Rework PoE2 module: pairwise currency exchange rates, 1h/24h/7d change

PoE2's economy is inherently pairwise (Exalted vs Chaos, Divine vs
Exalted), not everything quoted in one reference currency, so the
watchlist now tracks admin-picked currency pairs and shows both
directions with 1h/24h/7d change. poe.ninja doesn't expose per-pair
rates or multiple change windows, so both are self-computed: any
pair's rate comes from dividing the two currencies' primaryValue
(same reference currency cancels out), and change% is derived from
our own poll-history snapshots rather than poe.ninja's fixed 7-day
sparkline. The inverse direction's change is exact closed-form math
from the forward change, not a sign-flip approximation.

The old single-currency watchlist schema can't be mapped onto pairs,
so migrate() drops and rebuilds poe2_watchlist when it detects the
old shape.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014c1L8ghNBFjfiH64UMViP8

backend/src/api/admin.ts

@@ -292,11 +292,22 @@ export async function registerAdminRoutes(app: FastifyInstance) {
 	app.get('/api/admin/poe2/watchlist', async () => poe2WatchlistDb.listWatchlist());
 
 	app.post('/api/admin/poe2/watchlist', async (req, reply) => {
-		const { currencyId, name, icon } = req.body as { currencyId?: string; name?: string; icon?: string | null };
-		if (!currencyId || !name) return reply.code(400).send({ error: 'currencyId and name are required' });
-		const created = poe2WatchlistDb.addWatchlistEntry(currencyId, name, icon ?? null);
+		const { base, quote } = req.body as {
+			base?: { currencyId?: string; name?: string; icon?: string | null };
+			quote?: { currencyId?: string; name?: string; icon?: string | null };
+		};
+		if (!base?.currencyId || !base?.name || !quote?.currencyId || !quote?.name) {
+			return reply.code(400).send({ error: 'base and quote currencies (currencyId, name) are required' });
+		}
+		if (base.currencyId === quote.currencyId) {
+			return reply.code(400).send({ error: 'Base and quote currencies must be different' });
+		}
+		const created = poe2WatchlistDb.addWatchlistEntry(
+			{ currencyId: base.currencyId, name: base.name, icon: base.icon ?? null },
+			{ currencyId: quote.currencyId, name: quote.name, icon: quote.icon ?? null }
+		);
 		// Poll immediately rather than waiting for the next tick (up to 15 minutes) — cheap,
-		// and refreshes every existing entry's value too.
+		// and refreshes every existing entry's rate too.
 		pollPoe2Now().catch((err) => logger.error('poe2', `Immediate poll failed: ${err.message}`));
 		return reply.code(201).send(created);
 	});

backend/src/api/public.ts

@@ -72,7 +72,7 @@ export async function registerPublicRoutes(app: FastifyInstance) {
 	});
 
 	app.get('/api/poe2', async () => {
-		const { leagueName, primaryCurrencyName, updatedAt } = settingsDb.getSettings().poe2;
-		return { leagueName, primaryCurrencyName, updatedAt, entries: poe2WatchlistDb.listWatchlist() };
+		const { leagueName, updatedAt } = settingsDb.getSettings().poe2;
+		return { leagueName, updatedAt, entries: poe2WatchlistDb.listWatchlist() };
 	});
 }

backend/src/poe2/client.ts

@@ -7,9 +7,15 @@
 // imprecise on two points): currency name/icon metadata lives in a top-level `items[]` array
 // on the overview response, NOT `core.items` (that only holds the handful of currencies used
 // for `core.rates`/`primary`/`secondary`). The icon field is `image` (a path relative to this
-// same host), not `icon`. Confirmed `sparkline.totalChange` always equals the last entry of
-// `sparkline.data`, and every observed `data` array has exactly 7 entries — so this is a
-// 7-day cumulative % change, not some other window.
+// same host), not `icon`.
+//
+// Deliberately not using poe.ninja's own `core` (reference currency) or `sparkline` (a fixed
+// 7-day window) fields at all — the watchlist tracks arbitrary currency pairs with 1h/24h/7d
+// change, neither of which poe.ninja's overview exposes directly. Every line's `primaryValue`
+// is expressed in the same (unspecified, and irrelevant) reference currency, so any pair's
+// rate is just baseValue / quoteValue with the reference cancelling out — see
+// fetchCurrencyValues below and poe2/poller.ts, which self-computes change from its own
+// polling history instead.
 const BASE_URL = 'https://poe.ninja';
 
 export interface LeagueInfo {
@@ -23,12 +29,6 @@ export interface CurrencyBrowseEntry {
 	icon: string | null;
 }
 
