feat(marmot): show member pictures and names when group has no name

Marmot groups without a configured display name now fall back to the
NIP-17 strategy: a stacked avatar of the members and a comma-separated
list of their first names. Applied to both the group list row and the
chat top app bar.

NonClickableUserPictures and DisplayUserSetAsSubject get List<HexKey>
overloads so the renderers can be reused without dragging Marmot through
ChatroomKey (which is also a NIP-17 dedup key — different Marmot groups
can share the same member set).

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/note/UserProfilePicture.kt

@@ -231,19 +231,28 @@ fun NonClickableUserPictures(
     room: ChatroomKey,
     size: Dp,
     accountViewModel: AccountViewModel,
+) {
+    NonClickableUserPictures(room.users.toList(), size, accountViewModel)
+}
+
+@Composable
+fun NonClickableUserPictures(
+    userHexList: List<HexKey>,
+    size: Dp,
+    accountViewModel: AccountViewModel,
 ) {
     Box(Modifier.size(size), contentAlignment = Alignment.TopEnd) {
-        when (room.users.size) {
+        when (userHexList.size) {
             0 -> {}
 
             1 -> {
-                LoadUser(baseUserHex = room.users.first(), accountViewModel) {
+                LoadUser(baseUserHex = userHexList.first(), accountViewModel) {
                     it?.let { BaseUserPicture(it, size, accountViewModel, outerModifier = Modifier) }
                 }
             }
 
             2 -> {
-                val userList = room.users.toList()
+                val userList = userHexList
 
                 LoadUser(baseUserHex = userList[0], accountViewModel) {
                     it?.let {
@@ -268,7 +277,7 @@ fun NonClickableUserPictures(
             }
 
             3 -> {
-                val userList = room.users.toList()
+                val userList = userHexList
 
                 LoadUser(baseUserHex = userList[0], accountViewModel) {
                     it?.let {
@@ -303,7 +312,7 @@ fun NonClickableUserPictures(
             }
 
             else -> {
-                val userList = room.users.toList()
+                val userList = userHexList
 
                 LoadUser(baseUserHex = userList[0], accountViewModel) {
                     it?.let {

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/chats/marmotGroup/MarmotGroupChatScreen.kt

@@ -21,7 +21,9 @@
 package com.vitorpamplona.amethyst.ui.screen.loggedIn.chats.marmotGroup
 
 import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.padding
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.filled.ArrowBack
@@ -35,12 +37,16 @@ import androidx.compose.material3.TopAppBar
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.remember
+import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.unit.dp
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import com.vitorpamplona.amethyst.ui.layouts.DisappearingScaffold
 import com.vitorpamplona.amethyst.ui.navigation.navs.INav
 import com.vitorpamplona.amethyst.ui.navigation.routes.Route
+import com.vitorpamplona.amethyst.ui.note.NonClickableUserPictures
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.chats.privateDM.header.DisplayUserSetAsSubject
 import com.vitorpamplona.quartz.nip01Core.core.HexKey
 
 @OptIn(ExperimentalMaterial3Api::class)
@@ -56,6 +62,8 @@ fun MarmotGroupChatScreen(
         }
     val displayName by chatroom.displayName.collectAsStateWithLifecycle()
     val memberCount by chatroom.memberCount.collectAsStateWithLifecycle()
+    val members by chatroom.members.collectAsStateWithLifecycle()
+    val memberPubkeys = remember(members) { members.map { it.pubkey } }
 
     DisappearingScaffold(
         isInvertedLayout = true,
@@ -70,19 +78,39 @@ fun MarmotGroupChatScreen(
                     }
                 },
                 title = {
-                    Column(
+                    Row(
                         modifier =
                             Modifier.clickable {
                                 nav.nav(Route.MarmotGroupInfo(nostrGroupId))
                             },
+                        verticalAlignment = Alignment.CenterVertically,
+                        horizontalArrangement = Arrangement.spacedBy(8.dp),
                     ) {
-                        Text(displayName ?: "Marmot Group")
-                        if (memberCount > 0) {
-                            Text(
-                                text = "$memberCount members",
-                                style = MaterialTheme.typography.bodySmall,
+                        if (memberPubkeys.isNotEmpty()) {
+                            NonClickableUserPictures(
+                                userHexList = memberPubkeys,
+                                size = 36.dp,
+                                accountViewModel = accountViewModel,
                             )
                         }
+                        Column {
+                            if (!displayName.isNullOrBlank()) {
+                                Text(displayName!!)
+                            } else if (memberPubkeys.isNotEmpty()) {
+                                DisplayUserSetAsSubject(
+                                    userList = memberPubkeys,
+                                    accountViewModel = accountViewModel,
+                                )
+                            } else {
+                                Text("Marmot Group")
+                            }
+                            if (memberCount > 0) {
+                                Text(
+                                    text = "$memberCount members",
+                                    style = MaterialTheme.typography.bodySmall,
+                                )
+                            }
+                        }
                     }
                 },
                 actions = {

