feat: add worker main poll loop

worker/index.ts

@@ -0,0 +1,41 @@
+import { prisma } from '@/lib/prisma'
+import { config } from '../config/app.config'
+import { processDownload } from './processor'
+
+export async function pollOnce(): Promise<void> {
+  const pending = await prisma.download.findMany({
+    where: { status: 'PENDING' },
+    orderBy: { submittedAt: 'asc' },
+    take: config.WORKER_CONCURRENCY,
+    select: { id: true },
+  })
+
+  if (pending.length === 0) return
+
+  const ids = pending.map((d) => d.id)
+
+  await prisma.download.updateMany({
+    where: { id: { in: ids }, status: 'PENDING' },
+    data: { status: 'PROCESSING', startedAt: new Date() },
+  })
+
+  await Promise.all(ids.map((id) => processDownload(id)))
+}
+
+export async function runWorker(): Promise<never> {
+  console.log('[worker] started')
+  while (true) {
+    try {
+      await pollOnce()
+    } catch (err) {
+      console.error('[worker] poll error:', err)
+    }
+    await new Promise((resolve) =>
+      setTimeout(resolve, config.WORKER_POLL_INTERVAL_MS)
+    )
+  }
+}
+
+if (require.main === module) {
+  runWorker().catch(console.error)
+}