-export interface CurrencyQuote {
-	value: number;
-	/** 7-day cumulative % change (see file header) — null if this line had no sparkline data. */
-	changePercent: number | null;
-}
-
 interface RawCurrencyItem {
 	id: string;
 	name: string;
@@ -38,11 +38,9 @@ interface RawCurrencyItem {
 interface RawCurrencyLine {
 	id: string;
 	primaryValue: number;
-	sparkline?: { totalChange: number; data: number[] } | null;
 }
 
 interface RawCurrencyOverview {
-	core: { primary: string };
 	lines: RawCurrencyLine[];
 	items: RawCurrencyItem[]; // top-level, not core.items — see file header
 }
@@ -80,27 +78,13 @@ export async function browseCurrencies(leagueId: string): Promise<CurrencyBrowse
 		.sort((a, b) => a.name.localeCompare(b.name));
 }
 
-// One overview fetch covers every watchlisted currency regardless of list size — unlike
+// One overview fetch covers every watchlisted pair regardless of list size — unlike
 // Stocks, which needs one request per ticker (Yahoo has no equivalent single "give me all of
-// these" endpoint without a cookie/crumb handshake).
-export async function fetchWatchlistQuotes(
-	leagueId: string,
-	currencyIds: string[]
-): Promise<{ quotes: Map<string, CurrencyQuote | Error>; primaryCurrencyName: string | null }> {
-	const { lines, items, core } = await fetchCurrencyOverview(leagueId);
-	const lineById = new Map(lines.map((line) => [line.id, line]));
-	const nameById = new Map(items.map((item) => [item.id, item.name]));
-
-	const quotes = new Map<string, CurrencyQuote | Error>();
-	for (const id of currencyIds) {
-		const line = lineById.get(id);
-		if (!line) {
-			quotes.set(id, new Error('No longer traded in this league'));
-			continue;
-		}
-		quotes.set(id, { value: line.primaryValue, changePercent: line.sparkline?.totalChange ?? null });
-	}
-
-	const primaryCurrencyName = nameById.get(core.primary) ?? core.primary;
-	return { quotes, primaryCurrencyName };
+// these" endpoint without a cookie/crumb handshake). Every line's primaryValue is expressed
+// in the same reference currency, so any pair's rate is just baseValue / quoteValue — the
+// reference currency itself cancels out, meaning this same one fetch works for arbitrary
+// pairs without needing to know or care what poe.ninja's own reference currency is.
+export async function fetchCurrencyValues(leagueId: string): Promise<Map<string, number>> {
+	const { lines } = await fetchCurrencyOverview(leagueId);
+	return new Map(lines.map((line) => [line.id, line.primaryValue]));
 }

backend/src/poe2/poller.ts

@@ -1,13 +1,21 @@
 import * as poe2WatchlistDb from '../storage/db/poe2Watchlist.js';
 import * as settingsDb from '../storage/db/settings.js';
 import { logger } from '../storage/db/logs.js';
-import { fetchCurrentLeague, fetchWatchlistQuotes } from './client.js';
+import { fetchCurrentLeague, fetchCurrencyValues } from './client.js';
 
-// Called on a schedule (see queue/scheduler.ts) and immediately after the admin adds a
-// currency (see api/admin.ts) — always re-detects the current challenge league fresh (cheap,
-// guarantees correctness across league rotations with no separate staleness logic), then one
-// overview request covers the whole watchlist. A currency no longer traded this league gets
-// its own lastError, it never aborts the rest of the batch.
+const HOUR_MS = 60 * 60_000;
+const DAY_MS = 24 * HOUR_MS;
+
+function pctChange(current: number, past: number | null): number | null {
+	if (past === null || past === 0) return null;
+	return ((current - past) / past) * 100;
+}
+
+// Called on a schedule (see queue/scheduler.ts) and immediately after the admin adds a pair
+// (see api/admin.ts) — always re-detects the current challenge league fresh (cheap, guarantees
+// correctness across league rotations with no separate staleness logic), then one overview
+// request covers the whole watchlist. A pair whose base or quote currency is no longer traded
+// this league gets its own lastError, it never aborts the rest of the batch.
 export async function pollPoe2Now(): Promise<void> {
 	let league;
 	try {
@@ -27,22 +35,32 @@ export async function pollPoe2Now(): Promise<void> {
 	}
 
