From 5c98f1638ab23ef6fbcfa2d55d86037de96788db Mon Sep 17 00:00:00 2001
From: kerboul <crowbar51kerbal@gmail.com>
Date: Sun, 17 May 2026 18:33:06 +0200
Subject: [PATCH] feat: stats + chat + frontend pages (Stats, Chat, NavBar)

Backend:
- StatsManager.js: JSON persistence, leaderboard, rate-limit 1/5s
- ChatManager.js: 200-msg buffer, JSON persistence
- index.js: routes GET/POST /stats, /chat/history, /chat/send (Zod validation)
- ArenaRoom.js: chat handler broadcasts to room + persists via ChatManager

Unity:
- StatsTracker.cs: distance, maxSpeed, jumps, bumps, checkpoints, raceTime tracking
- ChatUI.cs: F3 toggle, bottom-right panel, polling 3s, unread badge
- NetworkManager.cs: SendChatMessage() + OnMessage<ChatUI.ChatMessage>(chat)
- CheckpointSystem.cs: RegisterCheckpoint/Finish hooks
- PlayerController.cs: RegisterJump/Bump hooks, physics rebalance, billboard fix
- GameHUD.cs: LocalRaceTimer, SetTotalRounds, OnRoundStart signature fix
- GameManager.cs: spectator cam reconnect fix

Frontend:
- NavBar.jsx: fixed top nav, Accueil/Stats/Chat/Jouer
- App.jsx: page state (home/play/stats/chat) + NavBar
- StatsPage.jsx: 6-tab leaderboard, auto-refresh 30s
- ChatPage.jsx: polling 3s, localStorage name, Enter to send

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 frontend/src/App.jsx                          |  31 ++-
 frontend/src/components/NavBar.jsx            |  50 ++++
 frontend/src/pages/ChatPage.jsx               | 185 +++++++++++++
 frontend/src/pages/StatsPage.jsx              | 139 ++++++++++
 game/Assets/PlayerController.cs               |  10 +-
 game/Assets/Scripts/GameManager.cs            |   1 -
 game/Assets/Scripts/Network/NetworkManager.cs |  10 +
 game/Assets/Scripts/Race/CheckpointSystem.cs  |   2 +
 game/Assets/Scripts/Stats/StatsTracker.cs     | 229 ++++++++++++++++
 game/Assets/Scripts/UI/ChatUI.cs              | 259 ++++++++++++++++++
 game/Assets/Scripts/UI/GameHUD.cs             |   2 +
 rolld_backend/game/src/chat/ChatManager.js    |  52 ++++
 rolld_backend/game/src/index.js               |  82 +++++-
 rolld_backend/game/src/rooms/ArenaRoom.js     |   8 +
 rolld_backend/game/src/stats/StatsManager.js  | 101 +++++++
 15 files changed, 1144 insertions(+), 17 deletions(-)
 create mode 100644 frontend/src/components/NavBar.jsx
 create mode 100644 frontend/src/pages/ChatPage.jsx
 create mode 100644 frontend/src/pages/StatsPage.jsx
 create mode 100644 game/Assets/Scripts/Stats/StatsTracker.cs
 create mode 100644 game/Assets/Scripts/UI/ChatUI.cs
 create mode 100644 rolld_backend/game/src/chat/ChatManager.js
 create mode 100644 rolld_backend/game/src/stats/StatsManager.js

diff --git a/frontend/src/App.jsx b/frontend/src/App.jsx
index f1b1cf5..37e9267 100644
--- a/frontend/src/App.jsx
+++ b/frontend/src/App.jsx
@@ -1,28 +1,41 @@
 import { useState } from 'react'
 import { IS_DEV } from './env'
 import DevBanner from './components/DevBanner'
+import NavBar from './components/NavBar'
 import Hero from './components/Hero'
 import GelShowcase from './components/GelShowcase'
 import KerboulistanBanner from './components/KerboulistanBanner'
 import GameCanvas from './components/GameCanvas'
 import Footer from './components/Footer'
+import StatsPage from './pages/StatsPage'
+import ChatPage from './pages/ChatPage'
 
 function App() {
-  const [isPlaying, setIsPlaying] = useState(false)
+  const [page, setPage] = useState('home')
 
-  if (isPlaying) {
-    return <GameCanvas onBack={() => setIsPlaying(false)} />
+  if (page === 'play') {
+    return <GameCanvas onBack={() => setPage('home')} />
   }
 
