feat(nip29): join / leave / create / invite actions

Wire the NIP-29 membership + admin flows into the UI, all published only to the
group's host relay:

- Account: joinRelayGroup (9021 + follow), leaveRelayGroup (9022 + unfollow),
  createRelayGroup (9007 + 9002, returns the new GroupId), createRelayGroupInvite
  (9009); AccountViewModel wrappers.
- RelayGroupTopBar: a Join button when not a member; once joined, an overflow
  with Invite + Leave. Membership is read from the kind-10009 list.
- CreateRelayGroupDialog: name/topic/private/invite-only; mints a random group id,
  publishes, and navigates into the new channel. Reachable from a FAB on the
  relay channel-list screen.
- InviteRelayGroupDialog: mints a kind-9009 invite code on open and offers copy.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B5MLY4hq5LXJ2D5WeLRyXj

amethyst/src/main/java/com/vitorpamplona/amethyst/model/Account.kt

@@ -202,6 +202,13 @@ import com.vitorpamplona.quartz.nip19Bech32.entities.NProfile
 import com.vitorpamplona.quartz.nip19Bech32.entities.NPub
 import com.vitorpamplona.quartz.nip19Bech32.entities.NRelay
 import com.vitorpamplona.quartz.nip19Bech32.entities.NSec
+import com.vitorpamplona.quartz.nip29RelayGroups.GroupId
+import com.vitorpamplona.quartz.nip29RelayGroups.metadata.GroupMetadataEvent
+import com.vitorpamplona.quartz.nip29RelayGroups.moderation.CreateGroupEvent
+import com.vitorpamplona.quartz.nip29RelayGroups.moderation.CreateInviteEvent
+import com.vitorpamplona.quartz.nip29RelayGroups.moderation.EditMetadataEvent
+import com.vitorpamplona.quartz.nip29RelayGroups.request.JoinRequestEvent
+import com.vitorpamplona.quartz.nip29RelayGroups.request.LeaveRequestEvent
 import com.vitorpamplona.quartz.nip32Labeling.LabelEvent
 import com.vitorpamplona.quartz.nip36SensitiveContent.contentWarning
 import com.vitorpamplona.quartz.nip37Drafts.DraftEventCache
@@ -1455,6 +1462,65 @@ class Account(
 
     suspend fun unfollow(channel: RelayGroupChannel) = sendMyPublicAndPrivateOutbox(relayGroupList.unfollow(channel))
 
+    // ── NIP-29 relay-group actions ───────────────────────────────────────────
+    // All group commands are published ONLY to the group's host relay, where
+    // relay29 authorizes them. The relay is the source of truth; the kind-10009
+    // list is our own cross-device bookkeeping of what we joined.
+
+    /** Send a kind 9021 join request to the group's host relay and remember it. */
+    suspend fun joinRelayGroup(
+        channel: RelayGroupChannel,
+        code: String? = null,
+    ) {
+        val template = JoinRequestEvent.build(channel.groupId.id, inviteCode = code)
+        signAndSendPrivatelyOrBroadcast(template) { channel.relays().toList() }
+        follow(channel)
+    }
+
+    /** Send a kind 9022 leave request to the host relay and drop it from our list. */
+    suspend fun leaveRelayGroup(channel: RelayGroupChannel) {
+        val template = LeaveRequestEvent.build(channel.groupId.id)
+        signAndSendPrivatelyOrBroadcast(template) { channel.relays().toList() }
+        unfollow(channel)
+    }
+
+    /**
+     * Create a new group on [relay]: kind 9007 (create-group) then kind 9002
+     * (edit-metadata) with the chosen name/visibility, then remember it. Returns
+     * the new group's id.
+     */
+    suspend fun createRelayGroup(
+        relay: NormalizedRelayUrl,
+        groupId: String,
+        name: String,
+        about: String? = null,
+        isPrivate: Boolean = false,
+        isClosed: Boolean = false,
+    ): GroupId {
+        signAndSendPrivatelyOrBroadcast(CreateGroupEvent.build(groupId)) { listOf(relay) }
+
+        val status =
+            buildSet {
+                add(if (isPrivate) GroupMetadataEvent.GroupStatus.PRIVATE else GroupMetadataEvent.GroupStatus.PUBLIC)
+                add(if (isClosed) GroupMetadataEvent.GroupStatus.CLOSED else GroupMetadataEvent.GroupStatus.OPEN)
+            }
+        val edit = EditMetadataEvent.build(groupId, name = name, about = about, status = status)
+        signAndSendPrivatelyOrBroadcast(edit) { listOf(relay) }
+
+        val id = GroupId(groupId, relay)
+        follow(LocalCache.getOrCreateRelayGroupChannel(id))
+        return id
+    }
+
+    /** Mint a kind 9009 invite code for the group (admin/moderator only). */
+    suspend fun createRelayGroupInvite(
+        channel: RelayGroupChannel,
+        code: String,
+    ) {
+        val template = CreateInviteEvent.build(channel.groupId.id, code)
+        signAndSendPrivatelyOrBroadcast(template) { channel.relays().toList() }
+    }
+
     suspend fun follow(community: AddressableNote) = sendMyPublicAndPrivateOutbox(communityList.follow(community))
 
