From dd1eb711df98a8583e0ff31217e958fcfcb0235f Mon Sep 17 00:00:00 2001
From: yiekheng <yiekheng@04080616.xyz>
Date: Sat, 9 May 2026 16:16:09 +0800
Subject: [PATCH] feat(bot): add QR PNG renderer

---
 apps/bot/src/whatsapp/qr-renderer.test.ts | 15 +++++++++++++++
 apps/bot/src/whatsapp/qr-renderer.ts      |  6 ++++++
 2 files changed, 21 insertions(+)
 create mode 100644 apps/bot/src/whatsapp/qr-renderer.test.ts
 create mode 100644 apps/bot/src/whatsapp/qr-renderer.ts

diff --git a/apps/bot/src/whatsapp/qr-renderer.test.ts b/apps/bot/src/whatsapp/qr-renderer.test.ts
new file mode 100644
index 0000000..f5f51ff
--- /dev/null
+++ b/apps/bot/src/whatsapp/qr-renderer.test.ts
@@ -0,0 +1,15 @@
+import { describe, expect, it } from "vitest";
+import { renderQrPng } from "./qr-renderer.js";
+
+describe("renderQrPng", () => {
+  it("returns a PNG buffer for a non-empty string", async () => {
+    const png = await renderQrPng("test-qr-payload");
+    expect(png).toBeInstanceOf(Buffer);
+    expect(png[0]).toBe(0x89);
+    expect(png.subarray(1, 4).toString("ascii")).toBe("PNG");
+  });
+
+  it("rejects empty input", async () => {
+    await expect(renderQrPng("")).rejects.toThrow();
+  });
+});
diff --git a/apps/bot/src/whatsapp/qr-renderer.ts b/apps/bot/src/whatsapp/qr-renderer.ts
new file mode 100644
index 0000000..70050c6
--- /dev/null
+++ b/apps/bot/src/whatsapp/qr-renderer.ts
@@ -0,0 +1,6 @@
+import QRCode from "qrcode";
+
+export async function renderQrPng(payload: string): Promise<Buffer> {
+  if (!payload) throw new Error("renderQrPng: payload is empty");
+  return await QRCode.toBuffer(payload, { type: "png", width: 512, margin: 2 });
+}