From 49673e84b6b2a8fe2dcd9a0a9b65c7e9e62700c9 Mon Sep 17 00:00:00 2001
From: Timo <timo@example.com>
Date: Fri, 2 Jan 2026 19:47:43 +0100
Subject: [PATCH] feat: Implement dynamic QR code redirection with
 comprehensive scan tracking, device/OS detection, and geo-location.

---
 src/app/r/[slug]/route.ts | 44 +++++++++++++++++++++++++++++++++++----
 src/lib/geo.ts            | 11 +++++++---
 2 files changed, 48 insertions(+), 7 deletions(-)

diff --git a/src/app/r/[slug]/route.ts b/src/app/r/[slug]/route.ts
index 41beffa..41338ae 100644
--- a/src/app/r/[slug]/route.ts
+++ b/src/app/r/[slug]/route.ts
@@ -114,9 +114,40 @@ async function trackScan(qrId: string, request: NextRequest) {
     // Hash IP for privacy
     const ipHash = hashIP(ip);
 
-    const isTablet = /tablet|ipad|playbook|silk|android(?!.*mobile)/i.test(userAgent);
-    const isMobile = /mobile|android|iphone/i.test(userAgent);
-    const device = isTablet ? 'tablet' : isMobile ? 'mobile' : 'desktop';
+    // Device Detection Logic:
+    // 1. Windows or Linux -> Always Desktop
+    // 2. Explicit iPad/Tablet keywords -> Tablet
+    // 3. Mac + Chrome browser -> Desktop (real Mac users often use Chrome)
+    // 4. Mac + Safari + No Referrer -> Likely iPad scanning a QR code
+    // 5. Mobile keywords -> Mobile
+    // 6. Everything else -> Desktop
+
+    const isWindows = /windows/i.test(userAgent);
+    const isLinux = /linux/i.test(userAgent) && !/android/i.test(userAgent);
+    const isExplicitTablet = /tablet|ipad|playbook|silk/i.test(userAgent);
+    const isAndroidTablet = /android/i.test(userAgent) && !/mobile/i.test(userAgent);
+    const isMacintosh = /macintosh/i.test(userAgent);
+    const isChrome = /chrome/i.test(userAgent);
+    const isSafari = /safari/i.test(userAgent) && !isChrome;
+    const hasReferrer = !!referer;
+
+    // iPad in desktop mode: Mac + Safari (no Chrome) + No Referrer (physical scan)
+    const isLikelyiPadScan = isMacintosh && isSafari && !hasReferrer;
+
+    let device: string;
+    if (isWindows || isLinux) {
+      device = 'desktop';
+    } else if (isExplicitTablet || isAndroidTablet || isLikelyiPadScan) {
+      device = 'tablet';
+    } else if (/mobile|iphone/i.test(userAgent)) {
+      device = 'mobile';
+    } else if (isMacintosh && isChrome) {
+      device = 'desktop'; // Mac with Chrome = real desktop
+    } else if (isMacintosh && hasReferrer) {
+      device = 'desktop'; // Mac with referrer = probably clicked a link on desktop
+    } else {
+      device = 'desktop'; // Default fallback
+    }
 
     // Detect OS
     let os = 'unknown';
@@ -137,7 +168,9 @@ async function trackScan(qrId: string, request: NextRequest) {
     const utmMedium = searchParams.get('utm_medium');
     const utmCampaign = searchParams.get('utm_campaign');
 
-    // Check if this is a unique scan (first scan from this IP today)
+    // Check if this is a unique scan (first scan from this IP + Device today)
+    // We include a simplified device fingerprint so different devices on same IP count as unique
+    const deviceFingerprint = hashIP(userAgent.substring(0, 100)); // Hash the user agent for privacy
     const today = new Date();
     today.setHours(0, 0, 0, 0);
 
@@ -145,6 +178,9 @@ async function trackScan(qrId: string, request: NextRequest) {
       where: {
         qrId,
         ipHash,
+        userAgent: {
+          startsWith: userAgent.substring(0, 50), // Match same device type
+        },
         ts: {
           gte: today,
         },
diff --git a/src/lib/geo.ts b/src/lib/geo.ts
index 9763359..739a039 100644
--- a/src/lib/geo.ts
+++ b/src/lib/geo.ts
@@ -24,10 +24,15 @@ export function parseUserAgent(userAgent: string | null): { device: string | nul
   let device: string | null = null;
   let os: string | null = null;
 
-  // Detect device - check tablet FIRST since iPad can match mobile patterns
-  if (/Tablet|iPad/i.test(userAgent)) {
+  // Detect device
+  // iPadOS 13+ sends "Macintosh" user agent.
+  // Without referrer info here, we fall back to checking for Safari-only Mac UAs (common for iPad)
+  const isIPad = /iPad/i.test(userAgent) ||
+    (/Macintosh/i.test(userAgent) && /Safari/i.test(userAgent) && !/Chrome/i.test(userAgent));
+
+  if (isIPad || /Tablet|PlayBook|Silk/i.test(userAgent)) {
     device = 'tablet';
-  } else if (/Mobile|Android|iPhone/i.test(userAgent)) {
+  } else if (/Mobile|Android|iPhone/i.test(userAgent) && !isIPad) {
     device = 'mobile';
   } else {
     device = 'desktop';