#128: truncate usernames

src/main/kotlin/chatroom/users/Users.kt

@@ -1,13 +1,22 @@
 package chatroom.users
 
 import chatroom.ChatroomWindow
+import chatroom.LEFT_WIDTH
 import org.koin.dsl.module
 
 val usersModule =
     module {
         scope<ChatroomWindow> {
             scoped { UsersPanel(presenter = get()) }
             scoped { UsersListUseCase() }
-            scoped { UsersListPresenter(users = get(), scope = get<ChatroomWindow>().windowScope, dispatchers = get()) }
+            scoped {
+                UsersListPresenter(
+                    users = get(),
+                    truncate = get(),
+                    scope = get<ChatroomWindow>().windowScope,
+                    dispatchers = get(),
+                )
+            }
         }
+        factory { UsersListTruncation(LEFT_WIDTH - 3) }
     }

src/main/kotlin/chatroom/users/UsersListPresenter.kt

@@ -4,23 +4,27 @@ import arch.Presenter
 import arch.RokyDispatchers
 import chatroom.users.UsersViewState.*
 import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
 
 class UsersListPresenter(
     private val users: UsersListUseCase,
+    private val truncate: UsersListTruncation,
     private val scope: CoroutineScope,
     dispatchers: RokyDispatchers,
 ) : Presenter<UsersListView>(dispatchers) {
     override fun onAttach(view: UsersListView) {
         view.show(Empty)
         scope.launch(dispatchers.io) {
-            users().map(::Users).collect { state ->
-                withContext(dispatchers.main) {
-                    show(state)
+            users()
+                .truncateUsernames()
+                .map(::Users).collect { state ->
+                    withContext(dispatchers.main) {
+                        show(state)
+                    }
                 }
-            }
         }
     }
 
@@ -31,4 +35,9 @@ class UsersListPresenter(
     override fun onDetach(view: UsersListView) {
         // Deliberately empty
     }
+
+    private fun Flow<List<String>>.truncateUsernames() =
+        map { username ->
+            username.map(truncate::invoke)
+        }
 }

src/main/kotlin/chatroom/users/UsersListTruncation.kt

@@ -0,0 +1,7 @@
+package chatroom.users
+
+import utils.cutOff
+
+class UsersListTruncation(private val width: Int) {
+    operator fun invoke(input: String): String = input.cutOff(width)
+}

src/test/kotlin/chatroom/users/UsersListPresenterTest.kt

@@ -33,7 +33,7 @@ class UsersListPresenterTest {
                 every { io } returns dispatcher
             }
         scope = CoroutineScope(dispatcher)
-        presenter = UsersListPresenter(listUsers, scope, dispatchers)
+        presenter = UsersListPresenter(listUsers, UsersListTruncation(10), scope, dispatchers)
     }
 
     @Test
@@ -78,6 +78,24 @@ class UsersListPresenterTest {
             }
         }
 
+    @Test
+    fun `when users list contains very long usernames, then truncate long usernames only`() =
+        runTest(dispatcher) {
+            val userList = listOf("Allie", "Kai", "A very very long username")
+            coEvery { listUsers() } coAnswersDelayed { flowOf(userList) }
+            presenter.attach(view)
+            advanceUntilIdle()
+            verifyOrder {
+                view.show(Empty)
+                view.show(
+                    withArg {
+                        assertTrue { it is Users }
+                        assertTrue { (it as Users).users == listOf("Allie", "Kai", "A very ve…") }
+                    },
+                )
+            }
+        }
+
     companion object {
         private val dispatcher = StandardTestDispatcher()
     }