ThreadCount
0910bc32c1
Uniform stock management for healthcare linen rooms: the coordinator app, the phone counter and the staff app, for your own server. Built from 38e16eb on 2026-09-15. Licensed under the Functional Source License (FSL-1.1-ALv2).
73 lines
3.5 KiB
TypeScript
73 lines
3.5 KiB
TypeScript
/* The browser's barcode camera loop, shared by the full-screen scanner (components/MScan.tsx) and the
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* counter app's Scan tab (app/m/(app)/scan). Android's shell reads through MLKit instead
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* (lib/nativescan.ts); this is what a phone browser, or a shell without the plugin, uses.
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*
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* It opens the rear camera into the given <video>, asks BarcodeDetector every 300ms, and hands back
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* each code once per debounce window, so a garment held in frame is one garment. */
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import { scanTick } from "@/lib/feedback";
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type Detector = { detect: (src: HTMLVideoElement) => Promise<{ rawValue?: string }[]> };
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/* The same set the native scanner is held to (see lib/nativescan.ts for why ITF and 2D are not). */
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export const WEB_FORMATS = ["ean_13", "ean_8", "upc_a", "upc_e", "code_128", "code_39", "code_93"];
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export type WebScanStatus =
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| { state: "ready" }
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| { state: "unsupported"; msg: string }
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| { state: "denied"; msg: string };
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export type WebLive = { stop: () => void };
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/** Start reading. `onCode` gets each accepted code (scanTick has already fired). `active` lets a
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* paused screen keep the camera open without counting; `onStatus` reports whether it is reading. */
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export function startWebLive(
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video: HTMLVideoElement,
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onCode: (raw: string) => void,
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debounceMs = 900,
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opts?: { active?: () => boolean; onStatus?: (s: WebScanStatus) => void; tick?: boolean },
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): WebLive {
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let stream: MediaStream | null = null;
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let timer: ReturnType<typeof setInterval> | null = null;
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let stopped = false;
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let lastRaw = "", lastT = 0;
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const status = (s: WebScanStatus) => { if (!stopped) opts?.onStatus?.(s); };
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const w = window as unknown as { BarcodeDetector?: new (o?: { formats?: string[] }) => Detector };
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if (!navigator.mediaDevices?.getUserMedia) {
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status({ state: "denied", msg: "This browser has no camera access — type the code instead." });
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return { stop: () => { stopped = true; } };
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}
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navigator.mediaDevices.getUserMedia({ video: { facingMode: "environment" } }).then((st) => {
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if (stopped) { st.getTracks().forEach((t) => t.stop()); return; }
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stream = st;
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video.srcObject = st;
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video.play().catch(() => {});
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if (!w.BarcodeDetector) { status({ state: "unsupported", msg: "Live reading isn’t supported here — type the code instead." }); return; }
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let bd: Detector;
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try { bd = new w.BarcodeDetector({ formats: WEB_FORMATS }); } catch { bd = new w.BarcodeDetector(); }
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status({ state: "ready" });
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timer = setInterval(() => {
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if (stopped || (opts?.active && !opts.active())) return;
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if (video.readyState < 2) return;
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bd.detect(video).then((codes) => {
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if (stopped || !codes?.length) return;
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const raw = String(codes[0].rawValue || "").trim();
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if (!raw) return;
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// Same code again inside the debounce = the same garment still in frame, not a second one.
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if (raw === lastRaw && Date.now() - lastT < debounceMs) return;
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lastRaw = raw; lastT = Date.now();
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if (opts?.tick !== false) scanTick();
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onCode(raw);
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}).catch(() => {});
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}, 300);
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}).catch((e: Error) => {
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status({ state: "denied", msg: /denied|permission/i.test(e.message) ? "ThreadCount needs the camera to scan. Allow it in your browser or device settings, then try again." : "The camera isn’t available — " + e.message });
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});
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return {
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stop: () => {
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stopped = true;
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if (timer) clearInterval(timer);
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if (stream) stream.getTracks().forEach((t) => t.stop());
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},
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};
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}
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