   return (
     <div className="min-h-screen">
       <DevBanner />
-      {/* Offset content when dev banner is visible */}
-      {IS_DEV && <div className="h-8" />}
-      <Hero onPlay={() => setIsPlaying(true)} />
-      <GelShowcase />
-      <KerboulistanBanner />
-      <Footer />
+      <NavBar page={page} setPage={setPage} />
+
+      {page === 'home' && (
+        <>
+          {IS_DEV && <div className="h-8" />}
+          <div className="pt-14">
+            <Hero onPlay={() => setPage('play')} />
+            <GelShowcase />
+            <KerboulistanBanner />
+            <Footer />
+          </div>
+        </>
+      )}
+
+      {page === 'stats' && <StatsPage />}
+      {page === 'chat' && <ChatPage />}
     </div>
   )
 }
diff --git a/frontend/src/components/NavBar.jsx b/frontend/src/components/NavBar.jsx
new file mode 100644
index 0000000..393705e
--- /dev/null
+++ b/frontend/src/components/NavBar.jsx
@@ -0,0 +1,50 @@
+import { theme } from '../env'
+
+const LINKS = [
+  { id: 'home', label: 'Accueil' },
+  { id: 'stats', label: 'Stats' },
+  { id: 'chat', label: 'Chat' },
+]
+
+export default function NavBar({ page, setPage }) {
+  return (
+    <nav className="fixed top-0 left-0 right-0 z-50 glass border-b border-rolld-border/60">
+      <div className="max-w-6xl mx-auto px-4 h-14 flex items-center justify-between">
+        <button
+          onClick={() => setPage('home')}
+          className="font-black text-lg tracking-tight"
+          style={{ color: theme.accent }}
+        >
+          ROLL'D
+        </button>
+
+        <div className="flex items-center gap-1">
+          {LINKS.map(link => (
+            <button
+              key={link.id}
+              onClick={() => setPage(link.id)}
+              className={`px-4 py-2 rounded-xl text-sm font-medium transition-all duration-200 ${
+                page === link.id
+                  ? 'text-white'
+                  : 'text-rolld-muted hover:text-rolld-text'
+              }`}
+              style={page === link.id ? { background: `rgba(${theme.accentRgb}, 0.2)`, color: theme.accentLight } : {}}
+            >
+              {link.label}
+            </button>
+          ))}
+
+          <button
+            onClick={() => setPage('play')}
+            className="ml-3 px-4 py-2 rounded-xl text-sm font-bold text-white transition-all duration-200 hover:scale-105"
+            style={{
+              backgroundImage: `linear-gradient(to right, ${theme.accent}, ${theme.gradientTo})`,
+            }}
+          >
+            Jouer
+          </button>
+        </div>
+      </div>
+    </nav>
+  )
+}
diff --git a/frontend/src/pages/ChatPage.jsx b/frontend/src/pages/ChatPage.jsx
new file mode 100644
index 0000000..4253927
--- /dev/null
+++ b/frontend/src/pages/ChatPage.jsx
@@ -0,0 +1,185 @@
+import { useState, useEffect, useRef, useCallback } from 'react'
+import { theme } from '../env'
+
+const SERVER = 'https://game.rolld.kerboul.me'
+const POLL_INTERVAL = 3000
+
+export default function ChatPage() {
+  const [messages, setMessages] = useState([])
+  const [inputText, setInputText] = useState('')
+  const [playerName, setPlayerName] = useState(() => localStorage.getItem('rolld_chat_name') || '')
+  const [editingName, setEditingName] = useState(!localStorage.getItem('rolld_chat_name'))
+  const [nameInput, setNameInput] = useState(playerName)
+  const [sending, setSending] = useState(false)
+  const lastTimestampRef = useRef(0)
+  const bottomRef = useRef(null)
+  const inputRef = useRef(null)
+
+  const fetchMessages = useCallback(async () => {
+    try {
+      const res = await fetch(`${SERVER}/chat/history?since=${lastTimestampRef.current}`)
+      if (!res.ok) return
+      const data = await res.json()
+      if (!Array.isArray(data) || data.length === 0) return
+      setMessages(prev => {
+        const updated = [...prev, ...data]
+        // Deduplicate by id
+        const seen = new Set()
+        const deduped = updated.filter(m => {
+          if (seen.has(m.id)) return false
+          seen.add(m.id)
+          return true
+        })
+        return deduped.slice(-200)
+      })
+      const maxTs = Math.max(...data.map(m => m.timestamp))
+      if (maxTs > lastTimestampRef.current) lastTimestampRef.current = maxTs
+    } catch {
+      // silently ignore network errors
+    }
+  }, [])
+
+  useEffect(() => {
+    fetchMessages()
+    const id = setInterval(fetchMessages, POLL_INTERVAL)
+    return () => clearInterval(id)
+  }, [fetchMessages])
+
+  useEffect(() => {
+    bottomRef.current?.scrollIntoView({ behavior: 'smooth' })
+  }, [messages])
+
+  const saveName = () => {
+    const n = nameInput.trim()
+    if (!n) return
+    setPlayerName(n)
+    localStorage.setItem('rolld_chat_name', n)
+    setEditingName(false)
+    setTimeout(() => inputRef.current?.focus(), 50)
+  }
+
+  const sendMessage = async () => {
+    const text = inputText.trim()
+    if (!text || !playerName || sending) return
+    setSending(true)
+    setInputText('')
+    try {
+      await fetch(`${SERVER}/chat/send`, {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ name: playerName, text }),
+      })
+      // Immediately poll to get our own message back
+      await fetchMessages()
+    } catch {
+      // ignore
+    } finally {
+      setSending(false)
+      inputRef.current?.focus()
+    }
+  }
+
+  const handleKeyDown = (e) => {
+    if (e.key === 'Enter' && !e.shiftKey) {
+      e.preventDefault()
+      sendMessage()
+    }
+  }
+
+  const formatTime = (ts) => {
+    const d = new Date(ts)
+    return d.toLocaleTimeString('fr-FR', { hour: '2-digit', minute: '2-digit' })
+  }
+
+  return (
+    <div className="min-h-screen pt-20 px-4 flex flex-col">
+      <div className="max-w-2xl mx-auto w-full flex flex-col flex-1" style={{ maxHeight: 'calc(100vh - 5rem)' }}>
+
+        {/* Header */}
+        <div className="mb-4 flex items-center justify-between">
+          <div>
+            <h1 className="text-3xl font-black text-rolld-text">Chat général</h1>
+            <p className="text-rolld-muted text-sm mt-1">Partagé entre le jeu et le site — rafraîchi toutes les 3s</p>
+          </div>
+
+          {/* Name badge */}
+          {!editingName ? (
+            <button
+              onClick={() => { setNameInput(playerName); setEditingName(true) }}
+              className="flex items-center gap-2 px-3 py-1.5 rounded-xl border border-rolld-border bg-rolld-surface text-sm hover:border-rolld-accent/40 transition-colors"
+            >
+              <span className="text-rolld-muted">Joueur :</span>
+              <span className="font-bold" style={{ color: theme.accentLight }}>{playerName}</span>
+              <span className="text-rolld-muted text-xs">✏️</span>
+            </button>
+          ) : (
+            <div className="flex items-center gap-2">
+              <input
+                autoFocus
+                value={nameInput}
+                onChange={e => setNameInput(e.target.value)}
+                onKeyDown={e => e.key === 'Enter' && saveName()}
+                placeholder="Ton pseudo"
+                maxLength={24}
+                className="w-36 px-3 py-1.5 rounded-xl border border-rolld-accent/60 bg-rolld-surface text-rolld-text text-sm outline-none focus:border-rolld-accent"
+              />
+              <button
+                onClick={saveName}
+                className="px-3 py-1.5 rounded-xl text-sm font-bold text-white"
+                style={{ background: theme.accent }}
+              >
+                OK
+              </button>
+            </div>
+          )}
+        </div>
+
+        {/* Messages */}
+        <div className="flex-1 overflow-y-auto rounded-2xl border border-rolld-border bg-rolld-surface p-4 space-y-1 min-h-0">
+          {messages.length === 0 ? (
+            <div className="h-full flex items-center justify-center text-rolld-muted text-sm">
+              Aucun message pour l'instant. Soyez le premier !
+            </div>
+          ) : (
+            messages.map(msg => (
+              <div key={msg.id} className="flex items-baseline gap-2 py-0.5 group">
