Introduce AppNavigationStateService.

services/appnavstate/api/build.gradle.kts

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2022 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// TODO: Remove once https://youtrack.jetbrains.com/issue/KTIJ-19369 is fixed
+@Suppress("DSL_SCOPE_VIOLATION")
+plugins {
+    id("io.element.android-library")
+}
+
+android {
+    namespace = "io.element.android.services.appnavstate.api"
+}
+
+dependencies {
+    implementation(libs.coroutines.core)
+    implementation(projects.libraries.matrix.api)
+}

services/appnavstate/api/src/main/kotlin/io/element/android/services/appnavstate/api/AppNavigationState.kt

@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2023 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.element.android.services.appnavstate.api
+
+import io.element.android.libraries.matrix.api.core.RoomId
+import io.element.android.libraries.matrix.api.core.SessionId
+import io.element.android.libraries.matrix.api.core.SpaceId
+import io.element.android.libraries.matrix.api.core.ThreadId
+
+sealed interface AppNavigationState {
+    object Root : AppNavigationState
+
+    data class Session(
+        val sessionId: SessionId,
+    ) : AppNavigationState
+
+    data class Space(
+        // Can be fake value, if no space is selected
+        val spaceId: SpaceId,
+        val parentSession: Session,
+    ) : AppNavigationState
+
+    data class Room(
+        val roomId: RoomId,
+        val parentSpace: Space,
+    ) : AppNavigationState
+
+    data class Thread(
+        val threadId: ThreadId,
+        val parentRoom: Room,
+    ) : AppNavigationState
+}

services/appnavstate/api/src/main/kotlin/io/element/android/services/appnavstate/api/AppNavigationStateService.kt

@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2023 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.element.android.services.appnavstate.api
+
+import io.element.android.libraries.matrix.api.core.RoomId
+import io.element.android.libraries.matrix.api.core.SessionId
+import io.element.android.libraries.matrix.api.core.SpaceId
+import io.element.android.libraries.matrix.api.core.ThreadId
+import kotlinx.coroutines.flow.StateFlow
+
+interface AppNavigationStateService {
+    val appNavigationStateFlow: StateFlow<AppNavigationState>
+
+    fun onNavigateToSession(sessionId: SessionId)
+    fun onLeavingSession()
+
+    fun onNavigateToSpace(spaceId: SpaceId)
+    fun onLeavingSpace()
+
+    fun onNavigateToRoom(roomId: RoomId)
+    fun onLeavingRoom()
+
+    fun onNavigateToThread(threadId: ThreadId)
+    fun onLeavingThread()
+}