feat: add standalone Public Chats screen

Introduces a dedicated Public Chats screen accessible from the left drawer,
mirroring the architecture of the Shorts screen. It reuses the existing
Discover public-chats renderer (ChannelCardCompose + RenderPublicChatChannelThumb)
and its relay-filter helpers (makePublicChatsFilter), but with its own feed
content state, filter assembler/sub-assembler, and top-nav follow-list filter
setting so the selection is independent from Discover.

- New Route.PublicChats, drawer entry, screen/top-bar/feed composables
- PublicChatsFeedFilter scans LocalCache.publicChatChannels
- defaultPublicChatsFollowList persisted in AccountSettings / LocalPreferences
- Live per-relay follow list flow on Account for relay subscription

amethyst/src/main/java/com/vitorpamplona/amethyst/LocalPreferences.kt

@@ -103,6 +103,7 @@ private object PrefKeys {
     const val DEFAULT_PICTURES_FOLLOW_LIST = "defaultPicturesFollowList"
     const val DEFAULT_PRODUCTS_FOLLOW_LIST = "defaultProductsFollowList"
     const val DEFAULT_SHORTS_FOLLOW_LIST = "defaultShortsFollowList"
+    const val DEFAULT_PUBLIC_CHATS_FOLLOW_LIST = "defaultPublicChatsFollowList"
     const val DEFAULT_LONGS_FOLLOW_LIST = "defaultLongsFollowList"
     const val DEFAULT_ARTICLES_FOLLOW_LIST = "defaultArticlesFollowList"
     const val ZAP_PAYMENT_REQUEST_SERVER = "zapPaymentServer" // legacy, kept for migration
@@ -348,6 +349,7 @@ object LocalPreferences {
                     putString(PrefKeys.DEFAULT_PICTURES_FOLLOW_LIST, JsonMapper.toJson(settings.defaultPicturesFollowList.value))
                     putString(PrefKeys.DEFAULT_PRODUCTS_FOLLOW_LIST, JsonMapper.toJson(settings.defaultProductsFollowList.value))
                     putString(PrefKeys.DEFAULT_SHORTS_FOLLOW_LIST, JsonMapper.toJson(settings.defaultShortsFollowList.value))
+                    putString(PrefKeys.DEFAULT_PUBLIC_CHATS_FOLLOW_LIST, JsonMapper.toJson(settings.defaultPublicChatsFollowList.value))
                     putString(PrefKeys.DEFAULT_LONGS_FOLLOW_LIST, JsonMapper.toJson(settings.defaultLongsFollowList.value))
                     putString(PrefKeys.DEFAULT_ARTICLES_FOLLOW_LIST, JsonMapper.toJson(settings.defaultArticlesFollowList.value))
 
@@ -515,6 +517,7 @@ object LocalPreferences {
                     val defaultPicturesFollowListStr = getString(PrefKeys.DEFAULT_PICTURES_FOLLOW_LIST, null)
                     val defaultProductsFollowListStr = getString(PrefKeys.DEFAULT_PRODUCTS_FOLLOW_LIST, null)
                     val defaultShortsFollowListStr = getString(PrefKeys.DEFAULT_SHORTS_FOLLOW_LIST, null)
+                    val defaultPublicChatsFollowListStr = getString(PrefKeys.DEFAULT_PUBLIC_CHATS_FOLLOW_LIST, null)
                     val defaultLongsFollowListStr = getString(PrefKeys.DEFAULT_LONGS_FOLLOW_LIST, null)
                     val defaultArticlesFollowListStr = getString(PrefKeys.DEFAULT_ARTICLES_FOLLOW_LIST, null)
 
@@ -633,6 +636,7 @@ object LocalPreferences {
                         defaultPicturesFollowList = MutableStateFlow(defaultPicturesFollowList.await()),
                         defaultProductsFollowList = MutableStateFlow(defaultProductsFollowList.await()),
                         defaultShortsFollowList = MutableStateFlow(defaultShortsFollowList.await()),
+                        defaultPublicChatsFollowList = MutableStateFlow(parseTopFilterOrDefault(defaultPublicChatsFollowListStr, TopFilter.Global)),
                         defaultLongsFollowList = MutableStateFlow(defaultLongsFollowList.await()),
                         defaultArticlesFollowList = MutableStateFlow(defaultArticlesFollowList.await()),
                         nwcWallets = MutableStateFlow(nwcWalletsLoaded.await().first),

