chore: optimize the battery usage (#16)

Reviewed-on: #16

composeApp/src/androidMain/kotlin/su/reya/coop/App.kt

@@ -2,6 +2,7 @@ package su.reya.coop
 
 import android.app.Activity
 import android.content.Intent
+import android.os.Build
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.BackHandler
 import androidx.compose.foundation.isSystemInDarkTheme
@@ -31,7 +32,6 @@ import androidx.compose.material3.rememberModalBottomSheetState
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.CompositionLocalProvider
 import androidx.compose.runtime.LaunchedEffect
-import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
@@ -46,6 +46,7 @@ import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextAlign
 import androidx.compose.ui.unit.dp
 import androidx.core.util.Consumer
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.lifecycle.viewmodel.navigation3.rememberViewModelStoreNavEntryDecorator
 import androidx.navigation3.runtime.NavBackStack
 import androidx.navigation3.runtime.NavKey
@@ -93,8 +94,8 @@ fun App(viewModel: NostrViewModel) {
     val navigator = remember(backStack) { Navigator(backStack) }
     val qrScanResult = remember { QrScanResult() }
 
-    val signerRequired by viewModel.signerRequired.collectAsState(initial = null)
-    val isRelayListEmpty by viewModel.isRelayListEmpty.collectAsState()
+    val signerRequired by viewModel.signerRequired.collectAsStateWithLifecycle()
+    val isRelayListEmpty by viewModel.isRelayListEmpty.collectAsStateWithLifecycle()
 
     // Snackbar
     val snackbarHostState = remember { SnackbarHostState() }
@@ -105,7 +106,7 @@ fun App(viewModel: NostrViewModel) {
     // Enabled the dynamic color scheme
     val colorScheme = when {
         // Enable the dynamic color scheme for Android 12+
-        android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.S -> {
+        Build.VERSION.SDK_INT >= Build.VERSION_CODES.S -> {
             if (isSystemInDarkTheme()) dynamicDarkColorScheme(context) else dynamicLightColorScheme(
                 context
             )

composeApp/src/androidMain/kotlin/su/reya/coop/MainActivity.kt

@@ -1,13 +1,13 @@
 package su.reya.coop
 
 import android.content.Intent
-import android.os.Build
 import android.os.Bundle
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
 import androidx.activity.enableEdgeToEdge
 import androidx.activity.viewModels
 import androidx.core.splashscreen.SplashScreen.Companion.installSplashScreen
+import androidx.lifecycle.ProcessLifecycleOwner
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.ViewModelProvider
 import su.reya.coop.coop.storage.SecretStore
@@ -50,18 +50,16 @@ class MainActivity : ComponentActivity() {
         super.onCreate(savedInstanceState)
 
         val serviceIntent = Intent(this, NostrForegroundService::class.java)
-
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
-            startForegroundService(serviceIntent)
-        } else {
-            startService(serviceIntent)
-        }
+        startForegroundService(serviceIntent)
 
         // Keep the splash screen visible until the signer check is complete
         splashScreen.setKeepOnScreenCondition {
             viewModel.signerRequired.value == null
         }
 
+        // Bind the lifecycle of the ViewModel to the Activity's lifecycle'
+        viewModel.bindLifecycle(ProcessLifecycleOwner.get().lifecycle)
+
         setContent {
             App(viewModel = viewModel)
         }

composeApp/src/androidMain/kotlin/su/reya/coop/NostrForegroundService.kt

@@ -10,13 +10,13 @@ import android.content.pm.ServiceInfo
 import android.os.Build
 import android.os.IBinder
 import android.util.Log
-import androidx.annotation.RequiresApi
 import androidx.core.app.NotificationCompat
 import androidx.core.net.toUri
 import androidx.lifecycle.Lifecycle
 import androidx.lifecycle.ProcessLifecycleOwner
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.Job
 import kotlinx.coroutines.SupervisorJob
 import kotlinx.coroutines.cancel
 import kotlinx.coroutines.launch
@@ -25,6 +25,7 @@ import java.io.File
 class NostrForegroundService : Service() {
     private val serviceScope = CoroutineScope(Dispatchers.IO + SupervisorJob())
     private val nostr by lazy { NostrManager.instance }
+    private var notificationJob: Job? = null
 
     override fun onBind(intent: Intent?): IBinder? = null
 
@@ -46,10 +47,12 @@ class NostrForegroundService : Service() {
     }
 
     override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
-        serviceScope.launch {
+        if (notificationJob?.isActive == true) return START_STICKY
+
+        notificationJob = serviceScope.launch {
             try {
                 Log.d("Coop", "Starting Nostr in background")
-
+                
                 // Create a database directory
                 val dbDir = File(filesDir, "nostr")
                 dbDir.mkdirs()
@@ -82,10 +85,10 @@ class NostrForegroundService : Service() {
                 Log.e("Coop", "Failed to start Nostr", e)
             }
         }
+
         return START_STICKY
     }
 
