feat: refactor AlphaBetaSearch and ClassicalBot for improved evaluation and organization

modules/bot/src/main/scala/de/nowchess/bot/BotController.scala

@@ -1,5 +1,7 @@
 package de.nowchess.bot
 
+import de.nowchess.bot.bots.ClassicalBot
+
 object BotController {
 
   private var bots: Map[String, Bot] = Map.empty

modules/bot/src/main/scala/de/nowchess/bot/ai/Weights.scala

@@ -0,0 +1,12 @@
+package de.nowchess.bot.ai
+
+import de.nowchess.api.game.GameContext
+
+trait Weights {
+  
+  def CHECKMATE_SCORE: Int
+  def DRAW_SCORE: Int
+  
+  def evaluate(context: GameContext): Int
+
+}

modules/bot/src/main/scala/de/nowchess/bot/bots/ClassicalBot.scala

@@ -1,7 +1,11 @@
-package de.nowchess.bot
+package de.nowchess.bot.bots
 
 import de.nowchess.api.game.GameContext
 import de.nowchess.api.move.Move
+import de.nowchess.bot.bots.classic.EvaluationClassic
+import de.nowchess.bot.logic.AlphaBetaSearch
+import de.nowchess.bot.util.PolyglotBook
+import de.nowchess.bot.{Bot, BotDifficulty}
 import de.nowchess.rules.RuleSet
 import de.nowchess.rules.sets.DefaultRules
 
@@ -11,7 +15,7 @@ final class ClassicalBot(
   book: Option[PolyglotBook] = None
 ) extends Bot:
 
-  private val search: AlphaBetaSearch = AlphaBetaSearch(rules)
+  private val search: AlphaBetaSearch = AlphaBetaSearch(rules, weights = EvaluationClassic)
   private val TIME_BUDGET_MS = 1000L
 
   override val name: String = s"ClassicalBot(${difficulty.toString})"

modules/bot/src/main/scala/de/nowchess/bot/bots/classic/EvaluationClassic.scala

@@ -1,9 +1,10 @@
-package de.nowchess.bot
+package de.nowchess.bot.bots.classic
 
 import de.nowchess.api.board.{Color, PieceType, Square}
 import de.nowchess.api.game.GameContext
+import de.nowchess.bot.ai.Weights
 
-object Evaluation:
+object EvaluationClassic extends Weights:
 
   val CHECKMATE_SCORE: Int = 10_000_000
   val DRAW_SCORE: Int = 0

modules/bot/src/main/scala/de/nowchess/bot/logic/AlphaBetaSearch.scala

@@ -1,18 +1,23 @@
-package de.nowchess.bot
+package de.nowchess.bot.logic
 
 import de.nowchess.api.board.PieceType
 import de.nowchess.api.game.GameContext
 import de.nowchess.api.move.{Move, MoveType}
+import de.nowchess.bot.ai.Weights
+import de.nowchess.bot.logic.{MoveOrdering, TTEntry, TTFlag, TranspositionTable}
+import de.nowchess.bot.util.ZobristHash
 import de.nowchess.rules.RuleSet
 import de.nowchess.rules.sets.DefaultRules
-import scala.concurrent.{ExecutionContext, Future}
-import scala.concurrent.ExecutionContext.Implicits.global
+
 import java.util.concurrent.ForkJoinPool
 import java.util.concurrent.atomic.AtomicReference
+import scala.concurrent.ExecutionContext.Implicits.global
+import scala.concurrent.{ExecutionContext, Future}
 
 final class AlphaBetaSearch(
   rules: RuleSet = DefaultRules,
   tt: TranspositionTable = TranspositionTable(),
+  weights: Weights,
   numThreads: Int = Runtime.getRuntime().availableProcessors()
 ):
 
@@ -135,7 +140,7 @@ final class AlphaBetaSearch(
     // Periodic time check
     nodeCount += 1
     if nodeCount % TIME_CHECK_FREQUENCY == 0 && isOutOfTime() then
-      return (Evaluation.evaluate(context), None)
+      return (weights.evaluate(context), None)
 
     val hash = ZobristHash.hash(context)
 
