Additional Performance Improvements

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

@@ -297,8 +297,6 @@ object LocalCache {
       it.addReply(note)
     }
 
-    UrlCachedPreviewer.preloadPreviewsFor(note)
-
     refreshObservers()
   }
 

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

@@ -8,6 +8,10 @@ import com.vitorpamplona.amethyst.ui.components.isValidURL
 import com.vitorpamplona.amethyst.ui.components.noProtocolUrlValidator
 import com.vitorpamplona.amethyst.ui.components.videoExtension
 import java.util.concurrent.ConcurrentHashMap
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.launch
 
 object UrlCachedPreviewer {
   val cache = ConcurrentHashMap<String, UrlInfoItem>()
@@ -18,16 +22,19 @@ object UrlCachedPreviewer {
       return
     }
 
-    BahaUrlPreview(url, object : IUrlPreviewCallback {
-      override fun onComplete(urlInfo: UrlInfoItem) {
-        cache.put(url, urlInfo)
-        callback?.onComplete(urlInfo)
-      }
+    val scope = CoroutineScope(Job() + Dispatchers.Main)
+    scope.launch {
+      BahaUrlPreview(url, object : IUrlPreviewCallback {
+        override fun onComplete(urlInfo: UrlInfoItem) {
+          cache.put(url, urlInfo)
+          callback?.onComplete(urlInfo)
+        }
 
-      override fun onFailed(throwable: Throwable) {
-        callback?.onFailed(throwable)
-      }
-    }).fetchUrlPreview()
+        override fun onFailed(throwable: Throwable) {
+          callback?.onFailed(throwable)
+        }
+      }).fetchUrlPreview()
+    }
   }
 
   fun findUrlsInMessage(message: String): List<String> {

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

@@ -137,13 +137,14 @@ class UserMetadata {
 }
 
 class UserLiveData(val user: User): LiveData<UserState>(UserState(user)) {
+    val scope = CoroutineScope(Job() + Dispatchers.Main)
+
     fun refresh() {
         postValue(UserState(user))
     }
 
     override fun onActive() {
         super.onActive()
-        val scope = CoroutineScope(Job() + Dispatchers.Main)
         scope.launch {
             NostrSingleUserDataSource.add(user.pubkeyHex)
         }
@@ -151,7 +152,6 @@ class UserLiveData(val user: User): LiveData<UserState>(UserState(user)) {
 
     override fun onInactive() {
         super.onInactive()
-        val scope = CoroutineScope(Job() + Dispatchers.Main)
         scope.launch {
             NostrSingleUserDataSource.remove(user.pubkeyHex)
         }

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

@@ -1,5 +1,7 @@
 package com.vitorpamplona.amethyst.service
 
+import android.os.Handler
+import android.os.Looper
 import com.vitorpamplona.amethyst.model.LocalCache
 import com.vitorpamplona.amethyst.model.Note
 import com.vitorpamplona.amethyst.model.UrlCachedPreviewer
@@ -125,7 +127,7 @@ abstract class NostrDataSource<T>(val debugName: String) {
     return returningList
   }
 
-  suspend fun loadPreviews(list: List<T>) {
+  fun loadPreviews(list: List<T>) {
     list.forEach {
       if (it is Note) {
         UrlCachedPreviewer.preloadPreviewsFor(it)
@@ -146,6 +148,19 @@ abstract class NostrDataSource<T>(val debugName: String) {
     channelIds.remove(channel.id)
   }
 
+  val filterHandler = Handler(Looper.getMainLooper())
+  var handlerWaiting = false
+  @Synchronized
+  fun invalidateFilters() {
+    if (handlerWaiting) return
+
+    handlerWaiting = true
+    filterHandler.postDelayed({
+      resetFilters()
+      handlerWaiting = false
+    }, 200)
+  }
+
   fun resetFilters() {
     // saves the channels that are currently active
     val activeChannels = channels.filter { it.filter != null }