+                <span className="text-rolld-muted text-xs font-mono shrink-0 opacity-60 group-hover:opacity-100 transition-opacity w-11">
+                  {formatTime(msg.timestamp)}
+                </span>
+                <span className="text-sm font-bold shrink-0" style={{ color: theme.accentLight }}>
+                  {msg.name}
+                </span>
+                <span className="text-sm text-rolld-text break-words min-w-0">
+                  {msg.text}
+                </span>
+              </div>
+            ))
+          )}
+          <div ref={bottomRef} />
+        </div>
+
+        {/* Input */}
+        <div className="mt-3 flex gap-2 pb-4">
+          <input
+            ref={inputRef}
+            value={inputText}
+            onChange={e => setInputText(e.target.value)}
+            onKeyDown={handleKeyDown}
+            placeholder={playerName ? 'Écrire un message… (Entrée pour envoyer)' : 'Choisissez d\'abord un pseudo →'}
+            maxLength={200}
+            disabled={!playerName || editingName}
+            className="flex-1 px-4 py-3 rounded-xl border border-rolld-border bg-rolld-surface text-rolld-text text-sm outline-none focus:border-rolld-accent/60 disabled:opacity-40 transition-colors"
+          />
+          <button
+            onClick={sendMessage}
+            disabled={!inputText.trim() || !playerName || sending || editingName}
+            className="px-5 py-3 rounded-xl text-sm font-bold text-white transition-all duration-200 hover:scale-105 disabled:opacity-40 disabled:hover:scale-100"
+            style={{ backgroundImage: `linear-gradient(to right, ${theme.accent}, ${theme.gradientTo})` }}
+          >
+            Envoyer
+          </button>
+        </div>
+      </div>
+    </div>
+  )
+}
diff --git a/frontend/src/pages/StatsPage.jsx b/frontend/src/pages/StatsPage.jsx
new file mode 100644
index 0000000..1755b2d
--- /dev/null
+++ b/frontend/src/pages/StatsPage.jsx
@@ -0,0 +1,139 @@
+import { useState, useEffect, useCallback } from 'react'
+import { theme } from '../env'
+
+const SERVER = 'https://game.rolld.kerboul.me'
+
+const TABS = [
+  { key: 'totalDistance', label: 'Distance', unit: 'm', format: v => Math.round(v).toLocaleString('fr-FR') },
+  { key: 'maxSpeed', label: 'Vitesse max', unit: 'm/s', format: v => v.toFixed(1) },
+  { key: 'totalJumps', label: 'Sauts', unit: '', format: v => v.toLocaleString('fr-FR') },
+  { key: 'bestRaceTime', label: 'Meilleur temps', unit: '', format: v => {
+    const m = Math.floor(v / 60)
+    const s = (v % 60).toFixed(2).padStart(5, '0')
+    return `${m}:${s}`
+  }},
+  { key: 'racesPlayed', label: 'Courses', unit: '', format: v => v.toLocaleString('fr-FR') },
+  { key: 'bumpsGiven', label: 'Bumps', unit: '', format: v => v.toLocaleString('fr-FR') },
+]
+
+export default function StatsPage() {
+  const [activeTab, setActiveTab] = useState(TABS[0].key)
+  const [rows, setRows] = useState([])
+  const [loading, setLoading] = useState(false)
+  const [lastRefresh, setLastRefresh] = useState(null)
+
+  const fetchLeaderboard = useCallback(async (key) => {
+    setLoading(true)
+    try {
+      const res = await fetch(`${SERVER}/stats/leaderboard/${key}`)
+      if (!res.ok) throw new Error(res.statusText)
+      const data = await res.json()
+      setRows(data)
+      setLastRefresh(new Date())
+    } catch {
+      setRows([])
+    } finally {
+      setLoading(false)
+    }
+  }, [])
+
+  useEffect(() => {
+    fetchLeaderboard(activeTab)
+    const id = setInterval(() => fetchLeaderboard(activeTab), 30_000)
+    return () => clearInterval(id)
+  }, [activeTab, fetchLeaderboard])
+
+  const currentTab = TABS.find(t => t.key === activeTab)
+
+  const medalColor = (i) => {
+    if (i === 0) return '#f39c12'
+    if (i === 1) return '#9b9b9b'
+    if (i === 2) return '#cd7f32'
+    return theme.accentLight
+  }
+
+  return (
+    <div className="min-h-screen pt-20 px-4">
+      <div className="max-w-3xl mx-auto">
+        {/* Header */}
+        <div className="mb-8 text-center">
+          <h1 className="text-4xl font-black text-rolld-text mb-2">Classements</h1>
+          <p className="text-rolld-muted text-sm">Top 10 joueurs par catégorie — mis à jour en temps réel</p>
+        </div>
+
+        {/* Tabs */}
+        <div className="flex flex-wrap gap-2 justify-center mb-8">
+          {TABS.map(tab => (
+            <button
+              key={tab.key}
+              onClick={() => setActiveTab(tab.key)}
+              className={`px-4 py-2 rounded-xl text-sm font-medium transition-all duration-200 ${
+                activeTab === tab.key
+                  ? 'text-white'
+                  : 'text-rolld-muted hover:text-rolld-text bg-rolld-surface border border-rolld-border'
+              }`}
+              style={activeTab === tab.key ? {
+                background: `linear-gradient(to right, ${theme.accent}, ${theme.gradientTo})`,
+              } : {}}
+            >
+              {tab.label}
+            </button>
+          ))}
+        </div>
+
+        {/* Table */}
+        <div className="rounded-2xl overflow-hidden border border-rolld-border bg-rolld-surface">
+          <div className="px-6 py-4 border-b border-rolld-border flex items-center justify-between">
+            <span className="text-rolld-text font-semibold">{currentTab.label}</span>
+            <div className="flex items-center gap-3">
+              {lastRefresh && (
+                <span className="text-rolld-muted text-xs">
+                  {lastRefresh.toLocaleTimeString('fr-FR', { hour: '2-digit', minute: '2-digit', second: '2-digit' })}
+                </span>
+              )}
+              <button
+                onClick={() => fetchLeaderboard(activeTab)}
+                disabled={loading}
+                className="text-xs text-rolld-accent hover:text-rolld-accent-light transition-colors disabled:opacity-40"
+              >
+                {loading ? '...' : 'Actualiser'}
+              </button>
+            </div>
+          </div>
+
+          {loading && rows.length === 0 ? (
+            <div className="py-16 text-center text-rolld-muted text-sm">Chargement…</div>
+          ) : rows.length === 0 ? (
+            <div className="py-16 text-center text-rolld-muted text-sm">Aucune donnée pour l'instant.</div>
+          ) : (
+            <table className="w-full">
+              <tbody>
+                {rows.map((row, i) => (
+                  <tr
+                    key={row.name}
+                    className={`border-b border-rolld-border/50 last:border-0 transition-colors hover:bg-rolld-border/20 ${
+                      i === 0 ? 'bg-rolld-border/10' : ''
+                    }`}
+                  >
+                    <td className="px-6 py-4 w-12">
+                      <span className="text-sm font-bold" style={{ color: medalColor(i) }}>
+                        {i < 3 ? ['🥇', '🥈', '🥉'][i] : `#${i + 1}`}
+                      </span>
+                    </td>
+                    <td className="px-2 py-4 flex-1 text-rolld-text font-medium">
+                      {row.name}
+                    </td>
+                    <td className="px-6 py-4 text-right font-mono text-sm" style={{ color: theme.accentLight }}>
+                      {currentTab.format(row[activeTab])}
+                      {currentTab.unit && <span className="text-rolld-muted ml-1">{currentTab.unit}</span>}
+                    </td>
+                  </tr>
+                ))}
+              </tbody>
+            </table>
+          )}
+        </div>
+      </div>
+    </div>
+  )
+}
diff --git a/game/Assets/PlayerController.cs b/game/Assets/PlayerController.cs
index 28c1389..31eab6c 100644
--- a/game/Assets/PlayerController.cs
+++ b/game/Assets/PlayerController.cs
@@ -376,9 +376,9 @@ public class PlayerController : MonoBehaviour
     {
         if (context.started)
         {
-            // Touche appuyée
             isJumpPressed = true;
             jumpPressTime = 0f;
+            StatsTracker.Instance?.RegisterJump();
             Debug.Log("Jump Started");
         }
         else if (context.performed)
@@ -516,6 +516,7 @@ public class PlayerController : MonoBehaviour
             return;
 