 	try {
-		const { quotes, primaryCurrencyName } = await fetchWatchlistQuotes(
-			league.id,
-			entries.map((e) => e.currencyId)
-		);
+		const valuesById = await fetchCurrencyValues(league.id);
+		const now = new Date();
+		const nowIso = now.toISOString();
+		const cutoff1h = new Date(now.getTime() - HOUR_MS).toISOString();
+		const cutoff24h = new Date(now.getTime() - DAY_MS).toISOString();
+		const cutoff7d = new Date(now.getTime() - 7 * DAY_MS).toISOString();
+
 		for (const entry of entries) {
-			const quote = quotes.get(entry.currencyId);
-			if (!quote) {
-				poe2WatchlistDb.markPolled(entry.id, null, null, 'No quote returned');
-			} else if (quote instanceof Error) {
-				poe2WatchlistDb.markPolled(entry.id, null, null, quote.message);
-			} else {
-				poe2WatchlistDb.markPolled(entry.id, quote.value, quote.changePercent, null);
+			const baseValue = valuesById.get(entry.baseCurrencyId);
+			const quoteValue = valuesById.get(entry.quoteCurrencyId);
+			if (baseValue === undefined || quoteValue === undefined) {
+				poe2WatchlistDb.markPolled(entry.id, null, null, null, null, 'One or both currencies no longer traded in this league');
+				continue;
 			}
+
+			const rate = baseValue / quoteValue;
+			const change1h = pctChange(rate, poe2WatchlistDb.rateAtOrBefore(entry.id, cutoff1h));
+			const change24h = pctChange(rate, poe2WatchlistDb.rateAtOrBefore(entry.id, cutoff24h));
+			const change7d = pctChange(rate, poe2WatchlistDb.rateAtOrBefore(entry.id, cutoff7d));
+			poe2WatchlistDb.recordRate(entry.id, rate, nowIso);
+			poe2WatchlistDb.markPolled(entry.id, rate, change1h, change24h, change7d, null);
 		}
+
+		poe2WatchlistDb.pruneOldHistory();
 		settingsDb.updateSettings({
-			poe2: { leagueId: league.id, leagueName: league.name, primaryCurrencyName, updatedAt: new Date().toISOString() }
+			poe2: { leagueId: league.id, leagueName: league.name, updatedAt: nowIso }
 		});
 	} catch (err) {
 		logger.error('poe2', `Watchlist poll failed: ${(err as Error).message}`);

backend/src/storage/db/index.ts

@@ -25,6 +25,14 @@ export function migrate() {
 	db.exec('DROP TABLE IF EXISTS admin_users;');
 	db.exec('DROP TABLE IF EXISTS sessions;');
 
+	// PoE2 watchlist model changed from "value quoted in one primary currency" to arbitrary
+	// currency pairs (base/quote) — the old single-currency rows can't be mapped onto a pair,
+	// so the table is dropped and rebuilt fresh below rather than migrated column-by-column.
+	const poe2WatchlistCols = db.prepare(`PRAGMA table_info(poe2_watchlist)`).all() as { name: string }[];
+	if (poe2WatchlistCols.some((c) => c.name === 'currency_id')) {
+		db.exec('DROP TABLE IF EXISTS poe2_watchlist;');
+	}
+
 	db.exec(`
 		CREATE TABLE IF NOT EXISTS sources (
 			id TEXT PRIMARY KEY,
@@ -192,7 +200,7 @@ export function migrate() {
 			weather_updated_at TEXT, -- ISO timestamp, NULL pre-first-poll
 			poe2_league_id TEXT,
 			poe2_league_name TEXT,
-			poe2_primary_currency_name TEXT, -- e.g. "Divine Orb" — the unit every poe2_watchlist value is quoted in
+			poe2_primary_currency_name TEXT, -- unused since the watchlist moved to arbitrary currency pairs (no single "quoted in" currency anymore) — column kept rather than dropped, SQLite ALTER TABLE can't drop columns without a full table rebuild
 			poe2_updated_at TEXT
 		);
 
