working fen

board/fen.go

@@ -29,6 +29,7 @@ func (b Board) ToFen() string {
 				// empty squares we have encountered so far
 				if emptyCounter > 0 {
 					sb.WriteString(strconv.Itoa(emptyCounter))
+					emptyCounter = 0
 				}
 			}
 
@@ -40,6 +41,7 @@ func (b Board) ToFen() string {
 		// empty squares dump the number of empty squares
 		if emptyCounter > 0 {
 			sb.WriteString(strconv.Itoa(emptyCounter))
+			emptyCounter = 0
 		}
 
 		if r > 0 {
@@ -68,18 +70,21 @@ func FromFen(fen string) (Board, error) {
 	ranks := strings.Split(parts[0], "/")
 
 	for r, rank := range ranks {
-		for c, char := range rank {
+		col := 0
+		for _, char := range rank {
 			// Empty squares, append n empty pieces into the board
 			if char >= '1' && char <= '8' {
 				n := int(char - '0')
 				for i := 0; i < n; i++ {
-					b.Grid[7-r][c+i] = piece.Empty()
+					b.Grid[7-r][col] = piece.Empty()
+					col += 1
 				}
 				continue
 			}
 
 			p := piece.FromFen(string(char))
-			b.Grid[7-r][c] = p
+			b.Grid[7-r][col] = p
+			col += 1
 		}
 	}
 

board/fen_test.go

@@ -33,3 +33,30 @@ func TestFen(t *testing.T) {
 		t.Errorf("FromFen()\nActual = %s\nTarget = %s", fromFen.ToFen(), fen)
 	}
 }
+
+func TestFenMoved(t *testing.T) {
+	fen := "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR w KQkq - 0 1"
+	grid := [8][8]Piece{
+		{RW, NW, BW, QW, KW, BW, NW, RW},
+		{PW, PW, PW, PW, OO, PW, PW, PW},
+		{OO, OO, OO, OO, OO, OO, OO, OO},
+		{OO, OO, OO, OO, PW, OO, OO, OO},
+		{OO, OO, OO, OO, OO, OO, OO, OO},
+		{OO, OO, OO, OO, OO, OO, OO, OO},
+		{PB, PB, PB, PB, PB, PB, PB, PB},
+		{RB, NB, BB, QB, KB, BB, NB, RB},
+	}
+	b := board.Board{
+		Grid: grid,
+		Turn: White,
+	}
+
+	if b.ToFen() != fen {
+		t.Errorf("ToFen()\nActual = %s\nTarget = %s", b.ToFen(), fen)
+	}
+
+	fromFen, _ := board.FromFen(fen)
+	if fromFen.ToFen() != fen {
+		t.Errorf("FromFen()\nActual = %s\nTarget = %s", fromFen, fen)
+	}
+}

board/move.go

@@ -0,0 +1,13 @@
+package board
+
+import (
+	"github.com/maaslalani/gambit/piece"
+	"github.com/maaslalani/gambit/position"
+)
+
+func (b *Board) Move(from, to string) {
+	f := position.ToPosition(from)
+	t := position.ToPosition(to)
+	b.Grid[t.Row][t.Col] = b.Grid[f.Row][f.Col]
+	b.Grid[f.Row][f.Col] = piece.Empty()
+}

board/move_test.go

@@ -0,0 +1,19 @@
+package board
+
+import (
+	"testing"
+
+	. "github.com/maaslalani/gambit/squares"
+)
+
+func TestMove(t *testing.T) {
+	initial := "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"
+	expected := "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR w KQkq - 0 1"
+	b, _ := FromFen(initial)
+	b.reversed = true
+	b.Move(E2, E4)
+
+	if b.ToFen() != expected {
+		t.Errorf("Expected %s, got %s", expected, b.ToFen())
+	}
+}

game/game.go

@@ -10,8 +10,9 @@ type model struct {
 }
 
 func Model() tea.Model {
+	b, _ := board.FromFen("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1")
 	return model{
-		board: board.New(),
+		board: b,
 	}
 }