home: rows grow on demand; refocus content when the drawer closes

The three home rows were capped: continue at six, subscriptions at
twelve, with no way to move past. Continue and subscriptions now page
in place — each new page fetches only its own entries (the continue
row's resume info costs one detail call per entry, so a page enriches
what it appends and never re-reads earlier ones; the "New videos" row
already paged). Rows stay lazy lists and the image cache is LRU, so a
user scrolling far does not pile up memory.

Closing the drawer without a selection (RIGHT, tap-outside, BACK) also
turned out to orphan the D-pad — the drawer's focused item left the
composition and nothing took its place; every later press died. The
closing now bumps a pulse the screens observe to re-focus the last
focused card.

Closes #18

app/src/main/java/net/jeena/jtubetv/ui/screens/ChannelsScreen.kt

@@ -333,6 +333,7 @@ fun ChannelsScreen(
     onOpenChannel: (handle: String) -> Unit,
     epoch: Int = 0,
     onOpenDrawer: () -> Unit = {},
+    drawerPulse: Int = 0,
     viewModel: ChannelsViewModel = viewModel(key = "channels$epoch", factory = ChannelsViewModel.factory),
 ) {
     LaunchedEffect(epoch) { viewModel.load() }
@@ -374,6 +375,7 @@ fun ChannelsScreen(
                             group.channels,
                             onOpenChannel,
                             onOpenDrawer,
+                            drawerPulse = drawerPulse,
                             focused = !focusHandedOut.value &&
                                 group == viewModel.userRows.firstOrNull(),
                             onFocused = { focusHandedOut.value = true },
@@ -427,6 +429,7 @@ private fun ChannelRow(
     channels: List<VideoChannelDto>,
     onOpenChannel: (String) -> Unit,
     onOpenDrawer: () -> Unit = {},
+    drawerPulse: Int = 0,
     focused: Boolean,
     onFocused: () -> Unit = {},
     stats: (VideoChannelDto) -> net.jeena.jtubetv.data.api.ChannelStats?,
@@ -436,6 +439,13 @@ private fun ChannelRow(
     val focusRequesters = remember { HashMap<Int, FocusRequester>() }
     var focusedIndex by remember { mutableStateOf(-1) }
 
+    // Drawer closed without a selection → give the row's last card focus back.
+    LaunchedEffect(drawerPulse) {
+        if (drawerPulse > 0 && focusedIndex >= 0) {
+            runCatching { focusRequesters[focusedIndex]?.requestFocus() }
+        }
+    }
+
     LaunchedEffect(focusedIndex) {
         if (focusedIndex > 0) {
             val visible = rowState.layoutInfo.visibleItemsInfo

app/src/main/java/net/jeena/jtubetv/ui/screens/HomeRows.kt

@@ -66,6 +66,20 @@ class HomeRowsViewModel(private val repository: PeerTubeRepository) : ViewModel(
         private set
     private var loaded = false
 
+    // On-demand paging of the home rows (issue #18). Rows grow by one page per
+    // trigger, nothing is re-fetched for pages the user never scrolls to, and
+    // memory stays bounded: rows are lazy Lists (off-screen cards decompose)
+    // and Coil's image cache is LRU.
+    private var continueStart = 0L
+    private var continueInFlight = false
+    var continueExhausted by mutableStateOf(false)
+        private set
+    private var subsStart = 0L
+    private var subsInFlight = false
+    var subsExhausted by mutableStateOf(false)
+        private set
+    private var subsLoading = false
+
     val recent = RecentVideosViewModel(repository)
 
     init {
@@ -91,8 +105,12 @@ class HomeRowsViewModel(private val repository: PeerTubeRepository) : ViewModel(
 
     private fun fetchSubs() {
         viewModelScope.launch {
-            val subs = repository.subscriptionVideos(0, 12).getOrNull()?.data ?: emptyList()
+            subsLoading = true
+            val subs = repository.subscriptionVideos(0, SUB_PAGE).getOrNull()?.data ?: emptyList()
+            subsStart = subs.size.toLong() // for subsMore() (issue #18)
+            subsExhausted = subs.size < SUB_PAGE
             subItems = subs
+            subsLoading = false
             net.jeena.jtubetv.ui.list.ImagePrefetcher.videoThumbnails(subs)
             // Snapshot for the next cold start (issue #9).
             contextOrNull()?.let { ctx ->
@@ -119,23 +137,26 @@ class HomeRowsViewModel(private val repository: PeerTubeRepository) : ViewModel(
      *  the rows and killed the focus-restore effect before it could run, #2). */
     fun refresh() {
         loaded = true
+        // fetchContinue kicks the subs fetch too — one pass, not two (the double
+        // call used to fetch subscriptions twice per refresh).
         fetchContinue()
-        fetchSubs()
         recent.refresh()
     }
 