         _lastBumpTime[id] = Time.time;
+        StatsTracker.Instance?.RegisterBump();
 
         // Repulsion direction: from remote toward local player
         Vector3 dir = (transform.position - other.transform.position).normalized;
@@ -606,6 +607,13 @@ public class PlayerController : MonoBehaviour
             fontStyle = FontStyle.Bold
         };
         labelStyle.normal.textColor = new Color(1f, 1f, 1f, _gaugeDisplayAlpha * 0.9f);
+        // Outline: draw 4× in black at ±1px, then once in white
+        var shadowStyle = new GUIStyle(labelStyle);
+        shadowStyle.normal.textColor = new Color(0f, 0f, 0f, _gaugeDisplayAlpha * 0.55f);
+        GUI.Label(new Rect(x + 1f, y - 25f, barWidth, 24f), "JUMP POWER", shadowStyle);
+        GUI.Label(new Rect(x - 1f, y - 27f, barWidth, 24f), "JUMP POWER", shadowStyle);
+        GUI.Label(new Rect(x + 1f, y - 27f, barWidth, 24f), "JUMP POWER", shadowStyle);
+        GUI.Label(new Rect(x - 1f, y - 25f, barWidth, 24f), "JUMP POWER", shadowStyle);
         GUI.Label(new Rect(x, y - 26f, barWidth, 24f), "JUMP POWER", labelStyle);
 
         // Ensure textures
diff --git a/game/Assets/Scripts/GameManager.cs b/game/Assets/Scripts/GameManager.cs
index a1bc5ae..fff8985 100644
--- a/game/Assets/Scripts/GameManager.cs
+++ b/game/Assets/Scripts/GameManager.cs
@@ -142,7 +142,6 @@ public class GameManager : MonoBehaviour
         {
             case GamePhase.Lobby:
                 SetPlayerActive(NetworkManager.Instance?.IsConnected ?? false);
-                SetSpectatorActive(false);
                 gameHUD?.SetPhase("lobby");
                 break;
 
diff --git a/game/Assets/Scripts/Network/NetworkManager.cs b/game/Assets/Scripts/Network/NetworkManager.cs
index ab583bf..e12e27c 100644
--- a/game/Assets/Scripts/Network/NetworkManager.cs
+++ b/game/Assets/Scripts/Network/NetworkManager.cs
@@ -171,6 +171,10 @@ public class NetworkManager : MonoBehaviour
                 Debug.Log($"[Network] Game over — Winner: {msg.winner}");
                 OnGameEnd?.Invoke(msg.winner);
             });
+            _room.OnMessage<ChatUI.ChatMessage>("chat", msg =>
+            {
+                ChatUI.Instance?.ReceiveChatMessage(msg);
+            });
 
             _room.OnLeave += OnRoomLeave;
             OnConnected?.Invoke();
@@ -206,6 +210,12 @@ public class NetworkManager : MonoBehaviour
             await _room.Send("checkpointReached", new { index });
     }
 
+    public async void SendChatMessage(string text)
+    {
+        if (_room != null && IsConnected)
+            await _room.Send("chat", new { text });
+    }
+
     // ─── State Callbacks ─────────────────────────────────────────────────
 
     private void _OnPhaseChanged(string phase)
diff --git a/game/Assets/Scripts/Race/CheckpointSystem.cs b/game/Assets/Scripts/Race/CheckpointSystem.cs
index e3649cb..5e0e90f 100644
--- a/game/Assets/Scripts/Race/CheckpointSystem.cs
+++ b/game/Assets/Scripts/Race/CheckpointSystem.cs
@@ -67,6 +67,7 @@ public class CheckpointSystem : MonoBehaviour
         }
 
         _localCheckpointIndex++;
+        StatsTracker.Instance?.RegisterCheckpoint();
         NetworkManager.Instance?.SendCheckpoint(_localCheckpointIndex);
 