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

@@ -476,6 +476,9 @@ class Account(
     val liveShortsFollowLists: StateFlow<IFeedTopNavFilter> = topNavFilterFlow(settings.defaultShortsFollowList)
     val liveShortsFollowListsPerRelay = OutboxLoaderState(liveShortsFollowLists, cache, scope).flow
 
+    val livePublicChatsFollowLists: StateFlow<IFeedTopNavFilter> = topNavFilterFlow(settings.defaultPublicChatsFollowList)
+    val livePublicChatsFollowListsPerRelay = OutboxLoaderState(livePublicChatsFollowLists, cache, scope).flow
+
     val liveLongsFollowLists: StateFlow<IFeedTopNavFilter> = topNavFilterFlow(settings.defaultLongsFollowList)
     val liveLongsFollowListsPerRelay = OutboxLoaderState(liveLongsFollowLists, cache, scope).flow
 

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

@@ -185,6 +185,7 @@ class AccountSettings(
     val defaultPicturesFollowList: MutableStateFlow<TopFilter> = MutableStateFlow(TopFilter.Global),
     val defaultProductsFollowList: MutableStateFlow<TopFilter> = MutableStateFlow(TopFilter.AroundMe),
     val defaultShortsFollowList: MutableStateFlow<TopFilter> = MutableStateFlow(TopFilter.Global),
+    val defaultPublicChatsFollowList: MutableStateFlow<TopFilter> = MutableStateFlow(TopFilter.Global),
     val defaultLongsFollowList: MutableStateFlow<TopFilter> = MutableStateFlow(TopFilter.Global),
     val defaultArticlesFollowList: MutableStateFlow<TopFilter> = MutableStateFlow(TopFilter.AllFollows),
     val defaultBadgesFollowList: MutableStateFlow<TopFilter> = MutableStateFlow(TopFilter.Mine),
@@ -509,6 +510,17 @@ class AccountSettings(
         }
     }
 
+    fun changeDefaultPublicChatsFollowList(name: FeedDefinition) {
+        changeDefaultPublicChatsFollowList(name.code)
+    }
+
+    fun changeDefaultPublicChatsFollowList(name: TopFilter) {
+        if (defaultPublicChatsFollowList.value != name) {
+            defaultPublicChatsFollowList.tryEmit(name)
+            saveAccountSettings()
+        }
+    }
+
     fun changeDefaultLongsFollowList(name: FeedDefinition) {
         changeDefaultLongsFollowList(name.code)
     }

amethyst/src/main/java/com/vitorpamplona/amethyst/service/relayClient/reqCommand/RelaySubscriptionsCoordinator.kt

@@ -47,6 +47,7 @@ import com.vitorpamplona.amethyst.ui.screen.loggedIn.pictures.datasource.Picture
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.polls.datasource.PollsFilterAssembler
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.products.datasource.ProductsFilterAssembler
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.profile.datasource.UserProfileFilterAssembler
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.publicChats.datasource.PublicChatsFilterAssembler
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.relay.datasource.RelayFeedFilterAssembler
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.relays.datasource.RelayInfoNip66FilterAssembler
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.shorts.datasource.ShortsFilterAssembler
@@ -99,6 +100,7 @@ class RelaySubscriptionsCoordinator(
     val pictures = PicturesFilterAssembler(client)
     val products = ProductsFilterAssembler(client)
     val shorts = ShortsFilterAssembler(client)
+    val publicChats = PublicChatsFilterAssembler(client)
     val longs = LongsFilterAssembler(client)
     val articles = ArticlesFilterAssembler(client)
     val badges = BadgesFilterAssembler(client)
@@ -120,6 +122,7 @@ class RelaySubscriptionsCoordinator(
             pictures,
             products,
             shorts,
+            publicChats,
             longs,
             articles,
             badges,

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/feeds/RememberForeverStates.kt

@@ -64,6 +64,7 @@ object ScrollStateKeys {
     const val PICTURES_SCREEN = "PicturesFeed"
     const val PRODUCTS_SCREEN = "ProductsFeed"
     const val SHORTS_SCREEN = "ShortsFeed"
+    const val PUBLIC_CHATS_SCREEN = "PublicChatsFeed"
     const val LONGS_SCREEN = "LongsFeed"
     const val ARTICLES_SCREEN = "ArticlesFeed"
 

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/navigation/AppNavigation.kt

