Android picture-in-picture, and fix three dead Android config files

Add PiP for native (ExoPlayer) video on Android. Video renders into a
SurfaceView behind the WebView, so PiP is driven by the Activity shrinking
into a floating window rather than the HTML5 PiP API (which WebKitGTK does
not implement, hence Android-only).

- PictureInPictureManager.kt: enter PiP with the video's aspect ratio
  (clamped to the 1:2.39-2.39:1 range Android accepts, outside which it
  throws), plus a play/pause RemoteAction. Hides the WebView while in PiP -
  it is opaque and sits above the surface, so it would otherwise occlude the
  video entirely - and re-fits the surface on exit.
- MainActivity.kt: onUserLeaveHint auto-PiP, onPictureInPictureModeChanged,
  and an AndroidPictureInPicture JS interface following the existing
  AndroidAudioFocus pattern.
- pictureInPicture.ts + VideoPlayer.svelte: PiP button, rendered only when
  the native bridge reports support.
- proguard: keep rules for @JavascriptInterface methods, which are only
  referenced from JS and would be stripped in minified release builds.

Casting needs no special handling: canEnterPip() checks natively that a
local video surface is attached and playing, which a remote session lacks.

While wiring the manifest, found that three tracked files under
src-tauri/android/ were never reaching any build. Gradle reads only
gen/android/app/src/main/, and sync-android-sources.sh did not copy them:

- src/main/AndroidManifest.xml was a partial <application> fragment written
  as if Tauri merged it. It does not - there is no manifest-merger hook
  here, so its hardwareAccelerated flag never reached an APK. Promoted to
  the complete authoritative manifest (folding in that flag) and synced.
- src/main/res/values/themes.xml (transparent status bar, fitsSystemWindows)
  was never copied; the sync only globbed mipmap-*. Now synced.
- build.gradle.kts was a leftover com.android.library module config with
  stale media3 1.5.1 deps. The live deps are in app/build.gradle.kts at
  1.5.0. Deleted.

Verified: merged manifest now carries hardwareAccelerated,
supportsPictureInPicture, resizeableActivity and the density configChange;
themes.xml compiles into merged resources; Kotlin builds warning-free;
svelte-check clean; 537 frontend tests pass.

Not verified: PiP behaviour on a device, and the release keep rules against
a minified build. assembleUniversalDebug cannot complete in this
environment - the Rust step wants a dev-server addr file that only exists
under `tauri android dev`.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src-tauri/android/src/main/AndroidManifest.xml

@@ -1,5 +1,67 @@
 <?xml version="1.0" encoding="utf-8"?>
+<!--
+  Authoritative AndroidManifest for JellyTau.
+
+  NOTE: this is NOT a manifest-merger fragment. Gradle only ever reads
+  gen/android/app/src/main/AndroidManifest.xml, and `tauri android init`
+  regenerates that file from tauri.conf.json - dropping everything below.
+  scripts/sync-android-sources.sh copies this file over the generated one,
+  so this is the full manifest and the single source of truth.
+
+  (An earlier version of this file was a partial <application> fragment on the
+  assumption that Tauri merged it. It did not: the hardwareAccelerated flag it
+  declared never reached any built APK. It is folded in properly below.)
+-->
 <manifest xmlns:android="http://schemas.android.com/apk/res/android">
-    <!-- Enable hardware acceleration for video playback performance -->
-    <application android:hardwareAccelerated="true" />
+    <uses-permission android:name="android.permission.INTERNET" />
+    <uses-permission android:name="android.permission.WAKE_LOCK" />
+    <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
+    <uses-permission android:name="android.permission.FOREGROUND_SERVICE_MEDIA_PLAYBACK" />
+    <uses-permission android:name="android.permission.POST_NOTIFICATIONS" />
+
+    <!-- AndroidTV support -->
+    <uses-feature android:name="android.software.leanback" android:required="false" />
+
+    <application
+        android:icon="@mipmap/ic_launcher"
+        android:label="@string/app_name"
+        android:theme="@style/Theme.jellytau"
+        android:hardwareAccelerated="true"
+        android:usesCleartextTraffic="${usesCleartextTraffic}">
+        <activity
+            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|smallestScreenSize|screenLayout|uiMode|density"
+            android:launchMode="singleTask"
+            android:label="@string/main_activity_title"
+            android:name=".MainActivity"
+            android:exported="true"
+            android:supportsPictureInPicture="true"
+            android:resizeableActivity="true">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+                <!-- AndroidTV support -->
+                <category android:name="android.intent.category.LEANBACK_LAUNCHER" />
+            </intent-filter>
+        </activity>
+
+        <provider
+          android:name="androidx.core.content.FileProvider"
+          android:authorities="${applicationId}.fileprovider"
+          android:exported="false"
+          android:grantUriPermissions="true">
+          <meta-data
+            android:name="android.support.FILE_PROVIDER_PATHS"
+            android:resource="@xml/file_paths" />
+        </provider>
+
+        <!-- Media playback service for lockscreen controls -->
+        <service
+            android:name="com.dtourolle.jellytau.player.JellyTauPlaybackService"
+            android:foregroundServiceType="mediaPlayback"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="androidx.media3.session.MediaSessionService" />
+            </intent-filter>
+        </service>
+    </application>
 </manifest>

