Ensure the user can join the call even if they has joined a call in another session.

features/call/api/src/main/kotlin/io/element/android/features/call/api/CurrentCall.kt

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2024 New Vector Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ * Please see LICENSE in the repository root for full details.
+ */
+
+package io.element.android.features.call.api
+
+import io.element.android.libraries.matrix.api.core.RoomId
+
+/**
+ * Value for the local current call.
+ */
+sealed interface CurrentCall {
+    data object None : CurrentCall
+
+    data class RoomCall(
+        val roomId: RoomId,
+    ) : CurrentCall
+
+    data class ExternalUrl(
+        val url: String,
+    ) : CurrentCall
+}

features/call/api/src/main/kotlin/io/element/android/features/call/api/CurrentCallObserver.kt

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2024 New Vector Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ * Please see LICENSE in the repository root for full details.
+ */
+
+package io.element.android.features.call.api
+
+import kotlinx.coroutines.flow.StateFlow
+
+interface CurrentCallObserver {
+    /**
+     * The current call state flow, which will be updated when the active call changes.
+     * This value reflect the local state of the call. It is not updated if the user answers
+     * a call from another session.
+     */
+    val currentCall: StateFlow<CurrentCall>
+}

features/call/impl/src/main/kotlin/io/element/android/features/call/impl/utils/ActiveCallManager.kt

@@ -12,6 +12,7 @@ import androidx.core.app.NotificationManagerCompat
 import com.squareup.anvil.annotations.ContributesBinding
 import io.element.android.appconfig.ElementCallConfig
 import io.element.android.features.call.api.CallType
+import io.element.android.features.call.api.CurrentCall
 import io.element.android.features.call.impl.notifications.CallNotificationData
 import io.element.android.features.call.impl.notifications.RingingCallNotificationCreator
 import io.element.android.libraries.di.AppScope
@@ -82,6 +83,7 @@ class DefaultActiveCallManager @Inject constructor(
     private val ringingCallNotificationCreator: RingingCallNotificationCreator,
     private val notificationManagerCompat: NotificationManagerCompat,
     private val matrixClientProvider: MatrixClientProvider,
+    private val defaultCurrentCallObserver: DefaultCurrentCallObserver,
 ) : ActiveCallManager {
     private var timedOutCallJob: Job? = null
 
@@ -89,6 +91,7 @@ class DefaultActiveCallManager @Inject constructor(
 
     init {
         observeRingingCall()
+        observeCurrentCall()
     }
 
     override fun registerIncomingCall(notificationData: CallNotificationData) {
@@ -209,6 +212,28 @@ class DefaultActiveCallManager @Inject constructor(
             }
             .launchIn(coroutineScope)
     }
+
+    private fun observeCurrentCall() {
+        activeCall
+            .onEach { value ->
+                if (value == null) {
+                    defaultCurrentCallObserver.onCallEnded()
+                } else {
+                    when (value.callState) {
+                        is CallState.Ringing -> {
+                            // Nothing to do
+                        }
+                        is CallState.InCall -> {
+                            when (val callType = value.callType) {
+                                is CallType.ExternalUrl -> defaultCurrentCallObserver.onCallStarted(CurrentCall.ExternalUrl(callType.url))
+                                is CallType.RoomCall -> defaultCurrentCallObserver.onCallStarted(CurrentCall.RoomCall(callType.roomId))
+                            }
+                        }
+                    }
+                }
+            }
+            .launchIn(coroutineScope)
+    }
 }
 
 /**

features/call/impl/src/main/kotlin/io/element/android/features/call/impl/utils/DefaultCurrentCallObserver.kt

@@ -0,0 +1,30 @@
+/*
+ * Copyright 2024 New Vector Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ * Please see LICENSE in the repository root for full details.
+ */
+
+package io.element.android.features.call.impl.utils
+
+import com.squareup.anvil.annotations.ContributesBinding
+import io.element.android.features.call.api.CurrentCall
+import io.element.android.features.call.api.CurrentCallObserver
+import io.element.android.libraries.di.AppScope
+import io.element.android.libraries.di.SingleIn
+import kotlinx.coroutines.flow.MutableStateFlow
+import javax.inject.Inject
+
+@SingleIn(AppScope::class)
+@ContributesBinding(AppScope::class)
+class DefaultCurrentCallObserver @Inject constructor() : CurrentCallObserver {
+    override val currentCall = MutableStateFlow<CurrentCall>(CurrentCall.None)
+
+    fun onCallStarted(call: CurrentCall) {
+        currentCall.value = call
+    }
+
+    fun onCallEnded() {
+        currentCall.value = CurrentCall.None
+    }
+}

features/call/impl/src/test/kotlin/io/element/android/features/call/utils/DefaultActiveCallManagerTest.kt

