Upgrades the RelayPoolStatus to a Flow

app/src/main/java/com/vitorpamplona/amethyst/service/relays/RelayPool.kt

@@ -1,9 +1,13 @@
 package com.vitorpamplona.amethyst.service.relays
 
-import androidx.lifecycle.LiveData
+import androidx.compose.runtime.Immutable
 import com.vitorpamplona.amethyst.service.checkNotInMainThread
 import com.vitorpamplona.quartz.events.Event
 import com.vitorpamplona.quartz.events.EventInterface
+import kotlinx.coroutines.channels.BufferOverflow
+import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.flow.SharedFlow
+import kotlinx.coroutines.flow.asSharedFlow
 
 /**
  * RelayPool manages the connection to multiple Relays and lets consumers deal with simple events.
@@ -12,6 +16,11 @@ object RelayPool : Relay.Listener {
     private var relays = listOf<Relay>()
     private var listeners = setOf<Listener>()
 
+    // Backing property to avoid flow emissions from other classes
+    private var _lastStatus = RelayPoolStatus(0, 0)
+    private val _statusFlow = MutableSharedFlow<RelayPoolStatus>(1, 1, onBufferOverflow = BufferOverflow.DROP_OLDEST)
+    val statusFlow: SharedFlow<RelayPoolStatus> = _statusFlow.asSharedFlow()
+
     fun availableRelays(): Int {
         return relays.size
     }
@@ -76,11 +85,13 @@ object RelayPool : Relay.Listener {
     fun addRelay(relay: Relay) {
         relay.register(this)
         relays += relay
+        updateStatus()
     }
 
     fun removeRelay(relay: Relay) {
         relay.unregister(this)
         relays = relays.minus(relay)
+        updateStatus()
     }
 
     fun register(listener: Listener) {
@@ -109,12 +120,14 @@ object RelayPool : Relay.Listener {
 
     override fun onError(relay: Relay, subscriptionId: String, error: Error) {
         listeners.forEach { it.onError(error, subscriptionId, relay) }
-        refreshObservers()
+        updateStatus()
     }
 
     override fun onRelayStateChange(relay: Relay, type: Relay.Type, channel: String?) {
         listeners.forEach { it.onRelayStateChange(type, relay, channel) }
-        refreshObservers()
+        if (type != Relay.Type.EOSE) {
+            updateStatus()
+        }
     }
 
     override fun onSendResponse(relay: Relay, eventId: String, success: Boolean, message: String) {
@@ -125,18 +138,15 @@ object RelayPool : Relay.Listener {
         listeners.forEach { it.onAuth(relay, challenge) }
     }
 
-    // Observers line up here.
-    val live: RelayPoolLiveData = RelayPoolLiveData(this)
-
-    private fun refreshObservers() {
-        live.refresh()
+    private fun updateStatus() {
+        val connected = connectedRelays()
+        val available = availableRelays()
+        if (_lastStatus.connected != connected || _lastStatus.available != available) {
+            _lastStatus = RelayPoolStatus(connected, available)
+            _statusFlow.tryEmit(_lastStatus)
+        }
     }
 }
 
-class RelayPoolLiveData(val relays: RelayPool) : LiveData<RelayPoolState>(RelayPoolState(relays)) {
-    fun refresh() {
-        postValue(RelayPoolState(relays))
-    }
-}
-
-class RelayPoolState(val relays: RelayPool)
+@Immutable
+data class RelayPoolStatus(val connected: Int, val available: Int, val isConnected: Boolean = connected > 0)

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

@@ -40,6 +40,7 @@ import androidx.compose.material.icons.filled.Send
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.MutableState
+import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.derivedStateOf
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.livedata.observeAsState
@@ -63,7 +64,6 @@ import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
 import androidx.lifecycle.map
-import androidx.lifecycle.viewmodel.compose.viewModel
 import coil.compose.AsyncImage
 import com.vitorpamplona.amethyst.BuildConfig
 import com.vitorpamplona.amethyst.LocalPreferences
@@ -72,11 +72,12 @@ import com.vitorpamplona.amethyst.ServiceManager
 import com.vitorpamplona.amethyst.model.Account
 import com.vitorpamplona.amethyst.model.User
 import com.vitorpamplona.amethyst.service.HttpClient
+import com.vitorpamplona.amethyst.service.relays.RelayPool
+import com.vitorpamplona.amethyst.service.relays.RelayPoolStatus
 import com.vitorpamplona.amethyst.ui.actions.NewRelayListView
 import com.vitorpamplona.amethyst.ui.components.CreateTextWithEmoji
 import com.vitorpamplona.amethyst.ui.components.RobohashAsyncImageProxy
 import com.vitorpamplona.amethyst.ui.note.LoadStatuses
-import com.vitorpamplona.amethyst.ui.screen.RelayPoolViewModel
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountBackupDialog
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.ConnectOrbotDialog
@@ -454,7 +455,6 @@ fun ListContent(
     }
 