@@ -139,6 +139,7 @@ import com.vitorpamplona.amethyst.ui.screen.loggedIn.polls.PollsScreen
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.privacy.PrivacyOptionsScreen
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.products.ProductsScreen
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.profile.ProfileScreen
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.publicChats.PublicChatsScreen
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.qrcode.ShowQRScreen
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.redirect.LoadRedirectScreen
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.relay.RelayFeedScreen
@@ -239,6 +240,7 @@ fun BuildNavigation(
         composableFromEnd<Route.Pictures> { PicturesScreen(accountViewModel, nav) }
         composableFromEnd<Route.Products> { ProductsScreen(accountViewModel, nav) }
         composableFromEnd<Route.Shorts> { ShortsScreen(accountViewModel, nav) }
+        composableFromEnd<Route.PublicChats> { PublicChatsScreen(accountViewModel, nav) }
         composableFromEnd<Route.Longs> { LongsScreen(accountViewModel, nav) }
         composableFromEnd<Route.Articles> { ArticlesScreen(accountViewModel, nav) }
         composableFromEnd<Route.NewHlsVideo> { NewHlsVideoScreen(accountViewModel, nav) }

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/navigation/drawer/DrawerContent.kt

@@ -53,6 +53,7 @@ import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.filled.FormatListBulleted
 import androidx.compose.material.icons.automirrored.filled.Send
 import androidx.compose.material.icons.automirrored.outlined.Article
+import androidx.compose.material.icons.automirrored.outlined.Chat
 import androidx.compose.material.icons.filled.AccountCircle
 import androidx.compose.material.icons.filled.Delete
 import androidx.compose.material.icons.outlined.AccountBalanceWallet
@@ -648,6 +649,14 @@ fun ListContent(
                 route = Route.Shorts,
             )
 
+            NavigationRow(
+                title = R.string.public_chats,
+                icon = Icons.AutoMirrored.Outlined.Chat,
+                tint = MaterialTheme.colorScheme.onBackground,
+                nav = nav,
+                route = Route.PublicChats,
+            )
+
             NavigationRow(
                 title = R.string.longs,
                 icon = Icons.Outlined.SmartDisplay,

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/navigation/routes/Routes.kt

@@ -83,6 +83,8 @@ sealed class Route {
 
     @Serializable object Shorts : Route()
 
+    @Serializable object PublicChats : Route()
+
     @Serializable object Longs : Route()
 
     @Serializable object Articles : Route()

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

@@ -54,6 +54,7 @@ import com.vitorpamplona.amethyst.ui.screen.loggedIn.polls.dal.ClosedPollsFeedFi
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.polls.dal.OpenPollsFeedFilter
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.polls.dal.PollsFeedFilter
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.products.dal.ProductsFeedFilter
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.publicChats.dal.PublicChatsFeedFilter
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.shorts.dal.ShortsFeedFilter
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.video.dal.VideoFeedFilter
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.webBookmarks.dal.WebBookmarkFeedFilter
@@ -94,6 +95,7 @@ class AccountFeedContentStates(
     val picturesFeed = FeedContentState(PictureFeedFilter(account), scope, LocalCache)
     val productsFeed = FeedContentState(ProductsFeedFilter(account), scope, LocalCache)
     val shortsFeed = FeedContentState(ShortsFeedFilter(account), scope, LocalCache)
+    val publicChatsFeed = FeedContentState(PublicChatsFeedFilter(account), scope, LocalCache)
     val longsFeed = FeedContentState(LongsFeedFilter(account), scope, LocalCache)
     val articlesFeed = FeedContentState(ArticlesFeedFilter(account), scope, LocalCache)
 
@@ -156,6 +158,7 @@ class AccountFeedContentStates(
         picturesFeed.updateFeedWith(newNotes)
         productsFeed.updateFeedWith(newNotes)
         shortsFeed.updateFeedWith(newNotes)
+        publicChatsFeed.updateFeedWith(newNotes)
         longsFeed.updateFeedWith(newNotes)
         articlesFeed.updateFeedWith(newNotes)
 
@@ -199,6 +202,7 @@ class AccountFeedContentStates(
         picturesFeed.deleteFromFeed(newNotes)
         productsFeed.deleteFromFeed(newNotes)
         shortsFeed.deleteFromFeed(newNotes)
+        publicChatsFeed.deleteFromFeed(newNotes)
         longsFeed.deleteFromFeed(newNotes)
         articlesFeed.deleteFromFeed(newNotes)
 

