{}")
+      .when()
+      .post("/api/board/game")
+      .`then`()
+      .statusCode(201)
+      .body("gameId", matchesPattern("[A-Za-z0-9]{8}"))
+      .body("state.fen", notNullValue())
+      .body("state.turn", equalTo("white"))
+      .body("state.status", equalTo("started"))
+
+  @Test
+  def createGameWithPlayersReturns201(): Unit =
+    RestAssured.`given`()
+      .contentType("application/json")
+      .body("""{"white":{"id":"p1","displayName":"Alice"},"black":{"id":"p2","displayName":"Bob"}}""")
+      .when()
+      .post("/api/board/game")
+      .`then`()
+      .statusCode(201)
+      .body("white.id", equalTo("p1"))
+      .body("black.displayName", equalTo("Bob"))
+
+  @Test
+  def getGameReturns200ForExistingGame(): Unit =
+    val gameId = RestAssured.`given`()
+      .contentType("application/json")
+      .body("{}")
+      .when()
+      .post("/api/board/game")
+      .`then`()
+      .statusCode(201)
+      .extract()
+      .path[String]("gameId")
+
+    RestAssured.`given`()
+      .when()
+      .get(s"/api/board/game/$gameId")
+      .`then`()
+      .statusCode(200)
+      .body("gameId", equalTo(gameId))
+
+  @Test
+  def getGameReturns404ForUnknownId(): Unit =
+    RestAssured.`given`()
+      .when()
+      .get("/api/board/game/XXXXXXXX")
+      .`then`()
+      .statusCode(404)