fix(app): emit.maxlistener issue

BREAKING CHANGE: moved teh middleware to call the api hits to the main app and removed from
everywhere else

closes #18

backend/mobile/availableScanIds.route.ts

@@ -0,0 +1,54 @@
+import { eq } from "drizzle-orm";
+import { Router } from "express";
+import { db } from "../db/db.controller.js";
+import { scanUser } from "../db/schema/scanUsers.js";
+import { settings } from "../db/schema/settings.schema.js";
+import { apiReturn } from "../utils/returnHelper.utils.js";
+
+const r = Router();
+
+// scanners that are dedicated to specific users.
+const SPECIAL_SCANNERS = [69, 98];
+
+const buildAllowedScannerIds = (scannerCount: number) => {
+	const generatedIds = Array.from({ length: scannerCount }, (_, i) => i + 1);
+
+	return Array.from(new Set([...generatedIds, ...SPECIAL_SCANNERS])).sort(
+		(a, b) => a - b,
+	);
+};
+
+r.get("/", async (_, res) => {
+	// get the scan users and setting
+	const scanusers = await db.select().from(scanUser);
+	const scannerIdSetting = await db
+		.select()
+		.from(settings)
+		.where(eq(settings.name, "scannerIds"));
+
+	const usedScannerIds = scanusers.map((x) => Number(x.scannerId));
+	const allowedScannerIds = buildAllowedScannerIds(
+		Number(scannerIdSetting[0]?.value ?? 0),
+	);
+
+	const availableScannerIds = allowedScannerIds.filter(
+		(id) => !usedScannerIds.includes(id),
+	);
+
+	const data = availableScannerIds.map((id) => ({
+		label: `${id}`,
+		value: id,
+	}));
+
+	return apiReturn(res, {
+		success: true,
+		level: "info",
+		module: "mobile",
+		subModule: "scanner",
+		message: `There are ${availableScannerIds.length} scanner id's`,
+		data,
+		status: 200,
+	});
+});
+
+export default r;