fix: display snackbar notification on save failures (Closes #77) (#119)

sharedUI/src/commonMain/kotlin/org/shahondin1624/App.kt

@@ -12,6 +12,7 @@ import androidx.compose.material.icons.filled.Settings
 import androidx.compose.material3.*
 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
@@ -48,6 +49,7 @@ import org.shahondin1624.theme.WindowSizeClass
 import org.shahondin1624.viewmodel.CharacterCreationViewModel
 import org.shahondin1624.logging.AppLogger
 import org.shahondin1624.viewmodel.CharacterViewModel
+import org.shahondin1624.viewmodel.SaveStatus
 
 @OptIn(ExperimentalMaterial3Api::class)
 @Preview
@@ -276,6 +278,19 @@ private fun MainScaffold(
     val currentRoute = currentRoute(navController)
     val character by characterViewModel.character.collectAsState()
     val saveStatus by characterViewModel.saveStatus.collectAsState()
+    val snackbarHostState = remember { SnackbarHostState() }
+
+    // Show snackbar when a save error occurs
+    LaunchedEffect(saveStatus) {
+        if (saveStatus is SaveStatus.Error) {
+            val errorMessage = (saveStatus as SaveStatus.Error).message
+            snackbarHostState.showSnackbar(
+                message = "Save failed: $errorMessage",
+                actionLabel = "Dismiss",
+                duration = SnackbarDuration.Long
+            )
+        }
+    }
 
     // Dice roll history (in-memory, not persisted)
     val diceRollHistory = remember { DiceRollHistory() }
@@ -306,6 +321,12 @@ private fun MainScaffold(
 
     Scaffold(
         modifier = modifier.fillMaxSize(),
+        snackbarHost = {
+            SnackbarHost(
+                hostState = snackbarHostState,
+                modifier = Modifier.testTag(TestTags.SAVE_ERROR_SNACKBAR)
+            )
+        },
         topBar = {
             TopAppBar(
                 title = { Text(topBarTitle) },

sharedUI/src/commonMain/kotlin/org/shahondin1624/lib/components/TestTags.kt

@@ -135,6 +135,7 @@ object TestTags {
     const val SAVE_STATUS_SAVING = "save_status_saving"
     const val SAVE_STATUS_SAVED = "save_status_saved"
     const val SAVE_STATUS_ERROR = "save_status_error"
+    const val SAVE_ERROR_SNACKBAR = "save_error_snackbar"
 
     // --- Top app bar ---
     const val TOP_APP_BAR = "top_app_bar"

sharedUI/src/commonMain/kotlin/org/shahondin1624/lib/components/charactermodel/SaveStatusIndicator.kt

@@ -94,7 +94,7 @@ fun SaveStatusIndicator(
                 ) {
                     Icon(
                         imageVector = Icons.Default.ErrorOutline,
-                        contentDescription = "Save failed",
+                        contentDescription = "Save failed: ${currentStatus.message}",
                         modifier = Modifier.size(16.dp),
                         tint = MaterialTheme.colorScheme.error
                     )