@@ -211,22 +219,40 @@ export function migrate() {
 			created_at TEXT NOT NULL
 		);
 
-		-- Sidebar "PoE2" widget — currency watchlist priced off poe.ninja's PoE2 economy API
+		-- Sidebar "PoE2" widget — tracks exchange rates between arbitrary currency pairs
 		-- (see poe2/poller.ts), always against the current challenge league (auto-detected,
-		-- no admin config). Same shape as stock_tickers — poll state lives on the row.
+		-- no admin config). Rate is "1 base = last_rate quote"; both currencies' names/icons
+		-- are captured at add-time from the browse picker, not re-resolved.
 		CREATE TABLE IF NOT EXISTS poe2_watchlist (
 			id TEXT PRIMARY KEY,
-			currency_id TEXT NOT NULL, -- opaque id from the exchange overview's lines[].id, e.g. "divine"
-			name TEXT NOT NULL, -- captured at add-time from the browse picker, not re-resolved
-			icon TEXT,
+			base_currency_id TEXT NOT NULL, -- opaque id from the exchange overview's lines[].id, e.g. "exalted"
+			base_name TEXT NOT NULL,
+			base_icon TEXT,
+			quote_currency_id TEXT NOT NULL,
+			quote_name TEXT NOT NULL,
+			quote_icon TEXT,
 			priority_rank INTEGER NOT NULL,
-			last_value REAL,
-			last_change_percent REAL,
+			last_rate REAL,
+			last_change_1h REAL,
+			last_change_24h REAL,
+			last_change_7d REAL,
 			last_polled_at TEXT,
 			last_error TEXT,
 			created_at TEXT NOT NULL
 		);
 
+		-- Per-poll rate snapshots for the pairs above — poe.ninja only exposes one 7-day
+		-- change window, so 1h/24h/7d change is computed ourselves from this history
+		-- (see poe2/poller.ts), rather than trusting a field poe.ninja doesn't provide.
+		-- Pruned to the last 8 days on every poll.
+		CREATE TABLE IF NOT EXISTS poe2_rate_history (
+			id INTEGER PRIMARY KEY AUTOINCREMENT,
+			watchlist_id TEXT NOT NULL,
+			rate REAL NOT NULL,
+			recorded_at TEXT NOT NULL
+		);
+		CREATE INDEX IF NOT EXISTS idx_poe2_rate_history_watchlist ON poe2_rate_history(watchlist_id, recorded_at);
+
 		-- Sidebar "Bookmarks" widget — admin-curated links, each independently hidden/public
 		-- via is_private (same private-access lock feature as categories.is_private).
 		CREATE TABLE IF NOT EXISTS bookmarks (

backend/src/storage/db/poe2Watchlist.ts

@@ -2,15 +2,26 @@ import { randomUUID } from 'node:crypto';
 import { db } from './index.js';
 import type { Poe2WatchlistEntry } from './types.js';
 
+interface CurrencyRef {
+	currencyId: string;
+	name: string;
+	icon: string | null;
+}
+
 function rowToEntry(row: any): Poe2WatchlistEntry {
 	return {
 		id: row.id,
-		currencyId: row.currency_id,
-		name: row.name,
-		icon: row.icon,
+		baseCurrencyId: row.base_currency_id,
+		baseName: row.base_name,
+		baseIcon: row.base_icon,
+		quoteCurrencyId: row.quote_currency_id,
+		quoteName: row.quote_name,
+		quoteIcon: row.quote_icon,
 		priorityRank: row.priority_rank,
-		lastValue: row.last_value,
-		lastChangePercent: row.last_change_percent,
+		lastRate: row.last_rate,
+		lastChange1h: row.last_change_1h,
+		lastChange24h: row.last_change_24h,
+		lastChange7d: row.last_change_7d,
 		lastPolledAt: row.last_polled_at,
 		lastError: row.last_error,
 		createdAt: row.created_at
@@ -22,28 +33,83 @@ export function listWatchlist(): Poe2WatchlistEntry[] {
 	return rows.map(rowToEntry);
 }
 
