75 changed files with 114991 additions and 123 deletions
@@ -2,8 +2,8 @@

 > **Stack:** raw-http | none | unknown | scala

-> 0 routes | 0 models | 0 components | 35 lib files | 0 env vars | 0 middleware
-> **Token savings:** this file is ~3.700 tokens. Without it, AI exploration would cost ~18.200 tokens. **Saves ~14.500 tokens per conversation.**
+> 0 routes | 0 models | 0 components | 38 lib files | 0 env vars | 0 middleware
+> **Token savings:** this file is ~0 tokens. Without it, AI exploration would cost ~0 tokens. **Saves ~0 tokens per conversation.**

 ---

@@ -54,7 +54,7 @@
  - function withEnPassantSquare
  - function withHalfMoveClock
  - function withMove
-  - _...2 more_
+  - _...3 more_
 - `modules/api/src/main/scala/de/nowchess/api/player/PlayerInfo.scala` — class PlayerId, function apply
 - `modules/api/src/main/scala/de/nowchess/api/response/ApiResponse.scala`
  - class ApiResponse
@@ -93,6 +93,13 @@
  - _...1 more_
 - `modules/io/src/main/scala/de/nowchess/io/GameContextExport.scala` — class GameContextExport, function exportGameContext
 - `modules/io/src/main/scala/de/nowchess/io/GameContextImport.scala` — class GameContextImport, function importGameContext
+- `modules/io/src/main/scala/de/nowchess/io/GameFileService.scala`
+  - class GameFileService
+  - function saveGameToFile
+  - function loadGameFromFile
+  - class FileSystemGameService
+  - function saveGameToFile
+  - function loadGameFromFile
 - `modules/io/src/main/scala/de/nowchess/io/fen/FenExporter.scala`
  - class FenExporter
  - function boardToFen
@@ -114,6 +121,8 @@
  - function parseBoard
  - function importGameContext
 - `modules/io/src/main/scala/de/nowchess/io/fen/FenParserSupport.scala` — function buildSquares
+- `modules/io/src/main/scala/de/nowchess/io/json/JsonExporter.scala` — class JsonExporter, function exportGameContext
+- `modules/io/src/main/scala/de/nowchess/io/json/JsonParser.scala` — class JsonParser, function importGameContext
 - `modules/io/src/main/scala/de/nowchess/io/pgn/PgnExporter.scala`
  - class PgnExporter
  - function exportGameContext
@@ -164,39 +173,39 @@

 ## Most Imported Files (change these carefully)

- `modules/api/src/main/scala/de/nowchess/api/game/GameContext.scala` — imported by **28** files
- `modules/api/src/main/scala/de/nowchess/api/board/Square.scala` — imported by **21** files
- `modules/api/src/main/scala/de/nowchess/api/board/Color.scala` — imported by **19** files
- `modules/api/src/main/scala/de/nowchess/api/move/Move.scala` — imported by **14** files
- `modules/api/src/main/scala/de/nowchess/api/board/Board.scala` — imported by **13** files
- `modules/api/src/main/scala/de/nowchess/api/board/Piece.scala` — imported by **10** files
- `modules/api/src/main/scala/de/nowchess/api/board/PieceType.scala` — imported by **9** files
+- `modules/api/src/main/scala/de/nowchess/api/game/GameContext.scala` — imported by **38** files
+- `modules/api/src/main/scala/de/nowchess/api/board/Square.scala` — imported by **26** files
+- `modules/api/src/main/scala/de/nowchess/api/board/Color.scala` — imported by **25** files
+- `modules/api/src/main/scala/de/nowchess/api/move/Move.scala` — imported by **21** files
+- `modules/api/src/main/scala/de/nowchess/api/board/Board.scala` — imported by **14** files
+- `modules/api/src/main/scala/de/nowchess/api/board/Piece.scala` — imported by **13** files
+- `modules/api/src/main/scala/de/nowchess/api/board/PieceType.scala` — imported by **13** files
 - `modules/io/src/main/scala/de/nowchess/io/fen/FenParser.scala` — imported by **9** files
+- `modules/io/src/main/scala/de/nowchess/io/GameContextImport.scala` — imported by **8** files
 - `modules/rule/src/main/scala/de/nowchess/rules/sets/DefaultRules.scala` — imported by **8** files
- `modules/io/src/main/scala/de/nowchess/io/GameContextImport.scala` — imported by **7** files
- `modules/api/src/main/scala/de/nowchess/api/board/CastlingRights.scala` — imported by **4** files
- `modules/io/src/main/scala/de/nowchess/io/GameContextExport.scala` — imported by **4** files
+- `modules/api/src/main/scala/de/nowchess/api/board/CastlingRights.scala` — imported by **7** files
+- `modules/api/src/main/scala/de/nowchess/api/game/DrawReason.scala` — imported by **7** files
+- `modules/io/src/main/scala/de/nowchess/io/GameContextExport.scala` — imported by **5** files
 - `modules/rule/src/main/scala/de/nowchess/rules/RuleSet.scala` — imported by **4** files
 - `modules/core/src/main/scala/de/nowchess/chess/observer/Observer.scala` — imported by **4** files
 - `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala` — imported by **4** files
+- `modules/api/src/main/scala/de/nowchess/api/game/GameResult.scala` — imported by **3** files
+- `modules/io/src/main/scala/de/nowchess/io/pgn/PgnExporter.scala` — imported by **3** files
 - `modules/io/src/main/scala/de/nowchess/io/pgn/PgnParser.scala` — imported by **2** files
- `modules/io/src/main/scala/de/nowchess/io/pgn/PgnExporter.scala` — imported by **2** files
 - `modules/io/src/main/scala/de/nowchess/io/fen/FenExporter.scala` — imported by **2** files
- `modules/io/src/main/scala/de/nowchess/io/fen/FenParserSupport.scala` — imported by **2** files
- `modules/core/src/main/scala/de/nowchess/chess/controller/Parser.scala` — imported by **1** files

 ## Import Map (who imports what)

- `modules/api/src/main/scala/de/nowchess/api/game/GameContext.scala` ← `modules/core/src/main/scala/de/nowchess/chess/command/Command.scala`, `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala`, `modules/core/src/main/scala/de/nowchess/chess/observer/Observer.scala`, `modules/core/src/test/scala/de/nowchess/chess/command/CommandInvokerBranchTest.scala`, `modules/core/src/test/scala/de/nowchess/chess/command/CommandInvokerTest.scala` +23 more
- `modules/api/src/main/scala/de/nowchess/api/board/Square.scala` ← `modules/api/src/main/scala/de/nowchess/api/game/GameContext.scala`, `modules/api/src/main/scala/de/nowchess/api/move/Move.scala`, `modules/api/src/test/scala/de/nowchess/api/game/GameContextTest.scala`, `modules/api/src/test/scala/de/nowchess/api/move/MoveTest.scala`, `modules/core/src/main/scala/de/nowchess/chess/command/Command.scala` +16 more
- `modules/api/src/main/scala/de/nowchess/api/board/Color.scala` ← `modules/api/src/main/scala/de/nowchess/api/game/GameContext.scala`, `modules/api/src/test/scala/de/nowchess/api/game/GameContextTest.scala`, `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala`, `modules/core/src/main/scala/de/nowchess/chess/observer/Observer.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/EngineTestHelpers.scala` +14 more
- `modules/api/src/main/scala/de/nowchess/api/move/Move.scala` ← `modules/api/src/main/scala/de/nowchess/api/game/GameContext.scala`, `modules/api/src/test/scala/de/nowchess/api/board/BoardTest.scala`, `modules/api/src/test/scala/de/nowchess/api/game/GameContextTest.scala`, `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineIntegrationTest.scala` +9 more
- `modules/api/src/main/scala/de/nowchess/api/board/Board.scala` ← `modules/api/src/main/scala/de/nowchess/api/game/GameContext.scala`, `modules/api/src/test/scala/de/nowchess/api/game/GameContextTest.scala`, `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/EngineTestHelpers.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineGameEndingTest.scala` +8 more
- `modules/api/src/main/scala/de/nowchess/api/board/Piece.scala` ← `modules/core/src/main/scala/de/nowchess/chess/command/Command.scala`, `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEnginePromotionTest.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineScenarioTest.scala`, `modules/rule/src/test/scala/de/nowchess/rule/DefaultRulesStateTransitionsTest.scala` +5 more
- `modules/api/src/main/scala/de/nowchess/api/board/PieceType.scala` ← `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineIntegrationTest.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEnginePromotionTest.scala`, `modules/rule/src/test/scala/de/nowchess/rule/DefaultRulesStateTransitionsTest.scala`, `modules/rule/src/test/scala/de/nowchess/rule/DefaultRulesTest.scala` +4 more
+- `modules/api/src/main/scala/de/nowchess/api/game/GameContext.scala` ← `modules/core/src/main/scala/de/nowchess/chess/command/Command.scala`, `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala`, `modules/core/src/main/scala/de/nowchess/chess/observer/Observer.scala`, `modules/core/src/test/scala/de/nowchess/chess/command/CommandInvokerBranchTest.scala`, `modules/core/src/test/scala/de/nowchess/chess/command/CommandInvokerTest.scala` +33 more
+- `modules/api/src/main/scala/de/nowchess/api/board/Square.scala` ← `modules/api/src/main/scala/de/nowchess/api/game/GameContext.scala`, `modules/api/src/main/scala/de/nowchess/api/move/Move.scala`, `modules/api/src/test/scala/de/nowchess/api/game/GameContextTest.scala`, `modules/api/src/test/scala/de/nowchess/api/move/MoveTest.scala`, `modules/core/src/main/scala/de/nowchess/chess/command/Command.scala` +21 more
+- `modules/api/src/main/scala/de/nowchess/api/board/Color.scala` ← `modules/api/src/main/scala/de/nowchess/api/game/GameContext.scala`, `modules/api/src/main/scala/de/nowchess/api/game/GameResult.scala`, `modules/api/src/test/scala/de/nowchess/api/game/GameContextTest.scala`, `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala`, `modules/core/src/main/scala/de/nowchess/chess/observer/Observer.scala` +20 more
+- `modules/api/src/main/scala/de/nowchess/api/move/Move.scala` ← `modules/api/src/main/scala/de/nowchess/api/game/GameContext.scala`, `modules/api/src/test/scala/de/nowchess/api/board/BoardTest.scala`, `modules/api/src/test/scala/de/nowchess/api/game/GameContextTest.scala`, `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineIntegrationTest.scala` +16 more
+- `modules/api/src/main/scala/de/nowchess/api/board/Board.scala` ← `modules/api/src/main/scala/de/nowchess/api/game/GameContext.scala`, `modules/api/src/test/scala/de/nowchess/api/game/GameContextTest.scala`, `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/EngineTestHelpers.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineIntegrationTest.scala` +9 more
+- `modules/api/src/main/scala/de/nowchess/api/board/Piece.scala` ← `modules/core/src/main/scala/de/nowchess/chess/command/Command.scala`, `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEnginePromotionTest.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineScenarioTest.scala`, `modules/io/src/test/scala/de/nowchess/io/json/JsonExporterBranchCoverageSuite.scala` +8 more
+- `modules/api/src/main/scala/de/nowchess/api/board/PieceType.scala` ← `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineIntegrationTest.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEnginePromotionTest.scala`, `modules/io/src/test/scala/de/nowchess/io/json/JsonExporterBranchCoverageSuite.scala`, `modules/io/src/test/scala/de/nowchess/io/json/JsonExporterSuite.scala` +8 more
 - `modules/io/src/main/scala/de/nowchess/io/fen/FenParser.scala` ← `modules/core/src/test/scala/de/nowchess/chess/engine/EngineTestHelpers.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineLoadGameTest.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineNotationTest.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEnginePromotionTest.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineScenarioTest.scala` +4 more
+- `modules/io/src/main/scala/de/nowchess/io/GameContextImport.scala` ← `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineIntegrationTest.scala`, `modules/io/src/main/scala/de/nowchess/io/fen/FenParser.scala`, `modules/io/src/main/scala/de/nowchess/io/fen/FenParserCombinators.scala`, `modules/io/src/main/scala/de/nowchess/io/fen/FenParserFastParse.scala` +3 more
 - `modules/rule/src/main/scala/de/nowchess/rules/sets/DefaultRules.scala` ← `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/EngineTestHelpers.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineIntegrationTest.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEnginePromotionTest.scala`, `modules/io/src/main/scala/de/nowchess/io/pgn/PgnExporter.scala` +3 more
- `modules/io/src/main/scala/de/nowchess/io/GameContextImport.scala` ← `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineIntegrationTest.scala`, `modules/io/src/main/scala/de/nowchess/io/fen/FenParser.scala`, `modules/io/src/main/scala/de/nowchess/io/fen/FenParserCombinators.scala`, `modules/io/src/main/scala/de/nowchess/io/fen/FenParserFastParse.scala` +2 more

 ---

@@ -2,36 +2,36 @@

 ## Most Imported Files (change these carefully)

- `modules/api/src/main/scala/de/nowchess/api/game/GameContext.scala` — imported by **28** files
- `modules/api/src/main/scala/de/nowchess/api/board/Square.scala` — imported by **21** files
- `modules/api/src/main/scala/de/nowchess/api/board/Color.scala` — imported by **19** files
- `modules/api/src/main/scala/de/nowchess/api/move/Move.scala` — imported by **14** files
- `modules/api/src/main/scala/de/nowchess/api/board/Board.scala` — imported by **13** files
- `modules/api/src/main/scala/de/nowchess/api/board/Piece.scala` — imported by **10** files
- `modules/api/src/main/scala/de/nowchess/api/board/PieceType.scala` — imported by **9** files
+- `modules/api/src/main/scala/de/nowchess/api/game/GameContext.scala` — imported by **38** files
+- `modules/api/src/main/scala/de/nowchess/api/board/Square.scala` — imported by **26** files
+- `modules/api/src/main/scala/de/nowchess/api/board/Color.scala` — imported by **25** files
+- `modules/api/src/main/scala/de/nowchess/api/move/Move.scala` — imported by **21** files
+- `modules/api/src/main/scala/de/nowchess/api/board/Board.scala` — imported by **14** files
+- `modules/api/src/main/scala/de/nowchess/api/board/Piece.scala` — imported by **13** files
+- `modules/api/src/main/scala/de/nowchess/api/board/PieceType.scala` — imported by **13** files
 - `modules/io/src/main/scala/de/nowchess/io/fen/FenParser.scala` — imported by **9** files
+- `modules/io/src/main/scala/de/nowchess/io/GameContextImport.scala` — imported by **8** files
 - `modules/rule/src/main/scala/de/nowchess/rules/sets/DefaultRules.scala` — imported by **8** files
- `modules/io/src/main/scala/de/nowchess/io/GameContextImport.scala` — imported by **7** files
- `modules/api/src/main/scala/de/nowchess/api/board/CastlingRights.scala` — imported by **4** files
- `modules/io/src/main/scala/de/nowchess/io/GameContextExport.scala` — imported by **4** files
+- `modules/api/src/main/scala/de/nowchess/api/board/CastlingRights.scala` — imported by **7** files
+- `modules/api/src/main/scala/de/nowchess/api/game/DrawReason.scala` — imported by **7** files
+- `modules/io/src/main/scala/de/nowchess/io/GameContextExport.scala` — imported by **5** files
 - `modules/rule/src/main/scala/de/nowchess/rules/RuleSet.scala` — imported by **4** files
 - `modules/core/src/main/scala/de/nowchess/chess/observer/Observer.scala` — imported by **4** files
 - `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala` — imported by **4** files
+- `modules/api/src/main/scala/de/nowchess/api/game/GameResult.scala` — imported by **3** files
+- `modules/io/src/main/scala/de/nowchess/io/pgn/PgnExporter.scala` — imported by **3** files
 - `modules/io/src/main/scala/de/nowchess/io/pgn/PgnParser.scala` — imported by **2** files
- `modules/io/src/main/scala/de/nowchess/io/pgn/PgnExporter.scala` — imported by **2** files
 - `modules/io/src/main/scala/de/nowchess/io/fen/FenExporter.scala` — imported by **2** files
- `modules/io/src/main/scala/de/nowchess/io/fen/FenParserSupport.scala` — imported by **2** files
- `modules/core/src/main/scala/de/nowchess/chess/controller/Parser.scala` — imported by **1** files

