From b9b7937a961b6779cba81374c78332b15a4277ea Mon Sep 17 00:00:00 2001
From: satr14 <admin@satr14.my.id>
Date: Sat, 25 Jul 2026 21:56:38 +0700
Subject: [PATCH 1/6] optimize to use 1 less bit for color

---
 src/lib/chess/types.ts | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/lib/chess/types.ts b/src/lib/chess/types.ts
index dde6bce..e033ad7 100644
--- a/src/lib/chess/types.ts
+++ b/src/lib/chess/types.ts
@@ -2,6 +2,7 @@ import { Game } from "./utils";
 export type GameListener = (board: Game) => void;
 
 export enum Piece {
+  // bit 0-2: piece type (0-6)
   EMPTY = 0,
   KING = 1,
   QUEEN = 2,
@@ -10,8 +11,9 @@ export enum Piece {
   KNIGHT = 5,
   PAWN = 6,
 
-  WHITE = 8,
-  BLACK = 16,
+  // bit 3: color (0-1)
+  WHITE = 0,
+  BLACK = 8,
 }
 
 export const CHAR_TO_PIECE: Record<string, number> = {

From 125356d3219b68ea1633c81d25abb021fd08348c Mon Sep 17 00:00:00 2001
From: satr14 <admin@satr14.my.id>
Date: Sun, 26 Jul 2026 08:35:41 +0700
Subject: [PATCH 2/6] use bit shifts

---
 src/lib/chess/types.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/lib/chess/types.ts b/src/lib/chess/types.ts
index e033ad7..7f943e9 100644
--- a/src/lib/chess/types.ts
+++ b/src/lib/chess/types.ts
@@ -12,8 +12,8 @@ export enum Piece {
   PAWN = 6,
 
   // bit 3: color (0-1)
-  WHITE = 0,
-  BLACK = 8,
+  WHITE = 0<<3,
+  BLACK = 1<<3,
 }
 
 export const CHAR_TO_PIECE: Record<string, number> = {

From 3f9c5afb6bfd1506debdc88a2e90289a7d872671 Mon Sep 17 00:00:00 2001
From: satr14 <admin@satr14.my.id>
Date: Sun, 26 Jul 2026 09:10:38 +0700
Subject: [PATCH 3/6] rename to game.ts

---
 src/lib/chess/{utils.ts => game.ts} | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename src/lib/chess/{utils.ts => game.ts} (100%)

diff --git a/src/lib/chess/utils.ts b/src/lib/chess/game.ts
similarity index 100%
rename from src/lib/chess/utils.ts
rename to src/lib/chess/game.ts

From fb70f9ab1b37eb22d0054b3074a96e466e8fa122 Mon Sep 17 00:00:00 2001
From: satr14 <admin@satr14.my.id>
Date: Sun, 26 Jul 2026 09:19:02 +0700
Subject: [PATCH 4/6] update imports

---
 src/lib/chess/types.ts  | 2 +-
 src/routes/+page.svelte | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/lib/chess/types.ts b/src/lib/chess/types.ts
index 7f943e9..679d494 100644
--- a/src/lib/chess/types.ts
+++ b/src/lib/chess/types.ts
@@ -1,4 +1,4 @@
-import { Game } from "./utils";
+import { Game } from "./game";
 export type GameListener = (board: Game) => void;
 
 export enum Piece {
diff --git a/src/routes/+page.svelte b/src/routes/+page.svelte
index ea6797a..51577d3 100644
--- a/src/routes/+page.svelte
+++ b/src/routes/+page.svelte
@@ -1,6 +1,6 @@
 <script lang="ts">
   import { PIECE_TO_CHAR } from "$lib/chess/types";
-  import { boardToAscii, Game, startFEN } from "$lib/chess/utils";
+  import { boardToAscii, Game, startFEN } from "$lib/chess/game";
 
   let showIndex = $state(false);
   let fen = $state(startFEN);

From e20f297fc6216a92f1df576e3527863c4205d609 Mon Sep 17 00:00:00 2001
From: satr14 <admin@satr14.my.id>
Date: Sun, 26 Jul 2026 09:19:41 +0700
Subject: [PATCH 5/6] tweak piece enum

---
 src/lib/chess/types.ts | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/lib/chess/types.ts b/src/lib/chess/types.ts
index 679d494..5acc114 100644
--- a/src/lib/chess/types.ts
+++ b/src/lib/chess/types.ts
@@ -4,12 +4,12 @@ export type GameListener = (board: Game) => void;
 export enum Piece {
   // bit 0-2: piece type (0-6)
   EMPTY = 0,
-  KING = 1,
-  QUEEN = 2,
-  ROOK = 3,
-  BISHOP = 4,
-  KNIGHT = 5,
-  PAWN = 6,
+  QUEEN = 1,
+  ROOK = 2,
+  BISHOP = 3,
+  KNIGHT = 4,
+  PAWN = 5,
+  KING = 6,
 
   // bit 3: color (0-1)
   WHITE = 0<<3,

From 3aa70f903e2b2812087eb7b47bbbd9117f3530ee Mon Sep 17 00:00:00 2001
From: satr14 <admin@satr14.my.id>
Date: Sun, 26 Jul 2026 09:31:24 +0700
Subject: [PATCH 6/6] movegen enums

---
 src/lib/chess/types.ts | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/src/lib/chess/types.ts b/src/lib/chess/types.ts
index 5acc114..4db0114 100644
--- a/src/lib/chess/types.ts
+++ b/src/lib/chess/types.ts
@@ -1,6 +1,33 @@
 import { Game } from "./game";
 export type GameListener = (board: Game) => void;
 
+export enum MoveFlag {
+  NORMAL = 0,
+  PAWN_DOUBLE = 1,
+  EN_PASSANT = 2,
+  CASTLE_KING = 3,
+  CASTLE_QUEEN = 4,
+  PROMOTION = 5,
+  CAPTURE = 6,
+  CAPTURE_PROMOTE = 7,
+}
+
+export enum Promotion {
+  QUEEN = 0,
+  ROOK = 1,
+  BISHOP = 2,
+  KNIGHT = 3,
+}
+
+export enum Capture {
+  NONE = 0,
+  PAWN = 1,
+  KNIGHT = 2,
+  BISHOP = 3,
+  ROOK = 4,
+  QUEEN = 5,
+}
+
 export enum Piece {
   // bit 0-2: piece type (0-6)
   EMPTY = 0,