-// No update() — entries are picked from a live browse list (see poe2/client.ts's
+// No update() — currencies are picked from a live browse list (see poe2/client.ts's
 // browseCurrencies), not typed, so there's nothing to edit; remove and re-add covers the
 // rare "picked the wrong one" case.
-export function addWatchlistEntry(currencyId: string, name: string, icon: string | null): Poe2WatchlistEntry {
-	const id = `poe2-${currencyId.toLowerCase().replace(/[^a-z0-9]+/g, '-').replace(/(^-|-$)/g, '')}-${randomUUID().slice(0, 6)}`;
+export function addWatchlistEntry(base: CurrencyRef, quote: CurrencyRef): Poe2WatchlistEntry {
+	const id = `poe2-${base.currencyId.toLowerCase().replace(/[^a-z0-9]+/g, '-')}-${quote.currencyId.toLowerCase().replace(/[^a-z0-9]+/g, '-')}-${randomUUID().slice(0, 6)}`
+		.replace(/-+/g, '-')
+		.replace(/(^-|-$)/g, '');
 	const maxRank = db.prepare('SELECT COALESCE(MAX(priority_rank), 0) as m FROM poe2_watchlist').get() as { m: number };
 	const createdAt = new Date().toISOString();
 	db.prepare(
-		'INSERT INTO poe2_watchlist (id, currency_id, name, icon, priority_rank, created_at) VALUES (?, ?, ?, ?, ?, ?)'
-	).run(id, currencyId, name, icon, maxRank.m + 1, createdAt);
+		`INSERT INTO poe2_watchlist
+			(id, base_currency_id, base_name, base_icon, quote_currency_id, quote_name, quote_icon, priority_rank, created_at)
+			VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)`
+	).run(id, base.currencyId, base.name, base.icon, quote.currencyId, quote.name, quote.icon, maxRank.m + 1, createdAt);
 	return {
-		id, currencyId, name, icon, priorityRank: maxRank.m + 1,
-		lastValue: null, lastChangePercent: null, lastPolledAt: null, lastError: null, createdAt
+		id,
+		baseCurrencyId: base.currencyId,
+		baseName: base.name,
+		baseIcon: base.icon,
+		quoteCurrencyId: quote.currencyId,
+		quoteName: quote.name,
+		quoteIcon: quote.icon,
+		priorityRank: maxRank.m + 1,
+		lastRate: null,
+		lastChange1h: null,
+		lastChange24h: null,
+		lastChange7d: null,
+		lastPolledAt: null,
+		lastError: null,
+		createdAt
 	};
 }
 
 export function removeWatchlistEntry(id: string) {
+	db.prepare('DELETE FROM poe2_rate_history WHERE watchlist_id = ?').run(id);
 	db.prepare('DELETE FROM poe2_watchlist WHERE id = ?').run(id);
 }
 
-export function markPolled(id: string, value: number | null, changePercent: number | null, error: string | null) {
-	db.prepare(
-		'UPDATE poe2_watchlist SET last_value = ?, last_change_percent = ?, last_polled_at = ?, last_error = ? WHERE id = ?'
-	).run(value, changePercent, new Date().toISOString(), error, id);
+// One snapshot per poll (see poe2/poller.ts) — the raw material 1h/24h/7d change is
+// computed from, since poe.ninja itself doesn't expose per-pair rates or multiple
+// change windows.
+export function recordRate(watchlistId: string, rate: number, recordedAt: string) {
+	db.prepare('INSERT INTO poe2_rate_history (watchlist_id, rate, recorded_at) VALUES (?, ?, ?)').run(
+		watchlistId,
+		rate,
+		recordedAt
+	);
+}
+
+// The closest snapshot at-or-before cutoffIso — null if there isn't one yet (e.g. a
+// pair added less than a window ago), which the poller treats as "no change data yet"
+// rather than fabricating a 0% figure.
+export function rateAtOrBefore(watchlistId: string, cutoffIso: string): number | null {
+	const row = db
+		.prepare('SELECT rate FROM poe2_rate_history WHERE watchlist_id = ? AND recorded_at <= ? ORDER BY recorded_at DESC LIMIT 1')
+		.get(watchlistId, cutoffIso) as { rate: number } | undefined;
+	return row ? row.rate : null;
+}
+
+export function markPolled(
+	id: string,
+	rate: number | null,
+	change1h: number | null,
+	change24h: number | null,
+	change7d: number | null,
+	error: string | null
+) {
+	db.prepare(
+		`UPDATE poe2_watchlist
+			SET last_rate = ?, last_change_1h = ?, last_change_24h = ?, last_change_7d = ?, last_polled_at = ?, last_error = ?
+			WHERE id = ?`
+	).run(rate, change1h, change24h, change7d, new Date().toISOString(), error, id);
+}
+
+// Keeps history bounded — 8 days is enough slack past the 7d window for a poll to be
+// briefly late without losing the data point it needs.
+export function pruneOldHistory() {
+	const cutoff = new Date(Date.now() - 8 * 24 * 60 * 60 * 1000).toISOString();
+	db.prepare('DELETE FROM poe2_rate_history WHERE recorded_at < ?').run(cutoff);
 }

