feat(finance): watchlist sparklines (last week, Datatype font)

src/app/api/finance/sparklines/route.ts

@@ -0,0 +1,66 @@
+/**
+ * GET /api/finance/sparklines?symbols=NVDA,AAPL,…
+ *
+ * Returns last-week close samples per symbol for the tiny watchlist sparklines.
+ * Paid-gated; uses the per-profile market-data provider (connected Alpaca →
+ * Yahoo fallback) and read-through caches each symbol's samples.
+ */
+
+import { NextRequest, NextResponse } from 'next/server';
+import { requireActiveSubscription } from '@/lib/subscription/guard';
+import { getActiveProfileId } from '@/lib/profiles/profile-utils';
+import { getFallbackMarketDataProvider, type MarketDataProvider } from '@/lib/finance/market-data';
+import { getMarketDataProviderForProfile } from '@/lib/finance/market-data/for-profile';
+import { readThrough, CANDLES_TTL_SECONDS } from '@/lib/finance/market-data/cache';
+import { parseSymbolList } from '@/lib/finance/watchlist';
+
+export const dynamic = 'force-dynamic';
+
+const MAX_SYMBOLS = 60;
+const MAX_POINTS = 24;
+
+/** Downsample an array to at most `max` evenly-spaced points (keeps last). */
+function downsample(values: number[], max: number): number[] {
+  if (values.length <= max) return values;
+  const step = values.length / max;
+  const out: number[] = [];
+  for (let i = 0; i < max; i++) out.push(values[Math.min(values.length - 1, Math.floor(i * step))]);
+  out[out.length - 1] = values[values.length - 1];
+  return out;
+}
+
+async function samplesFor(provider: MarketDataProvider, symbol: string): Promise<number[]> {
+  return readThrough<number[]>(symbol, `sparkline:${provider.id}`, CANDLES_TTL_SECONDS, async () => {
+    const candles = await provider.getCandles(symbol, '5D');
+    return downsample(candles.map((c) => c.close), MAX_POINTS);
+  });
+}
+
+export async function GET(request: NextRequest): Promise<NextResponse> {
+  const gate = await requireActiveSubscription(request);
+  if (gate) return gate;
+
+  const { valid } = parseSymbolList(request.nextUrl.searchParams.get('symbols') ?? '');
+  if (valid.length === 0) return NextResponse.json({ samples: {} });
+
+  const profileId = await getActiveProfileId();
+  const provider = await getMarketDataProviderForProfile(profileId);
+  const fallback = getFallbackMarketDataProvider();
+
+  const symbols = valid.slice(0, MAX_SYMBOLS);
+  const entries = await Promise.all(
+    symbols.map(async (symbol): Promise<[string, number[]]> => {
+      try {
+        return [symbol, await samplesFor(provider, symbol)];
+      } catch {
+        try {
+          return [symbol, await samplesFor(fallback, symbol)];
+        } catch {
+          return [symbol, []];
+        }
+      }
+    }),
+  );
+
+  return NextResponse.json({ samples: Object.fromEntries(entries) });
+}

src/app/finance/finance-hub.tsx

@@ -9,6 +9,7 @@ import { useRouter } from 'next/navigation';
 import Link from 'next/link';
 import { normalizeSymbol } from '@/lib/finance/market-data/stooq';
 import { BrokerConnect } from './broker-connect';
+import { Sparkline } from '@/components/finance/sparkline';
 
 const RECENT_KEY = 'finance:recent';
 
@@ -26,6 +27,7 @@ export function FinanceHub(): React.ReactElement {
   const [bulk, setBulk] = useState('');
   const [bulkBusy, setBulkBusy] = useState(false);
   const [bulkMsg, setBulkMsg] = useState<string | null>(null);
+  const [sparklines, setSparklines] = useState<Record<string, number[]>>({});
 
   useEffect(() => {
     try {
@@ -47,6 +49,25 @@ export function FinanceHub(): React.ReactElement {
     loadWatchlist();
   }, [loadWatchlist]);
 