@@ -159,13 +164,13 @@ final class AlphaBetaSearch(
     val legalMoves = rules.allLegalMoves(context)
     if legalMoves.isEmpty then
       val score = if rules.isCheckmate(context) then
-        -(Evaluation.CHECKMATE_SCORE - ply)
+        -(weights.CHECKMATE_SCORE - ply)
       else
-        Evaluation.DRAW_SCORE
+        weights.DRAW_SCORE
       return (score, None)
 
     if rules.isInsufficientMaterial(context) || rules.isFiftyMoveRule(context) then
-      return (Evaluation.DRAW_SCORE, None)
+      return (weights.DRAW_SCORE, None)
 
     // Leaf node: call quiescence
     if depth == 0 then
@@ -211,7 +216,7 @@ final class AlphaBetaSearch(
 
       // Futility pruning at frontier nodes: if static eval + margin is still below alpha, skip quiet moves
       if depth == 1 && isQuiet && moveNumber > 2 then
-        val staticEval = Evaluation.evaluate(context)
+        val staticEval = weights.evaluate(context)
         if staticEval + FUTILITY_MARGIN < alpha then
           moveNumber += 1
 
@@ -328,7 +333,7 @@ final class AlphaBetaSearch(
     beta: Int
   ): Int =
     // Stand-pat: evaluate current position
-    val standPat = Evaluation.evaluate(context)
+    val standPat = weights.evaluate(context)
     if standPat >= beta then
       return beta
 

modules/bot/src/main/scala/de/nowchess/bot/logic/MoveOrdering.scala

@@ -1,8 +1,9 @@
-package de.nowchess.bot
+package de.nowchess.bot.logic
 
 import de.nowchess.api.board.PieceType
 import de.nowchess.api.game.GameContext
 import de.nowchess.api.move.{Move, MoveType, PromotionPiece}
+
 import scala.collection.mutable
 
 object MoveOrdering:

modules/bot/src/main/scala/de/nowchess/bot/logic/TranspositionTable.scala

@@ -1,4 +1,4 @@
-package de.nowchess.bot
+package de.nowchess.bot.logic
 
 import de.nowchess.api.move.Move
 

modules/bot/src/main/scala/de/nowchess/bot/util/PolyglotBook.scala

@@ -1,8 +1,9 @@
-package de.nowchess.bot
+package de.nowchess.bot.util
 
-import de.nowchess.api.board.{Color, File, PieceType, Rank, Square}
+import de.nowchess.api.board.*
 import de.nowchess.api.game.GameContext
 import de.nowchess.api.move.{Move, MoveType, PromotionPiece}
+
 import java.io.{DataInputStream, FileInputStream}
 import scala.collection.mutable
 import scala.util.Random

modules/bot/src/main/scala/de/nowchess/bot/util/PolyglotHash.scala

@@ -1,4 +1,4 @@
-package de.nowchess.bot
+package de.nowchess.bot.util
 
 import de.nowchess.api.board.{Color, Piece, PieceType, Square}
 import de.nowchess.api.game.GameContext

modules/bot/src/main/scala/de/nowchess/bot/util/ZobristHash.scala

@@ -1,7 +1,8 @@
-package de.nowchess.bot
+package de.nowchess.bot.util
 
 import de.nowchess.api.board.{Color, File, PieceType, Square}
 import de.nowchess.api.game.GameContext
+
 import scala.util.Random
 
 object ZobristHash:

modules/bot/src/test/scala/de/nowchess/bot/AlphaBetaSearchTest.scala

@@ -3,6 +3,7 @@ package de.nowchess.bot
 import de.nowchess.api.board.{Board, Color, File, Piece, PieceType, Rank, Square}
 import de.nowchess.api.game.GameContext
 import de.nowchess.api.move.{Move, MoveType}
+import de.nowchess.bot.logic.AlphaBetaSearch
 import de.nowchess.rules.RuleSet
 import org.scalatest.funsuite.AnyFunSuite
 import org.scalatest.matchers.should.Matchers

modules/bot/src/test/scala/de/nowchess/bot/ClassicalBotTest.scala

@@ -3,6 +3,7 @@ package de.nowchess.bot
 import de.nowchess.api.board.Square
 import de.nowchess.api.game.GameContext
 import de.nowchess.api.move.Move
+import de.nowchess.bot.bots.ClassicalBot
 import de.nowchess.rules.RuleSet
 import org.scalatest.funsuite.AnyFunSuite
 import org.scalatest.matchers.should.Matchers