-    private fun fetchContinue() {
+    /**
-        fetchSubs()
+     * One history page, enriched: each entry's resume info needs its own detail
-        viewModelScope.launch {
+     * call (parallel), so a page only fetches what it appends (issue #18).
-            continueLoading = true
+     * Advances [continueStart]; marks exhaustion on a short page.
-            val history = repository.history(0, 12).getOrNull()?.takeIf { it.isNotEmpty() }
+     */
-            if (history == null) {
+    private suspend fun fetchContinuePage(): List<ContinueItem> = kotlinx.coroutines.coroutineScope {
-                continueLoading = false
+        val entries = repository.history(continueStart, CONTINUE_PAGE).getOrNull()
-                return@launch
+        if (entries.isNullOrEmpty()) {
-            }
+            if (entries != null) continueExhausted = true
-            // Resume info needs one detail call with ?userHistory=true per entry;
+            emptyList()
-            // keep it small — only the first six videos.
+        } else {
-            val items = history.take(6).map { entry ->
+            continueStart += entries.size
+            if (entries.size < CONTINUE_PAGE) continueExhausted = true
+            entries.map { entry ->
                 async {
                     val detail = repository.video(entry.video.shortUUID, userHistory = true).getOrNull()
                     val watched = detail?.userHistory?.currentTime ?: 0
@@ -145,6 +166,44 @@ class HomeRowsViewModel(private val repository: PeerTubeRepository) : ViewModel(
                     ContinueItem(entry.video, progress)
                 }
             }.awaitAll()
+        }
+    }
+
+    /** Append the next page to an already-rendered row. */
+    fun continueMore() {
+        if (continueInFlight || continueExhausted || continueItems.isEmpty()) return
+        continueInFlight = true
+        viewModelScope.launch {
+            val page = fetchContinuePage()
+            if (page.isNotEmpty()) {
+                continueItems = continueItems + page
+                net.jeena.jtubetv.ui.list.ImagePrefetcher.videoThumbnails(page.map { it.video })
+            }
+            continueInFlight = false
+        }
+    }
+
+    /** Second+ subscription page (see continueMore). */
+    fun subsMore() {
+        if (subsInFlight || subsExhausted || subItems.isEmpty()) return
+        subsInFlight = true
+        viewModelScope.launch {
+            val page = repository.subscriptionVideos(subsStart, SUB_PAGE).getOrNull()?.data ?: emptyList()
+            subsStart += page.size
+            if (page.size < SUB_PAGE) subsExhausted = true
+            if (page.isNotEmpty()) {
+                subItems = subItems + page
+                net.jeena.jtubetv.ui.list.ImagePrefetcher.videoThumbnails(page)
+            }
+            subsInFlight = false
+        }
+    }
+
+    private fun fetchContinue() {
+        fetchSubs()
+        viewModelScope.launch {
+            continueLoading = true
+            val items = fetchContinuePage()
             continueItems = items
             continueLoading = false
             net.jeena.jtubetv.ui.list.ImagePrefetcher.videoThumbnails(items.map { it.video })
@@ -158,6 +217,10 @@ class HomeRowsViewModel(private val repository: PeerTubeRepository) : ViewModel(
     }
 
