From 337afb11dbb6bb82825651eb225cf01d1eeeb4ad Mon Sep 17 00:00:00 2001
From: Alex Hart <alex@signal.org>
Date: Thu, 4 Jun 2026 12:26:30 -0300
Subject: [PATCH] Add screen size check for link and sync.

---
 .../screens/welcome/WelcomeScreen.kt          | 42 ++++++++++++++++---
 1 file changed, 37 insertions(+), 5 deletions(-)

diff --git a/feature/registration/src/main/java/org/signal/registration/screens/welcome/WelcomeScreen.kt b/feature/registration/src/main/java/org/signal/registration/screens/welcome/WelcomeScreen.kt
index c16f05effa..43066ac7ae 100644
--- a/feature/registration/src/main/java/org/signal/registration/screens/welcome/WelcomeScreen.kt
+++ b/feature/registration/src/main/java/org/signal/registration/screens/welcome/WelcomeScreen.kt
@@ -7,6 +7,8 @@
 
 package org.signal.registration.screens.welcome
 
+import android.content.pm.PackageManager
+import android.util.DisplayMetrics
 import androidx.compose.foundation.Image
 import androidx.compose.foundation.background
 import androidx.compose.foundation.clickable
@@ -35,22 +37,26 @@ import androidx.compose.material3.TextButton
 import androidx.compose.material3.adaptive.currentWindowAdaptiveInfo
 import androidx.compose.material3.rememberModalBottomSheetState
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.State
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.runtime.rememberUpdatedState
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
 import androidx.compose.ui.graphics.painter.Painter
 import androidx.compose.ui.layout.ContentScale
+import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.platform.testTag
 import androidx.compose.ui.res.painterResource
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.text.TextStyle
 import androidx.compose.ui.text.style.TextAlign
 import androidx.compose.ui.unit.dp
+import androidx.window.layout.WindowMetricsCalculator
 import kotlinx.coroutines.CoroutineScope
 import org.signal.core.ui.WindowBreakpoint
 import org.signal.core.ui.compose.AllDevicePreviews
@@ -67,6 +73,8 @@ import org.signal.registration.R
 import org.signal.registration.screens.RegistrationScaffold
 import org.signal.registration.screens.attachDebugLogHelper
 import org.signal.registration.test.TestTags
+import kotlin.math.pow
+import kotlin.math.sqrt
 
 /**
  * Welcome screen for the registration flow.
@@ -74,14 +82,15 @@ import org.signal.registration.test.TestTags
  */
 @Composable
 fun WelcomeScreen(
-  isLinkAndSyncAvailable: Boolean = false,
   onEvent: (WelcomeScreenEvents) -> Unit,
-  modifier: Modifier = Modifier
+  modifier: Modifier = Modifier,
+  isLinkAndSyncAvailable: Boolean = false
 ) {
   var showBottomSheet by remember { mutableStateOf(false) }
   val windowBreakpoint = rememberWindowBreakpoint()
   val onRestoreOrTransferClick = { showBottomSheet = true }
   val onTermsAndPrivacyClick = { onEvent(WelcomeScreenEvents.ViewTermsAndPrivacy) }
+  val displayLinkAsPrimaryOption by rememberDisplayLinkAndSyncAsPrimaryPath(isLinkAndSyncAvailable)
 
   when (windowBreakpoint) {
     is WindowBreakpoint.Small -> {
@@ -104,7 +113,7 @@ fun WelcomeScreen(
 
     is WindowBreakpoint.Large -> {
       LargeLayout(
-        isLinkAndSyncAvailable = isLinkAndSyncAvailable,
+        displayLinkAsPrimaryOption = displayLinkAsPrimaryOption,
         onEvent = onEvent,
         onTermsAndPrivacyClick = onTermsAndPrivacyClick,
         onRestoreOrTransferClick = onRestoreOrTransferClick,
@@ -240,7 +249,7 @@ private fun MediumLayout(
 
 @Composable
 private fun LargeLayout(
-  isLinkAndSyncAvailable: Boolean,
+  displayLinkAsPrimaryOption: Boolean,
   onEvent: (WelcomeScreenEvents) -> Unit,
   onTermsAndPrivacyClick: () -> Unit,
   onRestoreOrTransferClick: () -> Unit,
@@ -285,7 +294,7 @@ private fun LargeLayout(
                 .padding(bottom = 8.dp)
             )
 
-            if (isLinkAndSyncAvailable) {
+            if (displayLinkAsPrimaryOption) {
               SecondaryDeviceCallToActionButtons(
                 onEvent = onEvent
               )
@@ -519,6 +528,29 @@ private fun RestoreActionRow(
   }
 }
 
+private const val TABLET_MIN_DIAGONAL_INCHES = 7f
+
+@Composable
+private fun rememberDisplayLinkAndSyncAsPrimaryPath(isLinkAndSyncAvailable: Boolean): State<Boolean> {
+  val context = LocalContext.current
+  val hasHinge = currentWindowAdaptiveInfo().windowPosture.hingeList.isNotEmpty()
+
+  val supportsTelephony = remember(context) {
+    context.packageManager.hasSystemFeature(PackageManager.FEATURE_TELEPHONY)
+  }
+
+  val isLargeDevice = remember(context) {
+    val metrics = WindowMetricsCalculator.getOrCreate().computeMaximumWindowMetrics(context)
+    val dpi = metrics.density * DisplayMetrics.DENSITY_DEFAULT
+    val widthInches = metrics.bounds.width() / dpi
+    val heightInches = metrics.bounds.height() / dpi
+    sqrt(widthInches.pow(2) + heightInches.pow(2)) >= TABLET_MIN_DIAGONAL_INCHES
+  }
+
+  // A hinge means a foldable, which counts as a phone rather than a tablet.
+  return rememberUpdatedState(isLinkAndSyncAvailable && (!supportsTelephony || (isLargeDevice && !hasHinge)))
+}
+
 @AllDevicePreviews
 @Composable
 private fun WelcomeScreenPreview() {