feat: refactor IO module to API structure and add FEN export functionality

2026-04-21 21:37:43 +02:00
parent b4d197a9b2
commit 96d4f995fa
20 changed files with 166 additions and 144 deletions
@@ -0,0 +1,58 @@
+package de.nowchess.rules.pgn
+
+import de.nowchess.api.board.*
+import de.nowchess.api.game.GameContext
+import de.nowchess.api.io.GameContextExport
+import de.nowchess.api.move.{Move, MoveType, PromotionPiece}
+import de.nowchess.rules.sets.DefaultRules
+
+object PgnExporter extends GameContextExport:
+
+  def exportGameContext(context: GameContext): String =
+    exportGame(
+      Map("Event" -> "?", "White" -> "?", "Black" -> "?", "Result" -> "*"),
+      context.moves,
+    )
+
+  def exportGame(headers: Map[String, String], moves: List[Move]): String =
+    val headerLines = headers.map { case (k, v) => s"""[$k "$v"]""" }.mkString("\n")
+    val moveText    = if moves.isEmpty then "" else buildMoveText(headers, moves)
+    if headerLines.isEmpty then moveText
+    else if moveText.isEmpty then headerLines
+    else s"$headerLines\n\n$moveText"
+
+  private def buildMoveText(headers: Map[String, String], moves: List[Move]): String =
+    val contexts  = moves.scanLeft(GameContext.initial)((ctx, move) => DefaultRules.applyMove(ctx)(move))
+    val sanMoves  = moves.zip(contexts).map { case (move, ctx) => moveToAlgebraic(move, ctx.board) }
+    val grouped   = sanMoves.zipWithIndex.groupBy(_._2 / 2)
+    val moveLines = grouped.toList.sortBy(_._1).map { case (n, pairs) =>
+      val w = pairs.find(_._2 % 2 == 0).map(_._1).getOrElse("")
+      val b = pairs.find(_._2 % 2 == 1).map(_._1).getOrElse("")
+      if b.isEmpty then s"${n + 1}. $w" else s"${n + 1}. $w $b"
+    }
+    moveLines.mkString(" ") + s" ${headers.getOrElse("Result", "*")}"
+
+  private def moveToAlgebraic(move: Move, boardBefore: Board): String =
+    move.moveType match
+      case MoveType.CastleKingside  => "O-O"
+      case MoveType.CastleQueenside => "O-O-O"
+      case MoveType.EnPassant       => s"${move.from.file.toString.toLowerCase}x${move.to}"
+      case MoveType.Promotion(pp) =>
+        val suffix    = pp match
+          case PromotionPiece.Queen  => "=Q"
+          case PromotionPiece.Rook   => "=R"
+          case PromotionPiece.Bishop => "=B"
+          case PromotionPiece.Knight => "=N"
+        val isCapture = boardBefore.pieceAt(move.to).isDefined
+        if isCapture then s"${move.from.file.toString.toLowerCase}x${move.to}$suffix"
+        else s"${move.to}$suffix"
+      case MoveType.Normal(isCapture) =>
+        val dest   = move.to.toString
+        val capStr = if isCapture then "x" else ""
+        boardBefore.pieceAt(move.from).map(_.pieceType).getOrElse(PieceType.Pawn) match
+          case PieceType.Pawn   => if isCapture then s"${move.from.file.toString.toLowerCase}x$dest" else dest
+          case PieceType.Knight => s"N$capStr$dest"
+          case PieceType.Bishop => s"B$capStr$dest"
+          case PieceType.Rook   => s"R$capStr$dest"
+          case PieceType.Queen  => s"Q$capStr$dest"
+          case PieceType.King   => s"K$capStr$dest"