poker elo calculation update

Will be more balanced for larger groups of players

game.js

@@ -222,6 +222,7 @@ export async function eloHandler(p1, p2, p1score, p2score, type) {
 
 export async function pokerEloHandler(room) {
   if (room.fakeMoney) return
+
   let DBplayers = []
   Object.keys(room.players).forEach(playerId => {
     const DBuser = getUser.get(playerId)
@@ -231,46 +232,52 @@ export async function pokerEloHandler(room) {
   })
 
   const winnerIds = new Set(room.winners)
-  const baseK = 5
   const playerCount = Object.keys(room.players).length
-  const K = baseK * Math.log2(playerCount)
+  const baseK = 10
+
+  const avgOpponentElo = (player) => {
+    const opponents = DBplayers.filter(p => p.id !== player.id);
+    return opponents.reduce((sum, p) => sum + p.elo, 0) / opponents.length;
+  };
 
   DBplayers.forEach(player => {
-    const others = DBplayers.filter(p => p.id !== player.id)
-    const avgOppElo = others.reduce((sum, p) => sum + p.elo, 0) / others.length
+    const avgElo = avgOpponentElo(player);
+    const expectedScore = 1 / (1 + 10 ** ((avgElo - player.elo) / 400))
 
-    const expectedScore = 1 / (1 + Math.pow(10, (avgOppElo - player.elo) / 400))
     let actualScore;
-
     if (winnerIds.has(player.id)) {
-      if (winnerIds.size === DBplayers.length) {
-        actualScore = 0.5
-      } else {
-        actualScore = 1
-      }
+      actualScore = (winnerIds.size === playerCount) ? 0.5 : 1;
     } else {
-      actualScore = 0
+      actualScore = 0;
     }
 
+    const K = winnerIds.has(player.id) ? (baseK * playerCount) : baseK
     const delta = K * (actualScore - expectedScore)
+
     const newElo = Math.max(Math.floor(player.elo + delta), 0)
 
-    console.log(`${player.id} elo update : ${player.elo} -> ${newElo} (K: ${K})`)
-    updateElo.run({ id: player.id, elo: newElo })
 
-    insertGame.run({
-      id: player.id + '-' + Date.now().toString(),
-      p1: player.id,
-      p2: null,
-      p1_score: actualScore,
-      p2_score: null,
-      p1_elo: player.elo,
-      p2_elo: avgOppElo,
-      p1_new_elo: newElo,
-      p2_new_elo: null,
-      type: 'POKER_ROUND',
-      timestamp: Date.now(),
-    })
+
+    if (!isNaN(newElo)) {
+      console.log(`${player.id} elo update: ${player.elo} -> ${newElo} (K: ${K.toFixed(2)}, Δ: ${delta.toFixed(2)})`);
+      updateElo.run({ id: player.id, elo: newElo })
+
+      insertGame.run({
+        id: player.id + '-' + Date.now().toString(),
+        p1: player.id,
+        p2: null,
+        p1_score: actualScore,
+        p2_score: null,
+        p1_elo: player.elo,
+        p2_elo: avgElo,
+        p1_new_elo: newElo,
+        p2_new_elo: null,
+        type: 'POKER_ROUND',
+        timestamp: Date.now(),
+      })
+    } else {
+      console.log(`# ELO UPDATE ERROR -> ${player.id} elo update: ${player.elo} -> ${newElo} (K: ${K.toFixed(2)}, Δ: ${delta.toFixed(2)})`);
+    }
   })
 }
 

index.js

@@ -609,7 +609,7 @@ client.on('messageCreate', async (message) => {
         }
       }
       else if (message.content.startsWith(prefix + ':poker')) {
-        io.emit('message', message.content);
+        console.log('poker')
       }
       else if (message.content.startsWith(prefix + ':elo-test')) {
         const numbers = message.content.match(/\d+/g);
@@ -3599,8 +3599,8 @@ app.post('/poker-room/join', async (req, res) => {
   let amount = getUser.get(userId)?.coins
   let fakeMoney = false
 
-  if (!amount || amount < 100) {
-    amount = 100
+  if (!amount || amount < 1000) {
+    amount = 1000
     fakeMoney = true
   }
 
@@ -4432,6 +4432,7 @@ async function updatePokerPlayersSolve(roomId) {
 
 import http from 'http';
 import { Server } from 'socket.io';
+import * as test from "node:test";
 const server = http.createServer(app);
 
 const io = new Server(server, {