Add mapping on FocusEventException.

Extract FocusRequestState to its own file and add preview.

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/room/MatrixRoom.kt

@@ -100,7 +100,7 @@ interface MatrixRoom : Closeable {
 
     val liveTimeline: Timeline
 
-    suspend fun timelineFocusedOnEvent(eventId: EventId): Timeline
+    suspend fun timelineFocusedOnEvent(eventId: EventId): Result<Timeline>
 
     fun destroy()
 

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/room/errors/FocusEventException.kt

@@ -0,0 +1,34 @@
+/*
+ * Copyright (c) 2024 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.libraries.matrix.api.room.errors
+
+import io.element.android.libraries.matrix.api.core.EventId
+
+sealed class FocusEventException : Exception() {
+    data class InvalidEventId(
+        val eventId: String,
+        val err: String
+    ) : FocusEventException()
+
+    data class EventNotFound(
+        val eventId: EventId
+    ) : FocusEventException()
+
+    data class Other(
+        val msg: String
+    ) : FocusEventException()
+}