feat : add elo estimation feature (#6)

* feat: ✨ add elo estimation feature

src/lib/engine/helpers/estimateElo.ts

@@ -0,0 +1,54 @@
+import { ceilsNumber } from "@/lib/math";
+import { EstimatedElo, PositionEval } from "@/types/eval";
+
+export const estimateEloFromEngineOutput = (
+  positions: PositionEval[]
+): EstimatedElo => {
+  try {
+    if (!positions || positions.length === 0) {
+      return { white: null, black: null };
+    }
+
+    let totalCPLWhite = 0;
+    let totalCPLBlack = 0;
+    let moveCount = 0;
+    let previousCp = null;
+    let flag = true;
+    for (const moveAnalysis of positions) {
+      if (moveAnalysis.lines && moveAnalysis.lines.length > 0) {
+        const bestLine = moveAnalysis.lines[0];
+        if (bestLine.cp !== undefined) {
+          if (previousCp !== null) {
+            const diff = Math.abs(bestLine.cp - previousCp);
+            if (flag) {
+              totalCPLWhite += ceilsNumber(diff, -1000, 1000);
+            } else {
+              totalCPLBlack += ceilsNumber(diff, -1000, 1000);
+            }
+            flag = !flag;
+            moveCount++;
+          }
+          previousCp = bestLine.cp;
+        }
+      }
+    }
+
+    if (moveCount === 0) {
+      return { white: null, black: null };
+    }
+
+    const averageCPLWhite = totalCPLWhite / Math.ceil(moveCount / 2);
+    const averageCPLBlack = totalCPLBlack / Math.floor(moveCount / 2);
+
+    const estimateElo = (averageCPL: number) =>
+      3100 * Math.exp(-0.01 * averageCPL);
+
+    const whiteElo = estimateElo(Math.abs(averageCPLWhite));
+    const blackElo = estimateElo(Math.abs(averageCPLBlack));
+
+    return { white: whiteElo, black: blackElo };
+  } catch (error) {
+    console.error("Error estimating Elo: ", error);
+    return { white: null, black: null };
+  }
+};

src/lib/engine/uciEngine.ts

@@ -1,5 +1,6 @@
 import { EngineName } from "@/types/enums";
 import {
+  EstimatedElo,
   EvaluateGameParams,
   EvaluatePositionWithUpdateParams,
   GameEval,
@@ -13,6 +14,7 @@ import { computeAccuracy } from "./helpers/accuracy";
 import { getIsStalemate, getWhoIsCheckmated } from "../chess";
 import { getLichessEval } from "../lichess";
 import { getMovesClassification } from "./helpers/moveClassification";
+import { estimateEloFromEngineOutput } from "./helpers/estimateElo";
 import { EngineWorker, WorkerJob } from "@/types/engine";
 
 export class UciEngine {
@@ -276,10 +278,12 @@ export class UciEngine {
       fens
     );
     const accuracy = computeAccuracy(positions);
+    const estimatedElo: EstimatedElo = estimateEloFromEngineOutput(positions);
 
     this.isReady = true;
     return {
       positions: positionsWithClassification,
+      estimatedElo,
       accuracy,
       settings: {
         engine: this.engineName,

src/sections/analysis/panelBody/analysisTab/accuracies.tsx

@@ -1,8 +1,11 @@
 import { Grid2 as Grid, Typography } from "@mui/material";
 import { useAtomValue } from "jotai";
 import { gameEvalAtom } from "../../states";
+type props = {
+  params: "accurecy" | "rating";
+};
 
-export default function Accuracies() {
+export default function Accuracies(props: props) {
   const gameEval = useAtomValue(gameEvalAtom);
 
   if (!gameEval) return null;
@@ -24,11 +27,14 @@ export default function Accuracies() {
         fontWeight="bold"
         border="1px solid #424242"
       >
-        {`${gameEval?.accuracy.white.toFixed(1)} %`}
+        {props.params === "accurecy"
+          ? `${gameEval?.accuracy.white.toFixed(1)} %`
+          : `${Math.round(gameEval?.estimatedElo.white as number)}`}
       </Typography>
 
-      <Typography align="center">Accuracies</Typography>
-
+      <Typography align="center">
+        {props.params === "accurecy" ? "Accuracies" : "Estimated Elo"}
+      </Typography>
       <Typography
         align="center"
         sx={{ backgroundColor: "black", color: "white" }}
@@ -38,7 +44,9 @@ export default function Accuracies() {
         fontWeight="bold"
         border="1px solid #424242"
       >
-        {`${gameEval?.accuracy.black.toFixed(1)} %`}
+        {props.params === "accurecy"
+          ? `${gameEval?.accuracy.black.toFixed(1)} %`
+          : `${Math.round(gameEval?.estimatedElo.black as number)}`}
       </Typography>
     </Grid>
   );

src/sections/analysis/panelBody/analysisTab/index.tsx

@@ -57,7 +57,8 @@ export default function AnalysisTab(props: GridProps) {
           : { overflow: "hidden", overflowY: "auto", ...props.sx }
       }
     >
-      <Accuracies />
+      <Accuracies params={"accurecy"} />
+      <Accuracies params={"rating"} />
 
       <MoveInfo />
 

src/types/eval.ts

@@ -21,6 +21,10 @@ export interface Accuracy {
   black: number;
 }
 
+export interface EstimatedElo {
+  white: number | null;
+  black: number | null;
+}
 export interface EngineSettings {
   engine: EngineName;
   depth: number;
@@ -31,6 +35,7 @@ export interface EngineSettings {
 export interface GameEval {
   positions: PositionEval[];
   accuracy: Accuracy;
+  estimatedElo: EstimatedElo;
   settings: EngineSettings;
 }