feat : add lichess cloud eval

src/lib/engine/helpers/parseResults.ts

@@ -57,7 +57,7 @@ export const parseEvaluationResults = (
   return parsedResults;
 };
 
-const sortLines = (a: LineEval, b: LineEval): number => {
+export const sortLines = (a: LineEval, b: LineEval): number => {
   if (a.mate !== undefined && b.mate !== undefined) {
     return a.mate - b.mate;
   }

src/lib/engine/uciEngine.ts

@@ -7,6 +7,7 @@ import {
 import { parseEvaluationResults } from "./helpers/parseResults";
 import { computeAccuracy } from "./helpers/accuracy";
 import { getWhoIsCheckmated } from "../chess";
+import { getLichessEval } from "../lichess";
 
 export abstract class UciEngine {
   private worker: Worker;
@@ -143,6 +144,14 @@ export abstract class UciEngine {
   private async evaluatePosition(fen: string, depth = 16): Promise<MoveEval> {
     console.log(`Evaluating position: ${fen}`);
 
+    const lichessEval = await getLichessEval(fen, this.multiPv);
+    if (
+      lichessEval.lines.length >= this.multiPv &&
+      lichessEval.lines[0].depth >= depth
+    ) {
+      return lichessEval;
+    }
+
     const results = await this.sendCommands(
       [`position fen ${fen}`, `go depth ${depth}`],
       "bestmove"
@@ -161,6 +170,8 @@ export abstract class UciEngine {
   }: EvaluatePositionWithUpdateParams): Promise<void> {
     this.throwErrorIfNotReady();
 
+    const lichessEvalPromise = getLichessEval(fen, multiPv);
+
     await this.stopSearch();
     await this.setMultiPv(multiPv);
 
@@ -172,6 +183,16 @@ export abstract class UciEngine {
     };
 
     console.log(`Evaluating position: ${fen}`);
+
+    const lichessEval = await lichessEvalPromise;
+    if (
+      lichessEval.lines.length >= multiPv &&
+      lichessEval.lines[0].depth >= depth
+    ) {
+      setPartialEval(lichessEval);
+      return;
+    }
+
     await this.sendCommands(
       [`position fen ${fen}`, `go depth ${depth}`],
       "bestmove",

src/lib/lichess.ts

@@ -0,0 +1,51 @@
+import { LineEval, MoveEval } from "@/types/eval";
+import { sortLines } from "./engine/helpers/parseResults";
+import {
+  LichessError,
+  LichessEvalBody,
+  LichessResponse,
+} from "@/types/lichess";
+
+export const getLichessEval = async (
+  fen: string,
+  multiPv = 1
+): Promise<MoveEval> => {
+  try {
+    const res = await fetch(
+      `https://lichess.org/api/cloud-eval?fen=${fen}&multiPv=${multiPv}`
+    );
+
+    const data: LichessResponse<LichessEvalBody> = await res.json();
+
+    if ("error" in data) {
+      if (data.error === LichessError.NotFound) {
+        return {
+          bestMove: "",
+          lines: [],
+        };
+      }
+      throw new Error(data.error);
+    }
+
+    const lines: LineEval[] = data.pvs.map((pv, index) => ({
+      pv: pv.moves.split(" "),
+      cp: pv.cp,
+      mate: pv.mate,
+      depth: data.depth,
+      multiPv: index + 1,
+    }));
+
+    lines.sort(sortLines);
+
+    return {
+      bestMove: lines[0].pv[0],
+      lines: lines.slice(0, multiPv),
+    };
+  } catch (error) {
+    console.error(error);
+    return {
+      bestMove: "",
+      lines: [],
+    };
+  }
+};