perf: optimize screen load times with progressive un-gating and SWR caching (#1192)

app/src/main/java/com/m57/hermescontrol/ui/gateway/GatewayScreen.kt

@@ -35,6 +35,7 @@ import androidx.compose.ui.unit.dp
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.lifecycle.viewmodel.compose.viewModel
 import com.m57.hermescontrol.R
+import com.m57.hermescontrol.data.local.AuthManager
 import com.m57.hermescontrol.theme.LocalHermesStatusColors
 import com.m57.hermescontrol.ui.common.ErrorState
 import com.m57.hermescontrol.ui.common.HermesScaffold
@@ -51,9 +52,11 @@ fun GatewayScreen(
     viewModel: GatewayViewModel = viewModel { GatewayViewModel() },
 ) {
     val state by viewModel.uiState.collectAsStateWithLifecycle()
+    val dataScope by AuthManager.dataScopeFlow.collectAsStateWithLifecycle()
     val statusColors = LocalHermesStatusColors.current
 
-    LaunchedEffect(Unit) {
+    LaunchedEffect(dataScope) {
+        viewModel.clearScopeOwnedState()
         viewModel.loadStatus()
     }
 
@@ -63,7 +66,7 @@ fun GatewayScreen(
         title = { Text(stringResource(R.string.screen_gateway)) },
         navigationIcon = onOpenDrawer?.let { NavIcon.Menu(it) },
         isRefreshing = state.isLoading,
-        onRefresh = { viewModel.loadStatus() },
+        onRefresh = { viewModel.loadStatus(forceRefresh = true) },
     ) { paddingValues ->
         when {
             state.isLoading && state.status == null -> {

app/src/main/java/com/m57/hermescontrol/ui/gateway/GatewayViewModel.kt

@@ -2,12 +2,14 @@ package com.m57.hermescontrol.ui.gateway
 
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
+import com.m57.hermescontrol.data.local.SwrCache
 import com.m57.hermescontrol.data.model.StatusResponse
 import com.m57.hermescontrol.data.remote.ApiClient
 import com.m57.hermescontrol.data.remote.NetworkResult
 import com.m57.hermescontrol.data.remote.safeApiCall
 import com.m57.hermescontrol.ui.common.ToastHost
 import com.m57.hermescontrol.ui.common.safeLaunchLoad
+import com.m57.hermescontrol.ui.common.safeLaunchSwrLoad
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.asStateFlow
@@ -28,8 +30,19 @@ class GatewayViewModel :
     private val _uiState = MutableStateFlow(GatewayUiState())
     val uiState: StateFlow<GatewayUiState> = _uiState.asStateFlow()
 
-    fun loadStatus() {
-        safeLaunchLoad(
+    private val statusCache = SwrCache<String, StatusResponse>()
+
+    fun clearScopeOwnedState() {
+        _uiState.update { it.copy(isLoading = false, status = null, errorMessage = null) }
+    }
+
+    fun loadStatus(forceRefresh: Boolean = false) {
+        safeLaunchSwrLoad(
+            cache = statusCache,
+            forceRefresh = forceRefresh,
+            onCacheHit = { data ->
+                _uiState.update { it.copy(isLoading = false, status = data, errorMessage = null) }
+            },
             apiCall = { safeApiCall { ApiClient.hermesApi.getStatus() } },
             onStart = { _uiState.update { it.copy(isLoading = true, errorMessage = null) } },
             onSuccess = { data ->
@@ -73,7 +86,7 @@ class GatewayViewModel :
                             toastMessage = "Gateway ${actionName}ed successfully",
                         )
                     }
-                    loadStatus()
+                    loadStatus(forceRefresh = true)
                 }
 
                 is NetworkResult.Failure -> {