 ## Import Map (who imports what)

- `modules/api/src/main/scala/de/nowchess/api/game/GameContext.scala` ← `modules/core/src/main/scala/de/nowchess/chess/command/Command.scala`, `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala`, `modules/core/src/main/scala/de/nowchess/chess/observer/Observer.scala`, `modules/core/src/test/scala/de/nowchess/chess/command/CommandInvokerBranchTest.scala`, `modules/core/src/test/scala/de/nowchess/chess/command/CommandInvokerTest.scala` +23 more
- `modules/api/src/main/scala/de/nowchess/api/board/Square.scala` ← `modules/api/src/main/scala/de/nowchess/api/game/GameContext.scala`, `modules/api/src/main/scala/de/nowchess/api/move/Move.scala`, `modules/api/src/test/scala/de/nowchess/api/game/GameContextTest.scala`, `modules/api/src/test/scala/de/nowchess/api/move/MoveTest.scala`, `modules/core/src/main/scala/de/nowchess/chess/command/Command.scala` +16 more
- `modules/api/src/main/scala/de/nowchess/api/board/Color.scala` ← `modules/api/src/main/scala/de/nowchess/api/game/GameContext.scala`, `modules/api/src/test/scala/de/nowchess/api/game/GameContextTest.scala`, `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala`, `modules/core/src/main/scala/de/nowchess/chess/observer/Observer.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/EngineTestHelpers.scala` +14 more
- `modules/api/src/main/scala/de/nowchess/api/move/Move.scala` ← `modules/api/src/main/scala/de/nowchess/api/game/GameContext.scala`, `modules/api/src/test/scala/de/nowchess/api/board/BoardTest.scala`, `modules/api/src/test/scala/de/nowchess/api/game/GameContextTest.scala`, `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineIntegrationTest.scala` +9 more
- `modules/api/src/main/scala/de/nowchess/api/board/Board.scala` ← `modules/api/src/main/scala/de/nowchess/api/game/GameContext.scala`, `modules/api/src/test/scala/de/nowchess/api/game/GameContextTest.scala`, `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/EngineTestHelpers.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineGameEndingTest.scala` +8 more
- `modules/api/src/main/scala/de/nowchess/api/board/Piece.scala` ← `modules/core/src/main/scala/de/nowchess/chess/command/Command.scala`, `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEnginePromotionTest.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineScenarioTest.scala`, `modules/rule/src/test/scala/de/nowchess/rule/DefaultRulesStateTransitionsTest.scala` +5 more
- `modules/api/src/main/scala/de/nowchess/api/board/PieceType.scala` ← `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineIntegrationTest.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEnginePromotionTest.scala`, `modules/rule/src/test/scala/de/nowchess/rule/DefaultRulesStateTransitionsTest.scala`, `modules/rule/src/test/scala/de/nowchess/rule/DefaultRulesTest.scala` +4 more
+- `modules/api/src/main/scala/de/nowchess/api/game/GameContext.scala` ← `modules/core/src/main/scala/de/nowchess/chess/command/Command.scala`, `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala`, `modules/core/src/main/scala/de/nowchess/chess/observer/Observer.scala`, `modules/core/src/test/scala/de/nowchess/chess/command/CommandInvokerBranchTest.scala`, `modules/core/src/test/scala/de/nowchess/chess/command/CommandInvokerTest.scala` +33 more
+- `modules/api/src/main/scala/de/nowchess/api/board/Square.scala` ← `modules/api/src/main/scala/de/nowchess/api/game/GameContext.scala`, `modules/api/src/main/scala/de/nowchess/api/move/Move.scala`, `modules/api/src/test/scala/de/nowchess/api/game/GameContextTest.scala`, `modules/api/src/test/scala/de/nowchess/api/move/MoveTest.scala`, `modules/core/src/main/scala/de/nowchess/chess/command/Command.scala` +21 more
+- `modules/api/src/main/scala/de/nowchess/api/board/Color.scala` ← `modules/api/src/main/scala/de/nowchess/api/game/GameContext.scala`, `modules/api/src/main/scala/de/nowchess/api/game/GameResult.scala`, `modules/api/src/test/scala/de/nowchess/api/game/GameContextTest.scala`, `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala`, `modules/core/src/main/scala/de/nowchess/chess/observer/Observer.scala` +20 more
+- `modules/api/src/main/scala/de/nowchess/api/move/Move.scala` ← `modules/api/src/main/scala/de/nowchess/api/game/GameContext.scala`, `modules/api/src/test/scala/de/nowchess/api/board/BoardTest.scala`, `modules/api/src/test/scala/de/nowchess/api/game/GameContextTest.scala`, `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineIntegrationTest.scala` +16 more
+- `modules/api/src/main/scala/de/nowchess/api/board/Board.scala` ← `modules/api/src/main/scala/de/nowchess/api/game/GameContext.scala`, `modules/api/src/test/scala/de/nowchess/api/game/GameContextTest.scala`, `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/EngineTestHelpers.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineIntegrationTest.scala` +9 more
+- `modules/api/src/main/scala/de/nowchess/api/board/Piece.scala` ← `modules/core/src/main/scala/de/nowchess/chess/command/Command.scala`, `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEnginePromotionTest.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineScenarioTest.scala`, `modules/io/src/test/scala/de/nowchess/io/json/JsonExporterBranchCoverageSuite.scala` +8 more
+- `modules/api/src/main/scala/de/nowchess/api/board/PieceType.scala` ← `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineIntegrationTest.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEnginePromotionTest.scala`, `modules/io/src/test/scala/de/nowchess/io/json/JsonExporterBranchCoverageSuite.scala`, `modules/io/src/test/scala/de/nowchess/io/json/JsonExporterSuite.scala` +8 more
 - `modules/io/src/main/scala/de/nowchess/io/fen/FenParser.scala` ← `modules/core/src/test/scala/de/nowchess/chess/engine/EngineTestHelpers.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineLoadGameTest.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineNotationTest.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEnginePromotionTest.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineScenarioTest.scala` +4 more
+- `modules/io/src/main/scala/de/nowchess/io/GameContextImport.scala` ← `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineIntegrationTest.scala`, `modules/io/src/main/scala/de/nowchess/io/fen/FenParser.scala`, `modules/io/src/main/scala/de/nowchess/io/fen/FenParserCombinators.scala`, `modules/io/src/main/scala/de/nowchess/io/fen/FenParserFastParse.scala` +3 more
 - `modules/rule/src/main/scala/de/nowchess/rules/sets/DefaultRules.scala` ← `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/EngineTestHelpers.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineIntegrationTest.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEnginePromotionTest.scala`, `modules/io/src/main/scala/de/nowchess/io/pgn/PgnExporter.scala` +3 more
- `modules/io/src/main/scala/de/nowchess/io/GameContextImport.scala` ← `modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala`, `modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineIntegrationTest.scala`, `modules/io/src/main/scala/de/nowchess/io/fen/FenParser.scala`, `modules/io/src/main/scala/de/nowchess/io/fen/FenParserCombinators.scala`, `modules/io/src/main/scala/de/nowchess/io/fen/FenParserFastParse.scala` +2 more
@@ -45,7 +45,7 @@
  - function withEnPassantSquare
  - function withHalfMoveClock
  - function withMove
-  - _...2 more_
+  - _...3 more_
 - `modules/api/src/main/scala/de/nowchess/api/player/PlayerInfo.scala` — class PlayerId, function apply
 - `modules/api/src/main/scala/de/nowchess/api/response/ApiResponse.scala`
  - class ApiResponse
@@ -84,6 +84,13 @@
  - _...1 more_
 - `modules/io/src/main/scala/de/nowchess/io/GameContextExport.scala` — class GameContextExport, function exportGameContext
 - `modules/io/src/main/scala/de/nowchess/io/GameContextImport.scala` — class GameContextImport, function importGameContext
+- `modules/io/src/main/scala/de/nowchess/io/GameFileService.scala`
+  - class GameFileService
+  - function saveGameToFile
+  - function loadGameFromFile
+  - class FileSystemGameService
+  - function saveGameToFile
+  - function loadGameFromFile
 - `modules/io/src/main/scala/de/nowchess/io/fen/FenExporter.scala`
  - class FenExporter
  - function boardToFen
@@ -105,6 +112,8 @@
  - function parseBoard
  - function importGameContext
 - `modules/io/src/main/scala/de/nowchess/io/fen/FenParserSupport.scala` — function buildSquares
+- `modules/io/src/main/scala/de/nowchess/io/json/JsonExporter.scala` — class JsonExporter, function exportGameContext
+- `modules/io/src/main/scala/de/nowchess/io/json/JsonParser.scala` — class JsonParser, function importGameContext
 - `modules/io/src/main/scala/de/nowchess/io/pgn/PgnExporter.scala`
  - class PgnExporter
  - function exportGameContext
@@ -0,0 +1,133 @@
+<component name="ProjectCodeStyleConfiguration">
+  <code_scheme name="Project" version="173">
+    <AndroidXmlCodeStyleSettings>
+      <option name="USE_CUSTOM_SETTINGS" value="true" />
+    </AndroidXmlCodeStyleSettings>
+    <JetCodeStyleSettings>
+      <option name="CODE_STYLE_DEFAULTS" value="KOTLIN_OFFICIAL" />
+    </JetCodeStyleSettings>
+    <ScalaCodeStyleSettings>
+      <option name="FORMATTER" value="1" />
+    </ScalaCodeStyleSettings>
+    <XML>
+      <option name="XML_KEEP_LINE_BREAKS" value="false" />
+      <option name="XML_ALIGN_ATTRIBUTES" value="false" />
+      <option name="XML_SPACE_INSIDE_EMPTY_TAG" value="true" />
+    </XML>
+    <codeStyleSettings language="XML">
+      <option name="FORCE_REARRANGE_MODE" value="1" />
+      <indentOptions>
+        <option name="CONTINUATION_INDENT_SIZE" value="4" />
+      </indentOptions>
+      <arrangement>
+        <rules>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>xmlns:android</NAME>
+                  <XML_ATTRIBUTE />
+                  <XML_NAMESPACE>^$</XML_NAMESPACE>
+                </AND>
+              </match>
+            </rule>
+          </section>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>xmlns:.*</NAME>
+                  <XML_ATTRIBUTE />
+                  <XML_NAMESPACE>^$</XML_NAMESPACE>
+                </AND>
+              </match>
+              <order>BY_NAME</order>
+            </rule>
+          </section>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>.*:id</NAME>
+                  <XML_ATTRIBUTE />
+                  <XML_NAMESPACE>http://schemas.android.com/apk/res/android</XML_NAMESPACE>
+                </AND>
+              </match>
+            </rule>
+          </section>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>.*:name</NAME>
+                  <XML_ATTRIBUTE />
+                  <XML_NAMESPACE>http://schemas.android.com/apk/res/android</XML_NAMESPACE>
+                </AND>
+              </match>
+            </rule>
+          </section>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>name</NAME>
+                  <XML_ATTRIBUTE />
+                  <XML_NAMESPACE>^$</XML_NAMESPACE>
+                </AND>
+              </match>
+            </rule>
+          </section>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>style</NAME>
+                  <XML_ATTRIBUTE />
+                  <XML_NAMESPACE>^$</XML_NAMESPACE>
+                </AND>
+              </match>
+            </rule>
+          </section>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>.*</NAME>
+                  <XML_ATTRIBUTE />
+                  <XML_NAMESPACE>^$</XML_NAMESPACE>
+                </AND>
+              </match>
+              <order>BY_NAME</order>
+            </rule>
+          </section>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>.*</NAME>
+                  <XML_ATTRIBUTE />
+                  <XML_NAMESPACE>http://schemas.android.com/apk/res/android</XML_NAMESPACE>
+                </AND>
+              </match>
+            </rule>
+          </section>
+          <section>
+            <rule>
+              <match>
+                <AND>
+                  <NAME>.*</NAME>
+                  <XML_ATTRIBUTE />
+                  <XML_NAMESPACE>.*</XML_NAMESPACE>
+                </AND>
+              </match>
+              <order>BY_NAME</order>
+            </rule>
+          </section>
+        </rules>
+      </arrangement>
+    </codeStyleSettings>
+    <codeStyleSettings language="kotlin">
+      <option name="CODE_STYLE_DEFAULTS" value="KOTLIN_OFFICIAL" />
+    </codeStyleSettings>
+  </code_scheme>
+</component>
@@ -1,5 +1,5 @@
 <component name="ProjectCodeStyleConfiguration">
  <state>
-    <option name="PREFERRED_PROJECT_CODE_STYLE" value="Default" />
+    <option name="USE_PER_PROJECT_SETTINGS" value="true" />
  </state>
 </component>
@@ -5,7 +5,7 @@
      <option name="deprecationWarnings" value="true" />
      <option name="uncheckedWarnings" value="true" />
    </profile>
-    <profile name="Gradle 2" modules="NowChessSystems.modules.core.main,NowChessSystems.modules.core.scoverage,NowChessSystems.modules.core.test,NowChessSystems.modules.io.main,NowChessSystems.modules.io.scoverage,NowChessSystems.modules.io.test,NowChessSystems.modules.rule.main,NowChessSystems.modules.rule.scoverage,NowChessSystems.modules.rule.test,NowChessSystems.modules.ui.main,NowChessSystems.modules.ui.scoverage,NowChessSystems.modules.ui.test">
+    <profile name="Gradle 2" modules="NowChessSystems.modules.backcore.integrationTest,NowChessSystems.modules.backcore.main,NowChessSystems.modules.backcore.native-test,NowChessSystems.modules.backcore.quarkus-generated-sources,NowChessSystems.modules.backcore.quarkus-test-generated-sources,NowChessSystems.modules.backcore.scoverage,NowChessSystems.modules.backcore.test,NowChessSystems.modules.core.main,NowChessSystems.modules.core.scoverage,NowChessSystems.modules.core.test,NowChessSystems.modules.io.main,NowChessSystems.modules.io.scoverage,NowChessSystems.modules.io.test,NowChessSystems.modules.rule.main,NowChessSystems.modules.rule.scoverage,NowChessSystems.modules.rule.test,NowChessSystems.modules.ui.main,NowChessSystems.modules.ui.scoverage,NowChessSystems.modules.ui.test">
      <option name="deprecationWarnings" value="true" />
      <option name="uncheckedWarnings" value="true" />
      <parameters>
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ScalaProjectSettings">
+    <option name="scala3DisclaimerShown" value="true" />
+  </component>
+</project>
@@ -1,11 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
-  <component name="CommitMessageInspectionProfile">
-    <profile version="1.0">
-      <inspection_tool class="CommitFormat" enabled="true" level="WARNING" enabled_by_default="true" />
-      <inspection_tool class="CommitNamingConvention" enabled="true" level="WARNING" enabled_by_default="true" />
-    </profile>
-  </component>
  <component name="IssueNavigationConfiguration">
    <option name="links">
      <list>
@@ -0,0 +1,16 @@
+meta {
+  name: Draw offer
+  type: http
+  seq: 1
+}
+
+post {
+  url: {{baseUrl}}/api/board/game/{{gameId}}/draw/offer
+  body: none
+  auth: none
+}
+
+headers {
+  Accept: application/json
+}
+
@@ -0,0 +1,16 @@
+meta {
+  name: Draw accept
+  type: http
+  seq: 2
+}
+
+post {
+  url: {{baseUrl}}/api/board/game/{{gameId}}/draw/accept
+  body: none
+  auth: none
+}
+
+headers {
+  Accept: application/json
+}
+
@@ -0,0 +1,16 @@
+meta {
+  name: Draw decline
+  type: http
+  seq: 3
+}
+
+post {
+  url: {{baseUrl}}/api/board/game/{{gameId}}/draw/decline
+  body: none
+  auth: none
+}
+
+headers {
+  Accept: application/json
+}
+
@@ -0,0 +1,16 @@
+meta {
+  name: Draw claim fifty move
+  type: http
+  seq: 4
+}
+
+post {
+  url: {{baseUrl}}/api/board/game/{{gameId}}/draw/claim
+  body: none
+  auth: none
+}
+
+headers {
+  Accept: application/json
+}
+
@@ -0,0 +1,16 @@
+meta {
+  name: Export FEN
+  type: http
+  seq: 1
+}
+
+get {
+  url: {{baseUrl}}/api/board/game/{{gameId}}/export/fen
+  body: none
+  auth: none
+}
+
+headers {
+  Accept: text/plain
+}
+
@@ -0,0 +1,16 @@
+meta {
+  name: Export PGN
+  type: http
+  seq: 2
+}
+
+get {
+  url: {{baseUrl}}/api/board/game/{{gameId}}/export/pgn
+  body: none
+  auth: none
+}
+
+headers {
+  Accept: application/x-chess-pgn
+}
+
@@ -0,0 +1,30 @@
+meta {
+  name: Create game
+  type: http
+  seq: 1
+}
+
+post {
+  url: {{baseUrl}}/api/board/game
+  body: json
+  auth: none
+}
+
+headers {
+  Accept: application/json
+  Content-Type: application/json
+}
+
+body:json {
+  {
+    "white": {
+      "id": "player1",
+      "displayName": "Alice"
+    },
+    "black": {
+      "id": "player2",
+      "displayName": "Bob"
+    }
+  }
+}
+
@@ -0,0 +1,19 @@
+meta {
+  name: Get game
+  type: http
+  seq: 2
+}
+
+get {
+  url: {{baseUrl}}/api/board/game/{{gameId}}
+  body: none
+  auth: none
+}
+
+headers {
+  Accept: application/json
+}
+
+vars:pre-request {
+  gameId: DSooMdhj
+}
@@ -0,0 +1,16 @@
+meta {
+  name: Stream game (NDJSON)
+  type: http
+  seq: 3
+}
+
+get {
+  url: {{baseUrl}}/api/board/game/{{gameId}}/stream
+  body: none
+  auth: none
+}
+
+headers {
+  Accept: application/x-ndjson
+}
+
@@ -0,0 +1,19 @@
+meta {
+  name: Resign game
+  type: http
+  seq: 4
+}
+
+post {
+  url: {{baseUrl}}/api/board/game/{{gameId}}/resign
+  body: none
+  auth: none
+}
+
+headers {
+  Accept: application/json
+}
+
+vars:pre-request {
+  gameId: DSooMdhj
+}
@@ -0,0 +1,31 @@
+meta {
+  name: Import FEN
+  type: http
+  seq: 1
+}
+
+post {
+  url: {{baseUrl}}/api/board/game/import/fen
+  body: json
+  auth: none
+}
+
+headers {
+  Accept: application/json
+  Content-Type: application/json
+}
+
+body:json {
+  {
+    "fen": "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1",
+    "white": {
+      "id": "player1",
+      "displayName": "Alice"
+    },
+    "black": {
+      "id": "player2",
+      "displayName": "Bob"
+    }
+  }
+}
+
@@ -0,0 +1,23 @@
+meta {
+  name: Import PGN
+  type: http
+  seq: 2
+}
+
+post {
+  url: {{baseUrl}}/api/board/game/import/pgn
+  body: json
+  auth: none
+}
+
+headers {
+  Accept: application/json
+  Content-Type: application/json
+}
+
+body:json {
+  {
+    "pgn": "1. e4 e5 2. Nf3 Nc6 *"
+  }
+}
+
@@ -0,0 +1,20 @@
+meta {
+  name: Make move
+  type: http
+  seq: 1
+}
+
+post {
+  url: {{baseUrl}}/api/board/game/{{gameId}}/move/{{uci}}
+  body: none
+  auth: none
+}
+
+headers {
+  Accept: application/json
+}
+
+vars:pre-request {
+  gameId: DSooMdhj
+  uci: b1c3
+}
@@ -0,0 +1,23 @@
+meta {
+  name: Get legal moves
+  type: http
+  seq: 2
+}
+
+get {
+  url: {{baseUrl}}/api/board/game/{{gameId}}/moves
+  body: none
+  auth: none
+}
+
+params:query {
+  square: {{square}}
+}
+
+headers {
+  Accept: application/json
+}
+
+vars:pre-request {
+  gameId: DSooMdhj
+}
@@ -0,0 +1,19 @@
+meta {
+  name: Undo move
+  type: http
+  seq: 3
+}
+
+post {
+  url: {{baseUrl}}/api/board/game/{{gameId}}/undo
+  body: none
+  auth: none
+}
+
+headers {
+  Accept: application/json
+}
+
+vars:pre-request {
+  gameId: DSooMdhj
+}
@@ -0,0 +1,19 @@
+meta {
+  name: Redo move
+  type: http
+  seq: 4
+}
+
+post {
+  url: {{baseUrl}}/api/board/game/{{gameId}}/redo
+  body: none
+  auth: none
+}
+
+headers {
+  Accept: application/json
+}
+
+vars:pre-request {
+  gameId: DSooMdhj
+}
@@ -0,0 +1,6 @@
+{
+  "version": "1",
+  "name": "NowChessSystems",
+  "type": "collection"
+}
+
@@ -0,0 +1,3 @@
+vars {
+  baseUrl: http://localhost:8080
+}
@@ -21,7 +21,15 @@ sonar {
            if (report.exists()) report.absolutePath else null
        }.joinToString(",")

+        val jacocoReports = subprojects.mapNotNull { subproject ->
+            val report = subproject.file("build/reports/jacoco/test/jacocoTestReport.xml")
+            if (report.exists()) report.absolutePath else null
+        }.joinToString(",")
+
        property("sonar.scala.coverage.reportPaths", scoverageReports)
+        if (jacocoReports.isNotEmpty()) {
+            property("sonar.coverage.jacoco.xmlReportPaths", jacocoReports)
+        }
    }
 }