modules/bot/src/test/scala/de/nowchess/bot/EvaluationTest.scala

@@ -3,13 +3,14 @@ package de.nowchess.bot
 import de.nowchess.api.board.{Board, Color, File, Piece, PieceType, Rank, Square}
 import de.nowchess.api.game.GameContext
 import de.nowchess.api.board.Board
+import de.nowchess.bot.bots.classic.EvaluationClassic
 import org.scalatest.funsuite.AnyFunSuite
 import org.scalatest.matchers.should.Matchers
 
 class EvaluationTest extends AnyFunSuite with Matchers:
 
   test("initial position evaluates to tempo bonus"):
-    val eval = Evaluation.evaluate(GameContext.initial)
+    val eval = EvaluationClassic.evaluate(GameContext.initial)
     eval should equal(10)  // TEMPO_BONUS only
 
   test("remove white queen gives negative evaluation"):
@@ -18,7 +19,7 @@ class EvaluationTest extends AnyFunSuite with Matchers:
     val emptySquare = Square(File.D, Rank.R1)
     val boardWithoutQueen = board.pieces.filter((sq, _) => sq != emptySquare)
     val newContext = initial.withBoard(Board(boardWithoutQueen))
-    val eval = Evaluation.evaluate(newContext)
+    val eval = EvaluationClassic.evaluate(newContext)
     eval should be < 0
 
   test("remove black queen gives positive evaluation"):
@@ -27,7 +28,7 @@ class EvaluationTest extends AnyFunSuite with Matchers:
     val emptySquare = Square(File.D, Rank.R8)
     val boardWithoutQueen = board.pieces.filter((sq, _) => sq != emptySquare)
     val newContext = initial.withBoard(Board(boardWithoutQueen))
-    val eval = Evaluation.evaluate(newContext)
+    val eval = EvaluationClassic.evaluate(newContext)
     eval should be > 0
 
   test("different piece-square bonuses are applied"):
@@ -37,27 +38,27 @@ class EvaluationTest extends AnyFunSuite with Matchers:
     val knightD4 = GameContext.initial.withBoard(knightD4Board)
     val knightA1 = GameContext.initial.withBoard(knightA1Board)
 
-    val eval1 = Evaluation.evaluate(knightD4)
-    val eval2 = Evaluation.evaluate(knightA1)
+    val eval1 = EvaluationClassic.evaluate(knightD4)
+    val eval2 = EvaluationClassic.evaluate(knightA1)
     eval1 should be > eval2  // d4 (center) is better than a1 (corner) for knight
 
   test("all piece types are in material map"):
     PieceType.values.length should be > 0
     // Just verify evaluate works with all piece types
-    val eval = Evaluation.evaluate(GameContext.initial)
-    eval should not be (Evaluation.CHECKMATE_SCORE)
+    val eval = EvaluationClassic.evaluate(GameContext.initial)
+    eval should not be (EvaluationClassic.CHECKMATE_SCORE)
 
   test("CHECKMATE_SCORE and DRAW_SCORE are accessible"):
-    Evaluation.CHECKMATE_SCORE should equal(10_000_000)
-    Evaluation.DRAW_SCORE should equal(0)
+    EvaluationClassic.CHECKMATE_SCORE should equal(10_000_000)
+    EvaluationClassic.DRAW_SCORE should equal(0)
 
   test("active knight (center) scores higher than passive knight (corner)"):
     val knightD4Board = Board(Map(Square(File.D, Rank.R4) -> Piece.WhiteKnight))
     val knightA1Board = Board(Map(Square(File.A, Rank.R1) -> Piece.WhiteKnight))
     val knightD4Context = GameContext.initial.withBoard(knightD4Board)
     val knightA1Context = GameContext.initial.withBoard(knightA1Board)
-    val evalD4 = Evaluation.evaluate(knightD4Context)
-    val evalA1 = Evaluation.evaluate(knightA1Context)
+    val evalD4 = EvaluationClassic.evaluate(knightD4Context)
+    val evalA1 = EvaluationClassic.evaluate(knightA1Context)
     evalD4 should be > evalA1  // Knight on d4 (center, more mobility) should score higher
 
