open now playing when the media notification is tapped

app/src/main/kotlin/com/subtracks/MainActivity.kt

@@ -1,6 +1,7 @@
 package com.subtracks
 
 import android.Manifest
+import android.content.Intent
 import android.content.pm.PackageManager
 import android.os.Build
 import android.os.Bundle
@@ -8,11 +9,14 @@ import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
 import androidx.activity.enableEdgeToEdge
 import androidx.activity.result.contract.ActivityResultContracts
+import androidx.compose.runtime.mutableIntStateOf
 import androidx.core.content.ContextCompat
 import com.subtracks.ui.SubtracksRoot
 import com.subtracks.ui.theme.SubtracksTheme
 
 class MainActivity : ComponentActivity() {
+    private val nowPlayingRequest = mutableIntStateOf(0)
+
     private val requestNotifications =
         registerForActivityResult(ActivityResultContracts.RequestPermission()) { }
 
@@ -20,13 +24,20 @@ class MainActivity : ComponentActivity() {
         super.onCreate(savedInstanceState)
         requestNotificationPermission()
         enableEdgeToEdge()
+        if (intent?.action == ACTION_OPEN_NOW_PLAYING) nowPlayingRequest.intValue++
         setContent {
             SubtracksTheme {
-                SubtracksRoot()
+                SubtracksRoot(nowPlayingRequest = nowPlayingRequest.intValue)
             }
         }
     }
 
+    override fun onNewIntent(intent: Intent) {
+        super.onNewIntent(intent)
+        setIntent(intent)
+        if (intent.action == ACTION_OPEN_NOW_PLAYING) nowPlayingRequest.intValue++
+    }
+
     private fun requestNotificationPermission() {
         if (Build.VERSION.SDK_INT < Build.VERSION_CODES.TIRAMISU) return
         val granted =
@@ -34,4 +45,8 @@ class MainActivity : ComponentActivity() {
                 PackageManager.PERMISSION_GRANTED
         if (!granted) requestNotifications.launch(Manifest.permission.POST_NOTIFICATIONS)
     }
+
+    companion object {
+        const val ACTION_OPEN_NOW_PLAYING = "com.subtracks.action.OPEN_NOW_PLAYING"
+    }
 }

app/src/main/kotlin/com/subtracks/playback/PlaybackService.kt

@@ -129,7 +129,8 @@ class PlaybackService : MediaSessionService() {
                     PendingIntent.getActivity(
                         this,
                         0,
-                        Intent(this, MainActivity::class.java),
+                        Intent(this, MainActivity::class.java)
+                            .setAction(MainActivity.ACTION_OPEN_NOW_PLAYING),
                         PendingIntent.FLAG_IMMUTABLE or PendingIntent.FLAG_UPDATE_CURRENT,
                     ),
                 ).setBitmapLoader(loader)

app/src/main/kotlin/com/subtracks/ui/AppRoot.kt

@@ -166,6 +166,12 @@ internal fun resetOnSourceSwitch(
     if (route in DETAIL_ROUTES) popDetail()
 }
 
+internal fun shouldOpenNowPlaying(
+    request: Int,
+    handled: Int,
+    playerVisible: Boolean,
+): Boolean = playerVisible && request > handled
+
 internal data class BackStackKey(
     val route: String?,
     val argument: String?,
@@ -181,7 +187,10 @@ internal fun focusPops(
 }
 
 @Composable
-fun SubtracksRoot(root: RootViewModel = koinViewModel()) {
+fun SubtracksRoot(
+    root: RootViewModel = koinViewModel(),
+    nowPlayingRequest: Int = 0,
+) {
     when (val hasSource = root.hasSource.collectAsStateWithLifecycle().value) {
         null -> {
             LoadingState()
@@ -195,14 +204,14 @@ fun SubtracksRoot(root: RootViewModel = koinViewModel()) {
             val playbackController = koinInject<PlaybackController>()
             LaunchedEffect(Unit) { playbackController.connect() }
             val playbackReady by playbackController.ready.collectAsStateWithLifecycle()
-            if (playbackReady) MainNavigation() else LoadingState()
+            if (playbackReady) MainNavigation(nowPlayingRequest) else LoadingState()
         }
     }
 }
 
 @OptIn(ExperimentalLayoutApi::class)
 @Composable
-private fun MainNavigation() {
+private fun MainNavigation(nowPlayingRequest: Int) {
     val navController = rememberNavController()
     val currentRoute =
         navController
@@ -218,6 +227,7 @@ private fun MainNavigation() {
     val downloads by downloadRepository.states().collectAsStateWithLifecycle()
     var showingQueue by rememberSaveable { mutableStateOf(false) }
     var nowPlayingOpen by rememberSaveable { mutableStateOf(false) }
+    var handledNowPlayingRequest by rememberSaveable { mutableStateOf(0) }
     var nowPlayingProgress by remember { mutableFloatStateOf(0f) }
     var miniPlayerTopPx by remember { mutableFloatStateOf(0f) }
     var nowPlayingFadeOut by remember { mutableStateOf(false) }
@@ -302,6 +312,12 @@ private fun MainNavigation() {
             nowPlayingProgress = 0f
         }
     }
+    LaunchedEffect(nowPlayingRequest, playerVisible) {
+        if (shouldOpenNowPlaying(nowPlayingRequest, handledNowPlayingRequest, playerVisible)) {
+            handledNowPlayingRequest = nowPlayingRequest
+            settleNowPlaying(true)
+        }
+    }
     val density = LocalDensity.current
     val navBarInset = with(density) { WindowInsets.navigationBars.getBottom(this).toDp() }
     val keyboardUp = WindowInsets.imeAnimationTarget.getBottom(density) > 0

app/src/test/kotlin/com/subtracks/ui/NowPlayingRequestTest.kt

@@ -0,0 +1,33 @@
+package com.subtracks.ui
+
+import org.junit.Assert.assertFalse
+import org.junit.Assert.assertTrue
+import org.junit.Test
+
+class NowPlayingRequestTest {
+    @Test
+    fun aNotificationWithNothingPlayingDoesNotOpen() {
+        assertFalse(shouldOpenNowPlaying(request = 1, handled = 0, playerVisible = false))
+    }
+
+    @Test
+    fun aNotificationWithSomethingPlayingOpens() {
+        assertTrue(shouldOpenNowPlaying(request = 1, handled = 0, playerVisible = true))
+    }
+
+    @Test
+    fun anAlreadyHandledRequestDoesNotReopen() {
+        assertFalse(shouldOpenNowPlaying(request = 1, handled = 1, playerVisible = true))
+    }
+
+    @Test
+    fun aNewerRequestOpensAgain() {
+        assertTrue(shouldOpenNowPlaying(request = 2, handled = 1, playerVisible = true))
+    }
+
+    @Test
+    fun anOldRequestWaitsUntilSomethingIsPlaying() {
+        assertFalse(shouldOpenNowPlaying(request = 1, handled = 0, playerVisible = false))
+        assertTrue(shouldOpenNowPlaying(request = 1, handled = 0, playerVisible = true))
+    }
+}