     suspend fun unfollow(community: AddressableNote) = sendMyPublicAndPrivateOutbox(communityList.unfollow(community))

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/AccountViewModel.kt

@@ -1431,6 +1431,27 @@ class AccountViewModel(
 
     fun unfollow(channel: EphemeralChatChannel) = launchSigner { account.unfollow(channel) }
 
+    fun joinRelayGroup(
+        channel: RelayGroupChannel,
+        code: String? = null,
+    ) = launchSigner { account.joinRelayGroup(channel, code) }
+
+    fun leaveRelayGroup(channel: RelayGroupChannel) = launchSigner { account.leaveRelayGroup(channel) }
+
+    fun createRelayGroup(
+        relay: NormalizedRelayUrl,
+        groupId: String,
+        name: String,
+        about: String?,
+        isPrivate: Boolean,
+        isClosed: Boolean,
+    ) = launchSigner { account.createRelayGroup(relay, groupId, name, about, isPrivate, isClosed) }
+
+    fun createRelayGroupInvite(
+        channel: RelayGroupChannel,
+        code: String,
+    ) = launchSigner { account.createRelayGroupInvite(channel, code) }
+
     fun follow(users: List<User>) = launchSigner { account.follow(users) }
 
     fun follow(user: User) = launchSigner { account.follow(user) }

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/chats/publicChannels/relayGroup/CreateRelayGroupDialog.kt

@@ -0,0 +1,130 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.ui.screen.loggedIn.chats.publicChannels.relayGroup
+
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.AlertDialog
+import androidx.compose.material3.OutlinedTextField
+import androidx.compose.material3.Switch
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.unit.dp
+import com.vitorpamplona.amethyst.R
+import com.vitorpamplona.amethyst.ui.navigation.navs.INav
+import com.vitorpamplona.amethyst.ui.navigation.routes.Route
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
+import com.vitorpamplona.amethyst.ui.stringRes
+import com.vitorpamplona.quartz.nip01Core.core.toHexKey
+import com.vitorpamplona.quartz.nip01Core.relay.normalizer.NormalizedRelayUrl
+import com.vitorpamplona.quartz.utils.RandomInstance
+
+/** Random NIP-29 group id: 8 secure bytes, hex-encoded (matches Armada). */
+private fun randomGroupId(): String = RandomInstance.bytes(8).toHexKey()
+
+/**
+ * Create a NIP-29 group on [relay]: publishes kind 9007 + 9002 with the chosen
+ * name/visibility, then navigates into the new group. The user becomes its first
+ * admin.
+ */
+@Composable
+fun CreateRelayGroupDialog(
+    relay: NormalizedRelayUrl,
+    accountViewModel: AccountViewModel,
+    nav: INav,
+    onDismiss: () -> Unit,
+) {
+    var name by remember { mutableStateOf("") }
+    var about by remember { mutableStateOf("") }
+    var isPrivate by remember { mutableStateOf(false) }
+    var isClosed by remember { mutableStateOf(false) }
+
+    AlertDialog(
+        onDismissRequest = onDismiss,
+        title = { Text(stringRes(R.string.relay_group_create_title)) },
+        text = {
+            Column {
+                OutlinedTextField(
+                    value = name,
+                    onValueChange = { name = it },
+                    singleLine = true,
+                    label = { Text(stringRes(R.string.relay_group_create_name)) },
+                    modifier = Modifier.fillMaxWidth(),
+                )
+                OutlinedTextField(
+                    value = about,
+                    onValueChange = { about = it },
+                    label = { Text(stringRes(R.string.relay_group_create_topic)) },
+                    modifier = Modifier.fillMaxWidth().padding(top = 8.dp),
+                )
+                ToggleRow(stringRes(R.string.relay_group_create_private), isPrivate) { isPrivate = it }
+                ToggleRow(stringRes(R.string.relay_group_create_invite_only), isClosed) { isClosed = it }
+            }
+        },
+        confirmButton = {
+            TextButton(
+                enabled = name.isNotBlank(),
+                onClick = {
+                    val groupId = randomGroupId()
+                    accountViewModel.createRelayGroup(
+                        relay = relay,
+                        groupId = groupId,
+                        name = name.trim(),
+                        about = about.trim().ifBlank { null },
+                        isPrivate = isPrivate,
+                        isClosed = isClosed,
+                    )
+                    onDismiss()
+                    nav.nav(Route.RelayGroup(groupId, relay.url))
+                },
+            ) {
+                Text(stringRes(R.string.relay_group_create_confirm))
+            }
+        },
+        dismissButton = {
+            TextButton(onClick = onDismiss) { Text(stringRes(R.string.cancel)) }
+        },
+    )
+}
+
+@Composable
+private fun ToggleRow(
+    label: String,
+    checked: Boolean,
+    onChange: (Boolean) -> Unit,
+) {
+    Row(
+        modifier = Modifier.fillMaxWidth().padding(top = 8.dp),
+        verticalAlignment = Alignment.CenterVertically,
+    ) {
+        Text(label, modifier = Modifier.weight(1f))
+        Switch(checked = checked, onCheckedChange = onChange)
+    }
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/chats/publicChannels/relayGroup/InviteRelayGroupDialog.kt

