chore: Refactor chess logic to MVC pattern and enhance board representation

modules/core/src/test/scala/de/nowchess/chess/ModelTest.scala

@@ -1,5 +1,7 @@
 package de.nowchess.chess
 
+import de.nowchess.api.board.{Board, Color, File, Piece, PieceType, Rank, Square}
+import de.nowchess.chess.view.unicode
 import org.junit.jupiter.api.Test
 import org.junit.jupiter.api.Assertions.*
 
@@ -10,9 +12,9 @@ class ModelTest:
     assertEquals(Color.White, Color.Black.opposite)
 
   @Test def squareLabel(): Unit =
-    assertEquals("a1", Square(0, 0).label)
-    assertEquals("e4", Square(4, 3).label)
-    assertEquals("h8", Square(7, 7).label)
+    assertEquals("a1", Square(File.A, Rank.R1).toString)
+    assertEquals("e4", Square(File.E, Rank.R4).toString)
+    assertEquals("h8", Square(File.H, Rank.R8).toString)
 
   @Test def pieceUnicode(): Unit =
     assertEquals("\u2654", Piece(Color.White, PieceType.King).unicode)
@@ -24,36 +26,34 @@ class ModelTest:
     assertEquals(32, Board.initial.pieces.size)
 
   @Test def initialWhiteKingOnE1(): Unit =
-    val e1 = Square(4, 0)
+    val e1 = Square(File.E, Rank.R1)
     assertEquals(Some(Piece(Color.White, PieceType.King)), Board.initial.pieceAt(e1))
 
   @Test def initialBlackQueenOnD8(): Unit =
-    val d8 = Square(3, 7)
+    val d8 = Square(File.D, Rank.R8)
     assertEquals(Some(Piece(Color.Black, PieceType.Queen)), Board.initial.pieceAt(d8))
 
   @Test def initialWhitePawnsOnRank2(): Unit =
-    for file <- 0 until 8 do
-      val sq = Square(file, 1)
+    for file <- File.values do
+      val sq = Square(file, Rank.R2)
       assertEquals(Some(Piece(Color.White, PieceType.Pawn)), Board.initial.pieceAt(sq))
 
   @Test def withMoveMovesAndLeavesOriginEmpty(): Unit =
-    val e2 = Square(4, 1)
-    val e4 = Square(4, 3)
+    val e2 = Square(File.E, Rank.R2)
+    val e4 = Square(File.E, Rank.R4)
     val (newBoard, captured) = Board.initial.withMove(e2, e4)
     assertEquals(None, newBoard.pieceAt(e2))
     assertEquals(Some(Piece(Color.White, PieceType.Pawn)), newBoard.pieceAt(e4))
     assertEquals(None, captured)
 
   @Test def withMoveCaptureReturnsCapture(): Unit =
-    // Place a black pawn on e4 and a white pawn already there via two moves
-    val e2 = Square(4, 1)
-    val e4 = Square(4, 3)
+    val e2 = Square(File.E, Rank.R2)
+    val e4 = Square(File.E, Rank.R4)
     val (board2, _) = Board.initial.withMove(e2, e4)
-    // Place black pawn on d4 manually for capture test
-    val d7 = Square(3, 6)
-    val d4 = Square(3, 3)
+    val d7 = Square(File.D, Rank.R7)
+    val d4 = Square(File.D, Rank.R4)
     val (board3, _) = board2.withMove(d7, d4)
-    // Now white pawn on e4 captures black pawn on d4 (diagonal — no legality check)
+    // White pawn on e4 captures black pawn on d4 (diagonal — no legality check)
     val (board4, cap) = board3.withMove(e4, d4)
     assertEquals(Some(Piece(Color.Black, PieceType.Pawn)), cap)
     assertEquals(Some(Piece(Color.White, PieceType.Pawn)), board4.pieceAt(d4))

modules/core/src/test/scala/de/nowchess/chess/ParserTest.scala

@@ -1,18 +1,20 @@
 package de.nowchess.chess
 
+import de.nowchess.api.board.{File, Rank, Square}
+import de.nowchess.chess.controller.Parser
 import org.junit.jupiter.api.Test
 import org.junit.jupiter.api.Assertions.*
 
 class ParserTest:
 
   @Test def parsesValidMove(): Unit =
-    assertEquals(Some((Square(4, 1), Square(4, 3))), Parser.parseMove("e2e4"))
+    assertEquals(Some((Square(File.E, Rank.R2), Square(File.E, Rank.R4))), Parser.parseMove("e2e4"))
 
   @Test def parsesKnightMove(): Unit =
-    assertEquals(Some((Square(6, 0), Square(5, 2))), Parser.parseMove("g1f3"))
+    assertEquals(Some((Square(File.G, Rank.R1), Square(File.F, Rank.R3))), Parser.parseMove("g1f3"))
 
   @Test def ignoresExtraWhitespace(): Unit =
-    assertEquals(Some((Square(4, 1), Square(4, 3))), Parser.parseMove("  e2e4  "))
+    assertEquals(Some((Square(File.E, Rank.R2), Square(File.E, Rank.R4))), Parser.parseMove("  e2e4  "))
 
   @Test def rejectsShortInput(): Unit =
     assertEquals(None, Parser.parseMove("e2e"))
@@ -27,5 +29,5 @@ class ParserTest:
     assertEquals(None, Parser.parseMove("e9e4"))
 
   @Test def parsesUppercaseAsInvalid(): Unit =
-    // uppercase files are out of range after toLowerCase — stays lowercase internally
-    assertEquals(Some((Square(4, 1), Square(4, 3))), Parser.parseMove("E2E4"))
+    // Input is lowercased before parsing, so "E2E4" -> "e2e4" -> valid
+    assertEquals(Some((Square(File.E, Rank.R2), Square(File.E, Rank.R4))), Parser.parseMove("E2E4"))

modules/core/src/test/scala/de/nowchess/chess/RendererTest.scala

@@ -1,5 +1,7 @@
 package de.nowchess.chess
 
+import de.nowchess.api.board.Board
+import de.nowchess.chess.view.Renderer
 import org.junit.jupiter.api.Test
 import org.junit.jupiter.api.Assertions.*