         Debug.Log($"[Checkpoint] Reached {_localCheckpointIndex}/{checkpoints.Length}");
@@ -79,6 +80,7 @@ public class CheckpointSystem : MonoBehaviour
         if (_localCheckpointIndex >= checkpoints.Length)
         {
             _finished = true;
+            StatsTracker.Instance?.RegisterFinish(GameHUD.Instance != null ? GameHUD.Instance.LocalRaceTimer : 0f);
             Debug.Log("[Checkpoint] FINISH LINE reached!");
         }
         else
diff --git a/game/Assets/Scripts/Stats/StatsTracker.cs b/game/Assets/Scripts/Stats/StatsTracker.cs
new file mode 100644
index 0000000..b23d8bc
--- /dev/null
+++ b/game/Assets/Scripts/Stats/StatsTracker.cs
@@ -0,0 +1,229 @@
+using System.Collections;
+using System.Text;
+using UnityEngine;
+using UnityEngine.Networking;
+
+/// <summary>
+/// Tracks per-session and per-round player statistics and uploads them to the game server.
+/// All HTTP calls use UnityWebRequest coroutines (WebGL-safe, no async/await).
+/// </summary>
+public class StatsTracker : MonoBehaviour
+{
+    public static StatsTracker Instance { get; private set; }
+
+    private const string SERVER_URL = "https://game.rolld.kerboul.me";
+
+    // Cumulative session stats (accumulate across rounds)
+    private float _totalDistance;
+    private int   _totalJumps;
+    private float _maxSpeed;
+    private float _bestRaceTime;   // 0 = not set
+    private int   _racesPlayed;
+    private int   _qualifications;
+    private int   _eliminations;
+    private int   _checkpointsTotal;
+    private int   _bumpsGiven;
+    private float _totalPlaytime;
+
+    // Per-round deltas (reset after each send)
+    private float _roundDistance;
+    private float _roundMaxSpeed;
+    private float _sessionStart;
+
+    private Vector3 _lastPos;
+    private bool    _trackingActive;
+    private PlayerController _pc;
+    private Rigidbody _rb;
+
+    void Awake()
+    {
+        if (Instance != null && Instance != this) { Destroy(gameObject); return; }
+        Instance = this;
+        _sessionStart = Time.time;
+    }
+
+    void Start()
+    {
+        _pc = GetComponent<PlayerController>();
+        _rb = GetComponent<Rigidbody>();
+
+        var nm = NetworkManager.Instance;
+        if (nm != null)
+        {
+            nm.OnRoundStart  += OnRoundStart;
+            nm.OnRoundEnd    += OnRoundEnd;
+            nm.OnQualified   += OnQualified;
+            nm.OnEliminated  += OnEliminated;
+            nm.OnConnected   += OnConnected;
+            nm.OnDisconnected += OnDisconnected;
+        }
+    }
+
+    void OnDestroy()
+    {
+        var nm = NetworkManager.Instance;
+        if (nm != null)
+        {
+            nm.OnRoundStart  -= OnRoundStart;
+            nm.OnRoundEnd    -= OnRoundEnd;
+            nm.OnQualified   -= OnQualified;
+            nm.OnEliminated  -= OnEliminated;
+            nm.OnConnected   -= OnConnected;
+            nm.OnDisconnected -= OnDisconnected;
+        }
+    }
+
+    void FixedUpdate()
+    {
+        if (!_trackingActive || _rb == null || _pc == null || !_pc.enabled) return;
+
+        Vector3 pos = transform.position;
+        float delta = Vector3.Distance(pos, _lastPos);
+        if (delta < 20f) // sanity cap against teleports
+        {
+            _roundDistance  += delta;
+            _totalDistance  += delta;
+        }
+        _lastPos = pos;
+
+        float speed = _rb.linearVelocity.magnitude;
+        if (speed > _roundMaxSpeed) _roundMaxSpeed = speed;
+        if (speed > _maxSpeed)      _maxSpeed      = speed;
+    }
+
+    // ─── Public hooks ────────────────────────────────────────────────────
+
+    public void RegisterJump()
+    {
+        _totalJumps++;
+    }
+
+    public void RegisterBump()
+    {
+        _bumpsGiven++;
+    }
+
+    public void RegisterCheckpoint()
+    {
+        _checkpointsTotal++;
+    }
+
+    public void RegisterFinish(float raceTime)
+    {
+        if (raceTime <= 0f) return;
+        if (_bestRaceTime <= 0f || raceTime < _bestRaceTime)
+            _bestRaceTime = raceTime;
+    }
+
+    // ─── Event handlers ──────────────────────────────────────────────────
+
+    private void OnConnected()
+    {
+        _lastPos = transform.position;
+        _trackingActive = true;
+    }
+
+    private void OnDisconnected()
+    {
+        _trackingActive = false;
+        _totalPlaytime += Time.time - _sessionStart;
+        SendStats(); // best-effort on disconnect
+    }
+
+    private void OnRoundStart(int round, string mode, int totalRounds)
+    {
+        _racesPlayed++;
+        _roundDistance = 0f;
+        _roundMaxSpeed = 0f;
+        _lastPos = transform.position;
+        _trackingActive = true;
+    }
+
+    private void OnRoundEnd(int round)
+    {
+        _trackingActive = false;
+        SendStats();
+        _roundDistance = 0f;
+        _roundMaxSpeed = 0f;
+    }
+
+    private void OnQualified(string sessionId)
+    {
+        if (sessionId == NetworkManager.Instance?.LocalSessionId)
+            _qualifications++;
+    }
+
+    private void OnEliminated(string sessionId, string reason)
+    {
+        if (sessionId == NetworkManager.Instance?.LocalSessionId)
+            _eliminations++;
+    }
+
+    // ─── HTTP send ───────────────────────────────────────────────────────
+
+    private void SendStats()
+    {
+        var nm = NetworkManager.Instance;
+        if (nm == null || string.IsNullOrEmpty(nm.LocalPlayerName)) return;
+        StartCoroutine(DoSendStats(nm.LocalPlayerName));
+    }
+
+    private IEnumerator DoSendStats(string playerName)
+    {
+        _totalPlaytime += Time.time - _sessionStart;
+        _sessionStart = Time.time;
+
+        var payload = new StatsPayload
+        {
+            name = playerName,
+            stats = new StatsData
+            {
+                totalDistance    = _totalDistance,
+                totalJumps       = _totalJumps,
+                maxSpeed         = _maxSpeed,
+                bestRaceTime     = _bestRaceTime > 0f ? _bestRaceTime : 0f,
+                racesPlayed      = _racesPlayed,
+                qualifications   = _qualifications,
+                eliminations     = _eliminations,
+                checkpointsTotal = _checkpointsTotal,
+                bumpsGiven       = _bumpsGiven,
+                totalPlaytime    = _totalPlaytime,
+            }
+        };
+
+        string json = JsonUtility.ToJson(payload);
+        byte[] body = Encoding.UTF8.GetBytes(json);
+
+        using var req = new UnityWebRequest($"{SERVER_URL}/stats/update", "POST");
+        req.uploadHandler   = new UploadHandlerRaw(body);
+        req.downloadHandler = new DownloadHandlerBuffer();
+        req.SetRequestHeader("Content-Type", "application/json");
+
+        yield return req.SendWebRequest();
+
+        if (req.result != UnityWebRequest.Result.Success)
+            Debug.LogWarning($"[Stats] Upload failed: {req.error}");
+        else
+            Debug.Log($"[Stats] Uploaded for {playerName}");
+    }
+
+    // ─── DTOs ─────────────────────────────────────────────────────────────
+
+    [System.Serializable]
+    private class StatsPayload { public string name; public StatsData stats; }
+
+    [System.Serializable]
+    private class StatsData
+    {
+        public float totalDistance;
+        public int   totalJumps;
+        public float maxSpeed;
+        public float bestRaceTime;
+        public int   racesPlayed;
+        public int   qualifications;
+        public int   eliminations;
+        public int   checkpointsTotal;
+        public int   bumpsGiven;
+        public float totalPlaytime;
+    }
+}
diff --git a/game/Assets/Scripts/UI/ChatUI.cs b/game/Assets/Scripts/UI/ChatUI.cs
new file mode 100644
index 0000000..8294ecb
--- /dev/null
+++ b/game/Assets/Scripts/UI/ChatUI.cs
@@ -0,0 +1,259 @@
+using System.Collections;
+using System.Collections.Generic;
+using System.Text;
+using UnityEngine;
+using UnityEngine.InputSystem;
+using UnityEngine.Networking;
+
+/// <summary>
+/// General chat panel. Toggle with F3.
+/// Polls GET /chat/history every 3s and sends via POST /chat/send (or Colyseus if connected).
+/// Uses ImGuiSkin for visual consistency.
+/// </summary>
+public class ChatUI : MonoBehaviour
+{
+    public static ChatUI Instance { get; private set; }
+    public static bool IsVisible { get; private set; }
+
+    private const string SERVER_URL = "https://game.rolld.kerboul.me";
+    private const float POLL_INTERVAL = 3f;
+    private const int MAX_DISPLAY = 50;
+