backend/src/storage/db/settings.ts

@@ -40,7 +40,6 @@ function rowToSettings(row: any): GlobalSettings {
 		poe2: {
 			leagueId: row.poe2_league_id,
 			leagueName: row.poe2_league_name,
-			primaryCurrencyName: row.poe2_primary_currency_name,
 			updatedAt: row.poe2_updated_at
 		}
 	};
@@ -72,7 +71,7 @@ export function updateSettings(patch: Partial<GlobalSettings>): GlobalSettings {
 			weather_location_name=?, weather_latitude=?, weather_longitude=?, weather_unit=?,
 			weather_wind_unit=?, weather_pressure_unit=?,
 			weather_current=?, weather_hourly=?, weather_daily=?, weather_alerts=?, weather_updated_at=?,
-			poe2_league_id=?, poe2_league_name=?, poe2_primary_currency_name=?, poe2_updated_at=?
+			poe2_league_id=?, poe2_league_name=?, poe2_updated_at=?
 		 WHERE id = 1`
 	).run(
 		merged.mergeStrictness,
@@ -106,7 +105,6 @@ export function updateSettings(patch: Partial<GlobalSettings>): GlobalSettings {
 		merged.weather.updatedAt,
 		merged.poe2.leagueId,
 		merged.poe2.leagueName,
-		merged.poe2.primaryCurrencyName,
 		merged.poe2.updatedAt
 	);
 	return getSettings();

backend/src/storage/db/types.ts

@@ -235,14 +235,24 @@ export interface StockTicker {
 
 export interface Poe2WatchlistEntry {
 	id: string;
-	/** Opaque id from poe.ninja's exchange overview, e.g. "divine" — not a display name. */
-	currencyId: string;
-	name: string;
-	icon: string | null;
+	/** Opaque id from poe.ninja's exchange overview, e.g. "exalted" — not a display name. */
+	baseCurrencyId: string;
+	baseName: string;
+	baseIcon: string | null;
+	quoteCurrencyId: string;
+	quoteName: string;
+	quoteIcon: string | null;
 	priorityRank: number;
-	lastValue: number | null;
-	/** Cumulative % change over poe.ninja's own sparkline window — confirmed to be 7 days (see poe2/client.ts). */
-	lastChangePercent: number | null;
+	/** 1 base = lastRate quote. */
+	lastRate: number | null;
+	/**
+	 * % change over the last 1h/24h/7d, self-computed from poe2_rate_history since
+	 * poe.ninja only exposes one 7-day window (see poe2/poller.ts) — null when there
+	 * isn't yet enough history for that window (e.g. a pair just added).
+	 */
+	lastChange1h: number | null;
+	lastChange24h: number | null;
+	lastChange7d: number | null;
 	lastPolledAt: string | null;
 	lastError: string | null;
 	createdAt: string;
@@ -323,8 +333,6 @@ export interface GlobalSettings {
 	poe2: {
 		leagueId: string | null;
 		leagueName: string | null;
-		/** e.g. "Divine Orb" — the unit every poe2_watchlist value is quoted in. */
-		primaryCurrencyName: string | null;
 		updatedAt: string | null;
 	};
 }