@@ -0,0 +1,88 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.ui.screen.loggedIn.chats.publicChannels.relayGroup
+
+import androidx.compose.foundation.layout.Column
+import androidx.compose.material3.AlertDialog
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.platform.LocalClipboardManager
+import androidx.compose.ui.text.AnnotatedString
+import androidx.compose.ui.text.font.FontFamily
+import com.vitorpamplona.amethyst.R
+import com.vitorpamplona.amethyst.commons.model.nip29RelayGroups.RelayGroupChannel
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
+import com.vitorpamplona.amethyst.ui.stringRes
+import com.vitorpamplona.quartz.nip01Core.core.toHexKey
+import com.vitorpamplona.quartz.utils.RandomInstance
+
+/**
+ * Mint a NIP-29 invite (kind 9009) for the group as soon as the dialog opens and
+ * show the code to copy and share. Requires admin/moderator rights on the relay.
+ */
+@Composable
+fun InviteRelayGroupDialog(
+    channel: RelayGroupChannel,
+    accountViewModel: AccountViewModel,
+    onDismiss: () -> Unit,
+) {
+    val clipboard = LocalClipboardManager.current
+    val code by remember { mutableStateOf(RandomInstance.bytes(6).toHexKey()) }
+
+    // Publishing the invite is a one-shot side effect when the dialog opens.
+    LaunchedEffect(code) {
+        accountViewModel.createRelayGroupInvite(channel, code)
+    }
+
+    AlertDialog(
+        onDismissRequest = onDismiss,
+        title = { Text(stringRes(R.string.relay_group_invite_title)) },
+        text = {
+            Column {
+                Text(stringRes(R.string.relay_group_invite_description))
+                Text(
+                    text = code,
+                    fontFamily = FontFamily.Monospace,
+                    style = MaterialTheme.typography.titleLarge,
+                    color = MaterialTheme.colorScheme.primary,
+                )
+            }
+        },
+        confirmButton = {
+            TextButton(onClick = {
+                clipboard.setText(AnnotatedString(code))
+                onDismiss()
+            }) {
+                Text(stringRes(R.string.copy))
+            }
+        },
+        dismissButton = {
+            TextButton(onClick = onDismiss) { Text(stringRes(R.string.cancel)) }
+        },
+    )
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/chats/publicChannels/relayGroup/RelayGroupChannelListScreen.kt

@@ -26,14 +26,17 @@ import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.items
+import androidx.compose.material3.FloatingActionButton
 import androidx.compose.material3.HorizontalDivider
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Scaffold
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.produceState
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextOverflow
@@ -62,6 +65,8 @@ fun RelayGroupChannelListScreen(
 ) {
     val relay = remember(relayUrl) { RelayUrlNormalizer.normalizeOrNull(relayUrl) } ?: return
 
+    var showCreate by remember { mutableStateOf(false) }
+
     RelayGroupDirectorySubscription(relay, accountViewModel.dataSources().relayGroupDirectory, accountViewModel)
 
     // The channel set grows as directory events arrive; poll the cache while the
@@ -90,6 +95,11 @@ fun RelayGroupChannelListScreen(
                 popBack = nav::popBack,
             )
         },
+        floatingActionButton = {
+            FloatingActionButton(onClick = { showCreate = true }) {
+                Text("+", style = MaterialTheme.typography.headlineMedium)
+            }
+        },
     ) { padding ->
         LazyColumn(modifier = Modifier.padding(padding)) {
             items(channels, key = { it.groupId.id }) { channel ->
@@ -98,6 +108,10 @@ fun RelayGroupChannelListScreen(
             }
         }
     }
+
+    if (showCreate) {
+        CreateRelayGroupDialog(relay, accountViewModel, nav) { showCreate = false }
+    }
 }
 
