fix: prioritize web fallback over app store URL in redirect handler

Web fallback URLs take priority over store URLs for iOS and Android.
When the fallback is on the app's Universal Link / App Link domain,
the OS opens the app directly. If the app isn't installed, the
fallback page shows store download links. Previously, the store URL
was checked first, sending users to the App Store even when the app
was already installed.

Author: onamfc

src/routes/redirect.ts

@@ -273,12 +273,15 @@ export async function redirectRoutes(fastify: FastifyInstance) {
           } else if (link.app_scheme && link.deep_link_path) {
             redirectUrl = `${link.app_scheme}://${link.deep_link_path.replace(/^\//, '')}`;
             redirectReason = 'app_scheme';
-          } else if (iosStoreUrl) {
-            redirectUrl = iosStoreUrl;
-            redirectReason = 'ios_app_store_url';
           } else if (webFallback) {
+            // Web fallback takes priority over store URL — if the fallback is on
+            // the app's Universal Link domain, iOS will open the app directly.
+            // If the app isn't installed, the fallback page shows store links.
             redirectUrl = webFallback;
             redirectReason = 'web_fallback_url';
+          } else if (iosStoreUrl) {
+            redirectUrl = iosStoreUrl;
+            redirectReason = 'ios_app_store_url';
           }
         } else if (deviceType === 'android') {
           if (link.android_app_link) {
@@ -287,12 +290,12 @@ export async function redirectRoutes(fastify: FastifyInstance) {
           } else if (link.app_scheme && link.deep_link_path) {
             redirectUrl = `${link.app_scheme}://${link.deep_link_path.replace(/^\//, '')}`;
             redirectReason = 'app_scheme';
-          } else if (androidStoreUrl) {
-            redirectUrl = androidStoreUrl;
-            redirectReason = 'android_app_store_url';
           } else if (webFallback) {
             redirectUrl = webFallback;
             redirectReason = 'web_fallback_url';
+          } else if (androidStoreUrl) {
+            redirectUrl = androidStoreUrl;
+            redirectReason = 'android_app_store_url';
           }
         } else if (deviceType === 'web' && webFallback) {
           redirectUrl = webFallback;
@@ -392,8 +395,9 @@ export async function redirectRoutes(fastify: FastifyInstance) {
       // iOS Priority:
       // 1. Universal Link (HTTPS URL with AASA file) - if app installed, opens app
       // 2. URI scheme (myapp://path) - fallback when Universal Links fail
-      // 3. App Store URL (link → template → workspace) - for users who don't have the app
-      // 4. Web fallback URL - browser-based fallback
+      // 3. Web fallback URL - if on the app's Universal Link domain, iOS opens the app;
+      //    if app isn't installed, the page shows store download links
+      // 4. App Store URL (link → template → workspace) - direct store redirect
       // 5. Original URL - ultimate fallback
 
       if (link.ios_universal_link) {
@@ -402,18 +406,19 @@ export async function redirectRoutes(fastify: FastifyInstance) {
         // Build URI scheme URL: myapp://product/123
         redirectUrl = `${link.app_scheme}://${link.deep_link_path.replace(/^\//, '')}`;
         useSchemeUrl = true;
-      } else if (iosUrl) {
-        redirectUrl = iosUrl;
       } else if (webFallbackUrl) {
         redirectUrl = webFallbackUrl;
+      } else if (iosUrl) {
+        redirectUrl = iosUrl;
       }
 
     } else if (device === 'android') {
       // Android Priority:
       // 1. App Link (HTTPS URL with Digital Asset Links) - if app installed, opens app
       // 2. URI scheme (myapp://path) - fallback when App Links fail
-      // 3. Play Store URL (link → template → workspace) - for users who don't have the app
-      // 4. Web fallback URL - browser-based fallback
+      // 3. Web fallback URL - if on the app's App Link domain, Android opens the app;
+      //    if app isn't installed, the page shows store download links
+      // 4. Play Store URL (link → template → workspace) - direct store redirect
       // 5. Original URL - ultimate fallback
 
       if (link.android_app_link) {
@@ -422,10 +427,10 @@ export async function redirectRoutes(fastify: FastifyInstance) {
         // Build URI scheme URL: myapp://product/123
         redirectUrl = `${link.app_scheme}://${link.deep_link_path.replace(/^\//, '')}`;
         useSchemeUrl = true;
-      } else if (androidUrl) {
-        redirectUrl = androidUrl;
       } else if (webFallbackUrl) {
         redirectUrl = webFallbackUrl;
+      } else if (androidUrl) {
+        redirectUrl = androidUrl;
       }
 
     } else if (device === 'web') {