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

@@ -0,0 +1,76 @@
+/*
+ * 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.publicChats
+
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.LazyListState
+import androidx.compose.foundation.lazy.itemsIndexed
+import androidx.compose.material3.HorizontalDivider
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.ui.Modifier
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import com.vitorpamplona.amethyst.commons.ui.feeds.FeedState
+import com.vitorpamplona.amethyst.ui.layouts.rememberFeedContentPadding
+import com.vitorpamplona.amethyst.ui.navigation.navs.INav
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.discover.ChannelCardCompose
+import com.vitorpamplona.amethyst.ui.theme.DividerThickness
+import com.vitorpamplona.amethyst.ui.theme.FeedPadding
+import com.vitorpamplona.quartz.nip28PublicChat.admin.ChannelCreateEvent
+
+@Composable
+fun PublicChatsFeedLoaded(
+    loaded: FeedState.Loaded,
+    listState: LazyListState,
+    accountViewModel: AccountViewModel,
+    nav: INav,
+) {
+    val items by loaded.feed.collectAsStateWithLifecycle()
+
+    LazyColumn(
+        contentPadding = rememberFeedContentPadding(FeedPadding),
+        state = listState,
+    ) {
+        itemsIndexed(
+            items.list,
+            key = { _, item -> item.idHex },
+            contentType = { _, item -> item.event?.kind ?: -1 },
+        ) { _, item ->
+            Row(Modifier.fillMaxWidth().animateItem()) {
+                ChannelCardCompose(
+                    baseNote = item,
+                    routeForLastRead = "PublicChatsFeed",
+                    modifier = Modifier.fillMaxWidth(),
+                    forceEventKind = ChannelCreateEvent.KIND,
+                    accountViewModel = accountViewModel,
+                    nav = nav,
+                )
+            }
+
+            HorizontalDivider(
+                thickness = DividerThickness,
+            )
+        }
+    }
+}

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

@@ -0,0 +1,113 @@
+/*
+ * 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.publicChats
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import com.vitorpamplona.amethyst.commons.ui.feeds.FeedContentState
+import com.vitorpamplona.amethyst.ui.feeds.RefresheableBox
+import com.vitorpamplona.amethyst.ui.feeds.RenderFeedContentState
+import com.vitorpamplona.amethyst.ui.feeds.SaveableFeedContentState
+import com.vitorpamplona.amethyst.ui.feeds.ScrollStateKeys
+import com.vitorpamplona.amethyst.ui.feeds.WatchLifecycleAndUpdateModel
+import com.vitorpamplona.amethyst.ui.layouts.DisappearingScaffold
+import com.vitorpamplona.amethyst.ui.navigation.bottombars.AppBottomBar
+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.screen.loggedIn.publicChats.datasource.PublicChatsFilterAssemblerSubscription
+
+@Composable
+fun PublicChatsScreen(
+    accountViewModel: AccountViewModel,
+    nav: INav,
+) {
+    PublicChatsScreen(
+        publicChatsFeedContentState = accountViewModel.feedStates.publicChatsFeed,
+        accountViewModel = accountViewModel,
+        nav = nav,
+    )
+}
+
+@Composable
+fun PublicChatsScreen(
+    publicChatsFeedContentState: FeedContentState,
+    accountViewModel: AccountViewModel,
+    nav: INav,
+) {
+    WatchLifecycleAndUpdateModel(publicChatsFeedContentState)
+    WatchAccountForPublicChatsScreen(publicChatsFeedState = publicChatsFeedContentState, accountViewModel = accountViewModel)
+    PublicChatsFilterAssemblerSubscription(accountViewModel)
+
+    DisappearingScaffold(
+        isInvertedLayout = false,
+        topBar = {
+            PublicChatsTopBar(accountViewModel, nav)
+        },
+        bottomBar = {
+            AppBottomBar(Route.PublicChats, accountViewModel) { route ->
+                if (route == Route.PublicChats) {
+                    publicChatsFeedContentState.sendToTop()
+                } else {
+                    nav.newStack(route)
+                }
+            }
+        },
+        accountViewModel = accountViewModel,
+    ) {
+        RefresheableBox(publicChatsFeedContentState, true) {
+            SaveableFeedContentState(publicChatsFeedContentState, scrollStateKey = ScrollStateKeys.PUBLIC_CHATS_SCREEN) { listState ->
+                RenderFeedContentState(
+                    feedContentState = publicChatsFeedContentState,
+                    accountViewModel = accountViewModel,
+                    listState = listState,
+                    nav = nav,
+                    routeForLastRead = "PublicChatsFeed",
+                    onLoaded = { loaded ->
+                        PublicChatsFeedLoaded(
+                            loaded = loaded,
+                            listState = listState,
+                            accountViewModel = accountViewModel,
+                            nav = nav,
+                        )
+                    },
+                )
+            }
+        }
+    }
+}
+
+@Composable
+fun WatchAccountForPublicChatsScreen(
+    publicChatsFeedState: FeedContentState,
+    accountViewModel: AccountViewModel,
+) {
+    val listState by accountViewModel.account.livePublicChatsFollowLists.collectAsStateWithLifecycle()
+    val hiddenUsers =
+        accountViewModel.account.hiddenUsers.flow
+            .collectAsStateWithLifecycle()
+
+    LaunchedEffect(accountViewModel, listState, hiddenUsers) {
+        publicChatsFeedState.checkKeysInvalidateDataAndSendToTop()
+    }
+}