+    private bool _visible;
+    private string _inputText = "";
+    private Vector2 _scrollPos;
+    private float _pollTimer;
+    private long _lastTimestamp;
+    private bool _autoScroll = true;
+
+    private readonly List<ChatMessage> _messages = new();
+    private int _unreadCount;
+
+    // Cached textures for badge
+    private static Texture2D _badgeTex;
+
+    void Awake()
+    {
+        if (Instance != null && Instance != this) { Destroy(gameObject); return; }
+        Instance = this;
+        // Initial load
+        StartCoroutine(DoPoll());
+    }
+
+    void Update()
+    {
+        if (Keyboard.current != null && Keyboard.current[Key.F3].wasPressedThisFrame)
+            Toggle();
+
+        if (_visible)
+        {
+            _pollTimer += Time.deltaTime;
+            if (_pollTimer >= POLL_INTERVAL) { _pollTimer = 0f; StartCoroutine(DoPoll()); }
+
+            // Send on Enter (only when chat input has text)
+            if (!string.IsNullOrWhiteSpace(_inputText) &&
+                Keyboard.current != null && Keyboard.current[Key.Enter].wasPressedThisFrame)
+            {
+                TrySend();
+            }
+        }
+    }
+
+    private void Toggle()
+    {
+        _visible = !_visible;
+        IsVisible = _visible;
+
+        if (_visible)
+        {
+            _unreadCount = 0;
+            _autoScroll = true;
+            _pollTimer = POLL_INTERVAL; // poll immediately
+            Cursor.lockState = CursorLockMode.None;
+            Cursor.visible = true;
+        }
+        else
+        {
+            // Only re-lock if no other UI is open
+            if (!KeyBindingUI.IsVisible)
+            {
+                Cursor.lockState = CursorLockMode.Locked;
+                Cursor.visible = false;
+            }
+        }
+    }
+
+    void OnGUI()
+    {
+        if (!_visible)
+        {
+            DrawBadge();
+            return;
+        }
+
+        ImGuiSkin.EnsureReady();
+
+        // Panel bottom-right, doesn't obstruct the center
+        float w = 460f;
+        float h = 440f;
+        float x = Screen.width - w - 12f;
+        float y = Screen.height - h - 12f;
+
+        ImGuiSkin.BeginWindowAt(x, y, w, h, "CHAT GÉNÉRAL");
+
+        // ── Message history ───────────────────────────────────────────
+        float listH = h - 130f;
+        _scrollPos = GUILayout.BeginScrollView(_scrollPos, ImGuiSkin.ScrollView, GUILayout.Height(listH));
+
+        foreach (var msg in _messages)
+        {
+            var ts = System.DateTimeOffset.FromUnixTimeMilliseconds(msg.timestamp).ToLocalTime();
+            string timeStr = ts.ToString("HH:mm");
+
+            var timeStyle = new GUIStyle(ImGuiSkin.LabelDim) { fontSize = 10, fixedWidth = 36f };
+            var nameStyle = new GUIStyle(ImGuiSkin.LabelBold);
+            nameStyle.normal.textColor = ImGuiSkin.ColAccent;
+            var textStyle = new GUIStyle(ImGuiSkin.LabelRich);
+
+            GUILayout.BeginHorizontal();
+            GUILayout.Label(timeStr, timeStyle);
+            GUILayout.Label(msg.name + " :", nameStyle, GUILayout.Width(100f));
+            GUILayout.Label(msg.text, textStyle);
+            GUILayout.EndHorizontal();
+            GUILayout.Space(1f);
+        }
+
+        if (_autoScroll) _scrollPos.y = float.MaxValue;
+        GUILayout.EndScrollView();
+
+        ImGuiSkin.Separator();
+        GUILayout.Space(4f);
+
+        // ── Input row ────────────────────────────────────────────────
+        GUILayout.BeginHorizontal();
+        GUI.SetNextControlName("ChatInput");
+        _inputText = GUILayout.TextField(_inputText, 200, ImGuiSkin.TextField, GUILayout.Height(28f));
+
+        bool canSend = !string.IsNullOrWhiteSpace(_inputText) && PlayerName.Length > 0;
+        GUI.enabled = canSend;
+        if (GUILayout.Button("Envoyer", ImGuiSkin.Button, GUILayout.Width(80f), GUILayout.Height(28f)))
+            TrySend();
+        GUI.enabled = true;
+        GUILayout.EndHorizontal();
+
+        GUILayout.Space(4f);
+        GUILayout.Label("F3 — Ouvrir / Fermer  ·  Entrée — Envoyer", ImGuiSkin.Footer);
+
+        ImGuiSkin.EndWindow();
+
+        // Auto-focus input field
+        GUI.FocusControl("ChatInput");
+    }
+
+    private void DrawBadge()
+    {
+        if (_unreadCount <= 0) return;
+        if (_badgeTex == null)
+        {
+            _badgeTex = new Texture2D(1, 1);
+            _badgeTex.SetPixel(0, 0, Color.white);
+            _badgeTex.Apply();
+        }
+        float bx = Screen.width - 68f;
+        float by = Screen.height - 32f;
+        GUI.color = new Color(0.9f, 0.2f, 0.2f, 0.9f);
+        GUI.DrawTexture(new Rect(bx, by, 56f, 22f), _badgeTex);
+        GUI.color = Color.white;
+        var s = new GUIStyle(GUI.skin.label) { alignment = TextAnchor.MiddleCenter, fontSize = 11, fontStyle = FontStyle.Bold };
+        s.normal.textColor = Color.white;
+        GUI.Label(new Rect(bx, by, 56f, 22f), $"💬 {_unreadCount}", s);
+    }
+
+    // ─── Send ────────────────────────────────────────────────────────────
+
+    private string PlayerName => NetworkManager.Instance?.LocalPlayerName ?? "";
+
+    private void TrySend()
+    {
+        string text = _inputText.Trim();
+        if (string.IsNullOrEmpty(text) || PlayerName.Length == 0) return;
+        _inputText = "";
+        _autoScroll = true;
+
+        var nm = NetworkManager.Instance;
+        if (nm != null && nm.IsConnected)
+        {
+            // Fast path: through Colyseus (room broadcasts it back to all players AND saves to ChatManager)
+            nm.SendChatMessage(text);
+        }
+        else
+        {
+            // Fallback: direct HTTP (for frontend-only visitors or disconnected state)
+            StartCoroutine(DoSend(PlayerName, text));
+        }
+    }
+
+    // ─── HTTP polling ─────────────────────────────────────────────────────
+
+    private IEnumerator DoPoll()
+    {
+        string url = $"{SERVER_URL}/chat/history?since={_lastTimestamp}";
+        using var req = UnityWebRequest.Get(url);
+        yield return req.SendWebRequest();
+        if (req.result != UnityWebRequest.Result.Success) yield break;
+
+        var wrapper = JsonUtility.FromJson<MessageListWrapper>($"{{\"items\":{req.downloadHandler.text}}}");
+        if (wrapper?.items == null) yield break;
+
+        int added = 0;
+        foreach (var msg in wrapper.items)
+        {
+            if (msg.timestamp > _lastTimestamp)
+            {
+                _messages.Add(msg);
+                _lastTimestamp = msg.timestamp;
+                added++;
+            }
+        }
+        if (_messages.Count > MAX_DISPLAY)
+            _messages.RemoveRange(0, _messages.Count - MAX_DISPLAY);
+
+        if (added > 0 && !_visible)
+            _unreadCount += added;
+    }
+
+    private IEnumerator DoSend(string name, string text)
+    {
+        var payload = new SendPayload { name = name, text = text };
+        string json = JsonUtility.ToJson(payload);
+        byte[] body = Encoding.UTF8.GetBytes(json);
+
+        using var req = new UnityWebRequest($"{SERVER_URL}/chat/send", "POST");
+        req.uploadHandler   = new UploadHandlerRaw(body);
+        req.downloadHandler = new DownloadHandlerBuffer();
+        req.SetRequestHeader("Content-Type", "application/json");
+        yield return req.SendWebRequest();
+    }
+
+    // Called by NetworkManager when a "chat" message arrives via Colyseus
+    public void ReceiveChatMessage(ChatMessage msg)
+    {
+        if (_messages.Count >= MAX_DISPLAY)
+            _messages.RemoveAt(0);
+        _messages.Add(msg);
+        if (msg.timestamp > _lastTimestamp) _lastTimestamp = msg.timestamp;
+        if (!_visible) _unreadCount++;
+        _autoScroll = true;
+    }
+
+    // ─── DTOs ─────────────────────────────────────────────────────────────
+
+    [System.Serializable]
+    public class ChatMessage { public int id; public long timestamp; public string name; public string text; }
+
+    [System.Serializable]
+    private class SendPayload { public string name; public string text; }
+
+    [System.Serializable]
+    private class MessageListWrapper { public List<ChatMessage> items; }
+}
diff --git a/game/Assets/Scripts/UI/GameHUD.cs b/game/Assets/Scripts/UI/GameHUD.cs
index 3e01584..405a17d 100644
--- a/game/Assets/Scripts/UI/GameHUD.cs
+++ b/game/Assets/Scripts/UI/GameHUD.cs
@@ -89,6 +89,8 @@ public class GameHUD : MonoBehaviour
         _countdownPulse = Mathf.Max(0f, _countdownPulse - Time.deltaTime * 3f);
     }
 
