Issue/20 e2e movement fix

AGENTS.md

@@ -77,6 +77,11 @@ gamesung/
 - Reference the issue: "Closes #<number>"
 - Keep PRs small and focused
 
+### 7. Push
+
+- Push the working branch with `git push origin <branch-name>` (NOT `git push dev-rkb`, which is the contributor's personal fork and requires separate credentials).
+- Stop after pushing. Do not open a PR, do not merge, do not push to other remotes.
+
 ## Forbidden Actions
 
 - Do not commit secrets, API keys, or credentials

packages/server/bot/bot.go

@@ -15,15 +15,58 @@ var pieceValues = map[chess.PieceType]int{
 	chess.King:   20000,
 }
 
+// Piece-square tables (white-perspective, rank 8 at index 0 .. rank 1 at index 7).
+// Black mirrors the rank index. Values are added to the base material value.
+// Source: simplified evaluation tables (Tomasz Michniewski / Chess Programming Wiki).
+var pawnPST = [8][8]int{
+	{0, 0, 0, 0, 0, 0, 0, 0},
+	{50, 50, 50, 50, 50, 50, 50, 50},
+	{10, 10, 20, 30, 30, 20, 10, 10},
+	{5, 5, 10, 25, 25, 10, 5, 5},
+	{0, 0, 0, 20, 20, 0, 0, 0},
+	{5, -5, -10, 0, 0, -10, -5, 5},
+	{5, 10, 10, -20, -20, 10, 10, 5},
+	{0, 0, 0, 0, 0, 0, 0, 0},
+}
+
+var knightPST = [8][8]int{
+	{-50, -40, -30, -30, -30, -30, -40, -50},
+	{-40, -20, 0, 0, 0, 0, -20, -40},
+	{-30, 0, 10, 15, 15, 10, 0, -30},
+	{-30, 5, 15, 20, 20, 15, 5, -30},
+	{-30, 0, 15, 20, 20, 15, 0, -30},
+	{-30, 5, 10, 15, 15, 10, 5, -30},
+	{-40, -20, 0, 5, 5, 0, -20, -40},
+	{-50, -40, -30, -30, -30, -30, -40, -50},
+}
+
+// King PST for midgame: encourage castled position (corners), penalize center.
+var kingPST = [8][8]int{
+	{-30, -40, -40, -50, -50, -40, -40, -30},
+	{-30, -40, -40, -50, -50, -40, -40, -30},
+	{-30, -40, -40, -50, -50, -40, -40, -30},
+	{-30, -40, -40, -50, -50, -40, -40, -30},
+	{-20, -30, -30, -40, -40, -30, -30, -20},
+	{-10, -20, -20, -20, -20, -20, -20, -10},
+	{20, 20, 0, 0, 0, 0, 20, 20},
+	{20, 30, 10, 0, 0, 10, 30, 20},
+}
+
+const (
+	mateScore   = 99999
+	mobilityMul = 2
+)
+
 type Bot struct {
 	Depth int
+	rng   *rand.Rand
 }
 
 func NewBot(depth int) *Bot {
 	if depth < 1 {
 		depth = 2
 	}
-	return &Bot{Depth: depth}
+	return &Bot{Depth: depth, rng: rand.New(rand.NewSource(rand.Int63()))}
 }
 
 func (b *Bot) GetMove(game *chess.Game) *chess.Move {
@@ -36,27 +79,28 @@ func (b *Bot) GetMove(game *chess.Game) *chess.Move {
 		return b.pickBestMove(game, validMoves)
 	}
 
-	var bestMove *chess.Move
-	bestScore := -999999
+	bestScore := -mateScore - 1
+	candidates := []*chess.Move{}
 
 	for _, move := range validMoves {
-	 cloned := game.Clone()
+		cloned := game.Clone()
 		if err := cloned.Move(move); err != nil {
 			continue
 		}
 
-		score := -b.minimax(cloned, b.Depth-1, -999999, 999999)
+		score := -b.minimax(cloned, b.Depth-1, -mateScore, mateScore)
 		if score > bestScore {
 			bestScore = score
-			bestMove = move
+			candidates = []*chess.Move{move}
+		} else if score == bestScore {
+			candidates = append(candidates, move)
 		}
 	}
 
-	if bestMove == nil {
-		return validMoves[rand.Intn(len(validMoves))]
+	if len(candidates) == 0 {
+		return validMoves[b.rng.Intn(len(validMoves))]
 	}
-
-	return bestMove
+	return candidates[b.rng.Intn(len(candidates))]
 }
 
 func (b *Bot) minimax(game *chess.Game, depth int, alpha, beta int) int {
@@ -69,7 +113,7 @@ func (b *Bot) minimax(game *chess.Game, depth int, alpha, beta int) int {
 		return b.evaluate(game)
 	}
 
-	bestScore := -999999
+	bestScore := -mateScore - 1
 	for _, move := range validMoves {
 		cloned := game.Clone()
 		if err := cloned.Move(move); err != nil {
@@ -97,19 +141,20 @@ func (b *Bot) evaluate(game *chess.Game) int {
 
 	var score int
 
-	for square := chess.A1; square <= chess.H8; square++ {
-		piece := board.Piece(square)
+	for sq := chess.A1; sq <= chess.H8; sq++ {
+		piece := board.Piece(sq)
 		if piece == chess.NoPiece {
 			continue
 		}
 
