Refreshing new Channels when showing them up on screen.

app/src/main/java/com/vitorpamplona/amethyst/ServiceManager.kt

@@ -8,6 +8,7 @@ import com.vitorpamplona.amethyst.service.NostrChatroomListDataSource
 import com.vitorpamplona.amethyst.service.NostrGlobalDataSource
 import com.vitorpamplona.amethyst.service.NostrHomeDataSource
 import com.vitorpamplona.amethyst.service.NostrNotificationDataSource
+import com.vitorpamplona.amethyst.service.NostrSingleChannelDataSource
 import com.vitorpamplona.amethyst.service.NostrSingleEventDataSource
 import com.vitorpamplona.amethyst.service.NostrSingleUserDataSource
 import com.vitorpamplona.amethyst.service.NostrThreadDataSource
@@ -48,6 +49,7 @@ object ServiceManager {
       NostrHomeDataSource.start()
       NostrNotificationDataSource.start()
       NostrSingleEventDataSource.start()
+      NostrSingleChannelDataSource.start()
       NostrSingleUserDataSource.start()
       NostrThreadDataSource.start()
       NostrChatroomListDataSource.start()
@@ -68,6 +70,7 @@ object ServiceManager {
 
     NostrGlobalDataSource.stop()
     NostrNotificationDataSource.stop()
+    NostrSingleChannelDataSource.stop()
     NostrSingleEventDataSource.stop()
     NostrSingleUserDataSource.stop()
     NostrThreadDataSource.stop()

app/src/main/java/com/vitorpamplona/amethyst/model/Channel.kt

@@ -1,6 +1,7 @@
 package com.vitorpamplona.amethyst.model
 
 import androidx.lifecycle.LiveData
+import com.vitorpamplona.amethyst.service.NostrSingleEventDataSource
 import com.vitorpamplona.amethyst.service.model.ChannelCreateEvent
 import com.vitorpamplona.amethyst.ui.note.toShortenHex
 import java.util.concurrent.ConcurrentHashMap
@@ -52,6 +53,16 @@ class ChannelLiveData(val channel: Channel): LiveData<ChannelState>(ChannelState
     fun refresh() {
         postValue(ChannelState(channel))
     }
+
+    override fun onActive() {
+        super.onActive()
+        NostrSingleEventDataSource.add(channel.idHex)
+    }
+
+    override fun onInactive() {
+        super.onInactive()
+        NostrSingleEventDataSource.remove(channel.idHex)
+    }
 }
 
 class ChannelState(val channel: Channel)

app/src/main/java/com/vitorpamplona/amethyst/service/NostrSingleChannelDataSource.kt

@@ -0,0 +1,73 @@
+package com.vitorpamplona.amethyst.service
+
+import com.vitorpamplona.amethyst.model.LocalCache
+import com.vitorpamplona.amethyst.model.Note
+import com.vitorpamplona.amethyst.service.model.ChannelCreateEvent
+import com.vitorpamplona.amethyst.service.model.ChannelMessageEvent
+import com.vitorpamplona.amethyst.service.model.ChannelMetadataEvent
+import com.vitorpamplona.amethyst.service.model.ReactionEvent
+import com.vitorpamplona.amethyst.service.model.RepostEvent
+import java.util.Collections
+import nostr.postr.JsonFilter
+import nostr.postr.events.TextNoteEvent
+
+object NostrSingleChannelDataSource: NostrDataSource<Note>("SingleChannelFeed") {
+  private var channelsToWatch = setOf<String>()
+
+  private fun createRepliesAndReactionsFilter(): JsonFilter? {
+    val reactionsToWatch = channelsToWatch.map { it }
+
+    if (reactionsToWatch.isEmpty()) {
+      return null
+    }
+
+    // downloads all the reactions to a given event.
+    return JsonFilter(
+      kinds = listOf(ChannelMetadataEvent.kind),
+      tags = mapOf("e" to reactionsToWatch)
+    )
+  }
+
+  fun createLoadEventsIfNotLoadedFilter(): JsonFilter? {
+    val directEventsToLoad = channelsToWatch
+      .map { LocalCache.getOrCreateChannel(it) }
+      .filter { it.notes.isEmpty() }
+
+    val interestedEvents = (directEventsToLoad).map { it.idHex }.toSet()
+
+    if (interestedEvents.isEmpty()) {
+      return null
+    }
+
+    // downloads linked events to this event.
+    return JsonFilter(
+      kinds = listOf(ChannelCreateEvent.kind),
+      ids = interestedEvents.toList()
+    )
+  }
+
+  val repliesAndReactionsChannel = requestNewChannel()
+  val loadEventsChannel = requestNewChannel()
+
+  override fun feed(): List<Note> {
+    return emptyList()
+  }
+
+  override fun updateChannelFilters() {
+    val reactions = createRepliesAndReactionsFilter()
+    val missing = createLoadEventsIfNotLoadedFilter()
+
+    repliesAndReactionsChannel.filter = listOfNotNull(reactions).ifEmpty { null }
+    loadEventsChannel.filter = listOfNotNull(missing).ifEmpty { null }
+  }
+
+  fun add(eventId: String) {
+    channelsToWatch = channelsToWatch.plus(eventId)
+    invalidateFilters()
+  }
+
+  fun remove(eventId: String) {
+    channelsToWatch = channelsToWatch.minus(eventId)
+    invalidateFilters()
+  }
+}

app/src/main/java/com/vitorpamplona/amethyst/ui/note/NoteCompose.kt

@@ -155,6 +155,33 @@ fun NoteCompose(
                                 )
                             }
                         }
+
+                        // boosted picture
+                        val baseChannel = note.channel
+                        if (note.event is ChannelMessageEvent && baseChannel != null) {
+                            val channelState by baseChannel.live.observeAsState()
+                            val channel = channelState?.channel
+
+                            if (channel != null) {
+                                Box(
+                                    Modifier
+                                        .width(30.dp)
+                                        .height(30.dp)
+                                        .align(Alignment.BottomEnd)) {
+                                    AsyncImage(
+                                        model = channel.profilePicture(),
+                                        placeholder = null,
+                                        contentDescription = "Group Picture",
+                                        modifier = Modifier
+                                            .width(30.dp)
+                                            .height(30.dp)
+                                            .clip(shape = CircleShape)
+                                            .background(MaterialTheme.colors.background)
+                                            .border(2.dp, MaterialTheme.colors.background, CircleShape)
+                                    )
+                                }
+                            }
+                        }
                     }
                 }
 

app/src/main/java/com/vitorpamplona/amethyst/ui/note/ReplyInformation.kt

@@ -91,11 +91,14 @@ fun ReplyInformationChannel(replyTo: MutableList<Note>?, mentions: List<User>?,
 @Composable
 fun ReplyInformationChannel(replyTo: MutableList<Note>?,
                      mentions: List<User>?,
-                     channel: Channel,
+                     baseChannel: Channel,
                      prefix: String = "",
                      onUserTagClick: (User) -> Unit,
                      onChannelTagClick: (Channel) -> Unit
 ) {
+  val channelState by baseChannel.live.observeAsState()
+  val channel = channelState?.channel ?: return
+
   FlowRow() {
     Text(
       "in channel ",