 @Composable

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/chats/publicChannels/relayGroup/RelayGroupTopBar.kt

@@ -21,17 +21,28 @@
 package com.vitorpamplona.amethyst.ui.screen.loggedIn.chats.publicChannels.relayGroup
 
 import androidx.compose.foundation.layout.Column
+import androidx.compose.material3.DropdownMenu
+import androidx.compose.material3.DropdownMenuItem
+import androidx.compose.material3.FilledTonalButton
+import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextOverflow
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import com.vitorpamplona.amethyst.R
 import com.vitorpamplona.amethyst.commons.model.nip29RelayGroups.RelayGroupChannel
 import com.vitorpamplona.amethyst.service.relayClient.reqCommand.channel.observeChannel
 import com.vitorpamplona.amethyst.ui.navigation.navs.INav
 import com.vitorpamplona.amethyst.ui.navigation.topbars.TopBarExtensibleWithBackButton
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
+import com.vitorpamplona.amethyst.ui.stringRes
+import com.vitorpamplona.quartz.nip01Core.relay.normalizer.RelayUrlNormalizer
 
 @Composable
 fun RelayGroupTopBar(
@@ -43,6 +54,17 @@ fun RelayGroupTopBar(
     val channelState by observeChannel(baseChannel, accountViewModel)
     val channel = channelState?.channel as? RelayGroupChannel ?: baseChannel
 
+    val joinedGroups by accountViewModel.account.relayGroupList.liveRelayGroupList
+        .collectAsStateWithLifecycle()
+    val isJoined =
+        joinedGroups.any {
+            it.groupId == channel.groupId.id &&
+                RelayUrlNormalizer.normalizeOrNull(it.relayUrl) == channel.groupId.relayUrl
+        }
+
+    var menuOpen by remember { mutableStateOf(false) }
+    var showInvite by remember { mutableStateOf(false) }
+
     TopBarExtensibleWithBackButton(
         title = {
             Column {
@@ -61,6 +83,37 @@ fun RelayGroupTopBar(
                 )
             }
         },
+        actions = {
+            if (!isJoined) {
+                FilledTonalButton(onClick = { accountViewModel.joinRelayGroup(channel) }) {
+                    Text(stringRes(R.string.join))
+                }
+            } else {
+                IconButton(onClick = { menuOpen = true }) {
+                    Text("⋮", style = MaterialTheme.typography.titleLarge)
+                }
+                DropdownMenu(expanded = menuOpen, onDismissRequest = { menuOpen = false }) {
+                    DropdownMenuItem(
+                        text = { Text(stringRes(R.string.relay_group_invite_title)) },
+                        onClick = {
+                            menuOpen = false
+                            showInvite = true
+                        },
+                    )
+                    DropdownMenuItem(
+                        text = { Text(stringRes(R.string.leave)) },
+                        onClick = {
+                            menuOpen = false
+                            accountViewModel.leaveRelayGroup(channel)
+                        },
+                    )
+                }
+            }
+        },
         popBack = nav::popBack,
     )
+
+    if (showInvite) {
+        InviteRelayGroupDialog(channel, accountViewModel) { showInvite = false }
+    }
 }

amethyst/src/main/res/values/strings.xml

@@ -1931,6 +1931,16 @@
     <string name="messages_create_public_private_chat_description">New Public or Private Group</string>
     <string name="relay_group_view_inline">Inline</string>
     <string name="relay_group_view_grouped">By relay</string>
+    <string name="relay_group_create_title">Create a channel</string>
+    <string name="relay_group_create_name">Channel name</string>
+    <string name="relay_group_create_topic">Topic (optional)</string>
+    <string name="relay_group_create_private">Private (members-only read)</string>
+    <string name="relay_group_create_invite_only">Invite only</string>
+    <string name="relay_group_create_confirm">Create</string>
+    <string name="relay_group_invite_title">Invite people</string>
+    <string name="relay_group_invite_description">Share this code so people can join this channel.</string>
+    <string name="relay_group_invite_generating">Creating an invite…</string>
+    <string name="relay_group_invite_copied">Invite code copied</string>
     <string name="messages_new_message">Private</string>
     <string name="messages_new_message_to">To</string>
     <string name="messages_new_message_subject">Subject</string>