Avoid creating many PowerLevelRoomMemberComparator instance and also avoid doing the sorting twice.

features/rolesandpermissions/impl/src/main/kotlin/io/element/android/features/rolesandpermissions/impl/roles/ChangeRolesPresenter.kt

@@ -61,6 +61,8 @@ class ChangeRolesPresenter(
         fun create(role: RoomMember.Role): ChangeRolesPresenter
     }
 
+    private val powerLevelRoomMemberComparator = PowerLevelRoomMemberComparator()
+
     @Composable
     override fun present(): ChangeRolesState {
         val dataSource = remember { RoomMemberListDataSource(room, dispatchers) }
@@ -176,17 +178,7 @@ class ChangeRolesPresenter(
     }
 
     private fun List<RoomMember>.groupedByRole(): MembersByRole {
-        val groupedMembers = MembersByRole(this)
-        return MembersByRole(
-            owners = groupedMembers.owners.sorted(),
-            admins = groupedMembers.admins.sorted(),
-            moderators = groupedMembers.moderators.sorted(),
-            members = groupedMembers.members.sorted(),
-        )
-    }
-
-    private fun Iterable<RoomMember>.sorted(): ImmutableList<RoomMember> {
-        return sortedWith(PowerLevelRoomMemberComparator()).toImmutableList()
+        return MembersByRole(this, powerLevelRoomMemberComparator)
     }
 
     private fun CoroutineScope.save(

features/rolesandpermissions/impl/src/main/kotlin/io/element/android/features/rolesandpermissions/impl/roles/ChangeRolesState.kt

@@ -13,8 +13,8 @@ import io.element.android.libraries.designsystem.theme.components.SearchBarResul
 import io.element.android.libraries.matrix.api.core.UserId
 import io.element.android.libraries.matrix.api.room.RoomMember
 import io.element.android.libraries.matrix.api.user.MatrixUser
-import io.element.android.libraries.matrix.ui.room.PowerLevelRoomMemberComparator
 import kotlinx.collections.immutable.ImmutableList
+import kotlinx.collections.immutable.persistentListOf
 import kotlinx.collections.immutable.toImmutableList
 
 data class ChangeRolesState(
@@ -35,16 +35,23 @@ data class MembersByRole(
     val moderators: ImmutableList<RoomMember>,
     val members: ImmutableList<RoomMember>,
 ) {
-    constructor(members: List<RoomMember>) : this(
-        owners = members.filter { it.role is RoomMember.Role.Owner }.sorted(),
-        admins = members.filter { it.role == RoomMember.Role.Admin }.sorted(),
-        moderators = members.filter { it.role == RoomMember.Role.Moderator }.sorted(),
-        members = members.filter { it.role == RoomMember.Role.User }.sorted(),
+    constructor() : this(
+        owners = persistentListOf(),
+        admins = persistentListOf(),
+        moderators = persistentListOf(),
+        members = persistentListOf(),
+    )
+
+    constructor(members: List<RoomMember>, comparator: Comparator<RoomMember>) : this(
+        owners = members.filter { it.role is RoomMember.Role.Owner }.sorted(comparator),
+        admins = members.filter { it.role == RoomMember.Role.Admin }.sorted(comparator),
+        moderators = members.filter { it.role == RoomMember.Role.Moderator }.sorted(comparator),
+        members = members.filter { it.role == RoomMember.Role.User }.sorted(comparator),
     )
 
     fun isEmpty() = owners.isEmpty() && admins.isEmpty() && moderators.isEmpty() && members.isEmpty()
 }
 
-private fun Iterable<RoomMember>.sorted(): ImmutableList<RoomMember> {
-    return sortedWith(PowerLevelRoomMemberComparator()).toImmutableList()
+private fun Iterable<RoomMember>.sorted(comparator: Comparator<RoomMember>): ImmutableList<RoomMember> {
+    return sortedWith(comparator).toImmutableList()
 }

features/rolesandpermissions/impl/src/main/kotlin/io/element/android/features/rolesandpermissions/impl/roles/ChangeRolesStateProvider.kt