-    @RequiresApi(Build.VERSION_CODES.O)
     private fun createNotificationChannel() {
         val manager = getSystemService(NotificationManager::class.java)
 

composeApp/src/androidMain/kotlin/su/reya/coop/screens/ChatScreen.kt

@@ -39,6 +39,7 @@ import androidx.compose.material3.TopAppBarDefaults
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.derivedStateOf
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableIntStateOf
 import androidx.compose.runtime.mutableStateListOf
@@ -50,6 +51,7 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.dp
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import coop.composeapp.generated.resources.Res
 import coop.composeapp.generated.resources.ic_arrow_back
 import coop.composeapp.generated.resources.ic_send
@@ -73,28 +75,37 @@ fun ChatScreen(id: Long) {
     val navigator = LocalNavigator.current
     val viewModel = LocalNostrViewModel.current
 
-    val listState = rememberLazyListState()
-    val chatRooms by viewModel.chatRooms.collectAsState()
-    val room = remember(chatRooms, id) { chatRooms.firstOrNull { it.id == id } }
+    // Get chat room by ID
+    val chatRooms by viewModel.chatRooms.collectAsStateWithLifecycle()
+    val room by remember(id) {
+        derivedStateOf { chatRooms.firstOrNull { it.id == id } }
+    }
 
+    // Show empty screen
     if (room == null) {
         Box(
             modifier = Modifier.fillMaxSize(),
             contentAlignment = Alignment.Center
         ) {
-            LoadingIndicator()
+            Text(
+                text = "Chat room not found",
+                style = MaterialTheme.typography.titleMediumEmphasized,
+                color = MaterialTheme.colorScheme.onSurface
+            )
         }
         return
     }
 
-    val displayName by remember(room) { room.displayNameFlow(viewModel) }.collectAsState("Loading...")
-    val picture by remember(room) { room.pictureFlow(viewModel) }.collectAsState(null)
+    val displayName by remember(room) { room!!.displayNameFlow(viewModel) }.collectAsState("Loading...")
+    val picture by remember(room) { room!!.pictureFlow(viewModel) }.collectAsState(null)
 
     var text by remember { mutableStateOf("") }
     var loading by remember { mutableStateOf(true) }
     var newOtherMessages by remember { mutableIntStateOf(0) }
 
+    val listState = rememberLazyListState()
     val messages = remember { mutableStateListOf<UnsignedEvent>() }
+
     val groupedMessages = remember(messages.toList()) {
         messages.groupBy { it.createdAt().formatAsGroupHeader() }
     }
@@ -151,7 +162,7 @@ fun ChatScreen(id: Long) {
                     Row(
                         verticalAlignment = Alignment.CenterVertically,
                         modifier = Modifier.clickable {
-                            room.members.firstOrNull()?.let { pubkey ->
+                            room!!.members.firstOrNull()?.let { pubkey ->
                                 navigator.navigate(Screen.Profile(pubkey.toBech32()))
                             }
                         }

composeApp/src/androidMain/kotlin/su/reya/coop/screens/HomeScreen.kt

@@ -76,6 +76,7 @@ import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.dp
 import androidx.core.app.NotificationManagerCompat
 import androidx.lifecycle.compose.LifecycleResumeEffect
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import coop.composeapp.generated.resources.Res
 import coop.composeapp.generated.resources.ic_new_chat
 import coop.composeapp.generated.resources.ic_qr
@@ -108,8 +109,8 @@ fun HomeScreen() {
     val currentUser = viewModel.currentUser() ?: return
     val currentUserProfile = viewModel.getMetadata(currentUser) ?: return
 
-    val userProfile by currentUserProfile.collectAsState(initial = null)
-    val chatRooms by viewModel.chatRooms.collectAsState(initial = emptyList())
+    val userProfile by currentUserProfile.collectAsStateWithLifecycle()
+    val chatRooms by viewModel.chatRooms.collectAsStateWithLifecycle()
     val isPartialProcessedGiftWrap by viewModel.isPartialProcessedGiftWrap.collectAsState(initial = false)
     val isBannerDismissed by viewModel.isNotificationBannerDismissed.collectAsState()