refactor: remove NodeDB `users` StateFlow

app/src/main/java/com/geeksville/mesh/model/NodeDB.kt

@@ -3,7 +3,6 @@ package com.geeksville.mesh.model
 import androidx.lifecycle.Lifecycle
 import androidx.lifecycle.coroutineScope
 import com.geeksville.mesh.MeshProtos
-import com.geeksville.mesh.MeshUser
 import com.geeksville.mesh.MyNodeInfo
 import com.geeksville.mesh.NodeInfo
 import com.geeksville.mesh.database.dao.NodeInfoDao
@@ -44,9 +43,6 @@ class NodeDB @Inject constructor(
     val nodeDBbyID: StateFlow<Map<String, NodeInfo>> get() = _nodeDBbyID
     val nodes get() = nodeDBbyID
 
-    private val _users = MutableStateFlow<Map<String, MeshUser?>>(mapOf())
-    val users: StateFlow<Map<String, MeshUser?>> get() = _users
-
     init {
         nodeInfoDao.getMyNodeInfo().onEach { _myNodeInfo.value = it }
             .launchIn(processLifecycle.coroutineScope)
@@ -60,7 +56,6 @@ class NodeDB @Inject constructor(
 
         nodeInfoDao.nodeDBbyID().onEach {
             _nodeDBbyID.value = it
-            _users.value = it.mapValues { node -> node.value.user }
         }
             .launchIn(processLifecycle.coroutineScope)
     }

app/src/main/java/com/geeksville/mesh/model/UIState.kt

@@ -315,11 +315,9 @@ class UIViewModel @Inject constructor(
         initialValue = emptyList(),
     )
 
-    fun getMessagesFrom(contactKey: String) = combine(
-        nodeDB.users,
-        packetRepository.getMessagesFrom(contactKey),
-    ) { users, packets ->
-        packets.map {
+    @OptIn(ExperimentalCoroutinesApi::class)
+    fun getMessagesFrom(contactKey: String) = packetRepository.getMessagesFrom(contactKey).mapLatest { list ->
+        list.map {
             val defaultUser = MeshUser(
                 it.data.from ?: DataPacket.ID_LOCAL,
                 app.getString(R.string.unknown_username),
@@ -329,7 +327,7 @@ class UIViewModel @Inject constructor(
             Message(
                 uuid = it.uuid,
                 receivedTime = it.received_time,
-                user = users[it.data.from] ?: defaultUser,
+                user = nodeDB.nodes.value[it.data.from]?.user ?: defaultUser,
                 text = it.data.text.orEmpty(),
                 time = it.data.time,
                 read = it.read,