@@ -15,6 +15,7 @@ import io.element.android.features.call.impl.notifications.RingingCallNotificati
 import io.element.android.features.call.impl.utils.ActiveCall
 import io.element.android.features.call.impl.utils.CallState
 import io.element.android.features.call.impl.utils.DefaultActiveCallManager
+import io.element.android.features.call.impl.utils.DefaultCurrentCallObserver
 import io.element.android.features.call.test.aCallNotificationData
 import io.element.android.libraries.matrix.api.core.EventId
 import io.element.android.libraries.matrix.api.core.RoomId
@@ -299,5 +300,6 @@ class DefaultActiveCallManagerTest {
         ),
         notificationManagerCompat = notificationManagerCompat,
         matrixClientProvider = matrixClientProvider,
+        defaultCurrentCallObserver = DefaultCurrentCallObserver(),
     )
 }

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/components/CallMenuItem.kt

@@ -79,7 +79,7 @@ private fun OnGoingCallMenuItem(
     onJoinCallClick: () -> Unit,
     modifier: Modifier = Modifier,
 ) {
-    if (!roomCallState.isUserInTheCall) {
+    if (!roomCallState.isUserLocallyInTheCall) {
         Button(
             onClick = onJoinCallClick,
             colors = ButtonDefaults.buttonColors(

features/roomcall/api/src/main/kotlin/io/element/android/features/roomcall/api/RoomCallState.kt

@@ -20,6 +20,7 @@ sealed interface RoomCallState {
     data class OnGoing(
         val canJoinCall: Boolean,
         val isUserInTheCall: Boolean,
+        val isUserLocallyInTheCall: Boolean,
     ) : RoomCallState
 }
 

features/roomcall/api/src/main/kotlin/io/element/android/features/roomcall/api/RoomCallStateProvider.kt

@@ -22,9 +22,11 @@ open class RoomCallStateProvider : PreviewParameterProvider<RoomCallState> {
 fun anOngoingCallState(
     canJoinCall: Boolean = true,
     isUserInTheCall: Boolean = false,
+    isUserLocallyInTheCall: Boolean = isUserInTheCall,
 ) = RoomCallState.OnGoing(
     canJoinCall = canJoinCall,
     isUserInTheCall = isUserInTheCall,
+    isUserLocallyInTheCall = isUserLocallyInTheCall,
 )
 
 fun aStandByCallState(

features/roomcall/impl/build.gradle.kts

@@ -20,6 +20,7 @@ setupAnvil()
 dependencies {
     api(projects.features.roomcall.api)
     implementation(libs.kotlinx.collections.immutable)
+    implementation(projects.features.call.api)
     implementation(projects.libraries.architecture)
     implementation(projects.libraries.matrix.api)
     implementation(projects.libraries.matrixui)

features/roomcall/impl/src/main/kotlin/io/element/android/features/roomcall/impl/RoomCallStatePresenter.kt

@@ -12,6 +12,8 @@ import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.derivedStateOf
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.remember
+import io.element.android.features.call.api.CurrentCall
+import io.element.android.features.call.api.CurrentCallObserver
 import io.element.android.features.roomcall.api.RoomCallState
 import io.element.android.libraries.architecture.Presenter
 import io.element.android.libraries.matrix.api.room.MatrixRoom
@@ -20,6 +22,7 @@ import javax.inject.Inject
 
 class RoomCallStatePresenter @Inject constructor(
     private val room: MatrixRoom,
+    private val currentCallObserver: CurrentCallObserver,
 ) : Presenter<RoomCallState> {
     @Composable
     override fun present(): RoomCallState {
@@ -31,10 +34,17 @@ class RoomCallStatePresenter @Inject constructor(
                 room.sessionId in roomInfo?.activeRoomCallParticipants.orEmpty()
             }
         }
+        val currentCall by currentCallObserver.currentCall.collectAsState()
+        val isUserLocallyInTheCall by remember {
+            derivedStateOf {
+                (currentCall as? CurrentCall.RoomCall)?.roomId == room.roomId
+            }
+        }
         val callState = when {
             roomInfo?.hasRoomCall == true -> RoomCallState.OnGoing(
                 canJoinCall = canJoinCall,
                 isUserInTheCall = isUserInTheCall,
+                isUserLocallyInTheCall = isUserLocallyInTheCall,
             )
             else -> RoomCallState.StandBy(canStartCall = canJoinCall)
         }