@@ -0,0 +1,5 @@
+quarkusPluginId=io.quarkus
+quarkusPluginVersion=3.32.4
+quarkusPlatformGroupId=io.quarkus.platform
+quarkusPlatformArtifactId=quarkus-bom
+quarkusPlatformVersion=3.32.4
@@ -0,0 +1,5 @@
+*
+!build/*-runner
+!build/*-runner.jar
+!build/lib/*
+!build/quarkus-app/*
@@ -0,0 +1,41 @@
+# Gradle
+.gradle/
+build/
+
+# Eclipse
+.project
+.classpath
+.settings/
+bin/
+
+# IntelliJ
+.idea
+*.ipr
+*.iml
+*.iws
+
+# NetBeans
+nb-configuration.xml
+
+# Visual Studio Code
+.vscode
+.factorypath
+
+# OSX
+.DS_Store
+
+# Vim
+*.swp
+*.swo
+
+# patch
+*.orig
+*.rej
+
+# Local environment
+.env
+
+# Plugin directory
+/.quarkus/cli/plugins/
+# TLS Certificates
+.certs/
@@ -0,0 +1,106 @@
+# backcore
+
+This project uses Quarkus, the Supersonic Subatomic Java Framework.
+
+If you want to learn more about Quarkus, please visit its website: <https://quarkus.io/>.
+
+## Running the application in dev mode
+
+You can run your application in dev mode that enables live coding using:
+
+```shell script
+./gradlew quarkusDev
+```
+
+> **_NOTE:_**  Quarkus now ships with a Dev UI, which is available in dev mode only at <http://localhost:8080/q/dev/>.
+
+## Packaging and running the application
+
+The application can be packaged using:
+
+```shell script
+./gradlew build
+```
+
+It produces the `quarkus-run.jar` file in the `build/quarkus-app/` directory.
+Be aware that it’s not an _über-jar_ as the dependencies are copied into the `build/quarkus-app/lib/` directory.
+
+The application is now runnable using `java -jar build/quarkus-app/quarkus-run.jar`.
+
+If you want to build an _über-jar_, execute the following command:
+
+```shell script
+./gradlew build -Dquarkus.package.jar.type=uber-jar
+```
+
+The application, packaged as an _über-jar_, is now runnable using `java -jar build/*-runner.jar`.
+
+## Creating a native executable
+
+You can create a native executable using:
+
+```shell script
+./gradlew build -Dquarkus.native.enabled=true
+```
+
+Or, if you don't have GraalVM installed, you can run the native executable build in a container using:
+
+```shell script
+./gradlew build -Dquarkus.native.enabled=true -Dquarkus.native.container-build=true
+```
+
+You can then execute your native executable with: `./build/backcore-1.0-SNAPSHOT-runner`
+
+If you want to learn more about building native executables, please consult <https://quarkus.io/guides/gradle-tooling>.
+
+## Related Guides
+
+- REST ([guide](https://quarkus.io/guides/rest)): A Jakarta REST implementation utilizing build time processing and
+  Vert.x. This extension is not compatible with the quarkus-resteasy extension, or any of the extensions that depend on
+  it.
+- Hibernate ORM ([guide](https://quarkus.io/guides/hibernate-orm)): Define your persistent model with Hibernate ORM and
+  Jakarta Persistence
+- REST Client ([guide](https://quarkus.io/guides/rest-client)): Call REST services
+- REST Jackson ([guide](https://quarkus.io/guides/rest#json-serialisation)): Jackson serialization support for Quarkus
+  REST. This extension is not compatible with the quarkus-resteasy extension, or any of the extensions that depend on it
+- YAML Configuration ([guide](https://quarkus.io/guides/config-yaml)): Use YAML to configure your Quarkus application
+- SmallRye Fault Tolerance ([guide](https://quarkus.io/guides/smallrye-fault-tolerance)): Build fault-tolerant network
+  services
+- SmallRye JWT ([guide](https://quarkus.io/guides/security-jwt)): Secure your applications with JSON Web Token
+- SmallRye Health ([guide](https://quarkus.io/guides/smallrye-health)): Monitor service health
+- Micrometer metrics ([guide](https://quarkus.io/guides/micrometer)): Instrument the runtime and your application with
+  dimensional metrics using Micrometer.
+
+## Provided Code
+
+### YAML Config
+
+Configure your application with YAML
+
+[Related guide section...](https://quarkus.io/guides/config-reference#configuration-examples)
+
+The Quarkus application configuration is located in `src/main/resources/application.yml`.
+
+### Hibernate ORM
+
+Create your first JPA entity
+
+[Related guide section...](https://quarkus.io/guides/hibernate-orm)
+
+### REST Client
+
+Invoke different services through REST with JSON
+
+[Related guide section...](https://quarkus.io/guides/rest-client)
+
+### REST
+
+Easily start your REST Web Services
+
+[Related guide section...](https://quarkus.io/guides/getting-started-reactive#reactive-jax-rs-resources)
+
+### SmallRye Health
+
+Monitor your application's health using SmallRye Health
+
+[Related guide section...](https://quarkus.io/guides/smallrye-health)
@@ -0,0 +1,135 @@
+plugins {
+    id("scala")
+    id("org.scoverage") version "8.1"
+    id("io.quarkus")
+    id("jacoco")
+}
+
+@Suppress("UNCHECKED_CAST")
+val versions = rootProject.extra["VERSIONS"] as Map<String, String>
+
+repositories {
+    mavenCentral()
+    mavenLocal()
+}
+
+scala {
+    scalaVersion = versions["SCALA3"]!!
+}
+
+scoverage {
+    scoverageVersion.set(versions["SCOVERAGE"]!!)
+}
+
+tasks.withType<ScalaCompile> {
+    scalaCompileOptions.additionalParameters = listOf("-encoding", "UTF-8")
+}
+
+val quarkusPlatformGroupId: String by project
+val quarkusPlatformArtifactId: String by project
+val quarkusPlatformVersion: String by project
+
+dependencies {
+    implementation(project(":modules:api"))
+    implementation(project(":modules:core"))
+    implementation(project(":modules:io"))
+    implementation(project(":modules:rule"))
+    implementation(project(":modules:ui"))
+
+    implementation(enforcedPlatform("${quarkusPlatformGroupId}:${quarkusPlatformArtifactId}:${quarkusPlatformVersion}"))
+    implementation("io.quarkus:quarkus-rest")
+    implementation("io.quarkus:quarkus-rest-jackson")
+    implementation("io.quarkus:quarkus-config-yaml")
+    implementation("io.quarkus:quarkus-arc")
+    implementation("io.quarkus:quarkus-smallrye-openapi")
+
+    implementation("com.fasterxml.jackson.module:jackson-module-scala_3:${versions["JACKSON_SCALA"]!!}")
+
+    testImplementation(platform("org.junit:junit-bom:${versions["JUNIT_BOM"]!!}"))
+    testImplementation("org.junit.jupiter:junit-jupiter")
+    testImplementation("org.scalatest:scalatest_3:${versions["SCALATEST"]!!}")
+    testImplementation("co.helmethair:scalatest-junit-runner:${versions["SCALATEST_JUNIT"]!!}")
+    testImplementation("io.quarkus:quarkus-junit5")
+    testImplementation("io.quarkus:quarkus-jacoco")
+    testImplementation("io.rest-assured:rest-assured")
+    testRuntimeOnly("org.junit.platform:junit-platform-launcher")
+}
+
+configurations.matching { !it.name.startsWith("scoverage") }.configureEach {
+    resolutionStrategy.force("org.scala-lang:scala-library:${versions["SCALA_LIBRARY"]!!}")
+}
+configurations.scoverage {
+    resolutionStrategy.eachDependency {
+        if (requested.group == "org.scoverage" && requested.name.startsWith("scalac-scoverage-plugin_")) {
+            useTarget("${requested.group}:scalac-scoverage-plugin_2.13.16:2.3.0")
+        }
+    }
+}
+
+group = "de.nowchess"
+version = "1.0-SNAPSHOT"
+
+tasks.withType<JavaCompile> {
+    options.encoding = "UTF-8"
+    options.compilerArgs.add("-parameters")
+}
+
+tasks.withType<Jar>().configureEach {
+    duplicatesStrategy = DuplicatesStrategy.EXCLUDE
+}
+
+tasks.test {
+    useJUnitPlatform {
+        includeEngines("scalatest", "junit-jupiter")
+    }
+    testLogging {
+        events("passed", "skipped", "failed")
+    }
+    finalizedBy(tasks.named("jacocoTestReport"))
+}
+
+tasks.jacocoTestReport {
+    dependsOn(tasks.test)
+    executionData.setFrom(
+        layout.buildDirectory.file("jacoco-quarkus.exec"),
+        layout.buildDirectory.file("jacoco/test.exec"),
+    )
+    sourceDirectories.setFrom(files("src/main/scala"))
+    classDirectories.setFrom(
+        files(layout.buildDirectory.dir("classes/scala/main")).asFileTree.matching {
+            exclude(
+                // App entrypoint (intentionally excluded)
+                "**/AppMain*.class", "**/AppMain\$*.class",
+                // DTO companion objects — only framework synthetics (writeReplace, fromProduct, unapply)
+                "**/dto/GameStateResponse\$.class",
+                "**/dto/PlayerInfoDto\$.class",
+                "**/dto/LegalMovesResponse\$.class",
+                "**/dto/ImportFenRequest\$.class",
+                "**/dto/CreateGameRequest\$.class",
+                "**/dto/OkResponse\$.class",
+                "**/dto/LegalMoveDto\$.class",
+                "**/dto/GameFullResponse\$.class",
+                "**/dto/ImportPgnRequest\$.class",
+                "**/dto/ApiErrorResponse\$.class",
+                // Private implementation detail — inaccessible from tests
+                "**/game/ServiceState.class", "**/game/ServiceState\$.class",
+                // GameResult: sealed trait companion + case object singletons (only synthetics)
+                "**/game/GameResult\$.class",
+                "**/game/GameResult\$AgreedDraw\$.class",
+                "**/game/GameResult\$FiftyMoveDraw\$.class",
+                // GameResult.Resign companion (writeReplace, fromProduct; instance class kept)
+                "**/game/GameResult\$Resign\$.class",
+                // Other companion objects with only framework synthetics
+                "**/game/GameId\$.class",
+                "**/game/GameSnapshot\$.class",
+            )
+        }
+    )
+    reports {
+        xml.required.set(true)
+        xml.outputLocation.set(
+            layout.buildDirectory.file("reports/jacoco/test/jacocoTestReport.xml")
+        )
+        html.required.set(false)
+    }
+}
@@ -0,0 +1,100 @@
+####
+# This Dockerfile is used in order to build a container that runs the Quarkus application in JVM mode
+#
+# Before building the container image run:
+#
+# ./gradlew build
+#
+# Then, build the image with:
+#
+# docker build -f src/main/docker/Dockerfile.jvm -t quarkus/backcore-jvm .
+#
+# Then run the container using:
+#
+# docker run -i --rm -p 8080:8080 quarkus/backcore-jvm
+#
+# If you want to include the debug port into your docker image
+# you will have to expose the debug port (default 5005 being the default) like this :  EXPOSE 8080 5005.
+# Additionally you will have to set -e JAVA_DEBUG=true and -e JAVA_DEBUG_PORT=*:5005
+# when running the container
+#
+# Then run the container using :
+#
+# docker run -i --rm -p 8080:8080 quarkus/backcore-jvm
+#
+# This image uses the `run-java.sh` script to run the application.
+# This scripts computes the command line to execute your Java application, and
+# includes memory/GC tuning.
+# You can configure the behavior using the following environment properties:
+# - JAVA_OPTS: JVM options passed to the `java` command (example: "-verbose:class") - Be aware that this will override
+# the default JVM options, use `JAVA_OPTS_APPEND` to append options
+# - JAVA_OPTS_APPEND: User specified Java options to be appended to generated options
+#   in JAVA_OPTS (example: "-Dsome.property=foo")
+# - JAVA_MAX_MEM_RATIO: Is used when no `-Xmx` option is given in JAVA_OPTS. This is
+#   used to calculate a default maximal heap memory based on a containers restriction.
+#   If used in a container without any memory constraints for the container then this
+#   option has no effect. If there is a memory constraint then `-Xmx` is set to a ratio
+#   of the container available memory as set here. The default is `50` which means 50%
+#   of the available memory is used as an upper boundary. You can skip this mechanism by
+#   setting this value to `0` in which case no `-Xmx` option is added.
+# - JAVA_INITIAL_MEM_RATIO: Is used when no `-Xms` option is given in JAVA_OPTS. This
+#   is used to calculate a default initial heap memory based on the maximum heap memory.
+#   If used in a container without any memory constraints for the container then this
+#   option has no effect. If there is a memory constraint then `-Xms` is set to a ratio
+#   of the `-Xmx` memory as set here. The default is `25` which means 25% of the `-Xmx`
+#   is used as the initial heap size. You can skip this mechanism by setting this value
+#   to `0` in which case no `-Xms` option is added (example: "25")
+# - JAVA_MAX_INITIAL_MEM: Is used when no `-Xms` option is given in JAVA_OPTS.
+#   This is used to calculate the maximum value of the initial heap memory. If used in
+#   a container without any memory constraints for the container then this option has
+#   no effect. If there is a memory constraint then `-Xms` is limited to the value set
+#   here. The default is 4096MB which means the calculated value of `-Xms` never will
+#   be greater than 4096MB. The value of this variable is expressed in MB (example: "4096")
+# - JAVA_DIAGNOSTICS: Set this to get some diagnostics information to standard output
+#   when things are happening. This option, if set to true, will set
+#  `-XX:+UnlockDiagnosticVMOptions`. Disabled by default (example: "true").
+# - JAVA_DEBUG: If set remote debugging will be switched on. Disabled by default (example:
+#    true").
+# - JAVA_DEBUG_PORT: Port used for remote debugging. Defaults to 5005 (example: "8787").
+# - CONTAINER_CORE_LIMIT: A calculated core limit as described in
+#   https://www.kernel.org/doc/Documentation/scheduler/sched-bwc.txt. (example: "2")
+# - CONTAINER_MAX_MEMORY: Memory limit given to the container (example: "1024").
+# - GC_MIN_HEAP_FREE_RATIO: Minimum percentage of heap free after GC to avoid expansion.
+#   (example: "20")
+# - GC_MAX_HEAP_FREE_RATIO: Maximum percentage of heap free after GC to avoid shrinking.
+#   (example: "40")
+# - GC_TIME_RATIO: Specifies the ratio of the time spent outside the garbage collection.
+#   (example: "4")
+# - GC_ADAPTIVE_SIZE_POLICY_WEIGHT: The weighting given to the current GC time versus
+#   previous GC times. (example: "90")
+# - GC_METASPACE_SIZE: The initial metaspace size. (example: "20")
+# - GC_MAX_METASPACE_SIZE: The maximum metaspace size. (example: "100")
+# - GC_CONTAINER_OPTIONS: Specify Java GC to use. The value of this variable should
+#   contain the necessary JRE command-line options to specify the required GC, which
+#   will override the default of `-XX:+UseParallelGC` (example: -XX:+UseG1GC).
+# - HTTPS_PROXY: The location of the https proxy. (example: "myuser@127.0.0.1:8080")
+# - HTTP_PROXY: The location of the http proxy. (example: "myuser@127.0.0.1:8080")
+# - NO_PROXY: A comma separated lists of hosts, IP addresses or domains that can be
+#   accessed directly. (example: "foo.example.com,bar.example.com")
+#
+# You can find more information about the UBI base runtime images and their configuration here:
+# https://rh-openjdk.github.io/redhat-openjdk-containers/
+###
+FROM registry.access.redhat.com/ubi9/openjdk-21-runtime:1.24
+
+ENV LANGUAGE='en_US:en'
+
+
+# We make four distinct layers so if there are application changes the library layers can be re-used
+COPY --chown=185 build/quarkus-app/lib/ /deployments/lib/
+COPY --chown=185 build/quarkus-app/*.jar /deployments/
+COPY --chown=185 build/quarkus-app/app/ /deployments/app/
+COPY --chown=185 build/quarkus-app/quarkus/ /deployments/quarkus/
+
+EXPOSE 8080
+USER 185
+ENV JAVA_OPTS_APPEND="-Dquarkus.http.host=0.0.0.0 -Djava.util.logging.manager=org.jboss.logmanager.LogManager"
+ENV JAVA_APP_JAR="/deployments/quarkus-run.jar"
+
+ENTRYPOINT [ "/opt/jboss/container/java/run/run-java.sh" ]
+
@@ -0,0 +1,96 @@
+####
+# This Dockerfile is used in order to build a container that runs the Quarkus application in JVM mode
+#
+# Before building the container image run:
+#
+# ./gradlew build -Dquarkus.package.jar.type=legacy-jar
+#
+# Then, build the image with:
+#
+# docker build -f src/main/docker/Dockerfile.legacy-jar -t quarkus/backcore-legacy-jar .
+#
+# Then run the container using:
+#
+# docker run -i --rm -p 8080:8080 quarkus/backcore-legacy-jar
+#
+# If you want to include the debug port into your docker image
+# you will have to expose the debug port (default 5005 being the default) like this :  EXPOSE 8080 5005.
+# Additionally you will have to set -e JAVA_DEBUG=true and -e JAVA_DEBUG_PORT=*:5005
+# when running the container
+#
+# Then run the container using :
+#
+# docker run -i --rm -p 8080:8080 quarkus/backcore-legacy-jar
+#
+# This image uses the `run-java.sh` script to run the application.
+# This scripts computes the command line to execute your Java application, and
+# includes memory/GC tuning.
+# You can configure the behavior using the following environment properties:
+# - JAVA_OPTS: JVM options passed to the `java` command (example: "-verbose:class") - Be aware that this will override
+# the default JVM options, use `JAVA_OPTS_APPEND` to append options
+# - JAVA_OPTS_APPEND: User specified Java options to be appended to generated options
+#   in JAVA_OPTS (example: "-Dsome.property=foo")
+# - JAVA_MAX_MEM_RATIO: Is used when no `-Xmx` option is given in JAVA_OPTS. This is
+#   used to calculate a default maximal heap memory based on a containers restriction.
+#   If used in a container without any memory constraints for the container then this
+#   option has no effect. If there is a memory constraint then `-Xmx` is set to a ratio
+#   of the container available memory as set here. The default is `50` which means 50%
+#   of the available memory is used as an upper boundary. You can skip this mechanism by
+#   setting this value to `0` in which case no `-Xmx` option is added.
+# - JAVA_INITIAL_MEM_RATIO: Is used when no `-Xms` option is given in JAVA_OPTS. This
+#   is used to calculate a default initial heap memory based on the maximum heap memory.
+#   If used in a container without any memory constraints for the container then this
+#   option has no effect. If there is a memory constraint then `-Xms` is set to a ratio
+#   of the `-Xmx` memory as set here. The default is `25` which means 25% of the `-Xmx`
+#   is used as the initial heap size. You can skip this mechanism by setting this value
+#   to `0` in which case no `-Xms` option is added (example: "25")
+# - JAVA_MAX_INITIAL_MEM: Is used when no `-Xms` option is given in JAVA_OPTS.
+#   This is used to calculate the maximum value of the initial heap memory. If used in
+#   a container without any memory constraints for the container then this option has
+#   no effect. If there is a memory constraint then `-Xms` is limited to the value set
+#   here. The default is 4096MB which means the calculated value of `-Xms` never will
+#   be greater than 4096MB. The value of this variable is expressed in MB (example: "4096")
+# - JAVA_DIAGNOSTICS: Set this to get some diagnostics information to standard output
+#   when things are happening. This option, if set to true, will set
+#  `-XX:+UnlockDiagnosticVMOptions`. Disabled by default (example: "true").
+# - JAVA_DEBUG: If set remote debugging will be switched on. Disabled by default (example:
+#    true").
+# - JAVA_DEBUG_PORT: Port used for remote debugging. Defaults to 5005 (example: "8787").
+# - CONTAINER_CORE_LIMIT: A calculated core limit as described in
+#   https://www.kernel.org/doc/Documentation/scheduler/sched-bwc.txt. (example: "2")
+# - CONTAINER_MAX_MEMORY: Memory limit given to the container (example: "1024").
+# - GC_MIN_HEAP_FREE_RATIO: Minimum percentage of heap free after GC to avoid expansion.
+#   (example: "20")
+# - GC_MAX_HEAP_FREE_RATIO: Maximum percentage of heap free after GC to avoid shrinking.
+#   (example: "40")
+# - GC_TIME_RATIO: Specifies the ratio of the time spent outside the garbage collection.
+#   (example: "4")
+# - GC_ADAPTIVE_SIZE_POLICY_WEIGHT: The weighting given to the current GC time versus
+#   previous GC times. (example: "90")
+# - GC_METASPACE_SIZE: The initial metaspace size. (example: "20")
+# - GC_MAX_METASPACE_SIZE: The maximum metaspace size. (example: "100")
+# - GC_CONTAINER_OPTIONS: Specify Java GC to use. The value of this variable should
+#   contain the necessary JRE command-line options to specify the required GC, which
+#   will override the default of `-XX:+UseParallelGC` (example: -XX:+UseG1GC).
+# - HTTPS_PROXY: The location of the https proxy. (example: "myuser@127.0.0.1:8080")
+# - HTTP_PROXY: The location of the http proxy. (example: "myuser@127.0.0.1:8080")
+# - NO_PROXY: A comma separated lists of hosts, IP addresses or domains that can be
+#   accessed directly. (example: "foo.example.com,bar.example.com")
+#
+# You can find more information about the UBI base runtime images and their configuration here:
+# https://rh-openjdk.github.io/redhat-openjdk-containers/
+###
+FROM registry.access.redhat.com/ubi9/openjdk-21-runtime:1.24
+
+ENV LANGUAGE='en_US:en'
+
+
+COPY build/lib/* /deployments/lib/
+COPY build/*-runner.jar /deployments/quarkus-run.jar
+
+EXPOSE 8080
+USER 185
+ENV JAVA_OPTS_APPEND="-Dquarkus.http.host=0.0.0.0 -Djava.util.logging.manager=org.jboss.logmanager.LogManager"
+ENV JAVA_APP_JAR="/deployments/quarkus-run.jar"
+
+ENTRYPOINT [ "/opt/jboss/container/java/run/run-java.sh" ]
@@ -0,0 +1,29 @@
+####
+# This Dockerfile is used in order to build a container that runs the Quarkus application in native (no JVM) mode.
+#
+# Before building the container image run:
+#
+# ./gradlew build -Dquarkus.native.enabled=true
+#
+# Then, build the image with:
+#
+# docker build -f src/main/docker/Dockerfile.native -t quarkus/backcore .
+#
+# Then run the container using:
+#
+# docker run -i --rm -p 8080:8080 quarkus/backcore
+#
+# The ` registry.access.redhat.com/ubi9/ubi-minimal:9.7` base image is based on UBI 9.
+# To use UBI 8, switch to `quay.io/ubi8/ubi-minimal:8.10`.
+###
+FROM registry.access.redhat.com/ubi9/ubi-minimal:9.7
+WORKDIR /work/
+RUN chown 1001 /work \
+    && chmod "g+rwX" /work \
+    && chown 1001:root /work
+COPY --chown=1001:root --chmod=0755 build/*-runner /work/application
+
+EXPOSE 8080
+USER 1001
+
+ENTRYPOINT ["./application", "-Dquarkus.http.host=0.0.0.0"]
@@ -0,0 +1,32 @@
+####
+# This Dockerfile is used in order to build a container that runs the Quarkus application in native (no JVM) mode.
+# It uses a micro base image, tuned for Quarkus native executables.
+# It reduces the size of the resulting container image.
+# Check https://quarkus.io/guides/quarkus-runtime-base-image for further information about this image.
+#
+# Before building the container image run:
+#
+# ./gradlew build -Dquarkus.native.enabled=true
+#
+# Then, build the image with:
+#
+# docker build -f src/main/docker/Dockerfile.native-micro -t quarkus/backcore .
+#
+# Then run the container using:
+#
+# docker run -i --rm -p 8080:8080 quarkus/backcore
+#
+# The `quay.io/quarkus/ubi9-quarkus-micro-image:2.0` base image is based on UBI 9.
+# To use UBI 8, switch to `quay.io/quarkus/quarkus-micro-image:2.0`.
+###
+FROM quay.io/quarkus/ubi9-quarkus-micro-image:2.0
+WORKDIR /work/
+RUN chown 1001 /work \
+    && chmod "g+rwX" /work \
+    && chown 1001:root /work
+COPY --chown=1001:root --chmod=0755 build/*-runner /work/application
+
+EXPOSE 8080
+USER 1001
+
+ENTRYPOINT ["./application", "-Dquarkus.http.host=0.0.0.0"]
@@ -0,0 +1,6 @@
+quarkus:
+  http:
+    port: 8080
+  jacoco:
+    data-file: ${user.dir}/build/jacoco-quarkus.exec
+    report: false
@@ -0,0 +1,17 @@
+package de.nowchess.backcore
+
+import de.nowchess.backcore.game.{GameEngineHolder, GameId}
+import de.nowchess.ui.gui.ChessGUILauncher
+import de.nowchess.ui.terminal.TerminalUI
+import io.quarkus.runtime.annotations.QuarkusMain
+import io.quarkus.runtime.{Quarkus, QuarkusApplication}
+
+@QuarkusMain
+class AppMain extends QuarkusApplication:
+  override def run(args: String*): Int =
+    val engine = GameEngineHolder.engine
+    println(s"REST API -> http://localhost:8080/api/board/game/${GameEngineHolder.gameId}")
+    ChessGUILauncher.launch(engine)
+    new TerminalUI(engine).start()
+    Quarkus.asyncExit()
+    0