+  // Fetch last-week sparkline samples for the watchlist symbols (one batch call).
+  const watchlistKey = watchlist.map((w) => w.symbol).join(',');
+  useEffect(() => {
+    if (!watchlistKey) {
+      setSparklines({});
+      return;
+    }
+    let cancelled = false;
+    fetch(`/api/finance/sparklines?symbols=${encodeURIComponent(watchlistKey)}`, { cache: 'no-store' })
+      .then((res) => (res.ok ? res.json() : { samples: {} }))
+      .then((body: { samples?: Record<string, number[]> }) => {
+        if (!cancelled) setSparklines(body.samples ?? {});
+      })
+      .catch(() => undefined);
+    return () => {
+      cancelled = true;
+    };
+  }, [watchlistKey]);
+
   const addBulk = useCallback(
     async (e: React.FormEvent) => {
       e.preventDefault();
@@ -164,7 +185,10 @@ export function FinanceHub(): React.ReactElement {
           <div className="grid grid-cols-2 gap-3 sm:grid-cols-3">
             {watchlist.map((row) => (
               <Link key={row.id} href={`/finance/ticker/${row.symbol}`} className="card p-4 hover:bg-bg-tertiary">
-                <div className="text-lg font-semibold text-text-primary">{row.symbol}</div>
+                <div className="flex items-center justify-between gap-2">
+                  <div className="text-lg font-semibold text-text-primary">{row.symbol}</div>
+                  <Sparkline samples={sparklines[row.symbol]} width={56} />
+                </div>
                 {row.exchange ? <div className="text-xs text-text-muted">{row.exchange}</div> : null}
               </Link>
             ))}

src/components/finance/sparkline.tsx

@@ -0,0 +1,44 @@
+import { datatypeFont } from '@/lib/datatype-font';
+
+/**
+ * Inline price sparkline rendered via the Datatype variable font (ported from
+ * b1dz.com). Syntax: `{l:v1,v2,…}` where each v is 0–100; the font's ligatures
+ * substitute that text with a chart glyph. Color reflects last-vs-first
+ * direction (green up / red down).
+ */
+export function Sparkline({
+  samples,
+  width = 60,
+}: {
+  samples?: number[];
+  width?: number;
+}): React.ReactElement {
+  if (!samples || samples.length < 2) {
+    return <span className="text-text-muted">—</span>;
+  }
+
+  const min = Math.min(...samples);
+  const max = Math.max(...samples);
+  const range = max - min;
+  const normalized =
+    range === 0 ? samples.map(() => 50) : samples.map((v) => Math.round(((v - min) / range) * 100));
+
+  const isUp = samples[samples.length - 1] >= samples[0];
+  const colorClass = isUp ? 'text-green-400' : 'text-red-400';
+
+  return (
+    <span
+      className={`${datatypeFont.className} ${colorClass} inline-block`}
+      style={{
+        minWidth: width,
+        fontSize: '1.4em',
+        lineHeight: 1,
+        fontVariationSettings: "'wdth' 75, 'wght' 500",
+        fontFeatureSettings: "'calt' 1, 'liga' 1, 'dlig' 1",
+        WebkitFontFeatureSettings: "'calt' 1, 'liga' 1, 'dlig' 1",
+      }}
+    >
+      {`{l:${normalized.join(',')}}`}
+    </span>
+  );
+}

src/lib/datatype-font.ts

@@ -0,0 +1,15 @@
+import localFont from 'next/font/local';
+
+/**
+ * Datatype variable font — OpenType ligatures render the literal text
+ * `{l:v1,v2,…}` (each v 0–100) as an inline sparkline glyph at draw time.
+ * Loaded once at module scope so it's preloaded and shares one hash.
+ * (Ported from b1dz.com.)
+ */
+export const datatypeFont = localFont({
+  src: '../app/fonts/Datatype.woff2',
+  display: 'swap',
+  weight: '100 900',
+  preload: true,
+  variable: '--font-datatype',
+});