src-tauri/android/src/main/java/com/dtourolle/jellytau/MainActivity.kt

@@ -22,6 +22,14 @@ class MainActivity : TauriActivity() {
   private var audioFocusRequest: AudioFocusRequest? = null
   private val audioManager by lazy { getSystemService(Context.AUDIO_SERVICE) as AudioManager }
 
+  /**
+   * Whether backgrounding the app during video should auto-enter PiP.
+   * The frontend clears this when video isn't the active local surface
+   * (e.g. remote/cast playback) via AndroidPictureInPicture.setAutoEnterEnabled.
+   */
+  @Volatile
+  private var autoEnterPipEnabled = true
+
   override fun onCreate(savedInstanceState: Bundle?) {
     enableEdgeToEdge()
     super.onCreate(savedInstanceState)
@@ -37,6 +45,28 @@ class MainActivity : TauriActivity() {
     configureWebViewForMedia()
   }
 
+  /**
+   * Called when the user leaves the app via Home or the gesture equivalent
+   * (but NOT via Back). This is the standard hook for auto-entering PiP so
+   * video keeps playing in a floating window instead of being backgrounded.
+   */
+  override fun onUserLeaveHint() {
+    super.onUserLeaveHint()
+    if (autoEnterPipEnabled && PictureInPictureManager.canEnterPip(this)) {
+      android.util.Log.d("MainActivity", "User leaving with video active - entering PiP")
+      PictureInPictureManager.enterPip(this)
+    }
+  }
+
+  override fun onPictureInPictureModeChanged(
+    isInPictureInPictureMode: Boolean,
+    newConfig: android.content.res.Configuration
+  ) {
+    super.onPictureInPictureModeChanged(isInPictureInPictureMode, newConfig)
+    android.util.Log.d("MainActivity", "PiP mode changed: $isInPictureInPictureMode")
+    PictureInPictureManager.onPipModeChanged(this, isInPictureInPictureMode)
+  }
+
   private fun configureWebViewForMedia() {
     try {
       val webView = findWebView(window.decorView)
@@ -70,6 +100,35 @@ class MainActivity : TauriActivity() {
       }, "AndroidAudioFocus")
       android.util.Log.d("MainActivity", "JavaScript interface 'AndroidAudioFocus' added")
 