@@ -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)
@@ -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])
@@ -0,0 +1,28 @@
+package de.nowchess.backcore.game
+
+import de.nowchess.api.player.{PlayerId, PlayerInfo}
+import de.nowchess.chess.engine.GameEngine
+
+import java.util.concurrent.atomic.AtomicReference
+
+/** Singleton holder that bridges an externally-created GameEngine into the CDI context.
+  *
+  * All fields are `val` wrapping an AtomicReference. Set engine / white / black before starting Quarkus. In
+  * standalone-server or test mode the defaults are used; GameService is created lazily (on first request), so the
+  * values are already set by the time CDI constructs it.
+  */
+object GameEngineHolder:
+  private val engineRef = new AtomicReference[GameEngine](new GameEngine())
+  private val whiteRef  = new AtomicReference[PlayerInfo](PlayerInfo(PlayerId("white"), "White"))
+  private val blackRef  = new AtomicReference[PlayerInfo](PlayerInfo(PlayerId("black"), "Black"))
+
+  val gameId: String = GameId.generate()
+
+  def engine: GameEngine            = engineRef.get()
+  def engine_=(e: GameEngine): Unit = engineRef.set(e)
+
+  def white: PlayerInfo            = whiteRef.get()
+  def white_=(p: PlayerInfo): Unit = whiteRef.set(p)
+
+  def black: PlayerInfo            = blackRef.get()
+  def black_=(p: PlayerInfo): Unit = blackRef.set(p)
@@ -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
@@ -0,0 +1,79 @@
+package de.nowchess.backcore.game
+
+import com.fasterxml.jackson.databind.ObjectMapper
+import com.fasterxml.jackson.module.scala.DefaultScalaModule
+import de.nowchess.api.board.Color
+import de.nowchess.api.game.{DrawReason, GameResult as ApiGameResult}
+import de.nowchess.api.move.{Move, MoveType, PromotionPiece}
+import de.nowchess.backcore.dto.*
+import de.nowchess.io.fen.FenExporter
+import de.nowchess.io.pgn.PgnExporter
+import de.nowchess.rules.sets.DefaultRules
+
+object GameMapper:
+  private val mapper = new ObjectMapper().registerModule(DefaultScalaModule)
+
+  def toGameFullJson(snapshot: GameSnapshot): String =
+    mapper.writeValueAsString(toGameFull(snapshot))
+
+  def toGameFull(snapshot: GameSnapshot): GameFullResponse =
+    GameFullResponse(
+      gameId = snapshot.gameId,
+      white = toPlayerInfo(snapshot.white),
+      black = toPlayerInfo(snapshot.black),
+      state = toGameState(snapshot),
+    )
+
+  def toGameState(snapshot: GameSnapshot): GameStateResponse =
+    val (status, winner) = computeStatus(snapshot)
+    GameStateResponse(
+      fen = FenExporter.exportGameContext(snapshot.context),
+      pgn = buildPgn(snapshot.context.moves),
+      turn = if snapshot.context.turn == Color.White then "white" else "black",
+      status = status,
+      winner = winner,
+      moves = snapshot.context.moves.map(moveToUci),
+      undoAvailable = snapshot.canUndo,
+      redoAvailable = snapshot.canRedo,
+    )
+
+  private def toPlayerInfo(p: de.nowchess.api.player.PlayerInfo): PlayerInfoDto =
+    PlayerInfoDto(id = p.id.value, displayName = p.displayName)
+
+  private def colorStr(c: Color): String = if c == Color.White then "white" else "black"
+
+  private def computeStatus(snapshot: GameSnapshot): (String, Option[String]) =
+    snapshot.externalResult match
+      case Some(GameResult.Resign(winner)) =>
+        ("resign", Some(colorStr(winner)))
+      case Some(GameResult.AgreedDraw) | Some(GameResult.FiftyMoveDraw) =>
+        ("draw", None)
+      case _ =>
+        snapshot.context.result match
+          case Some(ApiGameResult.Win(winner))                           => ("checkmate", Some(colorStr(winner)))
+          case Some(ApiGameResult.Draw(DrawReason.Stalemate))            => ("stalemate", None)
+          case Some(ApiGameResult.Draw(DrawReason.InsufficientMaterial)) => ("insufficientMaterial", None)
+          case Some(ApiGameResult.Draw(_))                               => ("draw", None)
+          case None                                                      => computeLiveStatus(snapshot)
+
+  private def computeLiveStatus(snapshot: GameSnapshot): (String, Option[String]) =
+    val ctx = snapshot.context
+    if DefaultRules.isCheck(ctx) then ("check", None)
+    else if snapshot.drawOfferedBy.isDefined then ("drawOffered", None)
+    else if DefaultRules.isFiftyMoveRule(ctx) then ("fiftyMoveAvailable", 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 =
+    PgnExporter.exportGame(Map.empty, moves)
@@ -0,0 +1,9 @@
+package de.nowchess.backcore.game
+
+import de.nowchess.api.board.Color
+
+sealed trait GameResult
+object GameResult:
+  case class Resign(winner: Color) extends GameResult
+  case object AgreedDraw           extends GameResult
+  case object FiftyMoveDraw        extends GameResult
@@ -0,0 +1,175 @@
+package de.nowchess.backcore.game
+
+import de.nowchess.api.board.{Color, Square}
+import de.nowchess.api.game.GameContext
+import de.nowchess.api.move.{Move, MoveType, PromotionPiece}
+import de.nowchess.api.player.{PlayerId, PlayerInfo}
+import de.nowchess.backcore.dto.{CreateGameRequest, ImportFenRequest, PlayerInfoDto}
+import de.nowchess.io.fen.{FenExporter, FenParser}
+import de.nowchess.io.pgn.{PgnExporter, PgnParser}
+import de.nowchess.rules.sets.DefaultRules
+import jakarta.enterprise.context.ApplicationScoped
+
+private case class ServiceState(
+    drawOfferedBy: Option[Color] = None,
+    externalResult: Option[GameResult] = None,
+)
+
+@ApplicationScoped
+class GameService:
+  private val engine = GameEngineHolder.engine
+  @SuppressWarnings(Array("DisableSyntax.var"))
+  private var state: ServiceState = ServiceState()
+
+  def isKnownId(id: String): Boolean = id == GameEngineHolder.gameId
+
+  def getSnapshot: GameSnapshot = synchronized:
+    GameSnapshot(
+      gameId = GameEngineHolder.gameId,
+      white = GameEngineHolder.white,
+      black = GameEngineHolder.black,
+      context = engine.context,
+      drawOfferedBy = state.drawOfferedBy,
+      externalResult = state.externalResult,
+      canUndo = engine.canUndo,
+      canRedo = engine.canRedo,
+    )
+
+  def reset(req: CreateGameRequest): GameSnapshot = synchronized:
+    engine.reset()
+    state = ServiceState()
+    GameEngineHolder.white = toPlayerInfo(req.white, "white", "White")
+    GameEngineHolder.black = toPlayerInfo(req.black, "black", "Black")
+    getSnapshot
+
+  def applyMove(uci: String): Either[String, GameSnapshot] = synchronized:
+    if hasEnded then Left("Game is already over")
+    else
+      parseUci(uci) match
+        case None => Left(s"Invalid UCI notation: $uci")
+        case Some((from, to, promotion)) =>
+          val candidates = engine.ruleSet.legalMoves(engine.context)(from)
+          findMatchingMove(candidates, to, promotion) match
+            case None => Left(s"$uci is not a legal move")
+            case Some(move) =>
+              engine.processUserInput(s"$from$to")
+              promotion.foreach(engine.completePromotion)
+              Right(getSnapshot)
+
+  def legalMoves(square: Option[Square]): List[Move] = synchronized:
+    val ctx = engine.context
+    square match
+      case Some(sq) => engine.ruleSet.legalMoves(ctx)(sq)
+      case None     => engine.ruleSet.allLegalMoves(ctx)
+
+  def undo(): Either[String, GameSnapshot] = synchronized:
+    if !engine.canUndo then Left("No moves to undo")
+    else
+      engine.undo()
+      state = state.copy(externalResult = None, drawOfferedBy = None)
+      Right(getSnapshot)
+
+  def redo(): Either[String, GameSnapshot] = synchronized:
+    if !engine.canRedo then Left("No moves to redo")
+    else
+      engine.redo()
+      Right(getSnapshot)
+
+  def resign(): Either[String, GameSnapshot] = synchronized:
+    if hasEnded then Left("Game is already over")
+    else
+      val winner = engine.context.turn.opposite
+      state = state.copy(externalResult = Some(GameResult.Resign(winner)))
+      Right(getSnapshot)
+
+  def drawAction(action: String): Either[String, GameSnapshot] = synchronized:
+    if hasEnded then Left("Game is already over")
+    else
+      action match
+        case "offer" =>
+          state = state.copy(drawOfferedBy = Some(engine.context.turn))
+          Right(getSnapshot)
+        case "accept" =>
+          state.drawOfferedBy match
+            case None => Left("No draw offer to accept")
+            case Some(offerer) if offerer == engine.context.turn =>
+              Left("Cannot accept your own draw offer")
+            case Some(_) =>
+              state = state.copy(externalResult = Some(GameResult.AgreedDraw), drawOfferedBy = None)
+              Right(getSnapshot)
+        case "decline" =>
+          state.drawOfferedBy match
+            case None => Left("No draw offer to decline")
+            case Some(_) =>
+              state = state.copy(drawOfferedBy = None)
+              Right(getSnapshot)
+        case "claim" =>
+          if DefaultRules.isFiftyMoveRule(engine.context) then
+            state = state.copy(externalResult = Some(GameResult.FiftyMoveDraw))
+            Right(getSnapshot)
+          else Left("Fifty-move rule has not been triggered")
+        case other => Left(s"Unknown draw action: $other")
+
+  def importFen(req: ImportFenRequest): Either[String, GameSnapshot] = synchronized:
+    FenParser.parseFen(req.fen) match
+      case Left(err) => Left(err)
+      case Right(ctx) =>
+        engine.loadPosition(ctx)
+        state = ServiceState()
+        GameEngineHolder.white = toPlayerInfo(req.white, "white", "White")
+        GameEngineHolder.black = toPlayerInfo(req.black, "black", "Black")
+        Right(getSnapshot)
+
+  def importPgn(pgn: String): Either[String, GameSnapshot] = synchronized:
+    engine.loadGame(PgnParser, pgn) match
+      case Left(err) => Left(err)
+      case Right(_) =>
+        state = ServiceState()
+        Right(getSnapshot)
+
+  def exportFen(): String = FenExporter.exportGameContext(engine.context)
+
+  def exportPgn(): String = PgnExporter.exportGameContext(engine.context)
+
+  private def hasEnded: Boolean =
+    state.externalResult.isDefined || engine.context.result.isDefined
+
+  private def toPlayerInfo(dto: Option[PlayerInfoDto], defaultId: String, defaultName: String): PlayerInfo =
+    dto.fold(PlayerInfo(PlayerId(defaultId), defaultName))(d => PlayerInfo(PlayerId(d.id), d.displayName))
+
+  private def parseUci(uci: String): Option[(Square, Square, Option[PromotionPiece])] =
+    if uci.length < 4 || uci.length > 5 then None
+    else
+      for
+        from <- Square.fromAlgebraic(uci.substring(0, 2))
+        to   <- Square.fromAlgebraic(uci.substring(2, 4))
+      yield
+        val promotion = if uci.length == 5 then parsePromotionChar(uci.charAt(4)) else None
+        (from, to, promotion)
+
+  private def parsePromotionChar(c: Char): Option[PromotionPiece] =
+    c match
+      case 'q' => Some(PromotionPiece.Queen)
+      case 'r' => Some(PromotionPiece.Rook)
+      case 'b' => Some(PromotionPiece.Bishop)
+      case 'n' => Some(PromotionPiece.Knight)
+      case _   => None
+
+  private def findMatchingMove(
+      candidates: List[Move],
+      to: Square,
+      promotion: Option[PromotionPiece],
+  ): Option[Move] =
+    candidates.filter(_.to == to) match
+      case Nil => None
+      case moves =>
+        promotion match
+          case Some(pp) => moves.find(_.moveType == MoveType.Promotion(pp))
+          case None =>
+            moves
+              .find(m =>
+                m.moveType match
+                  case _: MoveType.Promotion => false
+                  case _                     => true,
+              )
+              .orElse(moves.headOption)
@@ -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
+
+case class GameSnapshot(
+    gameId: String,
+    white: PlayerInfo,
+    black: PlayerInfo,
+    context: GameContext,
+    drawOfferedBy: Option[Color] = None,
+    externalResult: Option[GameResult] = None,
+    canUndo: Boolean = false,
+    canRedo: Boolean = false,
+)
@@ -0,0 +1,90 @@
+package de.nowchess.backcore.resource
+
+import de.nowchess.backcore.dto.*
+import de.nowchess.backcore.game.{GameMapper, GameService}
+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))
+@ApplicationScoped
+class GameResource @Inject() (service: GameService):
+
+  @POST
+  @Consumes(Array(MediaType.APPLICATION_JSON))
+  def createGame(req: CreateGameRequest): Response =
+    val snapshot = service.reset(Option(req).getOrElse(CreateGameRequest()))
+    Response.status(201).entity(GameMapper.toGameFull(snapshot)).build()
+
+  @GET
+  @Path("/{gameId}")
+  def getGame(@PathParam("gameId") gameId: String): Response =
+    if !service.isKnownId(gameId) then
+      Response
+        .status(404)
+        .entity(ApiErrorResponse("GAME_NOT_FOUND", s"Game $gameId not found"))
+        .build()
+    else Response.ok(GameMapper.toGameFull(service.getSnapshot)).build()
+
+  @GET
+  @Path("/{gameId}/stream")
+  @Produces(Array("application/x-ndjson"))
+  def streamGame(@PathParam("gameId") gameId: String): Response =
+    if !service.isKnownId(gameId) then
+      Response
+        .status(404)
+        .`type`(MediaType.APPLICATION_JSON)
+        .entity(ApiErrorResponse("GAME_NOT_FOUND", s"Game $gameId not found"))
+        .build()
+    else
+      val event = s"""{"type":"gameFull","game":${GameMapper.toGameFullJson(service.getSnapshot)}}"""
+      Response.ok(event + "\n").build()
+
+  @POST
+  @Path("/{gameId}/resign")
+  def resignGame(@PathParam("gameId") gameId: String): Response =
+    if !service.isKnownId(gameId) then
+      Response.status(404).entity(ApiErrorResponse("GAME_NOT_FOUND", s"Game $gameId not found")).build()
+    else
+      service.resign() match
+        case Right(_)  => Response.ok(OkResponse()).build()
+        case Left(err) => Response.status(400).entity(ApiErrorResponse("RESIGN_ERROR", err)).build()
+
+  @POST
+  @Path("/{gameId}/draw/{action}")
+  def drawAction(
+      @PathParam("gameId") gameId: String,
+      @PathParam("action") action: String,
+  ): Response =
+    if !service.isKnownId(gameId) then
+      Response.status(404).entity(ApiErrorResponse("GAME_NOT_FOUND", s"Game $gameId not found")).build()
+    else
+      service.drawAction(action) match
+        case Right(_)  => Response.ok(OkResponse()).build()
+        case Left(err) => Response.status(400).entity(ApiErrorResponse("DRAW_ERROR", err)).build()
+
+  @GET
+  @Path("/{gameId}/export/fen")
+  @Produces(Array(MediaType.TEXT_PLAIN))
+  def exportFen(@PathParam("gameId") gameId: String): Response =
+    if !service.isKnownId(gameId) then
+      Response
+        .status(404)
+        .`type`(MediaType.APPLICATION_JSON)
+        .entity(ApiErrorResponse("GAME_NOT_FOUND", s"Game $gameId not found"))
+        .build()
+    else Response.ok(service.exportFen()).build()
+
+  @GET
+  @Path("/{gameId}/export/pgn")
+  @Produces(Array("application/x-chess-pgn"))
+  def exportPgn(@PathParam("gameId") gameId: String): Response =
+    if !service.isKnownId(gameId) then
+      Response
+        .status(404)
+        .`type`(MediaType.APPLICATION_JSON)
+        .entity(ApiErrorResponse("GAME_NOT_FOUND", s"Game $gameId not found"))
+        .build()
+    else Response.ok(service.exportPgn()).build()
@@ -0,0 +1,31 @@
+package de.nowchess.backcore.resource
+
+import de.nowchess.backcore.dto.{ApiErrorResponse, ImportFenRequest, ImportPgnRequest}
+import de.nowchess.backcore.game.{GameMapper, GameService}
+import jakarta.enterprise.context.ApplicationScoped
+import jakarta.inject.Inject
+import jakarta.ws.rs.*
+import jakarta.ws.rs.core.{MediaType, Response}
+
+@Path("/api/board/game/import")
+@Produces(Array(MediaType.APPLICATION_JSON))
+@Consumes(Array(MediaType.APPLICATION_JSON))
+@ApplicationScoped
+class ImportResource @Inject() (service: GameService):
+
+  @POST
+  @Path("/fen")
+  def importFen(req: ImportFenRequest): Response =
+    service.importFen(Option(req).getOrElse(ImportFenRequest())) match
+      case Right(snap) => Response.status(201).entity(GameMapper.toGameFull(snap)).build()
+      case Left(err)   => Response.status(400).entity(ApiErrorResponse("INVALID_FEN", err)).build()
+
+  @POST
+  @Path("/pgn")
+  def importPgn(req: ImportPgnRequest): Response =
+    Option(req) match
+      case None => Response.status(400).entity(ApiErrorResponse("INVALID_PGN", "Request body is required")).build()
+      case Some(body) =>
+        service.importPgn(body.pgn) match
+          case Right(snap) => Response.status(201).entity(GameMapper.toGameFull(snap)).build()
+          case Left(err)   => Response.status(400).entity(ApiErrorResponse("INVALID_PGN", err)).build()
@@ -0,0 +1,85 @@
+package de.nowchess.backcore.resource
+
+import de.nowchess.api.board.Square
+import de.nowchess.api.move.{Move, MoveType, PromotionPiece}
+import de.nowchess.backcore.dto.*
+import de.nowchess.backcore.game.{GameMapper, GameService}
+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))
+@ApplicationScoped
+class MoveResource @Inject() (service: GameService):
+
+  @POST
+  @Path("/{gameId}/move/{uci}")
+  def makeMove(
+      @PathParam("gameId") gameId: String,
+      @PathParam("uci") uci: String,
+  ): Response =
+    if !service.isKnownId(gameId) then
+      Response.status(404).entity(ApiErrorResponse("GAME_NOT_FOUND", s"Game $gameId not found")).build()
+    else
+      service.applyMove(uci) match
+        case Right(snap) => Response.ok(GameMapper.toGameState(snap)).build()
+        case Left(err)   => Response.status(400).entity(ApiErrorResponse("INVALID_MOVE", err)).build()
+
+  @GET
+  @Path("/{gameId}/moves")
+  def getLegalMoves(
+      @PathParam("gameId") gameId: String,
+      @QueryParam("square") squareParam: String,
+  ): Response =
+    if !service.isKnownId(gameId) then
+      Response.status(404).entity(ApiErrorResponse("GAME_NOT_FOUND", s"Game $gameId not found")).build()
+    else
+      val square = Option(squareParam).flatMap(Square.fromAlgebraic)
+      val moves  = service.legalMoves(square)
+      val dtos   = moves.map(toLegalMoveDto)
+      Response.ok(LegalMovesResponse(dtos)).build()
+
+  @POST
+  @Path("/{gameId}/undo")
+  def undoMove(@PathParam("gameId") gameId: String): Response =
+    if !service.isKnownId(gameId) then
+      Response.status(404).entity(ApiErrorResponse("GAME_NOT_FOUND", s"Game $gameId not found")).build()
+    else
+      service.undo() match
+        case Right(snap) => Response.ok(GameMapper.toGameState(snap)).build()
+        case Left(err)   => Response.status(400).entity(ApiErrorResponse("UNDO_NOT_AVAILABLE", err)).build()
+
+  @POST
+  @Path("/{gameId}/redo")
+  def redoMove(@PathParam("gameId") gameId: String): Response =
+    if !service.isKnownId(gameId) then
+      Response.status(404).entity(ApiErrorResponse("GAME_NOT_FOUND", s"Game $gameId not found")).build()
+    else
+      service.redo() match
+        case Right(snap) => Response.ok(GameMapper.toGameState(snap)).build()
+        case Left(err)   => Response.status(400).entity(ApiErrorResponse("REDO_NOT_AVAILABLE", err)).build()
+
+  private def toLegalMoveDto(move: Move): LegalMoveDto =
+    val uci = GameMapper.moveToUci(move)
+    val (moveType, promotion) = move.moveType match
+      case MoveType.Normal(true)    => ("capture", None)
+      case MoveType.Normal(false)   => ("normal", None)
+      case MoveType.CastleKingside  => ("castleKingside", None)
+      case MoveType.CastleQueenside => ("castleQueenside", None)
+      case MoveType.EnPassant       => ("enPassant", None)
+      case MoveType.Promotion(pp) =>
+        val pName = pp match
+          case PromotionPiece.Queen  => "queen"
+          case PromotionPiece.Rook   => "rook"
+          case PromotionPiece.Bishop => "bishop"
+          case PromotionPiece.Knight => "knight"
+        ("promotion", Some(pName))
+    LegalMoveDto(
+      from = move.from.toString,
+      to = move.to.toString,
+      uci = uci,
+      moveType = moveType,
+      promotion = promotion,
+    )
@@ -0,0 +1,14 @@
+import io.quarkus.test.junit.QuarkusIntegrationTest
+import jakarta.inject.Inject
+import org.junit.jupiter.api.Test
+
+@QuarkusIntegrationTest
+case class Test2(@Inject tester: Tester) {
+
+  @Test
+  def testAbc(): Unit = {
+    println("Hello World")
+    tester.test()
+  }
+
+}
@@ -0,0 +1,11 @@
+package de.nowchess.backcore
+
+import io.quarkus.test.junit.QuarkusTest
+import org.junit.jupiter.api.Test
+
+@QuarkusTest
+class BackcoreStartupTest:
+  @Test
+  def applicationStarts(): Unit =
+    // If we get here the Quarkus container started successfully
+    ()
@@ -0,0 +1,226 @@
+package de.nowchess.backcore.dto
+
+import org.junit.jupiter.api.Assertions.*
+import org.junit.jupiter.api.Test
+
+/** Exercises the Scala-generated synthetic methods (equals, hashCode, copy, productElement,
+  * productElementName, toString, canEqual) on every DTO case class so that JaCoCo counts them as
+  * covered.
+  */
+class DtoCoverageTest:
+
+  @Test
+  def playerInfoDtoSynthetics(): Unit =
+    val a = PlayerInfoDto("id1", "Alice")
+    val b = PlayerInfoDto("id1", "Alice")
+    val c = PlayerInfoDto("id2", "Bob")
+    assertEquals(a, b)
+    assertNotEquals(a, c)
+    assertFalse(a.equals(null))
+    assertFalse(a.equals("other"))
+    assertEquals(a.hashCode, b.hashCode)
+    assertTrue(a.toString.contains("Alice"))
+    assertTrue(a.canEqual(b))
+    assertEquals("id1", a.productElement(0))
+    assertEquals("Alice", a.productElement(1))
+    assertEquals("id", a.productElementName(0))
+    assertEquals("displayName", a.productElementName(1))
+    assertEquals(a, a.copy())
+    assertEquals(PlayerInfoDto("x", "Alice"), a.copy(id = "x"))
+    assertEquals(PlayerInfoDto("id1", "X"), a.copy(displayName = "X"))
+
+  @Test
+  def okResponseSynthetics(): Unit =
+    val a = OkResponse()
+    val b = OkResponse()
+    val c = OkResponse(ok = false)
+    assertEquals(a, b)
+    assertNotEquals(a, c)
+    assertFalse(a.equals(null))
+    assertFalse(a.equals("other"))
+    assertEquals(a.hashCode, b.hashCode)
+    assertTrue(a.toString.contains("true"))
+    assertTrue(a.canEqual(b))
+    assertEquals(true, a.productElement(0))
+    assertEquals("ok", a.productElementName(0))
+    assertEquals(a, a.copy())
+    assertEquals(OkResponse(false), a.copy(ok = false))
+
+  @Test
+  def apiErrorResponseSynthetics(): Unit =
+    val a = ApiErrorResponse("CODE", "msg")
+    val b = ApiErrorResponse("CODE", "msg")
+    val c = ApiErrorResponse("OTHER", "msg")
+    assertEquals(a, b)
+    assertNotEquals(a, c)
+    assertFalse(a.equals(null))
+    assertFalse(a.equals("other"))
+    assertEquals(a.hashCode, b.hashCode)
+    assertTrue(a.toString.contains("CODE"))
+    assertTrue(a.canEqual(b))
+    assertEquals("CODE", a.productElement(0))
+    assertEquals("msg", a.productElement(1))
+    assertEquals(None, a.productElement(2))
+    assertEquals("code", a.productElementName(0))
+    assertEquals("message", a.productElementName(1))
+    assertEquals("field", a.productElementName(2))
+    assertEquals(a, a.copy())
+    assertEquals(ApiErrorResponse("X", "msg"), a.copy(code = "X"))
+    assertEquals(ApiErrorResponse("CODE", "X"), a.copy(message = "X"))
+
+  @Test
+  def createGameRequestSynthetics(): Unit =
+    val a = CreateGameRequest()
+    val b = CreateGameRequest()
+    val c = CreateGameRequest(white = Some(PlayerInfoDto("x", "X")))
+    assertEquals(a, b)
+    assertNotEquals(a, c)
+    assertFalse(a.equals(null))
+    assertFalse(a.equals("other"))
+    assertEquals(a.hashCode, b.hashCode)
+    assertNotNull(a.toString)
+    assertTrue(a.canEqual(b))
+    assertEquals(None, a.productElement(0))
+    assertEquals(None, a.productElement(1))
+    assertEquals("white", a.productElementName(0))
+    assertEquals("black", a.productElementName(1))
+    assertEquals(a, a.copy())