sharedUI/src/commonTest/kotlin/org/shahondin1624/SaveErrorNotificationTest.kt

@@ -0,0 +1,188 @@
+package org.shahondin1624
+
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.SnackbarDuration
+import androidx.compose.material3.SnackbarHost
+import androidx.compose.material3.SnackbarHostState
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.testTag
+import androidx.compose.ui.test.ExperimentalTestApi
+import androidx.compose.ui.test.assertIsDisplayed
+import androidx.compose.ui.test.onNodeWithTag
+import androidx.compose.ui.test.onNodeWithText
+import androidx.compose.ui.test.runComposeUiTest
+import org.shahondin1624.lib.components.TestTags
+import org.shahondin1624.lib.components.charactermodel.SaveStatusIndicator
+import org.shahondin1624.viewmodel.SaveStatus
+import kotlin.test.Test
+
+/**
+ * Tests for save error notification behavior.
+ * Verifies that save failures produce user-visible error feedback
+ * (issue #77: Silent save failures).
+ */
+@OptIn(ExperimentalTestApi::class)
+class SaveErrorNotificationTest {
+
+    @Test
+    fun saveStatusIndicatorShowsErrorIcon() = runComposeUiTest {
+        setContent {
+            MaterialTheme {
+                SaveStatusIndicator(status = SaveStatus.Error("disk full"))
+            }
+        }
+
+        onNodeWithTag(TestTags.SAVE_STATUS_ERROR).assertIsDisplayed()
+        onNodeWithText("Save failed").assertIsDisplayed()
+    }
+
+    @Test
+    fun saveStatusIndicatorShowsNothingWhenIdle() = runComposeUiTest {
+        setContent {
+            MaterialTheme {
+                SaveStatusIndicator(status = SaveStatus.Idle)
+            }
+        }
+
+        onNodeWithTag(TestTags.SAVE_STATUS_SAVING).assertDoesNotExist()
+        onNodeWithTag(TestTags.SAVE_STATUS_SAVED).assertDoesNotExist()
+        onNodeWithTag(TestTags.SAVE_STATUS_ERROR).assertDoesNotExist()
+    }
+
+    @Test
+    fun saveStatusIndicatorShowsSavingSpinner() = runComposeUiTest {
+        setContent {
+            MaterialTheme {
+                SaveStatusIndicator(status = SaveStatus.Saving)
+            }
+        }
+
+        onNodeWithTag(TestTags.SAVE_STATUS_SAVING).assertIsDisplayed()
+        onNodeWithText("Saving...").assertIsDisplayed()
+    }
+
+    @Test
+    fun saveStatusIndicatorShowsSavedCheckmark() = runComposeUiTest {
+        setContent {
+            MaterialTheme {
+                SaveStatusIndicator(status = SaveStatus.Saved)
+            }
+        }
+
+        onNodeWithTag(TestTags.SAVE_STATUS_SAVED).assertIsDisplayed()
+        onNodeWithText("Saved").assertIsDisplayed()
+    }
+
+    @Test
+    fun snackbarAppearsOnSaveError() = runComposeUiTest {
+        setContent {
+            MaterialTheme {
+                val snackbarHostState = remember { SnackbarHostState() }
+                var saveStatus by remember { mutableStateOf<SaveStatus>(SaveStatus.Idle) }
+
+                LaunchedEffect(saveStatus) {
+                    if (saveStatus is SaveStatus.Error) {
+                        val errorMessage = (saveStatus as SaveStatus.Error).message
+                        snackbarHostState.showSnackbar(
+                            message = "Save failed: $errorMessage",
+                            actionLabel = "Dismiss",
+                            duration = SnackbarDuration.Long
+                        )
+                    }
+                }
+
+                Scaffold(
+                    snackbarHost = {
+                        SnackbarHost(
+                            hostState = snackbarHostState,
+                            modifier = Modifier.testTag(TestTags.SAVE_ERROR_SNACKBAR)
+                        )
+                    }
+                ) {
+                    // Content area is empty for this test
+                }
+
+                // Trigger the error state
+                LaunchedEffect(Unit) {
+                    saveStatus = SaveStatus.Error("serialization failed")
+                }
+            }
+        }
+
+        waitForIdle()
+        onNodeWithText("Save failed: serialization failed").assertIsDisplayed()
+    }
+
+    @Test
+    fun snackbarDoesNotAppearOnSuccessfulSave() = runComposeUiTest {
+        setContent {
+            MaterialTheme {
+                val snackbarHostState = remember { SnackbarHostState() }
+                val saveStatus = SaveStatus.Saved
+
+                LaunchedEffect(saveStatus) {
+                    if (saveStatus is SaveStatus.Error) {
+                        val errorMessage = (saveStatus as SaveStatus.Error).message
+                        snackbarHostState.showSnackbar(
+                            message = "Save failed: $errorMessage",
+                            actionLabel = "Dismiss",
+                            duration = SnackbarDuration.Long
+                        )
+                    }
+                }
+
+                Scaffold(
+                    snackbarHost = {
+                        SnackbarHost(
+                            hostState = snackbarHostState,
+                            modifier = Modifier.testTag(TestTags.SAVE_ERROR_SNACKBAR)
+                        )
+                    }
+                ) {
+                    // Content area is empty for this test
+                }
+            }
+        }
+
+        waitForIdle()
+        onNodeWithText("Save failed", substring = true).assertDoesNotExist()
+    }
+
+    @Test
+    fun snackbarIncludesErrorDetails() = runComposeUiTest {
+        setContent {
+            MaterialTheme {
+                val snackbarHostState = remember { SnackbarHostState() }
+
+                LaunchedEffect(Unit) {
+                    snackbarHostState.showSnackbar(
+                        message = "Save failed: Storage permission denied",
+                        actionLabel = "Dismiss",
+                        duration = SnackbarDuration.Long
+                    )
+                }
+
+                Scaffold(
+                    snackbarHost = {
+                        SnackbarHost(
+                            hostState = snackbarHostState,
+                            modifier = Modifier.testTag(TestTags.SAVE_ERROR_SNACKBAR)
+                        )
+                    }
+                ) {
+                    // Content area is empty for this test
+                }
+            }
+        }
+
+        waitForIdle()
+        onNodeWithText("Save failed: Storage permission denied").assertIsDisplayed()
+        onNodeWithText("Dismiss").assertIsDisplayed()
+    }
+}