+      // Add JavaScript interface for picture-in-picture control.
+      // enterPip/canEnterPip must run on the main thread; @JavascriptInterface
+      // methods are invoked on a WebView binder thread.
+      webView.addJavascriptInterface(object : Any() {
+        @JavascriptInterface
+        fun enterPip() {
+          handler.post { PictureInPictureManager.enterPip(this@MainActivity) }
+        }
+
+        /** Whether the PiP button should be offered in the player UI at all. */
+        @JavascriptInterface
+        fun isSupported(): Boolean {
+          return PictureInPictureManager.isPipSupported(this@MainActivity)
+        }
+
+        /** Whether entering PiP would work right now (local video playing). */
+        @JavascriptInterface
+        fun canEnterPip(): Boolean {
+          return PictureInPictureManager.canEnterPip(this@MainActivity)
+        }
+
+        /** Let the frontend opt out of auto-PiP (e.g. while casting). */
+        @JavascriptInterface
+        fun setAutoEnterEnabled(enabled: Boolean) {
+          autoEnterPipEnabled = enabled
+        }
+      }, "AndroidPictureInPicture")
+      android.util.Log.d("MainActivity", "JavaScript interface 'AndroidPictureInPicture' added")
+
       // Set WebChromeClient to handle video playback and audio focus
       webView.webChromeClient = object : WebChromeClient() {
         override fun onShowCustomView(view: View?, callback: CustomViewCallback?) {

src-tauri/android/src/main/java/com/dtourolle/jellytau/PictureInPictureManager.kt

