WIP

src/game/Game.ts

@@ -1,10 +1,21 @@
+import { PieceType } from "./../types";
 import { Chess, ChessInstance, Move } from "chess.js";
 import { cleanPGN } from "./PGNHelpers";
 
+export type MoveWithPly = Move & { ply: number; end: number };
+
+const MATERIAL_VALUE: Map<PieceType, number> = new Map([
+  ["q", 9],
+  ["r", 5],
+  ["b", 3],
+  ["n", 3],
+  ["p", 1],
+]);
+
 class Game {
   private game: ChessInstance;
   private replay: ChessInstance;
-  private moves: Move[];
+  private moves: MoveWithPly[];
   private currentPly: number = 0;
 
   constructor() {
@@ -16,7 +27,15 @@ class Game {
   loadPGN(pgn: string) {
     this.game.load_pgn(cleanPGN(pgn));
     this.game.delete_comments();
-    this.moves = this.game.history({ verbose: true });
+
+    const moves = this.game.history({ verbose: true });
+
+    this.moves = moves.map((item, i) => ({
+      ...item,
+      ply: i,
+      end: moves.length - 1 - i,
+    }));
+
     this.currentPly = 0;
 
     const fen = this.game.header().FEN;
@@ -58,20 +77,55 @@ class Game {
 
   last() {
     while (this.next()) {}
+    return this.moves[this.moves.length - 1];
   }
 
   first() {
     while (this.prev()) {}
+    return this.moves[0];
   }
 
   goto(ply: number) {
     if (ply === this.currentPly || ply < 0 || ply > this.moves.length - 1) {
-      return;
+      return null;
     }
 
     while (this.currentPly !== ply) {
       ply > this.currentPly ? this.next() : this.prev();
     }
+
+    return this.moves[ply];
+  }
+
+  materialInfo() {
+    const pieces = this.getBoardData().flat().filter(Boolean);
+
+    const sum = { w: 0, b: 0 };
+    const imbalance = {
+      w: { p: 0, n: 0, b: 0, r: 0, q: 0 },
+      b: { p: 0, n: 0, b: 0, r: 0, q: 0 },
+    };
+    const material = {
+      w: { p: 0, n: 0, b: 0, r: 0, q: 0 },
+      b: { p: 0, n: 0, b: 0, r: 0, q: 0 },
+    };
+
+    for (const piece of pieces) {
+      if (piece !== null && piece.type !== "k") {
+        sum[piece.color] += MATERIAL_VALUE.get(piece.type) ?? 0;
+        material[piece.color][piece.type] += 1;
+
+        const oppositeColor = piece.color === "b" ? "w" : "b";
+
+        if (imbalance[oppositeColor][piece.type] === 0) {
+          imbalance[piece.color][piece.type] += 1;
+        } else {
+          imbalance[oppositeColor][piece.type] -= 1;
+        }
+      }
+    }
+
+    return { sum, imbalance, material, diff: sum.w - sum.b };
   }
 
   getBoardData() {
@@ -87,4 +141,6 @@ class Game {
   }
 }
 
+export type Material = ReturnType<Game["materialInfo"]>;
+
 export default Game;