   test("bishop pair scores higher than bishop + knight"):
@@ -71,8 +72,8 @@ class EvaluationTest extends AnyFunSuite with Matchers:
     ))
     val pairContext = GameContext.initial.withBoard(bishopPairBoard)
     val knightContext = GameContext.initial.withBoard(bishopKnightBoard)
-    val evalPair = Evaluation.evaluate(pairContext)
-    val evalKnight = Evaluation.evaluate(knightContext)
+    val evalPair = EvaluationClassic.evaluate(pairContext)
+    val evalKnight = EvaluationClassic.evaluate(knightContext)
     evalPair should be > evalKnight  // Bishop pair should score higher
 
   test("rook on 7th rank scores higher than rook on 4th rank"):
@@ -80,6 +81,6 @@ class EvaluationTest extends AnyFunSuite with Matchers:
     val rook4thBoard = Board(Map(Square(File.A, Rank.R4) -> Piece.WhiteRook))
     val rook7thContext = GameContext.initial.withBoard(rook7thBoard)
     val rook4thContext = GameContext.initial.withBoard(rook4thBoard)
-    val eval7th = Evaluation.evaluate(rook7thContext)
-    val eval4th = Evaluation.evaluate(rook4thContext)
+    val eval7th = EvaluationClassic.evaluate(rook7thContext)
+    val eval4th = EvaluationClassic.evaluate(rook4thContext)
     eval7th should be > eval4th  // Rook on 7th rank should score higher

modules/bot/src/test/scala/de/nowchess/bot/MoveOrderingTest.scala

@@ -3,6 +3,7 @@ package de.nowchess.bot
 import de.nowchess.api.board.{Board, Color, File, Piece, PieceType, Rank, Square}
 import de.nowchess.api.game.GameContext
 import de.nowchess.api.move.{Move, MoveType, PromotionPiece}
+import de.nowchess.bot.logic.MoveOrdering
 import org.scalatest.funsuite.AnyFunSuite
 import org.scalatest.matchers.should.Matchers
 

modules/bot/src/test/scala/de/nowchess/bot/PolyglotBookTest.scala

@@ -3,9 +3,12 @@ package de.nowchess.bot
 import de.nowchess.api.board.{Color, File, Rank, Square}
 import de.nowchess.api.game.GameContext
 import de.nowchess.api.move.{Move, MoveType, PromotionPiece}
+import de.nowchess.bot.bots.ClassicalBot
+import de.nowchess.bot.util.{PolyglotBook, PolyglotHash}
 import de.nowchess.rules.sets.DefaultRules
 import org.scalatest.funsuite.AnyFunSuite
 import org.scalatest.matchers.should.Matchers
+
 import java.io.{DataOutputStream, FileOutputStream}
 import java.nio.file.Files
 import scala.util.Using

modules/bot/src/test/scala/de/nowchess/bot/PolyglotHashTest.scala

@@ -2,6 +2,7 @@ package de.nowchess.bot
 
 import de.nowchess.api.board.{Color, File, Rank, Square}
 import de.nowchess.api.game.GameContext
+import de.nowchess.bot.util.PolyglotHash
 import de.nowchess.io.fen.FenParser
 import org.scalatest.funsuite.AnyFunSuite
 import org.scalatest.matchers.should.Matchers

modules/bot/src/test/scala/de/nowchess/bot/TranspositionTableTest.scala

@@ -2,6 +2,7 @@ package de.nowchess.bot
 
 import de.nowchess.api.board.{File, Rank, Square}
 import de.nowchess.api.move.{Move, MoveType}
+import de.nowchess.bot.logic.{TTEntry, TTFlag, TranspositionTable}
 import org.scalatest.funsuite.AnyFunSuite
 import org.scalatest.matchers.should.Matchers
 

modules/bot/src/test/scala/de/nowchess/bot/ZobristHashTest.scala

@@ -1,8 +1,9 @@
 package de.nowchess.bot
 
-import de.nowchess.api.board.{Board, Color, CastlingRights, File, Piece, Rank, Square}
+import de.nowchess.api.board.{Board, CastlingRights, Color, File, Piece, Rank, Square}
 import de.nowchess.api.game.GameContext
 import de.nowchess.api.move.{Move, MoveType}
+import de.nowchess.bot.util.ZobristHash
 import org.scalatest.funsuite.AnyFunSuite
 import org.scalatest.matchers.should.Matchers