-		value := pieceValues[piece.Type()]
+		score += pieceScore(piece, sq)
+	}
 
-		if piece.Color() == chess.White {
-			score += value
-		} else {
-			score -= value
-		}
+	moves := pos.ValidMoves()
+	if pos.Turn() == chess.White {
+		score += len(moves) * mobilityMul
+	} else {
+		score -= len(moves) * mobilityMul
 	}
 
 	if pos.Turn() == chess.Black {
@@ -120,8 +165,8 @@ func (b *Bot) evaluate(game *chess.Game) int {
 }
 
 func (b *Bot) pickBestMove(game *chess.Game, moves []*chess.Move) *chess.Move {
-	var bestMove *chess.Move
-	bestScore := -999999
+	bestScore := -mateScore - 1
+	candidates := []*chess.Move{}
 
 	for _, move := range moves {
 		cloned := game.Clone()
@@ -132,13 +177,41 @@ func (b *Bot) pickBestMove(game *chess.Game, moves []*chess.Move) *chess.Move {
 		score := b.evaluate(cloned)
 		if score > bestScore {
 			bestScore = score
-			bestMove = move
+			candidates = []*chess.Move{move}
+		} else if score == bestScore {
+			candidates = append(candidates, move)
 		}
 	}
 
-	if bestMove == nil {
-		return moves[rand.Intn(len(moves))]
+	if len(candidates) == 0 {
+		return moves[b.rng.Intn(len(moves))]
 	}
+	return candidates[b.rng.Intn(len(candidates))]
+}
 
-	return bestMove
+func pieceScore(piece chess.Piece, sq chess.Square) int {
+	base := pieceValues[piece.Type()]
+
+	var pst int
+	rank := sq.Rank()
+	file := sq.File()
+	rankIdx := 7 - int(rank)
+	if piece.Color() == chess.Black {
+		rankIdx = int(rank)
+	}
+
+	switch piece.Type() {
+	case chess.Pawn:
+		pst = pawnPST[rankIdx][int(file)]
+	case chess.Knight:
+		pst = knightPST[rankIdx][int(file)]
+	case chess.King:
+		pst = kingPST[rankIdx][int(file)]
+	}
+
+	value := base + pst
+	if piece.Color() == chess.White {
+		return value
+	}
+	return -value
 }

packages/server/bot/bot_test.go

@@ -0,0 +1,38 @@
+package bot
+
+import (
+	"testing"
+
+	"github.com/notnil/chess"
+)
+
+func TestGetMoveReturnsNonKnightFromStart(t *testing.T) {
+	notKnight := 0
+	for i := 0; i < 50; i++ {
+		g := chess.NewGame()
+		b := NewBot(2)
+		m := b.GetMove(g)
+		if m == nil {
+			t.Fatalf("expected a move, got nil")
+		}
+		p := g.Position().Board().Piece(m.S1())
+		if p.Type() != chess.Knight {
+			notKnight++
+		}
+	}
+	if notKnight == 0 {
+		t.Fatalf("expected bot to play at least one non-knight move across 50 trials")
+	}
+}
+
+func TestGetMoveReturnsValidMove(t *testing.T) {
+	g := chess.NewGame()
+	b := NewBot(2)
+	m := b.GetMove(g)
+	if m == nil {
+		t.Fatalf("expected a move, got nil")
+	}
+	if err := g.Move(m); err != nil {
+		t.Fatalf("bot returned an illegal move: %v", err)
+	}
+}

packages/server/game/game.go

@@ -88,7 +88,7 @@ func (g *Game) MakeMove(moveStr string) (string, error) {
 		return "", ErrGameNotPlaying
 	}
 
-	move, err := chess.AlgebraicNotation{}.Decode(g.Board.Position(), moveStr)
+	move, err := chess.UCINotation{}.Decode(g.Board.Position(), moveStr)
 	if err != nil {
 		return "", ErrInvalidMove
 	}
@@ -143,7 +143,7 @@ func (g *Game) GetBotMove() (string, error) {
 		return "", ErrNoValidMoves
 	}
 
-	moveStr := chess.AlgebraicNotation{}.Encode(g.Board.Position(), move)
+	moveStr := chess.UCINotation{}.Encode(g.Board.Position(), move)
 
 	if err := g.Board.Move(move); err != nil {
 		return "", ErrInvalidMove

packages/web/package.json

@@ -6,8 +6,9 @@
     "dev": "next dev",
     "build": "next build",
     "start": "next start",
-    "lint": "eslint .",
-    "typecheck": "tsc --noEmit"
+    "lint": "eslint src/",
+    "typecheck": "tsc --noEmit",
+    "test:e2e": "playwright test"
   },
   "dependencies": {
     "clsx": "^2.1.1",
@@ -19,6 +20,7 @@
   },
   "devDependencies": {
     "@eslint/eslintrc": "^3.3.1",
+    "@playwright/test": "^1.61.0",
     "@tailwindcss/postcss": "^4.3.1",
     "@types/node": "^22.15.3",
     "@types/react": "19.2.17",
@@ -27,6 +29,7 @@
     "@typescript-eslint/parser": "^8.32.0",
     "eslint": "^9.27.0",
     "eslint-config-next": "^15.3.3",
+    "playwright": "^1.61.0",
     "tailwindcss": "^4.3.1",
     "typescript": "^5.8.3"
   }

packages/web/playwright.config.ts

@@ -0,0 +1,20 @@
+import { defineConfig, devices } from "@playwright/test";
+
+export default defineConfig({
+  testDir: "./tests",
+  fullyParallel: false,
+  retries: 0,
+  workers: 1,
+  reporter: [["list"]],
+  use: {
+    baseURL: "http://localhost:3000",
+    trace: "on-first-retry",
+    headless: true,
+  },
+  projects: [
+    {
+      name: "chromium",
+      use: { ...devices["Desktop Chrome"] },
+    },
+  ],
+});