+    public float LocalRaceTimer => _localRaceTimer;
+
     public void SetPhase(string phase) => _phase = phase;
     public void SetCountdown(float v) => _countdown = v;
     public void SetRoundInfo(int round, string mode) { _roundNumber = round; _gameMode = mode; }
diff --git a/rolld_backend/game/src/chat/ChatManager.js b/rolld_backend/game/src/chat/ChatManager.js
new file mode 100644
index 0000000..3173bad
--- /dev/null
+++ b/rolld_backend/game/src/chat/ChatManager.js
@@ -0,0 +1,52 @@
+const fs = require("fs");
+const path = require("path");
+
+const DATA_FILE = path.join(__dirname, "../../data/chat.json");
+const MAX_MESSAGES = 200;
+
+let _messages = [];
+let _nextId = 1;
+
+function _load() {
+  try {
+    if (fs.existsSync(DATA_FILE)) {
+      const data = JSON.parse(fs.readFileSync(DATA_FILE, "utf8"));
+      _messages = data.messages || [];
+      _nextId = data.nextId || (_messages.length + 1);
+    }
+  } catch (e) {
+    console.warn("[Chat] Failed to load chat.json:", e.message);
+  }
+}
+
+function _save() {
+  try {
+    fs.mkdirSync(path.dirname(DATA_FILE), { recursive: true });
+    fs.writeFileSync(DATA_FILE, JSON.stringify({ messages: _messages, nextId: _nextId }, null, 2));
+  } catch (e) {
+    console.warn("[Chat] Failed to save chat.json:", e.message);
+  }
+}
+
+function push(name, text) {
+  if (!name || !text || typeof name !== "string" || typeof text !== "string") return null;
+  name = name.slice(0, 32);
+  text = text.slice(0, 200);
+  if (text.trim().length === 0) return null;
+
+  const msg = { id: _nextId++, timestamp: Date.now(), name, text: text.trim() };
+  _messages.push(msg);
+  if (_messages.length > MAX_MESSAGES) _messages.splice(0, _messages.length - MAX_MESSAGES);
+  _save();
+  return msg;
+}
+
+function getHistory(since) {
+  const ts = Number(since) || 0;
+  return ts === 0 ? _messages.slice(-50) : _messages.filter((m) => m.timestamp > ts);
+}
+
+_load();
+console.log(`[Chat] Loaded ${_messages.length} message(s)`);
+
+module.exports = { push, getHistory };
diff --git a/rolld_backend/game/src/index.js b/rolld_backend/game/src/index.js
index 4cafba3..2e20831 100644
--- a/rolld_backend/game/src/index.js
+++ b/rolld_backend/game/src/index.js
@@ -2,28 +2,98 @@ const cors = require('cors');
 const { Server } = require('@colyseus/core');
 const { WebSocketTransport } = require('@colyseus/ws-transport');
 const { ArenaRoom } = require('./rooms/ArenaRoom');
+const Stats = require('./stats/StatsManager');
+const Chat = require('./chat/ChatManager');
+const { z } = require('zod');
 