@@ -0,0 +1,310 @@
+package com.dtourolle.jellytau
+
+import android.app.Activity
+import android.app.PictureInPictureParams
+import android.app.RemoteAction
+import android.content.BroadcastReceiver
+import android.content.Context
+import android.content.Intent
+import android.content.IntentFilter
+import android.graphics.drawable.Icon
+import android.os.Build
+import android.util.Rational
+import android.view.ViewGroup
+import android.webkit.WebView
+import androidx.annotation.RequiresApi
+import com.dtourolle.jellytau.player.JellyTauPlayer
+
+/**
+ * Drives Android picture-in-picture for native (ExoPlayer) video playback.
+ *
+ * PiP shrinks the whole Activity into a floating window, so the only thing that
+ * should remain visible is the video SurfaceView that [VideoOverlayManager]
+ * attached at the bottom of the z-order. The WebView carrying the Svelte UI is
+ * hidden for the duration - it is opaque and sits *above* the surface, so
+ * leaving it visible would occlude the video entirely.
+ *
+ * Playback itself is untouched: ExoPlayer keeps rendering into the same surface
+ * across the transition, so entering and leaving PiP never interrupts the video.
+ */
+object PictureInPictureManager {
+
+    private const val TAG = "PictureInPictureManager"
+
+    /** Action for the play/pause RemoteAction shown inside the PiP window. */
+    private const val ACTION_MEDIA_CONTROL = "com.dtourolle.jellytau.PIP_MEDIA_CONTROL"
+    private const val EXTRA_CONTROL_TYPE = "control_type"
+    private const val CONTROL_PLAY = 1
+    private const val CONTROL_PAUSE = 2
+
+    /** Request codes must differ per action or the PendingIntents collapse into one. */
+    private const val REQUEST_PLAY = 101
+    private const val REQUEST_PAUSE = 102
+
+    private var receiver: BroadcastReceiver? = null
+    private var hiddenWebView: WebView? = null
+
+    /**
+     * Whether this device/OS can do PiP at all. Android 8.0 introduced the API,
+     * and the user (or device manufacturer) can disable the feature per-app.
+     */
+    fun isPipSupported(activity: Activity): Boolean {
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.O) return false
+        return activity.packageManager.hasSystemFeature(
+            android.content.pm.PackageManager.FEATURE_PICTURE_IN_PICTURE
+        )
+    }
+
+    /**
+     * Whether entering PiP right now makes sense: a native video must actually
+     * be playing locally. Audio-only playback and remote/cast sessions render
+     * nothing on this device, so a PiP window would be an empty black box.
+     */
+    fun canEnterPip(activity: Activity): Boolean {
+        if (!isPipSupported(activity)) return false
+        return try {
+            val player = JellyTauPlayer.getInstance()
+            player.isPlayingVideo() &&
+                player.getSurfaceView() != null &&
+                VideoOverlayManager.isVideoSurfaceAttached()
+        } catch (e: Exception) {
+            android.util.Log.w(TAG, "canEnterPip check failed", e)
+            false
+        }
+    }
+
+    /**
+     * Enter picture-in-picture, sizing the window to the video's aspect ratio.
+     *
+     * @return true if the system accepted the transition.
+     */
+    fun enterPip(activity: Activity): Boolean {
+        if (!canEnterPip(activity)) {
+            android.util.Log.d(TAG, "Not entering PiP: no local video playing")
+            return false
+        }
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.O) return false
+
+        return try {
+            val params = buildParams(activity)
+            val entered = activity.enterPictureInPictureMode(params)
+            android.util.Log.d(TAG, "enterPictureInPictureMode returned $entered")
+            entered
+        } catch (e: Exception) {
+            // IllegalStateException here means PiP is disallowed (e.g. the user
+            // turned it off in system settings). Never crash over it.
+            android.util.Log.e(TAG, "Failed to enter PiP", e)
+            false
+        }
+    }
+
+    /**
+     * Build PiP params: aspect ratio from the current video, plus a play/pause
+     * RemoteAction reflecting the live playback state.
+     */
+    @RequiresApi(Build.VERSION_CODES.O)
+    private fun buildParams(activity: Activity): PictureInPictureParams {
+        val builder = PictureInPictureParams.Builder()
+
+        aspectRatioFor()?.let { builder.setAspectRatio(it) }
+        builder.setActions(listOf(buildPlayPauseAction(activity)))
+
+        return builder.build()
+    }
+
+    /**
+     * The video's aspect ratio, clamped to the range Android accepts.
+     *
+     * The platform rejects ratios outside roughly 1:2.39 - 2.39:1 with an
+     * IllegalArgumentException, which would otherwise take down the Activity on
+     * unusually tall or wide content.
+     */
+    private fun aspectRatioFor(): Rational? {
+        val player = try {
+            JellyTauPlayer.getInstance()
+        } catch (e: Exception) {
+            return null
+        }
+
+        val surface = player.getSurfaceView() ?: return null
+        // The surface has already been letterboxed to the video's aspect ratio
+        // by fitSurfaceToScreen(), so its measured bounds are the video shape.
+        val width = surface.width
+        val height = surface.height
+        if (width <= 0 || height <= 0) return null
+
+        val ratio = width.toDouble() / height.toDouble()
+        val minRatio = 1.0 / 2.39
+        val maxRatio = 2.39
+        val clamped = ratio.coerceIn(minRatio, maxRatio)
+
+        // Scale to integers; Rational(width, height) directly can overflow for
+        // large surfaces, and the clamped value may not match the raw pixels.
+        return Rational((clamped * 1000).toInt(), 1000)
