Add Wiener Linien API integration and departures monitoring

src/app/api/wienerlinien/monitor/route.ts

@@ -0,0 +1,37 @@
+import { NextRequest, NextResponse } from "next/server";
+import { randomUUID } from "crypto";
+import { WienerLinienClient } from "@/lib/wienerlinien-client";
+
+const client = new WienerLinienClient();
+
+export async function GET(request: NextRequest) {
+  const { searchParams } = new URL(request.url);
+  const stopIdsParam = searchParams.get("stopIds");
+
+  if (!stopIdsParam || stopIdsParam.trim() === "") {
+    return NextResponse.json({ error: "Missing 'stopIds' query parameter" }, { status: 400 });
+  }
+
+  const rawIds = stopIdsParam.split(",");
+  const validStopIds = rawIds
+    .map((id) => id.trim())
+    .filter((id) => id.length > 0)
+    .filter((id, index, self) => self.indexOf(id) === index);
+
+  if (validStopIds.length === 0) {
+    return NextResponse.json({ error: "No valid stop IDs provided" }, { status: 400 });
+  }
+
+  const cappedIds = validStopIds.slice(0, 10);
+
+  try {
+    const monitorData = await client.getMonitor(cappedIds);
+    // Flatten nested stops array into a single departures list
+    const departures = monitorData.stops.flatMap((s) => s.departures);
+    return NextResponse.json({ departures });
+  } catch (error) {
+    const corrId = randomUUID().slice(0, 8);
+    console.error(`[${corrId}] Wiener Linien monitor request failed:`, error);
+    return NextResponse.json({ error: "Failed to fetch departures", correlationId: corrId }, { status: 500 });
+  }
+}