From a6f7c05458c7a0777e6c8c695f719188babc952c Mon Sep 17 00:00:00 2001
From: Benoit Marty <benoit@matrix.org>
Date: Tue, 19 May 2026 09:24:21 +0200
Subject: [PATCH] [Link new device] Automatically rotate the QR Code - limit
 number of rotation to 10.

---
 .../impl/LinkNewMobileHandler.kt              |  8 ++++++++
 .../screens/qrcode/ShowQrCodePresenter.kt     | 19 ++++++++++++++++---
 2 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/LinkNewMobileHandler.kt b/features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/LinkNewMobileHandler.kt
index 12cf3af3b9..18d67f577a 100644
--- a/features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/LinkNewMobileHandler.kt
+++ b/features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/LinkNewMobileHandler.kt
@@ -12,6 +12,7 @@ import dev.zacsweers.metro.SingleIn
 import io.element.android.libraries.core.log.logger.LoggerTag
 import io.element.android.libraries.di.SessionScope
 import io.element.android.libraries.matrix.api.MatrixClient
+import io.element.android.libraries.matrix.api.linknewdevice.ErrorType
 import io.element.android.libraries.matrix.api.linknewdevice.LinkMobileHandler
 import io.element.android.libraries.matrix.api.linknewdevice.LinkMobileStep
 import io.element.android.libraries.matrix.api.logs.LoggerTags
@@ -69,4 +70,11 @@ class LinkNewMobileHandler(
     fun rotateQrCode() {
         createAndStartNewHandler()
     }
+
+    fun onTooManyRotation() {
+        reset()
+        sessionScope.launch {
+            linkMobileStepFlow.emit(LinkMobileStep.Error(ErrorType.Expired("Too many QR code rotations")))
+        }
+    }
 }
diff --git a/features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/qrcode/ShowQrCodePresenter.kt b/features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/qrcode/ShowQrCodePresenter.kt
index 1688a6469d..3deff8c603 100644
--- a/features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/qrcode/ShowQrCodePresenter.kt
+++ b/features/linknewdevice/impl/src/main/kotlin/io/element/android/features/linknewdevice/impl/screens/qrcode/ShowQrCodePresenter.kt
@@ -9,7 +9,10 @@ package io.element.android.features.linknewdevice.impl.screens.qrcode
 
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableIntStateOf
 import androidx.compose.runtime.produceState
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
 import dev.zacsweers.metro.Assisted
 import dev.zacsweers.metro.AssistedFactory
 import dev.zacsweers.metro.AssistedInject
@@ -35,6 +38,7 @@ class ShowQrCodePresenter(
 
     @Composable
     override fun present(): ShowQrCodeState {
+        var qrCodeRotationCounter by remember { mutableIntStateOf(MAX_QR_CODE_ROTATION) }
         val data by produceState<AsyncData<String>>(AsyncData.Success(initialData)) {
             linkNewMobileHandler.stepFlow.collect { step ->
                 when (step) {
@@ -42,9 +46,14 @@ class ShowQrCodePresenter(
                         value = AsyncData.Success(step.data)
                     }
                     is LinkMobileStep.QrRotating -> {
-                        Timber.tag(tag.value).d("Rotating QrCode")
-                        linkNewMobileHandler.rotateQrCode()
-                        value = AsyncData.Loading()
+                        if (qrCodeRotationCounter-- > 0) {
+                            Timber.tag(tag.value).d("Rotating QrCode")
+                            linkNewMobileHandler.rotateQrCode()
+                            value = AsyncData.Loading()
+                        } else {
+                            Timber.tag(tag.value).w("Max QR code rotation reached, not rotating anymore")
+                            linkNewMobileHandler.onTooManyRotation()
+                        }
                     }
                     else -> Unit
                 }
@@ -55,4 +64,8 @@ class ShowQrCodePresenter(
             data = data,
         )
     }
+
+    companion object {
+        const val MAX_QR_CODE_ROTATION = 10
+    }
 }