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

@@ -0,0 +1,70 @@
+/*
+ * 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.publicChats
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import com.vitorpamplona.amethyst.R
+import com.vitorpamplona.amethyst.model.TopFilter
+import com.vitorpamplona.amethyst.ui.navigation.navs.INav
+import com.vitorpamplona.amethyst.ui.navigation.topbars.FeedFilterSpinner
+import com.vitorpamplona.amethyst.ui.navigation.topbars.UserDrawerSearchTopBar
+import com.vitorpamplona.amethyst.ui.screen.FeedDefinition
+import com.vitorpamplona.amethyst.ui.screen.TopNavFilterState
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
+import com.vitorpamplona.amethyst.ui.stringRes
+
+@Composable
+fun PublicChatsTopBar(
+    accountViewModel: AccountViewModel,
+    nav: INav,
+) {
+    UserDrawerSearchTopBar(accountViewModel, nav) {
+        val list by accountViewModel.account.settings.defaultPublicChatsFollowList
+            .collectAsStateWithLifecycle()
+
+        PublicChatsTopNavFilterBar(
+            followListsModel = accountViewModel.feedStates.feedListOptions,
+            listName = list,
+            accountViewModel = accountViewModel,
+            onChange = accountViewModel.account.settings::changeDefaultPublicChatsFollowList,
+        )
+    }
+}
+
+@Composable
+private fun PublicChatsTopNavFilterBar(
+    followListsModel: TopNavFilterState,
+    listName: TopFilter,
+    accountViewModel: AccountViewModel,
+    onChange: (FeedDefinition) -> Unit,
+) {
+    val allLists by followListsModel.kind3GlobalPeopleRoutes.collectAsStateWithLifecycle()
+
+    FeedFilterSpinner(
+        placeholderCode = listName,
+        explainer = stringRes(R.string.select_list_to_filter),
+        options = allLists,
+        onSelect = { onChange(allLists.getOrNull(it) ?: followListsModel.allFollows) },
+        accountViewModel = accountViewModel,
+    )
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/publicChats/dal/PublicChatsFeedFilter.kt

