feat: add GET /spreads/:asset route to calculate bid-ask spreads for …

src/routes/spreads.ts

@@ -0,0 +1,32 @@
+import type { FastifyInstance } from 'fastify';
+import { pgPool } from '../db';
+
+/**
+ * GET /spreads/:asset - Return current bid, ask, and spread (bps) for the given asset.
+ * The bid is taken as the highest price among price points where the asset appears.
+ * The ask is the lowest price among those points.
+ * Spread basis points = ((ask - bid) / ask) * 10_000.
+ */
+export async function registerSpreadsRoutes(app: FastifyInstance) {
+  app.get('/spreads/:asset', async (req, reply) => {
+    const { asset } = req.params as { asset: string };
+    if (!asset) {
+      return reply.status(400).send({ error: 'Asset parameter is required' });
+    }
+
+    const result = await pgPool.query(
+      `SELECT MAX(price::numeric) AS bid, MIN(price::numeric) AS ask
+       FROM price_points
+       WHERE assetA = $1 OR assetB = $1`,
+      [asset]
+    );
+    const row = result.rows[0];
+    const bid = row.bid !== null ? parseFloat(row.bid) : null;
+    const ask = row.ask !== null ? parseFloat(row.ask) : null;
+    let spreadBps: number | null = null;
+    if (bid !== null && ask !== null && ask !== 0) {
+      spreadBps = ((ask - bid) / ask) * 10_000;
+    }
+    return { asset, bid, ask, spreadBps };
+  });
+}