     companion object {
+        /** Page sizes for the on-demand row growing (continue page = 6 detail calls). */
+        private const val CONTINUE_PAGE = 6
+        private const val SUB_PAGE = 12
+
         val factory: ViewModelProvider.Factory = object : ViewModelProvider.Factory {
             @Suppress("UNCHECKED_CAST")
             override fun <T : ViewModel> create(modelClass: Class<T>): T =
@@ -217,10 +280,12 @@ fun HomeRowsScreen(
     restoreToken: Int = 0,
     epoch: Int = 0,
     onOpenDrawer: () -> Unit = {},
+    drawerPulse: Int = 0,
     viewModel: HomeRowsViewModel = viewModel(key = "home$epoch", factory = HomeRowsViewModel.factory),
 ) {
     val continueRestore = androidx.compose.runtime.remember { androidx.compose.runtime.mutableIntStateOf(-1) }
     val recentRestore = androidx.compose.runtime.remember { androidx.compose.runtime.mutableIntStateOf(-1) }
+    val subRestore = androidx.compose.runtime.remember { androidx.compose.runtime.mutableIntStateOf(-1) }
     // Any D-pad press before the (slow) continue row resolves means the user is already
     // navigating: suppress the then-pending auto-focus of the first row (#3).
     var userNavigated by remember { mutableStateOf(false) }
@@ -265,7 +330,13 @@ fun HomeRowsScreen(
                     restoreToken = restoreToken,
                     autoFocusOnLoad = true,
                     autoFocusAllowed = { !userNavigated },
-                )
+                    refocusPulse = drawerPulse,
+                ) { index, video ->
+                    // Grow the row on demand (issue #18), same hook as the recent row.
+                    if (index >= viewModel.continueItems.size - PagedListViewModel.LOOKAHEAD) {
+                        LaunchedEffect(index) { viewModel.continueMore() }
+                    }
+                }
             }
         }
         item {
@@ -294,6 +365,7 @@ fun HomeRowsScreen(
                     onLeftAtStart = onOpenDrawer,
                     clickedIndex = recentRestore,
                     restoreToken = restoreToken,
+                    refocusPulse = drawerPulse,
                 ) { index, video ->
                     if (index >= recentItems.size - PagedListViewModel.LOOKAHEAD) {
                         LaunchedEffect(index) { viewModel.recent.loadMore() }
@@ -316,7 +388,14 @@ fun HomeRowsScreen(
                     progressOf = { null },
                     onOpenVideo = onOpenVideo,
                     onLeftAtStart = onOpenDrawer,
-                )
+                    clickedIndex = subRestore,
+                    restoreToken = restoreToken,
+                    refocusPulse = drawerPulse,
+                ) { index, video ->
+                    if (index >= viewModel.subItems.size - PagedListViewModel.LOOKAHEAD) {
+                        LaunchedEffect(index) { viewModel.subsMore() }
+                    }
+                }
             }
         }
     }
@@ -339,11 +418,21 @@ fun FocusScrollRow(
     autoFocusOnLoad: Boolean = false,
     // Screen-level gate: false while the user is already navigating.
     autoFocusAllowed: () -> Boolean = { true },
+    // Incremented by the home drawer closing without a selection: re-focus the
+    // row's last-focused card, otherwise the D-pad is orphaned (issue #16 bug).
+    // NOTE: stays before [afterItem] — the trailing lambda binds to the last
+    // declared parameter.
+    refocusPulse: Int = 0,
     afterItem: @Composable (index: Int, video: VideoDto) -> Unit = { _, _ -> },
 ) {
     val rowState = rememberLazyListState()
     val focusRequesters = remember { HashMap<Int, FocusRequester>() }
     var focusedIndex by remember { androidx.compose.runtime.mutableStateOf(-1) }
+    LaunchedEffect(refocusPulse) {
+        if (refocusPulse > 0 && focusedIndex >= 0) {
+            runCatching { focusRequesters[focusedIndex]?.requestFocus() }
+        }
+    }
     // BACK from playback: scroll to + focus the card that was opened (user request).
     LaunchedEffect(restoreToken) {
         if (restoreToken > 0) {

app/src/main/java/net/jeena/jtubetv/ui/screens/HomeScreen.kt

@@ -95,7 +95,10 @@ fun HomeScreen(viewModel: AppViewModel = androidx.lifecycle.viewmodel.compose.vi
     var lastBackAt by rememberSaveable { mutableStateOf(0L) }
 
     /** Close the drawer; focus falls back into the content pane. */
-    val dismissDrawer = { drawerOpen = false }
+    // Closing the drawer without a selection removes the drawer's focused item
+    // and orphans the D-pad; the pulse re-focuses the screen's last card (#16).
+    var drawerPulse by rememberSaveable { mutableStateOf(0) }
+    val dismissDrawer = { drawerOpen = false; drawerPulse++ }
 