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

@@ -70,11 +70,11 @@ object NostrSingleEventDataSource: NostrDataSource<Note>("SingleEventFeed") {
 
   fun add(eventId: String) {
     eventsToWatch = eventsToWatch.plus(eventId)
-    resetFilters()
+    invalidateFilters()
   }
 
   fun remove(eventId: String) {
     eventsToWatch = eventsToWatch.minus(eventId)
-    resetFilters()
+    invalidateFilters()
   }
 }

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

@@ -35,11 +35,11 @@ object NostrSingleUserDataSource: NostrDataSource<Note>("SingleUserFeed") {
 
   fun add(userId: String) {
     usersToWatch = usersToWatch.plus(userId)
-    resetFilters()
+    invalidateFilters()
   }
 
   fun remove(userId: String) {
     usersToWatch = usersToWatch.minus(userId)
-    resetFilters()
+    invalidateFilters()
   }
 }

app/src/main/java/com/vitorpamplona/amethyst/ui/MainActivity.kt

@@ -16,6 +16,7 @@ import coil.decode.ImageDecoderDecoder
 import coil.decode.SvgDecoder
 import com.vitorpamplona.amethyst.KeyStorage
 import com.vitorpamplona.amethyst.service.NostrAccountDataSource
+import com.vitorpamplona.amethyst.service.NostrChannelDataSource
 import com.vitorpamplona.amethyst.service.NostrChatroomListDataSource
 import com.vitorpamplona.amethyst.service.NostrGlobalDataSource
 import com.vitorpamplona.amethyst.service.NostrHomeDataSource
@@ -71,6 +72,7 @@ class MainActivity : ComponentActivity() {
   override fun onPause() {
     NostrAccountDataSource.stop()
     NostrHomeDataSource.stop()
+    NostrChannelDataSource.stop()
     NostrChatroomListDataSource.stop()
     NostrUserProfileDataSource.stop()
     NostrUserProfileFollowersDataSource.stop()

app/src/main/java/com/vitorpamplona/amethyst/ui/screen/AccountStateViewModel.kt

@@ -6,6 +6,7 @@ import com.vitorpamplona.amethyst.model.Account
 import com.vitorpamplona.amethyst.model.DefaultChannels
 import com.vitorpamplona.amethyst.model.toByteArray
 import com.vitorpamplona.amethyst.service.NostrAccountDataSource
+import com.vitorpamplona.amethyst.service.NostrChannelDataSource
 import com.vitorpamplona.amethyst.service.NostrChatroomListDataSource
 import com.vitorpamplona.amethyst.service.NostrGlobalDataSource
 import com.vitorpamplona.amethyst.service.NostrHomeDataSource
@@ -70,6 +71,7 @@ class AccountStateViewModel(private val encryptedPreferences: EncryptedSharedPre
     NostrNotificationDataSource.account = account
     NostrChatroomListDataSource.account = account
 
+    NostrChannelDataSource.start()
     NostrAccountDataSource.start()
     NostrGlobalDataSource.start()
     NostrHomeDataSource.start()

app/src/main/java/com/vitorpamplona/amethyst/ui/screen/FeedViewModel.kt

@@ -6,6 +6,9 @@ import com.vitorpamplona.amethyst.model.LocalCache
 import com.vitorpamplona.amethyst.model.LocalCacheState
 import com.vitorpamplona.amethyst.model.Note
 import com.vitorpamplona.amethyst.service.NostrDataSource
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.Job
 import kotlinx.coroutines.cancel
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.asStateFlow
@@ -18,13 +21,6 @@ class FeedViewModel(val dataSource: NostrDataSource<Note>): ViewModel() {
     val feedContent = _feedContent.asStateFlow()
 
     fun refresh() {
-        // For some reason, view Model Scope doesn't call
-        viewModelScope.launch {
-            refreshSuspend()
-        }
-    }
-
-    fun refreshSuspend() {
         val notes = dataSource.loadTop()
 
         val oldNotesState = feedContent.value

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

@@ -17,6 +17,7 @@ import androidx.compose.material.OutlinedTextField
 import androidx.compose.material.Text
 import androidx.compose.material.TextField
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.livedata.observeAsState
 import androidx.compose.runtime.mutableStateOf