set rating based on user score

src/lib/server/db/schema.ts

@@ -195,6 +195,8 @@ export const playerRating = pgTable('player_rating', {
 	elo: integer('elo').default(1000).notNull(),
 	wins: integer('wins').default(0).notNull(),
 	losses: integer('losses').default(0).notNull(),
+	initialElo: integer('initial_elo'),
+	osuRankAtSeed: integer('osu_rank_at_seed'),
 	updatedAt: timestamp('updated_at', { withTimezone: true }).defaultNow().notNull()
 });
 

src/lib/server/match/engine.ts

@@ -9,9 +9,42 @@ import {
 	playerRating,
 	teamMember
 } from '$lib/server/db/schema';
-import { eq, asc, sql, inArray, lt } from 'drizzle-orm';
+import { account } from '$lib/server/db/auth.schema';
+import { eq, and, asc, sql, inArray, lt } from 'drizzle-orm';
 import { MATCH_STATES, GAME_STATES, type MatchConfig } from './types';
 import { notifyMatchCreated, notifyMatchFinished } from '$lib/server/discord/client';
+import { getUser } from '$lib/server/osu/api';
+
+// ── Initial Rating ──────────────────────────────────────────────────────
+
+async function calculateInitialElo(userId: string): Promise<{ elo: number; osuRank: number | null }> {
+	const osuAccount = await db.query.account.findFirst({
+		where: and(eq(account.userId, userId), eq(account.providerId, 'osu'))
+	});
+
+	if (!osuAccount?.accountId) {
+		return { elo: 1000, osuRank: null };
+	}
+
+	try {
+		const osuUser = await getUser(osuAccount.accountId);
+		const rank = osuUser?.statistics?.global_rank;
+
+		if (!rank || rank <= 0) {
+			return { elo: 1000, osuRank: null };
+		}
+
+		// elo = 3500 - log10(rank) * 500
+		// rank 1 → 3500, rank 1000 → 2000, rank 100k → 1000, rank 1M → 500
+		const rawElo = 3500 - Math.log10(rank) * 500;
+		const elo = Math.round(Math.max(0, Math.min(3500, rawElo)));
+
+		return { elo, osuRank: rank };
+	} catch (err) {
+		console.warn(`[Rating] Failed to fetch osu! rank for user ${userId}, defaulting to 1000:`, err);
+		return { elo: 1000, osuRank: null };
+	}
+}
 
 // ── Queue ───────────────────────────────────────────────────────────────
 
@@ -36,9 +69,10 @@ export async function joinQueue(userId: string, teamId: string) {
 	});
 
 	if (!rating) {
+		const { elo: initialElo, osuRank } = await calculateInitialElo(userId);
 		[rating] = await db
 			.insert(playerRating)
-			.values({ userId, elo: 1000 })
+			.values({ userId, elo: initialElo, initialElo, osuRankAtSeed: osuRank })
 			.returning();
 	}
 
@@ -192,8 +226,8 @@ async function selectMappoolForRating(avgElo: number) {
 
 	if (pools.length === 0) return null;
 
-	// Map ELO range (e.g. 800-1200) to star rating range (e.g. 3-7)
-	const targetStars = 3 + ((avgElo - 800) / 400) * 4;
+	// Map ELO range (0-3500) to star rating range (2-8)
+	const targetStars = 2 + avgElo / 700;
 	const clampedTarget = Math.max(2, Math.min(8, targetStars));
 
 	// Score each pool by distance from target
@@ -513,29 +547,52 @@ export async function submitGameScores(
 // ── ELO ─────────────────────────────────────────────────────────────────
 
 async function updateElo(participants: { id: string; teamId: string }[], winnerId: string) {
+	// Gather all players and their ratings per participant (team side)
+	const sides = new Map<string, { userId: string; rating: typeof playerRating.$inferSelect }[]>();
+
 	for (const p of participants) {
 		const players = await db.query.matchParticipantPlayer.findMany({
 			where: eq(matchParticipantPlayer.participantId, p.id)
 		});
 
-		const isWinner = p.id === winnerId;
-
+		const playersWithRatings = [];
 		for (const player of players) {
 			let rating = await db.query.playerRating.findFirst({
 				where: eq(playerRating.userId, player.userId)
 			});
 
 			if (!rating) {
+				const { elo: initialElo, osuRank } = await calculateInitialElo(player.userId);
 				[rating] = await db
 					.insert(playerRating)
-					.values({ userId: player.userId, elo: 1000 })
+					.values({ userId: player.userId, elo: initialElo, initialElo, osuRankAtSeed: osuRank })
 					.returning();
 			}
 