@@ -0,0 +1,129 @@
+/*
+ * 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.publicChats.dal
+
+import com.vitorpamplona.amethyst.model.Account
+import com.vitorpamplona.amethyst.model.LocalCache
+import com.vitorpamplona.amethyst.model.Note
+import com.vitorpamplona.amethyst.model.TopFilter
+import com.vitorpamplona.amethyst.ui.dal.AdditiveFeedFilter
+import com.vitorpamplona.amethyst.ui.dal.FilterByListParams
+import com.vitorpamplona.quartz.nip28PublicChat.admin.ChannelCreateEvent
+import com.vitorpamplona.quartz.nip28PublicChat.base.IsInPublicChatChannel
+
+class PublicChatsFeedFilter(
+    val account: Account,
+) : AdditiveFeedFilter<Note>() {
+    override fun feedKey(): String = account.userProfile().pubkeyHex + "-" + followList().code
+
+    override fun limit() = 200
+
+    fun followList(): TopFilter = account.settings.defaultPublicChatsFollowList.value
+
+    fun TopFilter.isMuteList() = this is TopFilter.MuteList
+
+    fun TopFilter.isBlockList() = this is TopFilter.PeopleList && this.address == account.blockPeopleList.getBlockListAddress()
+
+    fun TopFilter.wantsToSeeNegativeStuff() = isMuteList() || isBlockList()
+
+    override fun showHiddenKey(): Boolean = followList().wantsToSeeNegativeStuff()
+
+    override fun feed(): List<Note> {
+        val params = buildFilterParams(account)
+
+        val allChannelNotes =
+            LocalCache.publicChatChannels.mapNotNullIntoSet { _, channel ->
+                val note = LocalCache.getNoteIfExists(channel.idHex)
+                val noteEvent = note?.event
+
+                if (noteEvent == null || params.match(noteEvent, note.relays)) {
+                    note
+                } else {
+                    null
+                }
+            }
+
+        return sort(allChannelNotes)
+    }
+
+    override fun applyFilter(newItems: Set<Note>): Set<Note> = innerApplyFilter(newItems)
+
+    fun buildFilterParams(account: Account): FilterByListParams =
+        FilterByListParams.create(
+            followLists = account.livePublicChatsFollowLists.value,
+            hiddenUsers = account.hiddenUsers.flow.value,
+        )
+
+    private fun innerApplyFilter(collection: Collection<Note>): Set<Note> {
+        val params = buildFilterParams(account)
+
+        return collection.mapNotNullTo(HashSet()) { note ->
+            val noteEvent = note.event
+            if (noteEvent is ChannelCreateEvent && params.match(noteEvent, note.relays)) {
+                if ((LocalCache.getPublicChatChannelIfExists(noteEvent.id)?.notes?.size() ?: 0) > 0) {
+                    note
+                } else {
+                    null
+                }
+            } else if (noteEvent is IsInPublicChatChannel) {
+                val channel = noteEvent.channelId()?.let { LocalCache.checkGetOrCreateNote(it) }
+                val channelEvent = channel?.event
+
+                if (channel != null &&
+                    (channelEvent == null || (channelEvent is ChannelCreateEvent && params.match(channelEvent, note.relays)))
+                ) {
+                    if ((LocalCache.getPublicChatChannelIfExists(channel.idHex)?.notes?.size() ?: 0) > 0) {
+                        channel
+                    } else {
+                        null
+                    }
+                } else {
+                    null
+                }
+            } else {
+                null
+            }
+        }
+    }
+
+    override fun sort(items: Set<Note>): List<Note> {
+        val lastNote =
+            items.associateWith { note ->
+                LocalCache.getPublicChatChannelIfExists(note.idHex)?.lastNote?.createdAt() ?: 0L
+            }
+
+        val createdNote =
+            items.associateWith { note ->
+                note.createdAt() ?: 0L
+            }
+
+        val comparator: Comparator<Note> =
+            compareByDescending<Note> {
+                lastNote[it]
+            }.thenByDescending {
+                createdNote[it]
+            }.thenBy {
+                it.idHex
+            }
+
+        return items.sortedWith(comparator)
+    }
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/publicChats/datasource/PublicChatsFilterAssembler.kt

@@ -0,0 +1,50 @@
+/*
+ * 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.publicChats.datasource
+
+import androidx.compose.runtime.Stable
+import com.vitorpamplona.amethyst.commons.relayClient.composeSubscriptionManagers.ComposeSubscriptionManager
+import com.vitorpamplona.amethyst.model.Account
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountFeedContentStates
+import com.vitorpamplona.quartz.nip01Core.relay.client.INostrClient
+import kotlinx.coroutines.CoroutineScope
+
+class PublicChatsQueryState(
+    val account: Account,
+    val feedStates: AccountFeedContentStates,
+    val scope: CoroutineScope,
+)
+
+@Stable
+class PublicChatsFilterAssembler(
+    client: INostrClient,
+) : ComposeSubscriptionManager<PublicChatsQueryState>() {
+    val group =
+        listOf(
+            PublicChatsSubAssembler(client, ::allKeys),
+        )
+
+    override fun invalidateKeys() = invalidateFilters()
+
+    override fun invalidateFilters() = group.forEach { it.invalidateFilters() }
+
+    override fun destroy() = group.forEach { it.destroy() }
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/publicChats/datasource/PublicChatsFilterAssemblerSubscription.kt

