show ascii

src/lib/chess/types.ts

@@ -1,3 +1,6 @@
+import { Game } from "./utils";
+export type GameListener = (board: Game) => void;
+
 export enum Piece {
   EMPTY = 0,
   KING = 1,

src/lib/chess/utils.ts

@@ -1,8 +1,8 @@
-import { CHAR_TO_PIECE, Piece } from "./types";
+import { CHAR_TO_PIECE, Piece, PIECE_TO_CHAR, type GameListener } from "./types";
 
 export const startFEN = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0";
 
-export class Board {
+export class Game {
   public board = new Int8Array(8 ** 2);
   public details = {
     whiteTurn: true,
@@ -15,10 +15,21 @@ export class Board {
     fullMove: 0,
   };
 
+  private listeners = new Set<GameListener>();
+  
   constructor() {
     this.loadFEN();
   }
 
+  private notify() {
+    for (const listener of this.listeners) listener(this);
+  }
+
+  subscribe(listener: GameListener): () => void {
+    this.listeners.add(listener);
+    return () => this.listeners.delete(listener);
+  }
+  
   loadFEN(fen = startFEN) {
     const [position, turn, castling, enPassant, halfMove, fullMove] = fen.split(" ");
     
@@ -43,9 +54,20 @@ export class Board {
 
     this.details.halfMove = parseInt(halfMove);
     this.details.fullMove = parseInt(fullMove);
+
+    this.notify();
   }
 }
 
+export function boardToAscii(board: Int8Array): string {
+  let ascii = '';
+  board.forEach((piece, i) => {
+    if (i % 8 === 0 && i !== 0) ascii += '\n';
+    ascii += PIECE_TO_CHAR[piece];
+  });
+  return ascii;
+}
+
 function algebraicToIndex(algebraic: string): number {
   const FILE_TO_INDEX: Record<string, number> = {
     a: 0, b: 1, c: 2, d: 3, e: 4, f: 5, g: 6, h: 7,

src/routes/+page.svelte

@@ -1,20 +1,25 @@
 <script lang="ts">
   import { PIECE_TO_CHAR } from "$lib/chess/types";
-  import { Board, startFEN } from "$lib/chess/utils";
+  import { boardToAscii, Game, startFEN } from "$lib/chess/utils";
 
-  const board = new Board();
-
-  let boardView = $state(Array.from(board.board));
   let showIndex = $state(false);
   let fen = $state(startFEN);
 
+  const game = new Game();
+  let board = $state(Array.from(game.board));
+  let ascii = $state(boardToAscii(game.board));
+  let details = $state(game.details)
+
+  game.subscribe(updateView);
   function updateView() {
-    boardView = Array.from(board.board);
+    board = Array.from(game.board);
+    ascii = boardToAscii(game.board);
+    details = game.details; 
   }
 </script>
 
 <div class="grid grid-cols-8 gap-0 border-2">
-  {#each boardView as square, index}
+  {#each board as square, index}
     <div class="h-20 aspect-square relative flex justify-center items-center
       {index % 2 === Math.floor(index / 8) % 2 ? 'bg-orange-200 text-stone-800' : 'bg-amber-800 text-stone-200'}
     ">
@@ -24,6 +29,37 @@
   {/each}
 </div>
 <div>
+  <pre>{ascii}</pre>
+  <ul>
+    {#each Object.entries(game.details).filter(([k]) => k !== "castling") as [key, val]}
+      <li>
+        <strong>{key}</strong>:
+        {val.toString()}
+      </li>
+    {/each}
+    <table>
+      <thead>
+        <tr>
+          <th>Castling</th>
+          <th>King</th>
+          <th>Queen</th>
+        </tr>
+      </thead>
+      <tbody>
+        <tr>
+          <th>White</th>
+          <td>{game.details.castling.white.king}</td>
+          <td>{game.details.castling.white.queen}</td>
+        </tr>
+        <tr>
+          <th>Black</th>
+          <td>{game.details.castling.black.king}</td>
+          <td>{game.details.castling.black.queen}</td>
+        </tr>
+      </tbody>
+    </table>
+  </ul>
+  <hr class="border border-stone-200 my-4">
   <label class="block">
     show index
     <input type="checkbox" bind:checked={showIndex} />
@@ -31,10 +67,9 @@
   <label class="block">
     fen (enter to set):
     <input type="text" onkeypress={(e) => e.key === 'Enter' && (() => {
-      board.loadFEN(fen)
+      game.loadFEN(fen);
-      updateView()
     })()} bind:value={fen} />
   </label>
   <button onclick={updateView}>update view</button>
-  <button onclick={() => console.log(board)}>dump game to console</button>
+  <button onclick={() => console.log(game)}>dump game to console</button>
 </div>

src/routes/layout.css

@@ -4,3 +4,7 @@ html, body { @apply h-full; }
 body { @apply bg-gray-900 text-gray-100; }
 
 input, button { @apply bg-stone-200 text-stone-800 px-2 py-1 m-1 rounded; }
+
+table { @apply w-full border-collapse; }
+th, td { @apply border border-gray-700 px-2 py-1 text-center }
+th { @apply font-bold; }