-			const K = 32;
-			const expected = 0.5;
+			playersWithRatings.push({ userId: player.userId, rating });
+		}
+		sides.set(p.id, playersWithRatings);
+	}
+
+	// Compute average ELO per side for expected-score calculation
+	const avgElo = new Map<string, number>();
+	for (const [pid, players] of sides) {
+		avgElo.set(pid, players.reduce((sum, p) => sum + p.rating.elo, 0) / players.length);
+	}
+
+	// Update each player's ELO using proper expected-score formula
+	for (const p of participants) {
+		const isWinner = p.id === winnerId;
+		const opponent = participants.find((op) => op.id !== p.id)!;
+		const opponentAvg = avgElo.get(opponent.id)!;
+
+		for (const { userId, rating } of sides.get(p.id)!) {
+			const gamesPlayed = rating.wins + rating.losses;
+			const K = gamesPlayed < 10 ? 40 : gamesPlayed < 30 ? 32 : 24;
+
+			const expected = 1 / (1 + Math.pow(10, (opponentAvg - rating.elo) / 400));
 			const actual = isWinner ? 1 : 0;
-			const newElo = Math.round(rating.elo + K * (actual - expected));
+			const newElo = Math.max(0, Math.round(rating.elo + K * (actual - expected)));
 
 			await db
 				.update(playerRating)
@@ -545,7 +602,7 @@ async function updateElo(participants: { id: string; teamId: string }[], winnerI
 					losses: isWinner ? rating.losses : rating.losses + 1,
 					updatedAt: new Date()
 				})
-				.where(eq(playerRating.userId, player.userId));
+				.where(eq(playerRating.userId, userId));
 		}
 	}
 }

src/routes/(app)/leaderboard/+page.svelte

@@ -10,9 +10,10 @@
 	];
 
 	function eloColor(elo: number): string {
-		if (elo >= 1400) return 'text-yellow-400';
-		if (elo >= 1200) return 'text-purple-400';
-		if (elo >= 1000) return 'text-blue-400';
+		if (elo >= 2500) return 'text-yellow-400';
+		if (elo >= 2000) return 'text-purple-400';
+		if (elo >= 1500) return 'text-blue-400';
+		if (elo >= 1000) return 'text-green-400';
 		return 'text-text-secondary';
 	}
 
@@ -235,10 +236,11 @@
 	<div class="mt-6 rounded-lg border border-border bg-surface-800 p-5">
 		<h2 class="text-sm font-600">How ELO Works</h2>
 		<p class="mt-2 text-xs text-text-secondary leading-relaxed">
-			Every player starts at 1000 ELO. Win a match to gain points, lose to drop.
-			The system uses K=32, so new players' ratings shift quickly. As you play more,
-			your rating stabilizes around your true skill level. Queue matchmaking pairs players
-			with similar ELO for fair matches.
+			Your initial rating is seeded from your osu! global rank. Winning gains ELO and
+			losing drops it, but the amount depends on your opponent's rating — beating a
+			stronger player earns more points. New players' ratings shift faster to help
+			find your true skill level quickly. Queue matchmaking pairs players with similar
+			ELO for fair matches.
 		</p>
 	</div>
 </div>

src/routes/(app)/settings/+page.server.ts

@@ -31,7 +31,7 @@ export const load: PageServerLoad = async ({ locals }) => {
 		},
 		rating: rating
 			? { elo: rating.elo, wins: rating.wins, losses: rating.losses }
-			: { elo: 1000, wins: 0, losses: 0 },
+			: null,
 		hasOsuLinked: !!osuAccount
 	};
 };

src/routes/(app)/settings/+page.svelte

@@ -12,7 +12,7 @@
 	const badge = $derived(roleBadge[data.profile.role] ?? roleBadge.player);
 
 	const winRate = $derived(
-		data.rating.wins + data.rating.losses > 0
+		data.rating && data.rating.wins + data.rating.losses > 0
 			? ((data.rating.wins / (data.rating.wins + data.rating.losses)) * 100).toFixed(1)
 			: '—'
 	);
@@ -79,15 +79,15 @@
 		<h3 class="text-xs font-600 text-text-secondary uppercase tracking-wider">Ranked Stats</h3>
 		<div class="mt-4 grid grid-cols-4 gap-4">
 			<div>
-				<p class="text-2xl font-800 tabular-nums text-accent">{data.rating.elo}</p>
+				<p class="text-2xl font-800 tabular-nums text-accent">{data.rating?.elo ?? '—'}</p>
 				<p class="mt-1 text-xs text-text-secondary">ELO Rating</p>
 			</div>
 			<div>
-				<p class="text-2xl font-800 tabular-nums text-green-400">{data.rating.wins}</p>
+				<p class="text-2xl font-800 tabular-nums text-green-400">{data.rating?.wins ?? 0}</p>
 				<p class="mt-1 text-xs text-text-secondary">Wins</p>
 			</div>
 			<div>
-				<p class="text-2xl font-800 tabular-nums text-red-400">{data.rating.losses}</p>
+				<p class="text-2xl font-800 tabular-nums text-red-400">{data.rating?.losses ?? 0}</p>
 				<p class="mt-1 text-xs text-text-secondary">Losses</p>
 			</div>
 			<div>