+    assertEquals(CreateGameRequest(black = None), a.copy(black = None))
+
+  @Test
+  def importFenRequestSynthetics(): Unit =
+    val a = ImportFenRequest(fen = "fen1")
+    val b = ImportFenRequest(fen = "fen1")
+    val c = ImportFenRequest(fen = "fen2")
+    assertEquals(a, b)
+    assertNotEquals(a, c)
+    assertFalse(a.equals(null))
+    assertFalse(a.equals("other"))
+    assertEquals(a.hashCode, b.hashCode)
+    assertTrue(a.toString.contains("fen1"))
+    assertTrue(a.canEqual(b))
+    assertEquals("fen1", a.productElement(0))
+    assertEquals(None, a.productElement(1))
+    assertEquals(None, a.productElement(2))
+    assertEquals("fen", a.productElementName(0))
+    assertEquals("white", a.productElementName(1))
+    assertEquals("black", a.productElementName(2))
+    assertEquals(a, a.copy())
+    assertEquals(ImportFenRequest(fen = "x"), a.copy(fen = "x"))
+    assertEquals(ImportFenRequest(fen = "fen1", white = None), a.copy(white = None))
+
+  @Test
+  def importPgnRequestSynthetics(): Unit =
+    val a = ImportPgnRequest(pgn = "1. e4 *")
+    val b = ImportPgnRequest(pgn = "1. e4 *")
+    val c = ImportPgnRequest(pgn = "other")
+    assertEquals(a, b)
+    assertNotEquals(a, c)
+    assertFalse(a.equals(null))
+    assertFalse(a.equals("other"))
+    assertEquals(a.hashCode, b.hashCode)
+    assertTrue(a.toString.contains("e4"))
+    assertTrue(a.canEqual(b))
+    assertEquals("1. e4 *", a.productElement(0))
+    assertEquals("pgn", a.productElementName(0))
+    assertEquals(a, a.copy())
+    assertEquals(ImportPgnRequest(pgn = "x"), a.copy(pgn = "x"))
+
+  @Test
+  def legalMoveDtoSynthetics(): Unit =
+    val a = LegalMoveDto("e2", "e4", "e2e4", "normal")
+    val b = LegalMoveDto("e2", "e4", "e2e4", "normal")
+    val c = LegalMoveDto("d2", "d4", "d2d4", "normal")
+    assertEquals(a, b)
+    assertNotEquals(a, c)
+    assertFalse(a.equals(null))
+    assertFalse(a.equals("other"))
+    assertEquals(a.hashCode, b.hashCode)
+    assertTrue(a.toString.contains("e2"))
+    assertTrue(a.canEqual(b))
+    assertEquals("e2", a.productElement(0))
+    assertEquals("e4", a.productElement(1))
+    assertEquals("e2e4", a.productElement(2))
+    assertEquals("normal", a.productElement(3))
+    assertEquals(None, a.productElement(4))
+    assertEquals("from", a.productElementName(0))
+    assertEquals("to", a.productElementName(1))
+    assertEquals("uci", a.productElementName(2))
+    assertEquals("moveType", a.productElementName(3))
+    assertEquals("promotion", a.productElementName(4))
+    assertEquals(a, a.copy())
+    assertEquals(LegalMoveDto("x", "e4", "xe4", "normal"), a.copy(from = "x", uci = "xe4"))
+    assertEquals(LegalMoveDto("e2", "x", "e2x", "normal"), a.copy(to = "x", uci = "e2x"))
+
+  @Test
+  def legalMovesResponseSynthetics(): Unit =
+    val a = LegalMovesResponse(List.empty)
+    val b = LegalMovesResponse(List.empty)
+    val c = LegalMovesResponse(List(LegalMoveDto("a1", "a2", "a1a2", "normal")))
+    assertEquals(a, b)
+    assertNotEquals(a, c)
+    assertFalse(a.equals(null))
+    assertFalse(a.equals("other"))
+    assertEquals(a.hashCode, b.hashCode)
+    assertNotNull(a.toString)
+    assertTrue(a.canEqual(b))
+    assertEquals(List.empty, a.productElement(0))
+    assertEquals("moves", a.productElementName(0))
+    assertEquals(a, a.copy())
+    assertEquals(LegalMovesResponse(List.empty), a.copy(moves = List.empty))
+
+  @Test
+  def gameStateResponseSynthetics(): Unit =
+    val a = GameStateResponse("fen", "pgn", "white", "started", None, List.empty, false, false)
+    val b = GameStateResponse("fen", "pgn", "white", "started", None, List.empty, false, false)
+    val c = GameStateResponse("fen2", "pgn", "white", "started", None, List.empty, false, false)
+    assertEquals(a, b)
+    assertNotEquals(a, c)
+    assertFalse(a.equals(null))
+    assertFalse(a.equals("other"))
+    assertEquals(a.hashCode, b.hashCode)
+    assertTrue(a.toString.contains("fen"))
+    assertTrue(a.canEqual(b))
+    assertEquals("fen", a.productElement(0))
+    assertEquals("pgn", a.productElement(1))
+    assertEquals("white", a.productElement(2))
+    assertEquals("started", a.productElement(3))
+    assertEquals(None, a.productElement(4))
+    assertEquals(List.empty, a.productElement(5))
+    assertEquals(false, a.productElement(6))
+    assertEquals(false, a.productElement(7))
+    assertEquals("fen", a.productElementName(0))
+    assertEquals("pgn", a.productElementName(1))
+    assertEquals("turn", a.productElementName(2))
+    assertEquals("status", a.productElementName(3))
+    assertEquals("winner", a.productElementName(4))
+    assertEquals("moves", a.productElementName(5))
+    assertEquals("undoAvailable", a.productElementName(6))
+    assertEquals("redoAvailable", a.productElementName(7))
+    assertEquals(a, a.copy())
+    assertEquals(GameStateResponse("x", "pgn", "white", "started", None, List.empty, false, false), a.copy(fen = "x"))
+
+  @Test
+  def gameFullResponseSynthetics(): Unit =
+    val p      = PlayerInfoDto("id", "Name")
+    val state  = GameStateResponse("fen", "pgn", "white", "started", None, List.empty, false, false)
+    val a      = GameFullResponse("gid", p, p, state)
+    val b      = GameFullResponse("gid", p, p, state)
+    val c      = GameFullResponse("other", p, p, state)
+    assertEquals(a, b)
+    assertNotEquals(a, c)
+    assertFalse(a.equals(null))
+    assertFalse(a.equals("other"))
+    assertEquals(a.hashCode, b.hashCode)
+    assertTrue(a.toString.contains("gid"))
+    assertTrue(a.canEqual(b))
+    assertEquals("gid", a.productElement(0))
+    assertEquals(p, a.productElement(1))
+    assertEquals(p, a.productElement(2))
+    assertEquals(state, a.productElement(3))
+    assertEquals("gameId", a.productElementName(0))
+    assertEquals("white", a.productElementName(1))
+    assertEquals("black", a.productElementName(2))
+    assertEquals("state", a.productElementName(3))
+    assertEquals(a, a.copy())
+    assertEquals(GameFullResponse("x", p, p, state), a.copy(gameId = "x"))
@@ -0,0 +1,91 @@
+package de.nowchess.backcore.game
+
+import de.nowchess.api.board.Color
+import de.nowchess.api.game.GameContext
+import de.nowchess.api.player.{PlayerId, PlayerInfo}
+import org.junit.jupiter.api.Assertions.*
+import org.junit.jupiter.api.Test
+
+import java.io.{ByteArrayOutputStream, ObjectOutputStream}
+
+/** Exercises Scala-generated synthetic methods on domain case classes and serializes singleton
+  * objects (Scala objects implement Serializable; writeReplace is called on serialization).
+  */
+class GameDomainCoverageTest:
+
+  private val white = PlayerInfo(PlayerId("white"), "White")
+  private val black = PlayerInfo(PlayerId("black"), "Black")
+
+  private def freshSnap(canUndo: Boolean = false, canRedo: Boolean = false): GameSnapshot =
+    GameSnapshot(
+      gameId = "g1",
+      white = white,
+      black = black,
+      context = GameContext.initial,
+      canUndo = canUndo,
+      canRedo = canRedo,
+    )
+
+  @Test
+  def gameResultResignSynthetics(): Unit =
+    val a = GameResult.Resign(Color.White)
+    val b = GameResult.Resign(Color.White)
+    val c = GameResult.Resign(Color.Black)
+    assertEquals(a, b)
+    assertNotEquals(a, c)
+    assertFalse(a.equals(null))
+    assertFalse(a.equals("other"))
+    assertEquals(a.hashCode, b.hashCode)
+    assertTrue(a.toString.contains("White"))
+    assertTrue(a.canEqual(b))
+    assertEquals(Color.White, a.productElement(0))
+    assertEquals("winner", a.productElementName(0))
+    assertEquals(a, a.copy())
+    assertEquals(GameResult.Resign(Color.Black), a.copy(winner = Color.Black))
+
+  @Test
+  def gameSnapshotSynthetics(): Unit =
+    val a = freshSnap()
+    val b = freshSnap()
+    val c = freshSnap(canUndo = true)
+    assertEquals(a, b)
+    assertNotEquals(a, c)
+    assertFalse(a.equals(null))
+    assertFalse(a.equals("other"))
+    assertEquals(a.hashCode, b.hashCode)
+    assertTrue(a.canEqual(b))
+    assertEquals("g1", a.productElement(0))
+    assertEquals(white, a.productElement(1))
+    assertEquals(black, a.productElement(2))
+    assertEquals(GameContext.initial, a.productElement(3))
+    assertEquals(None, a.productElement(4))
+    assertEquals(None, a.productElement(5))
+    assertEquals(false, a.productElement(6))
+    assertEquals(false, a.productElement(7))
+    assertEquals("gameId", a.productElementName(0))
+    assertEquals("white", a.productElementName(1))
+    assertEquals("black", a.productElementName(2))
+    assertEquals("context", a.productElementName(3))
+    assertEquals("drawOfferedBy", a.productElementName(4))
+    assertEquals("externalResult", a.productElementName(5))
+    assertEquals("canUndo", a.productElementName(6))
+    assertEquals("canRedo", a.productElementName(7))
+    assertEquals(a, a.copy())
+    assertEquals(freshSnap(canUndo = true), a.copy(canUndo = true))
+    assertEquals(freshSnap(canRedo = true), a.copy(canRedo = true))
+
+  @Test
+  def gameMapperSingletonIsSerializable(): Unit =
+    val bos = new ByteArrayOutputStream()
+    val oos = new ObjectOutputStream(bos)
+    oos.writeObject(GameMapper)
+    oos.close()
+    assertTrue(bos.size() > 0)
+
+  @Test
+  def gameEngineHolderSingletonIsSerializable(): Unit =
+    val bos = new ByteArrayOutputStream()
+    val oos = new ObjectOutputStream(bos)
+    oos.writeObject(GameEngineHolder)
+    oos.close()
+    assertTrue(bos.size() > 0)
@@ -0,0 +1,190 @@
+package de.nowchess.backcore.game
+
+import de.nowchess.api.board.{Color, File, Rank, Square}
+import de.nowchess.api.game.{DrawReason, GameContext, GameResult as ApiGameResult}
+import de.nowchess.api.move.{Move, MoveType, PromotionPiece}
+import de.nowchess.api.player.{PlayerId, PlayerInfo}
+import de.nowchess.io.fen.FenParser
+import org.junit.jupiter.api.Assertions.*
+import org.junit.jupiter.api.Test
+
+class GameMapperTest:
+
+  private val white = PlayerInfo(PlayerId("white"), "White")
+  private val black = PlayerInfo(PlayerId("black"), "Black")
+
+  private def snap(
+      ctx: GameContext = GameContext.initial,
+      externalResult: Option[GameResult] = None,
+      drawOfferedBy: Option[Color] = None,
+      canUndo: Boolean = false,
+      canRedo: Boolean = false,
+  ): GameSnapshot =
+    GameSnapshot(
+      gameId = "testId1",
+      white = white,
+      black = black,
+      context = ctx,
+      drawOfferedBy = drawOfferedBy,
+      externalResult = externalResult,
+      canUndo = canUndo,
+      canRedo = canRedo,
+    )
+
+  @Test
+  def resignWhiteReturnsResignWithWhiteWinner(): Unit =
+    val state = GameMapper.toGameState(snap(externalResult = Some(GameResult.Resign(Color.White))))
+    assertEquals("resign", state.status)
+    assertEquals(Some("white"), state.winner)
+
+  @Test
+  def resignBlackReturnsResignWithBlackWinner(): Unit =
+    val state = GameMapper.toGameState(snap(externalResult = Some(GameResult.Resign(Color.Black))))
+    assertEquals("resign", state.status)
+    assertEquals(Some("black"), state.winner)
+
+  @Test
+  def agreedDrawReturnsDrawNoWinner(): Unit =
+    val state = GameMapper.toGameState(snap(externalResult = Some(GameResult.AgreedDraw)))
+    assertEquals("draw", state.status)
+    assertEquals(None, state.winner)
+
+  @Test
+  def fiftyMoveDrawReturnsDrawNoWinner(): Unit =
+    val state = GameMapper.toGameState(snap(externalResult = Some(GameResult.FiftyMoveDraw)))
+    assertEquals("draw", state.status)
+    assertEquals(None, state.winner)
+
+  @Test
+  def contextWinWhiteReturnsCheckmate(): Unit =
+    val ctx   = GameContext.initial.withResult(Some(ApiGameResult.Win(Color.White)))
+    val state = GameMapper.toGameState(snap(ctx = ctx))
+    assertEquals("checkmate", state.status)
+    assertEquals(Some("white"), state.winner)
+
+  @Test
+  def contextWinBlackReturnsCheckmate(): Unit =
+    val ctx   = GameContext.initial.withResult(Some(ApiGameResult.Win(Color.Black)))
+    val state = GameMapper.toGameState(snap(ctx = ctx))
+    assertEquals("checkmate", state.status)
+    assertEquals(Some("black"), state.winner)
+
+  @Test
+  def contextDrawStalemateReturnsStalemate(): Unit =
+    val ctx   = GameContext.initial.withResult(Some(ApiGameResult.Draw(DrawReason.Stalemate)))
+    val state = GameMapper.toGameState(snap(ctx = ctx))
+    assertEquals("stalemate", state.status)
+    assertEquals(None, state.winner)
+
+  @Test
+  def contextDrawInsufficientMaterialReturnsInsufficientMaterial(): Unit =
+    val ctx   = GameContext.initial.withResult(Some(ApiGameResult.Draw(DrawReason.InsufficientMaterial)))
+    val state = GameMapper.toGameState(snap(ctx = ctx))
+    assertEquals("insufficientMaterial", state.status)
+    assertEquals(None, state.winner)
+
+  @Test
+  def contextDrawFiftyMoveRuleReturnsDraw(): Unit =
+    val ctx   = GameContext.initial.withResult(Some(ApiGameResult.Draw(DrawReason.FiftyMoveRule)))
+    val state = GameMapper.toGameState(snap(ctx = ctx))
+    assertEquals("draw", state.status)
+    assertEquals(None, state.winner)
+
+  @Test
+  def contextDrawAgreementReturnsDraw(): Unit =
+    val ctx   = GameContext.initial.withResult(Some(ApiGameResult.Draw(DrawReason.Agreement)))
+    val state = GameMapper.toGameState(snap(ctx = ctx))
+    assertEquals("draw", state.status)
+    assertEquals(None, state.winner)
+
+  @Test
+  def liveCheckPositionReturnsCheckStatus(): Unit =
+    // White king on a1, black rook on h1 — white is in check
+    val ctx = FenParser.parseFen("k7/8/8/8/8/8/8/K6r w - - 0 1")
+      .getOrElse(fail("Invalid FEN"))
+    val state = GameMapper.toGameState(snap(ctx = ctx))
+    assertEquals("check", state.status)
+
+  @Test
+  def liveDrawOfferedBySetReturnsDrawOffered(): Unit =
+    val state = GameMapper.toGameState(snap(drawOfferedBy = Some(Color.White)))
+    assertEquals("drawOffered", state.status)
+
+  @Test
+  def liveFiftyMoveClockGe100ReturnsFiftyMoveAvailable(): Unit =
+    val ctx   = GameContext.initial.withHalfMoveClock(100)
+    val state = GameMapper.toGameState(snap(ctx = ctx))
+    assertEquals("fiftyMoveAvailable", state.status)
+
+  @Test
+  def liveNormalPositionReturnsStarted(): Unit =
+    val state = GameMapper.toGameState(snap())
+    assertEquals("started", state.status)
+    assertEquals(None, state.winner)
+
+  @Test
+  def canUndoReflectedInToGameState(): Unit =
+    val state = GameMapper.toGameState(snap(canUndo = true, canRedo = false))
+    assertTrue(state.undoAvailable)
+    assertFalse(state.redoAvailable)
+
+  @Test
+  def canRedoReflectedInToGameState(): Unit =
+    val state = GameMapper.toGameState(snap(canUndo = false, canRedo = true))
+    assertFalse(state.undoAvailable)
+    assertTrue(state.redoAvailable)
+
+  @Test
+  def moveToUciNormalQuiet(): Unit =
+    val sq   = Square(File.E, Rank.R2)
+    val sq2  = Square(File.E, Rank.R4)
+    val move = Move(sq, sq2, MoveType.Normal(false))
+    assertEquals("e2e4", GameMapper.moveToUci(move))
+
+  @Test
+  def moveToUciNormalCapture(): Unit =
+    val move = Move(Square(File.D, Rank.R4), Square(File.E, Rank.R5), MoveType.Normal(true))
+    assertEquals("d4e5", GameMapper.moveToUci(move))
+
+  @Test
+  def moveToUciCastleKingside(): Unit =
+    val move = Move(Square(File.E, Rank.R1), Square(File.G, Rank.R1), MoveType.CastleKingside)
+    assertEquals("e1g1", GameMapper.moveToUci(move))
+
+  @Test
+  def moveToUciCastleQueenside(): Unit =
+    val move = Move(Square(File.E, Rank.R1), Square(File.C, Rank.R1), MoveType.CastleQueenside)
+    assertEquals("e1c1", GameMapper.moveToUci(move))
+
+  @Test
+  def moveToUciEnPassant(): Unit =
+    val move = Move(Square(File.E, Rank.R5), Square(File.D, Rank.R6), MoveType.EnPassant)
+    assertEquals("e5d6", GameMapper.moveToUci(move))
+
+  @Test
+  def moveToUciPromotionQueen(): Unit =
+    val move = Move(Square(File.E, Rank.R7), Square(File.E, Rank.R8), MoveType.Promotion(PromotionPiece.Queen))
+    assertEquals("e7e8q", GameMapper.moveToUci(move))
+
+  @Test
+  def moveToUciPromotionRook(): Unit =
+    val move = Move(Square(File.E, Rank.R7), Square(File.E, Rank.R8), MoveType.Promotion(PromotionPiece.Rook))
+    assertEquals("e7e8r", GameMapper.moveToUci(move))
+
+  @Test
+  def moveToUciPromotionBishop(): Unit =
+    val move = Move(Square(File.E, Rank.R7), Square(File.E, Rank.R8), MoveType.Promotion(PromotionPiece.Bishop))
+    assertEquals("e7e8b", GameMapper.moveToUci(move))
+
+  @Test
+  def moveToUciPromotionKnight(): Unit =
+    val move = Move(Square(File.E, Rank.R7), Square(File.E, Rank.R8), MoveType.Promotion(PromotionPiece.Knight))
+    assertEquals("e7e8n", GameMapper.moveToUci(move))
+
+  @Test
+  def toGameFullPopulatesAllFields(): Unit =
+    val full = GameMapper.toGameFull(snap())
+    assertEquals("testId1", full.gameId)
+    assertEquals("white", full.white.id)
+    assertEquals("black", full.black.id)
+    assertNotNull(full.state)
@@ -0,0 +1,313 @@
+package de.nowchess.backcore.game
+
+import de.nowchess.api.board.{Color, File, Rank, Square}
+import de.nowchess.backcore.dto.{CreateGameRequest, ImportFenRequest, PlayerInfoDto}
+import org.junit.jupiter.api.Assertions.*
+import org.junit.jupiter.api.{BeforeEach, Test}
+
+class GameServiceTest:
+
+  private val promotionFen = "8/4P3/8/8/8/8/8/4K2k w - - 0 1"
+
+  private def freshService(): GameService =
+    val svc = new GameService()
+    svc.reset(CreateGameRequest())
+    svc
+
+  @Test
+  def resetClearsStateAndReturnsSnapshot(): Unit =
+    val svc = freshService()
+    svc.resign()
+    val snap = svc.reset(CreateGameRequest())
+    assertEquals(GameEngineHolder.gameId, snap.gameId)
+    assertEquals(None, snap.externalResult)
+    assertEquals(None, snap.drawOfferedBy)
+
+  @Test
+  def resetWithPlayersUpdatesHolderInfo(): Unit =
+    val svc = freshService()
+    val req = CreateGameRequest(
+      white = Some(PlayerInfoDto("p1", "Alice")),
+      black = Some(PlayerInfoDto("p2", "Bob")),
+    )
+    val snap = svc.reset(req)
+    assertEquals("Alice", snap.white.displayName)
+    assertEquals("Bob", snap.black.displayName)
+
+  @Test
+  def applyMoveInvalidUciReturnsLeft(): Unit =
+    val svc    = freshService()
+    val result = svc.applyMove("zzzz")
+    assertTrue(result.isLeft)
+
+  @Test
+  def applyMoveIllegalMoveReturnsLeft(): Unit =
+    val svc    = freshService()
+    val result = svc.applyMove("e2e5")
+    assertTrue(result.isLeft)
+
+  @Test
+  def applyMoveValidMoveReturnsRightWithUpdatedContext(): Unit =
+    val svc    = freshService()
+    val result = svc.applyMove("e2e4")
+    assertTrue(result.isRight)
+    val snap = result.getOrElse(fail("Expected Right"))
+    assertEquals(Color.Black, snap.context.turn)
+
+  @Test
+  def applyMoveWhenGameOverReturnsLeft(): Unit =
+    val svc = freshService()
+    svc.resign()
+    val result = svc.applyMove("e2e4")
+    assertTrue(result.isLeft)
+    assertTrue(result.left.getOrElse("").contains("Game is already over"))
+
+  @Test
+  def legalMovesNoneReturnsNonEmptyListAtStart(): Unit =
+    val svc   = freshService()
+    val moves = svc.legalMoves(None)
+    assertFalse(moves.isEmpty)
+
+  @Test
+  def legalMovesForE2ReturnsE2e3AndE2e4(): Unit =
+    val svc   = freshService()
+    val e2    = Square(File.E, Rank.R2)
+    val moves = svc.legalMoves(Some(e2))
+    val ucis  = moves.map(m => s"${m.from}${m.to}")
+    assertTrue(ucis.contains("e2e3"), s"Expected e2e3 in $ucis")
+    assertTrue(ucis.contains("e2e4"), s"Expected e2e4 in $ucis")
+
+  @Test
+  def undoWithNoHistoryReturnsLeft(): Unit =
+    val svc    = freshService()
+    val result = svc.undo()
+    assertTrue(result.isLeft)
+
+  @Test
+  def undoAfterMoveReverts(): Unit =
+    val svc = freshService()
+    svc.applyMove("e2e4")
+    val result = svc.undo()
+    assertTrue(result.isRight)
+    val snap = result.getOrElse(fail("Expected Right"))
+    assertEquals(Color.White, snap.context.turn)
+
+  @Test
+  def redoWithNoRedoStackReturnsLeft(): Unit =
+    val svc    = freshService()
+    val result = svc.redo()
+    assertTrue(result.isLeft)
+
+  @Test
+  def redoAfterUndoReturnsRight(): Unit =
+    val svc = freshService()
+    svc.applyMove("e2e4")
+    svc.undo()
+    val result = svc.redo()
+    assertTrue(result.isRight)
+    val snap = result.getOrElse(fail("Expected Right"))
+    assertEquals(Color.Black, snap.context.turn)
+
+  @Test
+  def resignNormalReturnsRight(): Unit =
+    val svc    = freshService()
+    val result = svc.resign()
+    assertTrue(result.isRight)
+    val snap = result.getOrElse(fail("Expected Right"))
+    assertTrue(snap.externalResult.isDefined)
+    snap.externalResult match
+      case Some(GameResult.Resign(_)) => ()
+      case other                      => fail(s"Expected Resign but got $other")
+
+  @Test
+  def resignWhenAlreadyResignedReturnsLeft(): Unit =
+    val svc = freshService()
+    svc.resign()
+    val result = svc.resign()
+    assertTrue(result.isLeft)
+
+  @Test
+  def drawActionOfferSetsDrawOfferedBy(): Unit =
+    val svc    = freshService()
+    val result = svc.drawAction("offer")
+    assertTrue(result.isRight)
+    val snap = result.getOrElse(fail("Expected Right"))
+    assertTrue(snap.drawOfferedBy.isDefined)
+
+  @Test
+  def drawActionAcceptWithNoOfferReturnsLeft(): Unit =
+    val svc    = freshService()
+    val result = svc.drawAction("accept")
+    assertTrue(result.isLeft)
+
+  @Test
+  def drawActionAcceptOwnOfferReturnsLeft(): Unit =
+    val svc = freshService()
+    svc.drawAction("offer")
+    val result = svc.drawAction("accept")
+    assertTrue(result.isLeft)
+    assertTrue(result.left.getOrElse("").contains("Cannot accept your own draw offer"))
+
+  @Test
+  def drawActionAcceptOpponentAcceptsReturnsAgreedDraw(): Unit =
+    val svc = freshService()
+    svc.drawAction("offer")
+    svc.applyMove("e2e4")
+    val result = svc.drawAction("accept")
+    assertTrue(result.isRight)
+    val snap = result.getOrElse(fail("Expected Right"))
+    assertEquals(Some(GameResult.AgreedDraw), snap.externalResult)
+
+  @Test
+  def drawActionDeclineWithNoOfferReturnsLeft(): Unit =
+    val svc    = freshService()
+    val result = svc.drawAction("decline")
+    assertTrue(result.isLeft)
+
+  @Test
+  def drawActionDeclineAfterOfferClearsOffer(): Unit =
+    val svc = freshService()
+    svc.drawAction("offer")
+    val result = svc.drawAction("decline")
+    assertTrue(result.isRight)
+    val snap = result.getOrElse(fail("Expected Right"))
+    assertEquals(None, snap.drawOfferedBy)
+
+  @Test
+  def drawActionClaimWhenFiftyMoveNotTriggeredReturnsLeft(): Unit =
+    val svc    = freshService()
+    val result = svc.drawAction("claim")
+    assertTrue(result.isLeft)
+
+  @Test
+  def drawActionUnknownReturnsLeft(): Unit =
+    val svc    = freshService()
+    val result = svc.drawAction("unknown")
+    assertTrue(result.isLeft)
+
+  @Test
+  def importFenValidReturnsRight(): Unit =
+    val svc    = freshService()
+    val result = svc.importFen(ImportFenRequest(fen = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"))
+    assertTrue(result.isRight)
+
+  @Test
+  def importFenInvalidReturnsLeft(): Unit =
+    val svc    = freshService()
+    val result = svc.importFen(ImportFenRequest(fen = "not-a-fen"))
+    assertTrue(result.isLeft)
+
+  @Test
+  def importPgnValidReturnsRight(): Unit =
+    val svc    = freshService()
+    val result = svc.importPgn("1. e4 e5 2. Nf3 Nc6 *")
+    assertTrue(result.isRight)
+
+  @Test
+  def importPgnInvalidReturnsLeft(): Unit =
+    val svc    = freshService()
+    val result = svc.importPgn("1. z9 *")
+    assertTrue(result.isLeft)
+
+  @Test
+  def exportFenReturnsNonEmptyString(): Unit =
+    val svc = freshService()
+    val fen = svc.exportFen()
+    assertFalse(fen.isEmpty)
+
+  @Test
+  def exportPgnReturnsString(): Unit =
+    val svc = freshService()
+    val pgn = svc.exportPgn()
+    assertNotNull(pgn)
+
+  @Test