 const PORT = process.env.PORT || 2567;
 
-// Colyseus 0.17 – express callback receives the transport's internal Express app
+const statsUpdateSchema = z.object({
+  name: z.string().min(1).max(32),
+  stats: z.object({
+    totalDistance:    z.number().optional(),
+    totalJumps:       z.number().optional(),
+    maxSpeed:         z.number().optional(),
+    bestRaceTime:     z.number().optional(),
+    racesPlayed:      z.number().optional(),
+    qualifications:   z.number().optional(),
+    eliminations:     z.number().optional(),
+    checkpointsTotal: z.number().optional(),
+    bumpsGiven:       z.number().optional(),
+    totalPlaytime:    z.number().optional(),
+  }),
+});
+
+const chatSendSchema = z.object({
+  name: z.string().min(1).max(32),
+  text: z.string().min(1).max(200),
+});
+
+let _gameServer;
+
 const gameServer = new Server({
   transport: new WebSocketTransport(),
   express: (app) => {
     app.use(cors());
+    app.use(require('express').json());
 
     app.get('/health', (_req, res) => {
       res.json({ service: 'game', status: 'ok', timestamp: new Date().toISOString() });
     });
 
-    app.get('/', (_req, res) => {
-      res.send('🎮 Game server running');
+    app.get('/', (_req, res) => res.send('🎮 Game server running'));
+
+    // ── Stats ────────────────────────────────────────────────────────────
+    app.get('/stats', (_req, res) => {
+      res.json(Stats.getAll());
+    });
+
+    app.get('/stats/leaderboard/:key', (req, res) => {
+      const board = Stats.getLeaderboard(req.params.key);
+      if (!board) return res.status(400).json({ error: 'invalid key' });
+      res.json(board);
+    });
+
+    app.post('/stats/update', (req, res) => {
+      const parsed = statsUpdateSchema.safeParse(req.body);
+      if (!parsed.success) return res.status(400).json({ error: parsed.error.issues });
+      const ok = Stats.update(parsed.data.name, parsed.data.stats);
+      res.json({ ok });
+    });
+
+    // ── Chat ─────────────────────────────────────────────────────────────
+    app.get('/chat/history', (req, res) => {
+      res.json(Chat.getHistory(req.query.since));
+    });
+
+    app.post('/chat/send', (req, res) => {
+      const parsed = chatSendSchema.safeParse(req.body);
+      if (!parsed.success) return res.status(400).json({ error: parsed.error.issues });
+      const msg = Chat.push(parsed.data.name, parsed.data.text);
+      if (!msg) return res.status(429).json({ error: 'empty or invalid message' });
+
+      // Broadcast to all active Colyseus rooms
+      if (_gameServer) {
+        try {
+          const rooms = _gameServer.matchMaker?.rooms;
+          if (rooms) {
+            for (const room of rooms.values()) {
+              room.broadcast('chat', msg);
+            }
+          }
+        } catch (_) {}
+      }
+
+      res.json(msg);
     });
   },
 });
 
-// Define rooms
-gameServer.define('arena', ArenaRoom);
-console.log('✅ ArenaRoom registered');
+_gameServer = gameServer;
+
+gameServer.define('arena', ArenaRoom).then(() => {
+  console.log('✅ ArenaRoom registered');
+});
 
 gameServer.listen(PORT).then(() => {
   console.log(`🎮 Game server running on ws://localhost:${PORT}`);
diff --git a/rolld_backend/game/src/rooms/ArenaRoom.js b/rolld_backend/game/src/rooms/ArenaRoom.js
index aac5de4..da7d4c6 100644
--- a/rolld_backend/game/src/rooms/ArenaRoom.js
+++ b/rolld_backend/game/src/rooms/ArenaRoom.js
@@ -1,5 +1,6 @@
 const { Room } = require("@colyseus/core");
 const { GameState, Player } = require("../schema/GameState");
+const Chat = require("../chat/ChatManager");
 
 const LOBBY_TIMEOUT = 30;
 const COUNTDOWN_DURATION = 3;
@@ -46,6 +47,13 @@ class ArenaRoom extends Room {
       this._checkAllReady();
     });
 
+    this.onMessage("chat", (client, data) => {
+      const player = this.state.players.get(client.sessionId);
+      if (!player || !data.text) return;
+      const msg = Chat.push(player.name, data.text);
+      if (msg) this.broadcast("chat", msg);
+    });
+
     this.onMessage("checkpointReached", (client, data) => {
       if (this.state.phase !== "playing") return;
       const player = this.state.players.get(client.sessionId);
diff --git a/rolld_backend/game/src/stats/StatsManager.js b/rolld_backend/game/src/stats/StatsManager.js
new file mode 100644
index 0000000..2ecf645
--- /dev/null
+++ b/rolld_backend/game/src/stats/StatsManager.js
@@ -0,0 +1,101 @@
+const fs = require("fs");
+const path = require("path");
+
+const DATA_FILE = path.join(__dirname, "../../data/stats.json");
+
+const VALID_KEYS = [
+  "totalDistance", "totalJumps", "maxSpeed", "bestRaceTime",
+  "racesPlayed", "qualifications", "eliminations",
+  "checkpointsTotal", "bumpsGiven", "totalPlaytime",
+];
+
+let _stats = {};
+const _lastUpdate = new Map(); // name → timestamp, for rate-limiting
+
+function _load() {
+  try {
+    if (fs.existsSync(DATA_FILE)) {
+      _stats = JSON.parse(fs.readFileSync(DATA_FILE, "utf8"));
+    }
+  } catch (e) {
+    console.warn("[Stats] Failed to load stats.json, starting fresh:", e.message);
+    _stats = {};
+  }
+}
+
+function _save() {
+  try {
+    fs.mkdirSync(path.dirname(DATA_FILE), { recursive: true });
+    fs.writeFileSync(DATA_FILE, JSON.stringify(_stats, null, 2));
+  } catch (e) {
+    console.warn("[Stats] Failed to save stats.json:", e.message);
+  }
+}
+
+function _defaults() {
+  return {
+    totalDistance: 0,
+    totalJumps: 0,
+    maxSpeed: 0,
+    bestRaceTime: null,
+    racesPlayed: 0,
+    qualifications: 0,
+    eliminations: 0,
+    checkpointsTotal: 0,
+    bumpsGiven: 0,
+    totalPlaytime: 0,
+  };
+}
+
+function update(name, delta) {
+  if (!name || typeof name !== "string" || name.length > 32) return false;
+
+  const now = Date.now();
+  const last = _lastUpdate.get(name) || 0;
+  if (now - last < 5000) return false; // rate-limit: 1 update per 5s per player
+  _lastUpdate.set(name, now);
+
+  if (!_stats[name]) _stats[name] = _defaults();
+  const p = _stats[name];
+
+  for (const key of VALID_KEYS) {
+    if (delta[key] === undefined) continue;
+    const val = Number(delta[key]);
+    if (isNaN(val)) continue;
+
+    if (key === "maxSpeed") {
+      p.maxSpeed = Math.max(p.maxSpeed, val);
+    } else if (key === "bestRaceTime") {
+      if (val > 0 && (p.bestRaceTime === null || val < p.bestRaceTime)) {
+        p.bestRaceTime = val;
+      }
+    } else {
+      p[key] = (p[key] || 0) + val;
+    }
+  }
+
+  _save();
+  return true;
+}
+
+function getAll() {
+  return Object.entries(_stats).map(([name, s]) => ({ name, ...s }));
+}
+
+function getLeaderboard(key) {
+  if (!VALID_KEYS.includes(key)) return [];
+  return Object.entries(_stats)
+    .map(([name, s]) => ({ name, value: s[key] ?? 0 }))
+    .filter((e) => e.value !== null && e.value > 0)
+    .sort((a, b) => {
+      // bestRaceTime: lower is better
+      if (key === "bestRaceTime") return a.value - b.value;
+      return b.value - a.value;
+    })
+    .slice(0, 10);
+}
+
+_load();
+console.log(`[Stats] Loaded ${Object.keys(_stats).length} player(s)`);
+
+module.exports = { update, getAll, getLeaderboard, VALID_KEYS };