@@ -17,6 +17,7 @@ import io.element.android.libraries.matrix.api.room.RoomMembershipState
 import io.element.android.libraries.matrix.api.user.MatrixUser
 import io.element.android.libraries.matrix.ui.components.aMatrixUser
 import io.element.android.libraries.matrix.ui.components.aMatrixUserList
+import io.element.android.libraries.matrix.ui.room.PowerLevelRoomMemberComparator
 import io.element.android.libraries.previewutils.room.aRoomMember
 import io.element.android.libraries.previewutils.room.aRoomMemberList
 import kotlinx.collections.immutable.ImmutableList
@@ -36,7 +37,12 @@ class ChangeRolesStateProvider : PreviewParameterProvider<ChangeRolesState> {
             aChangeRolesStateWithSelectedUsers().copy(
                 query = "Alice",
                 isSearchActive = true,
-                searchResults = SearchBarResultState.Results(MembersByRole(aRoomMemberList().take(1).toImmutableList())),
+                searchResults = SearchBarResultState.Results(
+                    MembersByRole(
+                        members = aRoomMemberList().take(1),
+                        comparator = PowerLevelRoomMemberComparator(),
+                    )
+                ),
                 selectedUsers = aMatrixUserList().take(1).toImmutableList(),
             ),
             aChangeRolesStateWithSelectedUsers().copy(savingState = AsyncAction.ConfirmingCancellation),
@@ -87,7 +93,8 @@ internal fun aChangeRolesStateWithSelectedUsers() = aChangeRolesState(
                 } else {
                     roomMember
                 }
-            }
+            },
+            comparator = PowerLevelRoomMemberComparator(),
         )
     ),
     hasPendingChanges = true,
@@ -126,7 +133,8 @@ internal fun aChangeRolesStateWithOwners(
                     displayName = "David",
                     role = RoomMember.Role.User,
                 ),
-            )
+            ),
+            comparator = PowerLevelRoomMemberComparator(),
         ),
     ),
     canRemoveMember = { userId ->

features/rolesandpermissions/impl/src/main/kotlin/io/element/android/features/rolesandpermissions/impl/roles/ChangeRolesView.kt

@@ -145,7 +145,7 @@ fun ChangeRolesView(
                         SearchResultsList(
                             currentRole = state.role,
                             lazyListState = lazyListState,
-                            searchResults = (state.searchResults as? SearchBarResultState.Results)?.results ?: MembersByRole(emptyList()),
+                            searchResults = (state.searchResults as? SearchBarResultState.Results)?.results ?: MembersByRole(),
                             selectedUsers = state.selectedUsers,
                             canRemoveMember = state.canChangeMemberRole,
                             onToggleSelection = { state.eventSink(ChangeRolesEvent.UserSelectionToggled(it.toMatrixUser())) },

features/rolesandpermissions/impl/src/test/kotlin/io/element/android/features/rolesandpermissions/impl/roles/MembersByRoleTest.kt

@@ -18,6 +18,7 @@ import io.element.android.libraries.matrix.test.A_USER_ID_5
 import io.element.android.libraries.matrix.test.A_USER_ID_6
 import io.element.android.libraries.matrix.test.A_USER_ID_7
 import io.element.android.libraries.matrix.test.room.aRoomMember
+import io.element.android.libraries.matrix.ui.room.PowerLevelRoomMemberComparator
 import kotlinx.collections.immutable.persistentListOf
 import org.junit.Test
 
@@ -33,7 +34,7 @@ class MembersByRoleTest {
             aRoomMember(A_USER_ID_6, displayName = "Justin", role = RoomMember.Role.Owner(isCreator = true)),
             aRoomMember(A_USER_ID_7, displayName = "Mallory", role = RoomMember.Role.Owner(isCreator = false)),
         )
-        val membersByRole = MembersByRole(members = members)
+        val membersByRole = MembersByRole(members = members, comparator = PowerLevelRoomMemberComparator())
         assertThat(membersByRole.owners).containsExactly(
             aRoomMember(A_USER_ID_6, displayName = "Justin", role = RoomMember.Role.Owner(isCreator = true)),
             aRoomMember(A_USER_ID_7, displayName = "Mallory", role = RoomMember.Role.Owner(isCreator = false)),
@@ -52,7 +53,7 @@ class MembersByRoleTest {
 
     @Test
     fun `isEmpty - only returns true with no members of any role`() {
-        val emptyMembersByRole = MembersByRole(emptyList())
+        val emptyMembersByRole = MembersByRole()
         assertThat(emptyMembersByRole.isEmpty()).isTrue()
 
         val membersByRoleWithOwners = MembersByRole(