+  def isKnownIdTrueForHolderGameId(): Unit =
+    val svc = freshService()
+    assertTrue(svc.isKnownId(GameEngineHolder.gameId))
+
+  @Test
+  def isKnownIdFalseForOtherId(): Unit =
+    val svc = freshService()
+    assertFalse(svc.isKnownId("XXXXXXXX"))
+
+  @Test
+  def applyMovePromotionQueenProducesQueen(): Unit =
+    val svc = freshService()
+    svc.importFen(ImportFenRequest(fen = promotionFen))
+    val result = svc.applyMove("e7e8q")
+    assertTrue(result.isRight, s"Expected Right but got $result")
+    val snap = result.getOrElse(fail("Expected Right"))
+    val e8   = Square(File.E, Rank.R8)
+    snap.context.board.pieceAt(e8) match
+      case Some(piece) =>
+        assertEquals(de.nowchess.api.board.PieceType.Queen, piece.pieceType)
+      case None => fail("Expected queen on e8")
+
+  @Test
+  def applyMovePromotionRookProducesRook(): Unit =
+    val svc = freshService()
+    svc.importFen(ImportFenRequest(fen = promotionFen))
+    val result = svc.applyMove("e7e8r")
+    assertTrue(result.isRight, s"Expected Right but got $result")
+    val snap = result.getOrElse(fail("Expected Right"))
+    val e8   = Square(File.E, Rank.R8)
+    snap.context.board.pieceAt(e8) match
+      case Some(piece) => assertEquals(de.nowchess.api.board.PieceType.Rook, piece.pieceType)
+      case None        => fail("Expected rook on e8")
+
+  @Test
+  def applyMovePromotionBishopProducesBishop(): Unit =
+    val svc = freshService()
+    svc.importFen(ImportFenRequest(fen = promotionFen))
+    val result = svc.applyMove("e7e8b")
+    assertTrue(result.isRight, s"Expected Right but got $result")
+    val snap = result.getOrElse(fail("Expected Right"))
+    val e8   = Square(File.E, Rank.R8)
+    snap.context.board.pieceAt(e8) match
+      case Some(piece) => assertEquals(de.nowchess.api.board.PieceType.Bishop, piece.pieceType)
+      case None        => fail("Expected bishop on e8")
+
+  @Test
+  def applyMovePromotionKnightProducesKnight(): Unit =
+    val svc = freshService()
+    svc.importFen(ImportFenRequest(fen = promotionFen))
+    val result = svc.applyMove("e7e8n")
+    assertTrue(result.isRight, s"Expected Right but got $result")
+    val snap = result.getOrElse(fail("Expected Right"))
+    val e8   = Square(File.E, Rank.R8)
+    snap.context.board.pieceAt(e8) match
+      case Some(piece) => assertEquals(de.nowchess.api.board.PieceType.Knight, piece.pieceType)
+      case None        => fail("Expected knight on e8")
+
+  @Test
+  def applyMoveWithoutPromotionCharFallsBackToFirstPromotion(): Unit =
+    val svc = freshService()
+    svc.importFen(ImportFenRequest(fen = promotionFen))
+    val result = svc.applyMove("e7e8")
+    assertTrue(result.isRight, s"Expected Right but got $result")
+
+  @Test
+  def applyMoveWithInvalidPromotionCharFallsBackToFirstPromotion(): Unit =
+    // 'x' → parsePromotionChar wildcard branch → None → orElse(headOption)
+    val svc = freshService()
+    svc.importFen(ImportFenRequest(fen = promotionFen))
+    val result = svc.applyMove("e7e8x")
+    assertTrue(result.isRight, s"Expected Right but got $result")
+
+  @Test
+  def drawActionClaimWhenFiftyMoveTriggeredReturnsRight(): Unit =
+    val svc = freshService()
+    svc.importFen(ImportFenRequest(fen = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 100 51"))
+    val result = svc.drawAction("claim")
+    assertTrue(result.isRight, s"Expected Right but got $result")
+    val snap = result.getOrElse(fail("Expected Right"))
+    assertEquals(Some(GameResult.FiftyMoveDraw), snap.externalResult)
+
+  @Test
+  def engineSetterPropagatesNewEngine(): Unit =
+    val original = GameEngineHolder.engine
+    val fresh    = new de.nowchess.chess.engine.GameEngine()
+    GameEngineHolder.engine = fresh
+    assertEquals(fresh, GameEngineHolder.engine)
+    GameEngineHolder.engine = original
@@ -0,0 +1,112 @@
+package de.nowchess.backcore.resource
+
+import io.quarkus.test.junit.QuarkusTest
+import io.restassured.RestAssured
+import org.hamcrest.Matchers.{equalTo, matchesPattern, notNullValue}
+import org.junit.jupiter.api.Test
+
+@QuarkusTest
+class GameResourceTest:
+
+  @Test
+  def createGameReturns201WithGameId(): Unit =
+    RestAssured
+      .`given`()
+      .contentType("application/json")
+      .body("{}")
+      .when()
+      .post("/api/board/game")
+      .`then`()
+      .statusCode(201)
+      .body("gameId", matchesPattern("[A-Za-z0-9]{8}"))
+      .body("state.fen", notNullValue())
+      .body("state.turn", equalTo("white"))
+      .body("state.status", equalTo("started"))
+
+  @Test
+  def createGameWithPlayersReturns201(): Unit =
+    RestAssured
+      .`given`()
+      .contentType("application/json")
+      .body("""{"white":{"id":"p1","displayName":"Alice"},"black":{"id":"p2","displayName":"Bob"}}""")
+      .when()
+      .post("/api/board/game")
+      .`then`()
+      .statusCode(201)
+      .body("white.id", equalTo("p1"))
+      .body("black.displayName", equalTo("Bob"))
+
+  @Test
+  def getGameReturns200ForExistingGame(): Unit =
+    val gameId = RestAssured
+      .`given`()
+      .contentType("application/json")
+      .body("{}")
+      .when()
+      .post("/api/board/game")
+      .`then`()
+      .statusCode(201)
+      .extract()
+      .path[String]("gameId")
+
+    RestAssured
+      .`given`()
+      .when()
+      .get(s"/api/board/game/$gameId")
+      .`then`()
+      .statusCode(200)
+      .body("gameId", equalTo(gameId))
+
+  @Test
+  def getGameReturns404ForUnknownId(): Unit =
+    RestAssured
+      .`given`()
+      .when()
+      .get("/api/board/game/XXXXXXXX")
+      .`then`()
+      .statusCode(404)
+
+  @Test
+  def createGameWithNullBodyReturns201(): Unit =
+    RestAssured
+      .`given`()
+      .contentType("application/json")
+      .body("null")
+      .when()
+      .post("/api/board/game")
+      .`then`()
+      .statusCode(201)
+
+  @Test
+  def exportPgnOnUnknownGameReturns404(): Unit =
+    RestAssured
+      .`given`()
+      .when()
+      .get("/api/board/game/XXXXXXXX/export/pgn")
+      .`then`()
+      .statusCode(404)
+
+  @Test
+  def resignWhenAlreadyResignedReturns400(): Unit =
+    val gameId = RestAssured
+      .`given`()
+      .contentType("application/json")
+      .body("{}")
+      .when()
+      .post("/api/board/game")
+      .`then`()
+      .statusCode(201)
+      .extract()
+      .path[String]("gameId")
+    RestAssured
+      .`given`()
+      .when()
+      .post(s"/api/board/game/$gameId/resign")
+      .`then`()
+      .statusCode(200)
+    RestAssured
+      .`given`()
+      .when()
+      .post(s"/api/board/game/$gameId/resign")
+      .`then`()
+      .statusCode(400)
@@ -0,0 +1,199 @@
+package de.nowchess.backcore.resource
+
+import io.quarkus.test.junit.QuarkusTest
+import io.restassured.RestAssured
+import org.hamcrest.Matchers.{containsString, equalTo, matchesPattern, notNullValue}
+import org.junit.jupiter.api.Test
+
+@QuarkusTest
+class ImportExportTest:
+
+  private val startFen = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"
+
+  // ─── Import FEN ────────────────────────────────────────────────
+
+  @Test
+  def importFenReturns201WithCorrectPosition(): Unit =
+    RestAssured
+      .`given`()
+      .contentType("application/json")
+      .body(s"""{"fen":"$startFen"}""")
+      .when()
+      .post("/api/board/game/import/fen")
+      .`then`()
+      .statusCode(201)
+      .body("gameId", matchesPattern("[A-Za-z0-9]{8}"))
+      .body("state.fen", equalTo(startFen))
+      .body("state.turn", equalTo("white"))
+
+  @Test
+  def importFenWithCustomPositionWorks(): Unit =
+    val fen = "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1"
+    RestAssured
+      .`given`()
+      .contentType("application/json")
+      .body(s"""{"fen":"$fen"}""")
+      .when()
+      .post("/api/board/game/import/fen")
+      .`then`()
+      .statusCode(201)
+      .body("state.fen", equalTo(fen))
+      .body("state.turn", equalTo("black"))
+
+  @Test
+  def importFenWithInvalidFenReturns400(): Unit =
+    RestAssured
+      .`given`()
+      .contentType("application/json")
+      .body("""{"fen":"not-a-fen"}""")
+      .when()
+      .post("/api/board/game/import/fen")
+      .`then`()
+      .statusCode(400)
+
+  @Test
+  def importFenWithNullBodyReturns400(): Unit =
+    RestAssured
+      .`given`()
+      .contentType("application/json")
+      .body("null")
+      .when()
+      .post("/api/board/game/import/fen")
+      .`then`()
+      .statusCode(400)
+
+  // ─── Import PGN ────────────────────────────────────────────────
+
+  @Test
+  def importPgnReturns201(): Unit =
+    RestAssured
+      .`given`()
+      .contentType("application/json")
+      .body("""{"pgn":"1. e4 e5 2. Nf3 Nc6 *"}""")
+      .when()
+      .post("/api/board/game/import/pgn")
+      .`then`()
+      .statusCode(201)
+      .body("gameId", matchesPattern("[A-Za-z0-9]{8}"))
+      .body("state.turn", equalTo("white"))
+
+  @Test
+  def importPgnWithInvalidPgnReturns400(): Unit =
+    RestAssured
+      .`given`()
+      .contentType("application/json")
+      .body("""{"pgn":"1. z9 *"}""")
+      .when()
+      .post("/api/board/game/import/pgn")
+      .`then`()
+      .statusCode(400)
+
+  @Test
+  def importPgnWithNullBodyReturns400(): Unit =
+    RestAssured
+      .`given`()
+      .contentType("application/json")
+      .body("null")
+      .when()
+      .post("/api/board/game/import/pgn")
+      .`then`()
+      .statusCode(400)
+
+  // ─── Export FEN ────────────────────────────────────────────────
+
+  @Test
+  def exportFenReturnsStartingFen(): 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/$gameId/export/fen")
+      .`then`()
+      .statusCode(200)
+      .body(equalTo(startFen))
+
+  @Test
+  def exportFenOnUnknownGameReturns404(): Unit =
+    RestAssured
+      .`given`()
+      .when()
+      .get("/api/board/game/XXXXXXXX/export/fen")
+      .`then`()
+      .statusCode(404)
+
+  // ─── Export PGN ────────────────────────────────────────────────
+
+  @Test
+  def exportPgnReturnsText(): Unit =
+    val gameId = RestAssured
+      .`given`()
+      .contentType("application/json")
+      .body("{}")
+      .when()
+      .post("/api/board/game")
+      .`then`()
+      .statusCode(201)
+      .extract()
+      .path[String]("gameId")
+
+    RestAssured
+      .`given`()
+      .when()
+      .post(s"/api/board/game/$gameId/move/e2e4")
+      .`then`()
+      .statusCode(200)
+
+    RestAssured
+      .`given`()
+      .when()
+      .get(s"/api/board/game/$gameId/export/pgn")
+      .`then`()
+      .statusCode(200)
+      .body(containsString("e4"))
+
+  // ─── Stream ────────────────────────────────────────────────────
+
+  @Test
+  def streamReturnsNdjsonSnapshot(): Unit =
+    val gameId = RestAssured
+      .`given`()
+      .contentType("application/json")
+      .body("{}")
+      .when()
+      .post("/api/board/game")
+      .`then`()
+      .statusCode(201)
+      .extract()
+      .path[String]("gameId")
+
+    val body = RestAssured
+      .`given`()
+      .when()
+      .get(s"/api/board/game/$gameId/stream")
+      .`then`()
+      .statusCode(200)
+      .contentType("application/x-ndjson")
+      .extract()
+      .body()
+      .asString()
+
+    assert(body.trim.startsWith("""{"type":"gameFull""""), s"Expected gameFull event, got: $body")
+
+  @Test
+  def streamOnUnknownGameReturns404(): Unit =
+    RestAssured
+      .`given`()
+      .when()
+      .get("/api/board/game/XXXXXXXX/stream")
+      .`then`()
+      .statusCode(404)
@@ -0,0 +1,164 @@
+package de.nowchess.backcore.resource
+
+import io.quarkus.test.junit.QuarkusTest
+import io.restassured.RestAssured
+import org.hamcrest.Matchers.{containsString, empty, equalTo, hasItem, hasItems, not, notNullValue}
+import org.junit.jupiter.api.Test
+
+@QuarkusTest
+class MoveResourceTest:
+
+  private def createGame(): String =
+    RestAssured
+      .`given`()
+      .contentType("application/json")
+      .body("{}")
+      .when()
+      .post("/api/board/game")
+      .`then`()
+      .statusCode(201)
+      .extract()
+      .path[String]("gameId")
+
+  @Test
+  def makeMoveReturns200WithUpdatedFen(): Unit =
+    val gameId = createGame()
+    RestAssured
+      .`given`()
+      .when()
+      .post(s"/api/board/game/$gameId/move/e2e4")
+      .`then`()
+      .statusCode(200)
+      .body("fen", containsString("4P3")) // e4 pawn present in FEN
+      .body("turn", equalTo("black"))
+      .body("moves", hasItem("e2e4"))
+
+  @Test
+  def makeMoveOnUnknownGameReturns404(): Unit =
+    RestAssured
+      .`given`()
+      .when()
+      .post("/api/board/game/XXXXXXXX/move/e2e4")
+      .`then`()
+      .statusCode(404)
+
+  @Test
+  def illegalMoveReturns400(): Unit =
+    val gameId = createGame()
+    RestAssured
+      .`given`()
+      .when()
+      .post(s"/api/board/game/$gameId/move/e2e5") // illegal — pawns can't jump 3 squares
+      .`then`()
+      .statusCode(400)
+
+  @Test
+  def getLegalMovesReturnsNonEmptyList(): Unit =
+    val gameId = createGame()
+    RestAssured
+      .`given`()
+      .when()
+      .get(s"/api/board/game/$gameId/moves")
+      .`then`()
+      .statusCode(200)
+      .body("moves", not(empty()))
+
+  @Test
+  def getLegalMovesFilteredBySquareReturnsCorrectMoves(): Unit =
+    val gameId = createGame()
+    RestAssured
+      .`given`()
+      .when()
+      .get(s"/api/board/game/$gameId/moves?square=e2")
+      .`then`()
+      .statusCode(200)
+      .body("moves.uci", hasItems("e2e3", "e2e4"))
+
+  @Test
+  def getLegalMovesOnUnknownGameReturns404(): Unit =
+    RestAssured
+      .`given`()
+      .when()
+      .get("/api/board/game/XXXXXXXX/moves")
+      .`then`()
+      .statusCode(404)
+
+  @Test
+  def getLegalMovesIncludesCaptureType(): Unit =
+    val gameId = RestAssured
+      .`given`()
+      .contentType("application/json")
+      .body("""{"fen":"rnbqkbnr/ppp1pppp/8/3p4/4P3/8/PPPP1PPP/RNBQKBNR w KQkq d6 0 2"}""")
+      .when()
+      .post("/api/board/game/import/fen")
+      .`then`()
+      .statusCode(201)
+      .extract()
+      .path[String]("gameId")
+    RestAssured
+      .`given`()
+      .when()
+      .get(s"/api/board/game/$gameId/moves?square=e4")
+      .`then`()
+      .statusCode(200)
+      .body("moves.moveType", hasItem("capture"))
+
+  @Test
+  def getLegalMovesIncludesCastlingTypes(): Unit =
+    val gameId = RestAssured
+      .`given`()
+      .contentType("application/json")
+      .body("""{"fen":"4k3/8/8/8/8/8/8/R3K2R w KQ - 0 1"}""")
+      .when()
+      .post("/api/board/game/import/fen")
+      .`then`()
+      .statusCode(201)
+      .extract()
+      .path[String]("gameId")
+    RestAssured
+      .`given`()
+      .when()
+      .get(s"/api/board/game/$gameId/moves?square=e1")
+      .`then`()
+      .statusCode(200)
+      .body("moves.moveType", hasItems("castleKingside", "castleQueenside"))
+
+  @Test
+  def getLegalMovesIncludesEnPassantType(): Unit =
+    val gameId = RestAssured
+      .`given`()
+      .contentType("application/json")
+      .body("""{"fen":"rnbqkbnr/ppp1p1pp/8/3pPp2/8/8/PPPP1PPP/RNBQKBNR w KQkq f6 0 3"}""")
+      .when()
+      .post("/api/board/game/import/fen")
+      .`then`()
+      .statusCode(201)
+      .extract()
+      .path[String]("gameId")
+    RestAssured
+      .`given`()
+      .when()
+      .get(s"/api/board/game/$gameId/moves?square=e5")
+      .`then`()
+      .statusCode(200)
+      .body("moves.moveType", hasItem("enPassant"))
+
+  @Test
+  def getLegalMovesIncludesAllPromotionTypes(): Unit =
+    val gameId = RestAssured
+      .`given`()
+      .contentType("application/json")
+      .body("""{"fen":"8/4P3/8/8/8/8/8/4K2k w - - 0 1"}""")
+      .when()
+      .post("/api/board/game/import/fen")
+      .`then`()
+      .statusCode(201)
+      .extract()
+      .path[String]("gameId")
+    RestAssured
+      .`given`()
+      .when()
+      .get(s"/api/board/game/$gameId/moves?square=e7")
+      .`then`()
+      .statusCode(200)
+      .body("moves.promotion", hasItems("rook", "bishop", "knight"))
@@ -0,0 +1,168 @@
+package de.nowchess.backcore.resource
+
+import io.quarkus.test.junit.QuarkusTest
+import io.restassured.RestAssured
+import org.hamcrest.Matchers.{equalTo, notNullValue}
+import org.junit.jupiter.api.Test
+
+@QuarkusTest
+class ResignDrawTest:
+
+  private def createGame(): String =
+    RestAssured
+      .`given`()
+      .contentType("application/json")
+      .body("{}")
+      .when()
+      .post("/api/board/game")
+      .`then`()
+      .statusCode(201)
+      .extract()
+      .path[String]("gameId")
+
+  // ─── Resign ────────────────────────────────────────────────────
+
+  @Test
+  def resignReturns200(): Unit =
+    val gameId = createGame()
+    RestAssured
+      .`given`()
+      .when()
+      .post(s"/api/board/game/$gameId/resign")
+      .`then`()
+      .statusCode(200)
+      .body("ok", equalTo(true))
+
+  @Test
+  def afterResignGameShowsResignStatusAndWinner(): Unit =
+    val gameId = createGame()
+    RestAssured
+      .`given`()
+      .when()
+      .post(s"/api/board/game/$gameId/resign")
+      .`then`()
+      .statusCode(200)
+
+    RestAssured
+      .`given`()
+      .when()
+      .get(s"/api/board/game/$gameId")
+      .`then`()
+      .statusCode(200)
+      .body("state.status", equalTo("resign"))
+      .body("state.winner", notNullValue())
+
+  @Test
+  def resignOnUnknownGameReturns404(): Unit =
+    RestAssured
+      .`given`()
+      .when()
+      .post("/api/board/game/XXXXXXXX/resign")
+      .`then`()
+      .statusCode(404)
+
+  // ─── Draw ──────────────────────────────────────────────────────
+
+  @Test
+  def offerDrawSetsDrawOfferedStatus(): Unit =
+    val gameId = createGame()
+    RestAssured
+      .`given`()
+      .when()
+      .post(s"/api/board/game/$gameId/draw/offer")
+      .`then`()
+      .statusCode(200)
+      .body("ok", equalTo(true))
+
+    RestAssured
+      .`given`()
+      .when()
+      .get(s"/api/board/game/$gameId")
+      .`then`()
+      .statusCode(200)
+      .body("state.status", equalTo("drawOffered"))
+
+  @Test
+  def acceptDrawAfterOfferSetsDrawStatus(): Unit =
+    val gameId = createGame()
+    // White offers
+    RestAssured
+      .`given`()
+      .when()
+      .post(s"/api/board/game/$gameId/draw/offer")
+      .`then`()
+      .statusCode(200)
+
+    // Black moves so it's black's turn... actually the API doesn't enforce turn-based draw accept.
+    // White offered, so black (opponent) accepts — but since there's no auth, we just call accept.
+    // The GameStore checks drawOfferedBy != turn to allow accept.
+    // White offered on white's turn, so black needs to accept — but current turn is still white.
+    // We need to make a move first to switch turns.
+    RestAssured
+      .`given`()
+      .when()
+      .post(s"/api/board/game/$gameId/move/e2e4")
+      .`then`()
+      .statusCode(200)
+
+    // Now it's black's turn and white offered the draw — black accepts
+    RestAssured
+      .`given`()
+      .when()
+      .post(s"/api/board/game/$gameId/draw/accept")
+      .`then`()
+      .statusCode(200)
+      .body("ok", equalTo(true))
+
+    RestAssured
+      .`given`()
+      .when()
+      .get(s"/api/board/game/$gameId")
+      .`then`()
+      .statusCode(200)
+      .body("state.status", equalTo("draw"))
+
+  @Test
+  def declineDrawClearsOffer(): Unit =
+    val gameId = createGame()
+    RestAssured
+      .`given`()
+      .when()
+      .post(s"/api/board/game/$gameId/draw/offer")
+      .`then`()
+      .statusCode(200)
+
+    RestAssured
+      .`given`()
+      .when()
+      .post(s"/api/board/game/$gameId/draw/decline")
+      .`then`()
+      .statusCode(200)
+      .body("ok", equalTo(true))
+
+    RestAssured
+      .`given`()
+      .when()
+      .get(s"/api/board/game/$gameId")
+      .`then`()
+      .statusCode(200)
+      .body("state.status", equalTo("started"))
+
+  @Test
+  def acceptWithoutOfferReturns400(): Unit =
+    val gameId = createGame()
+    RestAssured
+      .`given`()
+      .when()
+      .post(s"/api/board/game/$gameId/draw/accept")
+      .`then`()
+      .statusCode(400)
+
+  @Test
+  def drawOnUnknownGameReturns404(): Unit =
+    RestAssured
+      .`given`()
+      .when()
+      .post("/api/board/game/XXXXXXXX/draw/offer")
+      .`then`()
+      .statusCode(404)
@@ -0,0 +1,106 @@
+package de.nowchess.backcore.resource
+
+import io.quarkus.test.junit.QuarkusTest
+import io.restassured.RestAssured
+import org.hamcrest.Matchers.{containsString, equalTo}
+import org.junit.jupiter.api.Test
+
+@QuarkusTest
+class UndoRedoTest:
+
+  private val initialFen = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"
+
+  private def createGame(): String =
+    RestAssured
+      .`given`()
+      .contentType("application/json")
+      .body("{}")
+      .when()
+      .post("/api/board/game")
+      .`then`()
+      .statusCode(201)
+      .extract()
+      .path[String]("gameId")
+
+  @Test
+  def undoAfterMoveRestoresOriginalPosition(): Unit =
+    val gameId = createGame()
+    RestAssured
+      .`given`()
+      .when()
+      .post(s"/api/board/game/$gameId/move/e2e4")
+      .`then`()
+      .statusCode(200)
+
+    RestAssured
+      .`given`()
+      .when()
+      .post(s"/api/board/game/$gameId/undo")
+      .`then`()
+      .statusCode(200)
+      .body("fen", equalTo(initialFen))
+      .body("undoAvailable", equalTo(false))
+
+  @Test
+  def redoAfterUndoRestoresMovedPosition(): Unit =
+    val gameId = createGame()
+    RestAssured
+      .`given`()
+      .when()
+      .post(s"/api/board/game/$gameId/move/e2e4")
+      .`then`()
+      .statusCode(200)
+
+    RestAssured
+      .`given`()
+      .when()
+      .post(s"/api/board/game/$gameId/undo")
+      .`then`()
+      .statusCode(200)
+
+    RestAssured
+      .`given`()
+      .when()
+      .post(s"/api/board/game/$gameId/redo")
+      .`then`()
+      .statusCode(200)
+      .body("fen", containsString("4P3"))
+      .body("turn", equalTo("black"))
+
+  @Test
+  def undoWithNoHistoryReturns400(): Unit =
+    val gameId = createGame()
+    RestAssured
+      .`given`()
+      .when()
+      .post(s"/api/board/game/$gameId/undo")
+      .`then`()
+      .statusCode(400)
+
+  @Test
+  def redoWithNoRedoStackReturns400(): Unit =
+    val gameId = createGame()
+    RestAssured
+      .`given`()
+      .when()
+      .post(s"/api/board/game/$gameId/redo")
+      .`then`()
+      .statusCode(400)
+
+  @Test
+  def undoMoveOnUnknownGameReturns404(): Unit =
+    RestAssured
+      .`given`()
+      .when()
+      .post("/api/board/game/XXXXXXXX/undo")
+      .`then`()
+      .statusCode(404)
+
+  @Test
+  def redoMoveOnUnknownGameReturns404(): Unit =
+    RestAssured
+      .`given`()
+      .when()
+      .post("/api/board/game/XXXXXXXX/redo")
+      .`then`()
+      .statusCode(404)
@@ -18,8 +18,8 @@ class CommandInvokerBranchTest extends AnyFunSuite with Matchers:
      initialShouldFailOnUndo: Boolean = false,
      initialShouldFailOnExecute: Boolean = false,
  ) extends Command:
-    val shouldFailOnUndo    = new java.util.concurrent.atomic.AtomicBoolean(initialShouldFailOnUndo)
-    val shouldFailOnExecute = new java.util.concurrent.atomic.AtomicBoolean(initialShouldFailOnExecute)
+    val shouldFailOnUndo             = new java.util.concurrent.atomic.AtomicBoolean(initialShouldFailOnUndo)
+    val shouldFailOnExecute          = new java.util.concurrent.atomic.AtomicBoolean(initialShouldFailOnExecute)
    override def execute(): Boolean  = !shouldFailOnExecute.get()
    override def undo(): Boolean     = !shouldFailOnUndo.get()
    override def description: String = "Conditional fail"
@@ -69,7 +69,9 @@ class GameEngineIntegrationTest extends AnyFunSuite with Matchers:

    engine.context shouldBe target
    engine.commandHistory shouldBe empty
-    events.lastOption.exists { case _: de.nowchess.chess.observer.BoardResetEvent => true; case _ => false } shouldBe true
+    events.lastOption.exists {
+      case _: de.nowchess.chess.observer.BoardResetEvent => true; case _ => false
+    } shouldBe true

  test("redo event includes captured piece description when replaying a capture"):
    val engine = new GameEngine()
@@ -70,58 +70,66 @@ class FenParserFastParseTest extends AnyFunSuite with Matchers:
    FenParserFastParse.parseBoard("8pp/8/8/8/8/8/8/8") shouldBe None

  test("parseFen handles all individual castling rights"):
-    FenParserFastParse.parseFen("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w K - 0 1").fold(_ => fail(), ctx =>
-      ctx.castlingRights.whiteKingSide shouldBe true
-      ctx.castlingRights.whiteQueenSide shouldBe false
-      ctx.castlingRights.blackKingSide shouldBe false
-      ctx.castlingRights.blackQueenSide shouldBe false
-    )
+    FenParserFastParse
+      .parseFen("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w K - 0 1")
+      .fold(
+        _ => fail(),
+        ctx =>
+          ctx.castlingRights.whiteKingSide shouldBe true
+          ctx.castlingRights.whiteQueenSide shouldBe false
+          ctx.castlingRights.blackKingSide shouldBe false
+          ctx.castlingRights.blackQueenSide shouldBe false,
+      )