@@ -0,0 +1,48 @@
+/*
+ * 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.publicChats.datasource
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.remember
+import androidx.lifecycle.viewModelScope
+import com.vitorpamplona.amethyst.commons.relayClient.subscriptions.KeyDataSourceSubscription
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
+
+@Composable
+fun PublicChatsFilterAssemblerSubscription(accountViewModel: AccountViewModel) {
+    PublicChatsFilterAssemblerSubscription(
+        accountViewModel.dataSources().publicChats,
+        accountViewModel,
+    )
+}
+
+@Composable
+fun PublicChatsFilterAssemblerSubscription(
+    dataSource: PublicChatsFilterAssembler,
+    accountViewModel: AccountViewModel,
+) {
+    val state =
+        remember(accountViewModel.account) {
+            PublicChatsQueryState(accountViewModel.account, accountViewModel.feedStates, accountViewModel.viewModelScope)
+        }
+
+    KeyDataSourceSubscription(state, dataSource)
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/publicChats/datasource/PublicChatsSubAssembler.kt

@@ -0,0 +1,98 @@
+/*
+ * 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.publicChats.datasource
+
+import com.vitorpamplona.amethyst.model.TopFilter
+import com.vitorpamplona.amethyst.model.User
+import com.vitorpamplona.amethyst.service.relayClient.eoseManagers.PerUserAndFollowListEoseManager
+import com.vitorpamplona.amethyst.service.relays.SincePerRelayMap
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.discover.nip28Chats.makePublicChatsFilter
+import com.vitorpamplona.quartz.nip01Core.relay.client.INostrClient
+import com.vitorpamplona.quartz.nip01Core.relay.client.pool.RelayBasedFilter
+import com.vitorpamplona.quartz.nip01Core.relay.client.subscriptions.Subscription
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.FlowPreview
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.flow.collectLatest
+import kotlinx.coroutines.flow.sample
+import kotlinx.coroutines.launch
+
+class PublicChatsSubAssembler(
+    client: INostrClient,
+    allKeys: () -> Set<PublicChatsQueryState>,
+) : PerUserAndFollowListEoseManager<PublicChatsQueryState, TopFilter>(client, allKeys) {
+    override fun updateFilter(
+        key: PublicChatsQueryState,
+        since: SincePerRelayMap?,
+    ): List<RelayBasedFilter> {
+        val feedSettings = key.followsPerRelay()
+
+        return makePublicChatsFilter(feedSettings, since, key.feedStates.publicChatsFeed.lastNoteCreatedAtIfFilled())
+    }
+
+    override fun user(key: PublicChatsQueryState) = key.account.userProfile()
+
+    override fun list(key: PublicChatsQueryState) = key.listName()
+
+    fun PublicChatsQueryState.listNameFlow() = account.settings.defaultPublicChatsFollowList
+
+    fun PublicChatsQueryState.listName() = listNameFlow().value
+
+    fun PublicChatsQueryState.followsPerRelayFlow() = account.livePublicChatsFollowListsPerRelay
+
+    fun PublicChatsQueryState.followsPerRelay() = followsPerRelayFlow().value
+
+    val userJobMap = mutableMapOf<User, List<Job>>()
+
+    @OptIn(FlowPreview::class)
+    override fun newSub(key: PublicChatsQueryState): Subscription {
+        val user = user(key)
+        userJobMap[user]?.forEach { it.cancel() }
+        userJobMap[user] =
+            listOf(
+                key.scope.launch(Dispatchers.IO) {
+                    key.listNameFlow().collectLatest {
+                        invalidateFilters()
+                    }
+                },
+                key.scope.launch(Dispatchers.IO) {
+                    key.followsPerRelayFlow().sample(500).collectLatest {
+                        invalidateFilters()
+                    }
+                },
+                key.account.scope.launch(Dispatchers.IO) {
+                    key.feedStates.publicChatsFeed.lastNoteCreatedAtWhenFullyLoaded.sample(5000).collectLatest {
+                        invalidateFilters()
+                    }
+                },
+            )
+
+        return super.newSub(key)
+    }
+
+    override fun endSub(
+        key: User,
+        subId: String,
+    ) {
+        super.endSub(key, subId)
+        userJobMap[key]?.forEach { it.cancel() }
+    }
+}

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

@@ -484,6 +484,7 @@
     <string name="profile_badges_empty">You haven\'t received any badges yet.</string>
     <string name="pictures">Pictures</string>
     <string name="shorts">Shorts</string>
+    <string name="public_chats">Public Chats</string>
     <string name="longs">Videos</string>
     <string name="articles">Articles</string>
     <string name="private_bookmarks">Private Bookmarks</string>