     val coroutineScope = rememberCoroutineScope()
-    val relayViewModel: RelayPoolViewModel = viewModel { RelayPoolViewModel() }
     var wantsToEditRelays by remember {
         mutableStateOf(false)
     }
@@ -490,7 +490,7 @@ fun ListContent(
         )
 
         IconRowRelays(
-            relayViewModel = relayViewModel,
+            accountViewModel = accountViewModel,
             onClick = {
                 coroutineScope.launch {
                     scaffoldState.drawerState.close()
@@ -633,27 +633,37 @@ private fun enableTor(
 }
 
 @Composable
-private fun RelayStatus(
-    relayViewModel: RelayPoolViewModel
-) {
-    val connectedRelaysText by relayViewModel.connectionStatus.observeAsState("--/--")
-    val isConnected by relayViewModel.isConnected.observeAsState(false)
+private fun RelayStatus(accountViewModel: AccountViewModel) {
+    val connectedRelaysText by RelayPool.statusFlow.collectAsState(initial = RelayPoolStatus(0, 0))
 
-    RenderRelayStatus(connectedRelaysText, isConnected)
+    RenderRelayStatus(connectedRelaysText)
 }
 
 @Composable
 private fun RenderRelayStatus(
-    connectedRelaysText: String,
-    isConnected: Boolean
+    relayPool: RelayPoolStatus
 ) {
+    val text by remember(relayPool) {
+        derivedStateOf {
+            "${relayPool.connected}/${relayPool.available}"
+        }
+    }
+
+    val placeHolder = MaterialTheme.colors.placeholderText
+
+    val color by remember(relayPool) {
+        derivedStateOf {
+            if (relayPool.isConnected) {
+                placeHolder
+            } else {
+                Color.Red
+            }
+        }
+    }
+
     Text(
-        text = connectedRelaysText,
-        color = if (isConnected) {
-            MaterialTheme.colors.placeholderText
-        } else {
-            Color.Red
-        },
+        text = text,
+        color = color,
         style = MaterialTheme.typography.subtitle1
     )
 }
@@ -709,7 +719,7 @@ fun IconRow(title: String, icon: Int, tint: Color, onClick: () -> Unit, onLongCl
 }
 
 @Composable
-fun IconRowRelays(relayViewModel: RelayPoolViewModel, onClick: () -> Unit) {
+fun IconRowRelays(accountViewModel: AccountViewModel, onClick: () -> Unit) {
     Row(
         modifier = Modifier
             .fillMaxWidth()
@@ -736,7 +746,7 @@ fun IconRowRelays(relayViewModel: RelayPoolViewModel, onClick: () -> Unit) {
 
             Spacer(modifier = Modifier.width(Size16dp))
 
-            RelayStatus(relayViewModel = relayViewModel)
+            RelayStatus(accountViewModel = accountViewModel)
         }
     }
 }

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

@@ -1,20 +0,0 @@
-package com.vitorpamplona.amethyst.ui.screen
-
-import androidx.compose.runtime.Stable
-import androidx.lifecycle.ViewModel
-import androidx.lifecycle.distinctUntilChanged
-import androidx.lifecycle.map
-import com.vitorpamplona.amethyst.service.relays.RelayPool
-
-@Stable
-class RelayPoolViewModel : ViewModel() {
-    val connectionStatus = RelayPool.live.map {
-        val connectedRelays = it.relays.connectedRelays()
-        val availableRelays = it.relays.availableRelays()
-        "$connectedRelays/$availableRelays"
-    }.distinctUntilChanged()
-
-    val isConnected = RelayPool.live.map {
-        it.relays.connectedRelays() > 0
-    }.distinctUntilChanged()
-}