import type { FastifyInstance } from "fastify"
import { createScannerInboxService, type ScannerInboxService } from "./scanner-inbox.service"

export function startScannerInboxWorker(server: FastifyInstance, service: Pick<ScannerInboxService, "processNextSuggestion"> = createScannerInboxService(server.db)) {
    let stopped = false
    let timer: ReturnType<typeof setTimeout> | undefined
    let running: Promise<void> | undefined
    const run = async () => {
        try {
            // One analysis per process; database claims coordinate multiple backend instances.
            while (!stopped && await service.processNextSuggestion()) { /* drain the durable queue */ }
        } catch {
            server.log.error("KI-Vorbereitung der Dokumentenablage unterbrochen; erneuter Versuch folgt.")
        } finally {
            if (!stopped) {
                timer = setTimeout(() => { running = run() }, 2000)
                timer.unref()
            }
        }
    }
    server.addHook("onReady", async () => { running = run() })
    server.addHook("onClose", async () => {
        stopped = true
        clearTimeout(timer)
        await running
    })
}