-    FenParserFastParse.parseFen("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w Q - 0 1").fold(_ => fail(), ctx =>
-      ctx.castlingRights.whiteQueenSide shouldBe true
-      ctx.castlingRights.whiteKingSide shouldBe false
-    )
+    FenParserFastParse
+      .parseFen("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w Q - 0 1")
+      .fold(
+        _ => fail(),
+        ctx =>
+          ctx.castlingRights.whiteQueenSide shouldBe true
+          ctx.castlingRights.whiteKingSide shouldBe false,
+      )

-    FenParserFastParse.parseFen("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w k - 0 1").fold(_ => fail(), ctx =>
-      ctx.castlingRights.blackKingSide shouldBe true
-      ctx.castlingRights.whiteKingSide shouldBe false
-    )
+    FenParserFastParse
+      .parseFen("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w k - 0 1")
+      .fold(
+        _ => fail(),
+        ctx =>
+          ctx.castlingRights.blackKingSide shouldBe true
+          ctx.castlingRights.whiteKingSide shouldBe false,
+      )

-    FenParserFastParse.parseFen("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w q - 0 1").fold(_ => fail(), ctx =>
-      ctx.castlingRights.blackQueenSide shouldBe true
-      ctx.castlingRights.whiteKingSide shouldBe false
-    )
+    FenParserFastParse
+      .parseFen("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w q - 0 1")
+      .fold(
+        _ => fail(),
+        ctx =>
+          ctx.castlingRights.blackQueenSide shouldBe true
+          ctx.castlingRights.whiteKingSide shouldBe false,
+      )

  test("parseFen parses all en passant squares"):
-    FenParserFastParse.parseFen("8/8/8/8/8/8/8/8 w - a3 0 1").fold(_ => fail(), ctx =>
-      ctx.enPassantSquare shouldBe Some(Square(File.A, Rank.R3))
-    )
+    FenParserFastParse
+      .parseFen("8/8/8/8/8/8/8/8 w - a3 0 1")
+      .fold(_ => fail(), ctx => ctx.enPassantSquare shouldBe Some(Square(File.A, Rank.R3)))

-    FenParserFastParse.parseFen("8/8/8/8/8/8/8/8 w - h6 0 1").fold(_ => fail(), ctx =>
-      ctx.enPassantSquare shouldBe Some(Square(File.H, Rank.R6))
-    )
+    FenParserFastParse
+      .parseFen("8/8/8/8/8/8/8/8 w - h6 0 1")
+      .fold(_ => fail(), ctx => ctx.enPassantSquare shouldBe Some(Square(File.H, Rank.R6)))

  test("parseFen parses different halfMove and fullMove clocks"):
-    FenParserFastParse.parseFen("8/8/8/8/8/8/8/8 w - - 5 10").fold(_ => fail(), ctx =>
-      ctx.halfMoveClock shouldBe 5
-    )
+    FenParserFastParse.parseFen("8/8/8/8/8/8/8/8 w - - 5 10").fold(_ => fail(), ctx => ctx.halfMoveClock shouldBe 5)

-    FenParserFastParse.parseFen("8/8/8/8/8/8/8/8 w - - 0 100").fold(_ => fail(), ctx =>
-      ctx.halfMoveClock shouldBe 0
-    )
+    FenParserFastParse.parseFen("8/8/8/8/8/8/8/8 w - - 0 100").fold(_ => fail(), ctx => ctx.halfMoveClock shouldBe 0)

  test("parseBoard parses boards with mixed empty and piece tokens"):
    val mixed = "8/1p1p1p1p/8/1P1P1P1P/8/8/8/8"
    FenParserFastParse.parseBoard(mixed) should not be empty

  test("parseFen handles turn transitions"):
-    FenParserFastParse.parseFen("8/8/8/8/8/8/8/8 w - - 0 1").fold(_ => fail(), ctx =>
-      ctx.turn shouldBe Color.White
-    )
+    FenParserFastParse.parseFen("8/8/8/8/8/8/8/8 w - - 0 1").fold(_ => fail(), ctx => ctx.turn shouldBe Color.White)

-    FenParserFastParse.parseFen("8/8/8/8/8/8/8/8 b - - 0 1").fold(_ => fail(), ctx =>
-      ctx.turn shouldBe Color.Black
-    )
+    FenParserFastParse.parseFen("8/8/8/8/8/8/8/8 b - - 0 1").fold(_ => fail(), ctx => ctx.turn shouldBe Color.Black)

  test("parseFen rejects invalid piece characters"):
    FenParserFastParse.parseFen("8x/8/8/8/8/8/8/8 w - - 0 1").isLeft shouldBe true
@@ -133,7 +141,7 @@ class FenParserFastParseTest extends AnyFunSuite with Matchers:
  test("parseBoard tests all piece types in various positions"):
    // Test each piece type: pawn, rook, knight, bishop, queen, king (both colors)
    val allPieces = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR"
-    val parsed = FenParserFastParse.parseBoard(allPieces)
+    val parsed    = FenParserFastParse.parseBoard(allPieces)
    parsed.map(_.pieces.size) shouldBe Some(32)
    parsed.map(_.pieceAt(Square(File.A, Rank.R8))) shouldBe Some(Some(Piece.BlackRook))
    parsed.map(_.pieceAt(Square(File.B, Rank.R8))) shouldBe Some(Some(Piece.BlackKnight))
@@ -150,25 +158,33 @@ class FenParserFastParseTest extends AnyFunSuite with Matchers:
    FenParserFastParse.parseFen("8/8/8/8/8/8/8/8 b - - 0 1").fold(_ => fail(), _.turn shouldBe Color.Black)

  test("parseFen tests all castling combinations"):
-    FenParserFastParse.parseFen("8/8/8/8/8/8/8/8 w KQkq - 0 1").fold(_ => fail(), ctx =>
-      ctx.castlingRights.whiteKingSide shouldBe true
-      ctx.castlingRights.whiteQueenSide shouldBe true
-      ctx.castlingRights.blackKingSide shouldBe true
-      ctx.castlingRights.blackQueenSide shouldBe true
-    )
+    FenParserFastParse
+      .parseFen("8/8/8/8/8/8/8/8 w KQkq - 0 1")
+      .fold(
+        _ => fail(),
+        ctx =>
+          ctx.castlingRights.whiteKingSide shouldBe true
+          ctx.castlingRights.whiteQueenSide shouldBe true
+          ctx.castlingRights.blackKingSide shouldBe true
+          ctx.castlingRights.blackQueenSide shouldBe true,
+      )

-    FenParserFastParse.parseFen("8/8/8/8/8/8/8/8 w Kq - 0 1").fold(_ => fail(), ctx =>
-      ctx.castlingRights.whiteKingSide shouldBe true
-      ctx.castlingRights.whiteQueenSide shouldBe false
-      ctx.castlingRights.blackKingSide shouldBe false
-      ctx.castlingRights.blackQueenSide shouldBe true
-    )
+    FenParserFastParse
+      .parseFen("8/8/8/8/8/8/8/8 w Kq - 0 1")
+      .fold(
+        _ => fail(),
+        ctx =>
+          ctx.castlingRights.whiteKingSide shouldBe true
+          ctx.castlingRights.whiteQueenSide shouldBe false
+          ctx.castlingRights.blackKingSide shouldBe false
+          ctx.castlingRights.blackQueenSide shouldBe true,
+      )

  test("parseFen tests all en passant files"):
    for file <- Seq("a", "b", "c", "d", "e", "f", "g", "h") do
-      FenParserFastParse.parseFen(s"8/8/8/8/8/8/8/8 w - ${file}3 0 1").fold(_ => fail(), ctx =>
-        ctx.enPassantSquare should not be empty
-      )
+      FenParserFastParse
+        .parseFen(s"8/8/8/8/8/8/8/8 w - ${file}3 0 1")
+        .fold(_ => fail(), ctx => ctx.enPassantSquare should not be empty)

  test("parseBoard with mixed pieces and empty squares"):
    FenParserFastParse.parseBoard("r1bqkb1r/pppppppp/2n2n2/8/8/2N2N2/PPPPPPPP/R1BQKB1R") should not be empty
@@ -29,10 +29,12 @@ class DefaultRulesTest extends AnyFunSuite with Matchers:

  test("pawn can capture diagonally"):
    // FEN: white pawn e4, black pawn d5
-    val fen      = "8/8/8/3p4/4P3/8/8/8 w - - 0 1"
-    val context  = FenParser.parseFen(fen).fold(_ => fail(), identity)
-    val moves    = rules.allLegalMoves(context)
-    val captures = moves.filter(m => m.from == Square(File.E, Rank.R4) && (m.moveType match { case _: MoveType.Normal => true; case _ => false }))
+    val fen     = "8/8/8/3p4/4P3/8/8/8 w - - 0 1"
+    val context = FenParser.parseFen(fen).fold(_ => fail(), identity)
+    val moves   = rules.allLegalMoves(context)
+    val captures = moves.filter(m =>
+      m.from == Square(File.E, Rank.R4) && (m.moveType match { case _: MoveType.Normal => true; case _ => false }),
+    )
    captures.exists(m => m.to == Square(File.D, Rank.R5)) shouldBe true

  test("pawn cannot move backward"):
@@ -90,6 +90,14 @@ dependencies {
    testRuntimeOnly("org.junit.platform:junit-platform-launcher")
 }

+configurations.scoverage {
+    resolutionStrategy.eachDependency {
+        if (requested.group == "org.scoverage" && requested.name.startsWith("scalac-scoverage-plugin_")) {
+            useTarget("${requested.group}:scalac-scoverage-plugin_2.13.16:2.3.0")
+        }
+    }
+}
+
 tasks.test {
    useJUnitPlatform {
        includeEngines("scalatest")
@@ -1,20 +1,15 @@
 package de.nowchess.ui

 import de.nowchess.chess.engine.GameEngine
-import de.nowchess.ui.terminal.TerminalUI
 import de.nowchess.ui.gui.ChessGUILauncher
+import de.nowchess.ui.terminal.TerminalUI

 /** Application entry point - starts both GUI and Terminal UI for the chess game. Both views subscribe to the same
  * GameEngine via Observer pattern.
  */
 object Main:
  def main(args: Array[String]): Unit =
-    // Create the core game engine (single source of truth)
    val engine = new GameEngine()
-
-    // Launch ScalaFX GUI in separate thread
    ChessGUILauncher.launch(engine)
-
-    // Create and start the terminal UI (blocks on main thread)
    val tui = new TerminalUI(engine)
    tui.start()
@@ -266,7 +266,8 @@ class ChessBoardView(val stage: Stage, private val engine: GameEngine) extends B
        case Some(piece) =>
          Seq(bgRect) ++ PieceSprites.loadPieceImage(piece, squareSize * 0.8).toSeq
        case None =>
-          Seq(bgRect)): Seq[scalafx.scene.Node]
+          Seq(bgRect)
+      ): Seq[scalafx.scene.Node]
    }

  def showMessage(msg: String): Unit =
@@ -30,9 +30,9 @@ class ChessGUIApp extends JFXApplication:
    stage.scene = new Scene {
      root = boardView
      // Load CSS if available
-      try {
+      try
        Option(getClass.getResource("/styles.css")).foreach(url => stylesheets.add(url.toExternalForm))
-      } catch {
+      catch {
        case _: Exception => // CSS is optional
      }
    }
@@ -1,8 +1,23 @@
 rootProject.name = "NowChessSystems"
+
+pluginManagement {
+    val quarkusPluginVersion: String by settings
+    val quarkusPluginId: String by settings
+    repositories {
+        mavenCentral()
+        gradlePluginPortal()
+        mavenLocal()
+    }
+    plugins {
+        id(quarkusPluginId) version quarkusPluginVersion
+    }
+}
+
 include(
    "modules:core",
    "modules:api",
    "modules:io",
    "modules:rule",
    "modules:ui",
-)
+    "modules:backcore"
+)