     // After BACK from the player: bump the restore token so lists re-focus the opened
     // card and re-fetch positions (UX report BUG-3 + BUG-7).
@@ -174,6 +177,7 @@ fun HomeScreen(viewModel: AppViewModel = androidx.lifecycle.viewmodel.compose.vi
                             restoreToken = restoreToken,
                             epoch = epoch,
                             onOpenDrawer = { drawerOpen = true },
+                            drawerPulse = drawerPulse,
                         )
                     else -> when (destination) {
                     Destination.Home ->
@@ -182,6 +186,7 @@ fun HomeScreen(viewModel: AppViewModel = androidx.lifecycle.viewmodel.compose.vi
                             restoreToken = restoreToken,
                             epoch = epoch,
                             onOpenDrawer = { drawerOpen = true },
+                            drawerPulse = drawerPulse,
                             // UP over the first row opens the drawer.
                         )
                     Destination.MyVideos ->
@@ -191,11 +196,13 @@ fun HomeScreen(viewModel: AppViewModel = androidx.lifecycle.viewmodel.compose.vi
                             restoreToken = restoreToken,
                             epoch = epoch,
                             onOpenDrawer = { drawerOpen = true },
+                            drawerPulse = drawerPulse,
                         )
                     Destination.Channels -> ChannelsScreen(
                         onOpenChannel = { handle -> channelDetails = handle },
                         epoch = epoch,
                         onOpenDrawer = { drawerOpen = true },
+                        drawerPulse = drawerPulse,
                     )
                     Destination.Search ->
                         VideoListScreen(
@@ -204,6 +211,7 @@ fun HomeScreen(viewModel: AppViewModel = androidx.lifecycle.viewmodel.compose.vi
                             restoreToken = restoreToken,
                             epoch = epoch,
                             onOpenDrawer = { drawerOpen = true },
+                            drawerPulse = drawerPulse,
                         )
                     Destination.Subscriptions ->
                         VideoListScreen(
@@ -212,6 +220,7 @@ fun HomeScreen(viewModel: AppViewModel = androidx.lifecycle.viewmodel.compose.vi
                             restoreToken = restoreToken,
                             epoch = epoch,
                             onOpenDrawer = { drawerOpen = true },
+                            drawerPulse = drawerPulse,
                         )
                     Destination.History ->
                         VideoListScreen(
@@ -220,6 +229,7 @@ fun HomeScreen(viewModel: AppViewModel = androidx.lifecycle.viewmodel.compose.vi
                             restoreToken = restoreToken,
                             epoch = epoch,
                             onOpenDrawer = { drawerOpen = true },
+                            drawerPulse = drawerPulse,
                         )
                     }
                 }

app/src/main/java/net/jeena/jtubetv/ui/screens/list/VideoListScreen.kt

@@ -56,6 +56,7 @@ fun VideoListScreen(
     restoreToken: Int = 0,
     epoch: Int = 0,
     onOpenDrawer: () -> Unit = {},
+    drawerPulse: Int = 0,
     viewModel: VideoListViewModel = viewModel(
         key = "v$epoch:" + sourceKey(source),
         factory = VideoListViewModel.factory(source),
@@ -107,6 +108,14 @@ fun VideoListScreen(
                 (rowCardWidth().value - 12)
             ).toInt(),
     )
+    // Last focused card for the drawer-close refocus (issue #16 bug): closing
+    // the drawer without a selection orphans the D-pad — re-focus the card.
+    var lastFocusedIndex by remember { mutableStateOf(-1) }
+    LaunchedEffect(drawerPulse) {
+        if (drawerPulse > 0 && lastFocusedIndex >= 0) {
+            runCatching { requesters[lastFocusedIndex]?.requestFocus() }
+        }
+    }
 
     if (viewModel.loadingInitial && items.isEmpty()) {
         Box(Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
@@ -176,6 +185,7 @@ fun VideoListScreen(
                 showPrivacy = source is ListSource.MyVideos,
                 compact = true,
                 onLeftAtStart = if (index % cardsPerRow == 0) onOpenDrawer else null,
+                onFocused = { lastFocusedIndex = index },
                 modifier = Modifier
                     .focusRequester(fr),
             )