android/app/src/main/java/com/fabledsword/minstrel/MainActivity.kt

@@ -21,6 +21,9 @@ import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.navigation.compose.rememberNavController
 import com.fabledsword.minstrel.auth.ui.AuthGateViewModel
 import com.fabledsword.minstrel.cache.CachedTrackIds
+import com.fabledsword.minstrel.connectivity.LocalServerHealth
+import com.fabledsword.minstrel.connectivity.ServerHealth
+import com.fabledsword.minstrel.connectivity.ServerHealthController
 import com.fabledsword.minstrel.nav.DetailSeedCache
 import com.fabledsword.minstrel.nav.LocalDetailSeedCache
 import com.fabledsword.minstrel.nav.MinstrelNavGraph
@@ -38,6 +41,7 @@ import javax.inject.Inject
 class MainActivity : ComponentActivity() {
     @Inject lateinit var seedCache: DetailSeedCache
     @Inject lateinit var cachedTrackIds: CachedTrackIds
+    @Inject lateinit var serverHealth: ServerHealthController
 
     // Flipped to true when the user taps the media notification (or
     // any other entry point that asks for the full player). The App
@@ -54,6 +58,7 @@ class MainActivity : ComponentActivity() {
             App(
                 seedCache = seedCache,
                 cachedTrackIds = cachedTrackIds,
+                serverHealth = serverHealth,
                 pendingOpenNowPlaying = pendingOpenNowPlaying.asStateFlow(),
                 onOpenedNowPlaying = { pendingOpenNowPlaying.value = false },
             )
@@ -86,6 +91,7 @@ class MainActivity : ComponentActivity() {
 private fun App(
     seedCache: DetailSeedCache,
     cachedTrackIds: CachedTrackIds,
+    serverHealth: ServerHealthController,
     pendingOpenNowPlaying: StateFlow<Boolean>,
     onOpenedNowPlaying: () -> Unit,
     themeVm: ThemePreferenceViewModel = hiltViewModel(),
@@ -93,11 +99,13 @@ private fun App(
 ) {
     val theme by themeVm.themeMode.collectAsStateWithLifecycle()
     val cached by cachedTrackIds.ids.collectAsStateWithLifecycle()
+    val health: ServerHealth by serverHealth.state.collectAsStateWithLifecycle()
     val pending by pendingOpenNowPlaying.collectAsStateWithLifecycle()
     MinstrelTheme(darkOverride = theme.toDarkOverride()) {
         CompositionLocalProvider(
             LocalDetailSeedCache provides seedCache,
             LocalCachedTrackIds provides cached,
+            LocalServerHealth provides health,
         ) {
             val startDestination by gate.startDestination.collectAsStateWithLifecycle()
             val resolved = startDestination

android/app/src/main/java/com/fabledsword/minstrel/connectivity/ServerHealthController.kt

@@ -1,5 +1,6 @@
 package com.fabledsword.minstrel.connectivity
 
+import androidx.compose.runtime.staticCompositionLocalOf
 import com.fabledsword.minstrel.di.ApplicationScope
 import com.fabledsword.minstrel.update.data.VersionCheckController
 import kotlinx.coroutines.CoroutineScope
@@ -51,3 +52,12 @@ class ServerHealthController @Inject constructor(
         initialValue = ServerHealth.Healthy,
     )
 }
+
+/**
+ * Reactive [ServerHealth] snapshot provided once at the app root from the
+ * controller's StateFlow. Lets leaf composables (TrackRow gating, write-
+ * affordance disabling) branch on health without each ViewModel re-
+ * injecting the controller. Defaults to Healthy so unwrapped previews
+ * and tests don't crash.
+ */
+val LocalServerHealth = staticCompositionLocalOf { ServerHealth.Healthy }

android/app/src/main/java/com/fabledsword/minstrel/shared/widgets/TrackRow.kt

@@ -1,5 +1,6 @@
 package com.fabledsword.minstrel.shared.widgets
 
+import android.widget.Toast
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
@@ -12,8 +13,14 @@ import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
+import com.fabledsword.minstrel.connectivity.LocalServerHealth
+import com.fabledsword.minstrel.connectivity.ServerHealth
+
+private const val OFFLINE_UNAVAILABLE_ALPHA = 0.4f
+private const val OFFLINE_TAP_MESSAGE = "Not downloaded — connect to play"
 
 /**
  * Shared track-list row. Replaces the 5 per-screen `TrackRow`s — every
@@ -30,6 +37,14 @@ import androidx.compose.ui.unit.dp
  * for applying its own alpha if it should match (the row doesn't
  * cascade because the trailing slot's content is the caller's, not
  * ours).
+ *
+ * Reads [LocalServerHealth] + [LocalCachedTrackIds] and intercepts taps
+ * on tracks that aren't downloaded when the server is unreachable —
+ * fires a Toast instead of attempting playback. The text dims so the
+ * user can see at a glance which rows in a long list will work offline.
+ * The trailing slot stays interactive so the kebab / like / playlist-
+ * add affordances can still queue mutations for offline replay (Phase
+ * 5 of #618 gates those at the action level).
  */
 @Composable
 fun TrackRow(
@@ -45,15 +60,28 @@ fun TrackRow(
     leading: @Composable () -> Unit = {},
     trailing: @Composable RowScope.() -> Unit = {},
 ) {
+    val context = LocalContext.current
+    val offlineUnavailable = LocalServerHealth.current != ServerHealth.Healthy &&
+        trackId !in LocalCachedTrackIds.current
     val titleColor = if (nowPlaying) {
         MaterialTheme.colorScheme.primary
     } else {
         MaterialTheme.colorScheme.onSurface
     }
+    val effectiveAlpha = if (offlineUnavailable) {
+        minOf(contentAlpha, OFFLINE_UNAVAILABLE_ALPHA)
+    } else {
+        contentAlpha
+    }
+    val effectiveOnClick: () -> Unit = if (offlineUnavailable) {
+        { Toast.makeText(context, OFFLINE_TAP_MESSAGE, Toast.LENGTH_SHORT).show() }
+    } else {
+        onClick
+    }
     Row(
         modifier = modifier
             .fillMaxWidth()
-            .clickable(enabled = enabled, onClick = onClick)
+            .clickable(enabled = enabled, onClick = effectiveOnClick)
             .padding(horizontal = 16.dp, vertical = 8.dp),
         verticalAlignment = Alignment.CenterVertically,
         horizontalArrangement = horizontalArrangement,
@@ -63,7 +91,7 @@ fun TrackRow(
             Text(
                 text = title,
                 style = MaterialTheme.typography.bodyLarge,
-                color = titleColor.copy(alpha = contentAlpha),
+                color = titleColor.copy(alpha = effectiveAlpha),
                 maxLines = 1,
                 overflow = TextOverflow.Ellipsis,
             )
@@ -71,7 +99,7 @@ fun TrackRow(
                 Text(
                     text = artist,
                     style = MaterialTheme.typography.bodySmall,
-                    color = MaterialTheme.colorScheme.onSurfaceVariant.copy(alpha = contentAlpha),
+                    color = MaterialTheme.colorScheme.onSurfaceVariant.copy(alpha = effectiveAlpha),
                     maxLines = 1,
                     overflow = TextOverflow.Ellipsis,
                 )