+    }
+
+    @RequiresApi(Build.VERSION_CODES.O)
+    private fun buildPlayPauseAction(activity: Activity): RemoteAction {
+        val isPlaying = try {
+            JellyTauPlayer.getInstance().getExoPlayer().isPlaying
+        } catch (e: Exception) {
+            false
+        }
+
+        val (iconRes, title, controlType, requestCode) = if (isPlaying) {
+            Quad(
+                android.R.drawable.ic_media_pause,
+                "Pause",
+                CONTROL_PAUSE,
+                REQUEST_PAUSE
+            )
+        } else {
+            Quad(
+                android.R.drawable.ic_media_play,
+                "Play",
+                CONTROL_PLAY,
+                REQUEST_PLAY
+            )
+        }
+
+        val intent = Intent(ACTION_MEDIA_CONTROL)
+            .putExtra(EXTRA_CONTROL_TYPE, controlType)
+            // Explicit package keeps the broadcast internal to the app.
+            .setPackage(activity.packageName)
+
+        val flags = android.app.PendingIntent.FLAG_UPDATE_CURRENT or
+            android.app.PendingIntent.FLAG_IMMUTABLE
+
+        val pendingIntent = android.app.PendingIntent.getBroadcast(
+            activity,
+            requestCode,
+            intent,
+            flags
+        )
+
+        return RemoteAction(
+            Icon.createWithResource(activity, iconRes),
+            title,
+            title,
+            pendingIntent
+        )
+    }
+
+    private data class Quad<A, B, C, D>(
+        val first: A,
+        val second: B,
+        val third: C,
+        val fourth: D
+    )
+
+    /**
+     * Refresh the PiP window's action button so it tracks play/pause state
+     * while the window is open. Safe to call when not in PiP (no-op).
+     */
+    fun updatePipActions(activity: Activity) {
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.O) return
+        if (!activity.isInPictureInPictureMode) return
+        try {
+            activity.setPictureInPictureParams(buildParams(activity))
+        } catch (e: Exception) {
+            android.util.Log.w(TAG, "Failed to update PiP actions", e)
+        }
+    }
+
+    /**
+     * Called from MainActivity.onPictureInPictureModeChanged.
+     *
+     * Entering: hide the WebView so only the video surface shows, and register
+     * the receiver backing the PiP play/pause button.
+     * Leaving: restore the WebView and unregister.
+     */
+    fun onPipModeChanged(activity: Activity, isInPipMode: Boolean) {
+        if (isInPipMode) {
+            hideWebView(activity)
+            registerReceiver(activity)
+        } else {
+            unregisterReceiver(activity)
+            showWebView()
+            // The surface was laid out against the tiny PiP bounds; re-fit it to
+            // the restored full-screen bounds or the video stays postage-stamp sized.
+            try {
+                JellyTauPlayer.getInstance().fitSurfaceToScreen()
+            } catch (e: Exception) {
+                android.util.Log.w(TAG, "Failed to re-fit surface after PiP", e)
+            }
+        }
+    }
+
+    private fun hideWebView(activity: Activity) {
+        val webView = findWebView(activity.window.decorView)
+        if (webView == null) {
+            android.util.Log.w(TAG, "No WebView found to hide for PiP")
+            return
+        }
+        // GONE rather than INVISIBLE: the WebView is opaque, and GONE also stops
+        // it from consuming layout space in the shrunken window.
+        webView.visibility = android.view.View.GONE
+        hiddenWebView = webView
+        android.util.Log.d(TAG, "WebView hidden for PiP")
+    }
+
+    private fun showWebView() {
+        hiddenWebView?.let {
+            it.visibility = android.view.View.VISIBLE
+            android.util.Log.d(TAG, "WebView restored after PiP")
+        }
+        hiddenWebView = null
+    }
+
+    private fun registerReceiver(activity: Activity) {
+        if (receiver != null) return
+
+        val r = object : BroadcastReceiver() {
+            override fun onReceive(context: Context?, intent: Intent?) {
+                if (intent?.action != ACTION_MEDIA_CONTROL) return
+                val player = try {
+                    JellyTauPlayer.getInstance()
+                } catch (e: Exception) {
+                    return
+                }
+                when (intent.getIntExtra(EXTRA_CONTROL_TYPE, 0)) {
+                    CONTROL_PLAY -> player.play()
+                    CONTROL_PAUSE -> player.pause()
+                }
+                // Swap the button to reflect the new state.
+                updatePipActions(activity)
+            }
+        }
+
+        val filter = IntentFilter(ACTION_MEDIA_CONTROL)
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
+            activity.registerReceiver(r, filter, Context.RECEIVER_NOT_EXPORTED)
+        } else {
+            @Suppress("UnspecifiedRegisterReceiverFlag")
+            activity.registerReceiver(r, filter)
+        }
+        receiver = r
+        android.util.Log.d(TAG, "PiP media control receiver registered")
+    }
+
+    private fun unregisterReceiver(activity: Activity) {
+        receiver?.let {
+            try {
+                activity.unregisterReceiver(it)
+            } catch (e: IllegalArgumentException) {
+                // Already unregistered - harmless.
+            }
+        }
+        receiver = null
+    }
+
+    private fun findWebView(view: android.view.View): WebView? {
+        if (view is WebView) return view
+        if (view is ViewGroup) {
+            for (i in 0 until view.childCount) {
+                findWebView(view.getChildAt(i))?.let { return it }
+            }
+        }
+        return null
+    }
+}