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/chats/marmotGroup/MarmotGroupListScreen.kt

@@ -65,7 +65,9 @@ import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import com.vitorpamplona.amethyst.commons.model.marmotGroups.MarmotGroupChatroom
 import com.vitorpamplona.amethyst.ui.navigation.navs.INav
 import com.vitorpamplona.amethyst.ui.navigation.routes.Route
+import com.vitorpamplona.amethyst.ui.note.NonClickableUserPictures
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.chats.privateDM.header.DisplayUserSetAsSubject
 import com.vitorpamplona.quartz.nip01Core.core.HexKey
 
 @OptIn(ExperimentalMaterial3Api::class)
@@ -179,6 +181,7 @@ fun MarmotGroupListScreen(
                         MarmotGroupListItem(
                             groupId = groupId,
                             chatroom = chatroom,
+                            accountViewModel = accountViewModel,
                             onClick = {
                                 nav.nav(Route.MarmotGroupChat(groupId))
                             },
@@ -213,10 +216,13 @@ private fun loadGroupList(
 fun MarmotGroupListItem(
     groupId: HexKey,
     chatroom: MarmotGroupChatroom,
+    accountViewModel: AccountViewModel,
     onClick: () -> Unit,
 ) {
     val displayName by chatroom.displayName.collectAsStateWithLifecycle()
     val unread by chatroom.unreadCount.collectAsStateWithLifecycle()
+    val members by chatroom.members.collectAsStateWithLifecycle()
+    val memberPubkeys = remember(members) { members.map { it.pubkey } }
     val newestMessage = chatroom.newestMessage
 
     Row(
@@ -225,17 +231,40 @@ fun MarmotGroupListItem(
                 .fillMaxWidth()
                 .clickable(onClick = onClick)
                 .padding(horizontal = 16.dp, vertical = 12.dp),
-        horizontalArrangement = Arrangement.SpaceBetween,
+        horizontalArrangement = Arrangement.spacedBy(12.dp),
         verticalAlignment = Alignment.CenterVertically,
     ) {
-        Column(modifier = Modifier.weight(1f)) {
-            Text(
-                text = displayName ?: "Group ${groupId.take(8)}...",
-                style = MaterialTheme.typography.titleSmall,
-                fontWeight = if (unread > 0) FontWeight.Bold else FontWeight.Normal,
-                maxLines = 1,
-                overflow = TextOverflow.Ellipsis,
+        if (memberPubkeys.isNotEmpty()) {
+            NonClickableUserPictures(
+                userHexList = memberPubkeys,
+                size = 55.dp,
+                accountViewModel = accountViewModel,
             )
+        }
+        Column(modifier = Modifier.weight(1f)) {
+            if (!displayName.isNullOrBlank()) {
+                Text(
+                    text = displayName!!,
+                    style = MaterialTheme.typography.titleSmall,
+                    fontWeight = if (unread > 0) FontWeight.Bold else FontWeight.Normal,
+                    maxLines = 1,
+                    overflow = TextOverflow.Ellipsis,
+                )
+            } else if (memberPubkeys.isNotEmpty()) {
+                DisplayUserSetAsSubject(
+                    userList = memberPubkeys,
+                    accountViewModel = accountViewModel,
+                    fontWeight = if (unread > 0) FontWeight.Bold else FontWeight.Normal,
+                )
+            } else {
+                Text(
+                    text = "Group ${groupId.take(8)}...",
+                    style = MaterialTheme.typography.titleSmall,
+                    fontWeight = if (unread > 0) FontWeight.Bold else FontWeight.Normal,
+                    maxLines = 1,
+                    overflow = TextOverflow.Ellipsis,
+                )
+            }
             if (newestMessage != null) {
                 Text(
                     text = newestMessage.event?.content ?: "",

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/chats/privateDM/header/RoomNameOnlyDisplay.kt

@@ -69,7 +69,15 @@ fun DisplayUserSetAsSubject(
     fontWeight: FontWeight = FontWeight.Bold,
 ) {
     val userList = remember(room) { room.users.toList() }
+    DisplayUserSetAsSubject(userList, accountViewModel, fontWeight)
+}
 
+@Composable
+fun DisplayUserSetAsSubject(
+    userList: List<HexKey>,
+    accountViewModel: AccountViewModel,
+    fontWeight: FontWeight = FontWeight.Bold,
+) {
     if (userList.size == 1) {
         // Regular Design
         Row {