feat(qr-generate): add live QR preview panel with qr-code-styling

apps/web/src/components/tools/qr-generate-preview.tsx

@@ -0,0 +1,127 @@
+import QRCodeStyling from "qr-code-styling";
+import { useEffect, useMemo, useRef, useState } from "react";
+import { encodeQrData, useQrStore } from "@/stores/qr-store";
+
+const CHECKER_BG = "repeating-conic-gradient(#e5e5e5 0% 25%, #ffffff 0% 50%) 0 0 / 20px 20px";
+
+function clearChildren(el: HTMLElement) {
+  while (el.firstChild) {
+    el.removeChild(el.firstChild);
+  }
+}
+
+export function QrGeneratePreview() {
+  const store = useQrStore();
+  const containerRef = useRef<HTMLDivElement>(null);
+  const qrRef = useRef<QRCodeStyling | null>(null);
+  const [isEmpty, setIsEmpty] = useState(true);
+
+  const data = encodeQrData(store);
+
+  const options = useMemo(() => {
+    const hasData = !!data;
+    setIsEmpty(!hasData);
+
+    const dotsColor = store.dotGradientEnabled ? undefined : store.dotColor;
+    const dotsGradient = store.dotGradientEnabled
+      ? {
+          type: store.dotGradientType as "linear" | "radial",
+          rotation: store.dotGradientRotation * (Math.PI / 180),
+          colorStops: [
+            { offset: 0, color: store.dotGradientColor1 },
+            { offset: 1, color: store.dotGradientColor2 },
+          ],
+        }
+      : undefined;
+
+    return {
+      width: 300,
+      height: 300,
+      data: hasData ? data : "https://example.com",
+      margin: 8,
+      qrOptions: {
+        errorCorrectionLevel: store.errorCorrection,
+      },
+      dotsOptions: {
+        type: store.dotType,
+        ...(dotsColor ? { color: dotsColor } : {}),
+        ...(dotsGradient ? { gradient: dotsGradient } : {}),
+      },
+      cornersSquareOptions: {
+        type: store.cornerSquareType,
+        color: store.useCustomCornerColors ? store.cornerSquareColor : undefined,
+      },
+      cornersDotOptions: {
+        type: store.cornerDotType,
+        color: store.useCustomCornerColors ? store.cornerDotColor : undefined,
+      },
+      backgroundOptions: store.bgTransparent ? { color: "transparent" } : { color: store.bgColor },
+      ...(store.logoDataUrl
+        ? {
+            image: store.logoDataUrl,
+            imageOptions: {
+              hideBackgroundDots: store.hideBackgroundDots,
+              imageSize: store.logoSize,
+              margin: store.logoMargin,
+              crossOrigin: "anonymous" as const,
+            },
+          }
+        : {}),
+    };
+  }, [
+    data,
+    store.dotType,
+    store.dotColor,
+    store.dotGradientEnabled,
+    store.dotGradientType,
+    store.dotGradientColor1,
+    store.dotGradientColor2,
+    store.dotGradientRotation,
+    store.cornerSquareType,
+    store.cornerDotType,
+    store.cornerSquareColor,
+    store.cornerDotColor,
+    store.useCustomCornerColors,
+    store.bgColor,
+    store.bgTransparent,
+    store.errorCorrection,
+    store.logoDataUrl,
+    store.logoSize,
+    store.logoMargin,
+    store.hideBackgroundDots,
+  ]);
+
+  // Create QR instance on mount
+  useEffect(() => {
+    const qr = new QRCodeStyling(options as never);
+    qrRef.current = qr;
+    if (containerRef.current) {
+      clearChildren(containerRef.current);
+      qr.append(containerRef.current);
+    }
+  }, []); // eslint-disable-line react-hooks/exhaustive-deps
+
+  // Update QR on state changes (debounced)
+  useEffect(() => {
+    const timer = setTimeout(() => {
+      if (qrRef.current) {
+        qrRef.current.update(options as never);
+      }
+    }, 150);
+    return () => clearTimeout(timer);
+  }, [options]);
+
+  return (
+    <div className="flex flex-col items-center justify-center h-full w-full gap-4">
+      <div
+        className="rounded-xl border border-border p-6 shadow-sm"
+        style={store.bgTransparent ? { background: CHECKER_BG } : undefined}
+      >
+        <div ref={containerRef} className="flex items-center justify-center" />
+      </div>
+      {isEmpty && (
+        <p className="text-sm text-muted-foreground">Enter content to generate a QR code</p>
+      )}
+    </div>
+  );
+}