Add YouTube live chat fallback when comments are disabled

app/src/main/java/org/schabi/newpipe/fragments/detail/TabAdapter.java

@@ -40,6 +40,11 @@ public void addFragment(final Fragment fragment, final String title) {
         mFragmentTitleList.add(title);
     }
 
+    public void addFragment(final Fragment fragment, final String title, final int position) {
+        mFragmentList.add(position, fragment);
+        mFragmentTitleList.add(position, title);
+    }
+
     public void clearAllItems() {
         mFragmentList.clear();
         mFragmentTitleList.clear();

app/src/main/java/org/schabi/newpipe/fragments/detail/VideoDetailFragment.kt

@@ -85,6 +85,7 @@ import org.schabi.newpipe.fragments.BaseStateFragment
 import org.schabi.newpipe.fragments.EmptyFragment
 import org.schabi.newpipe.fragments.MainFragment
 import org.schabi.newpipe.fragments.list.comments.CommentsFragment.Companion.getInstance
+import org.schabi.newpipe.fragments.list.comments.LiveChatFragment
 import org.schabi.newpipe.fragments.list.videos.RelatedItemsFragment.Companion.getInstance
 import org.schabi.newpipe.ktx.AnimationType
 import org.schabi.newpipe.ktx.animate
@@ -323,7 +324,10 @@ class VideoDetailFragment :
         if (tabSettingsChanged) {
             tabSettingsChanged = false
             initTabs()
-            currentInfo?.let { updateTabs(it) }
+            currentInfo?.let {
+                updateTabs(it)
+                addLiveChatTabIfNeeded(it)
+            }
         }
 
         // Check if it was loading when the fragment was stopped/paused
@@ -912,6 +916,31 @@ class VideoDetailFragment :
         }
     }
 
+    private fun addLiveChatTabIfNeeded(streamInfo: StreamInfo) {
+        if (!streamInfo.hasLiveChat()) {
+            return
+        }
+        val continuation = streamInfo.liveChatContinuation ?: return
+        if (continuation.isEmpty()) {
+            return
+        }
+        if (pageAdapter.getItemPositionByTitle(LIVE_CHAT_TAB_TAG) != -1) {
+            return
+        }
+
+        // Append live chat tab at the end to avoid FragmentPagerAdapter
+        // position synchronization issues when inserting in the middle
+        pageAdapter.addFragment(
+            LiveChatFragment.getInstance(serviceId, url, continuation),
+            LIVE_CHAT_TAB_TAG
+        )
+        tabIcons.add(R.drawable.ic_live_tv)
+        tabContentDescriptions.add(R.string.live_chat_tab_description)
+        pageAdapter.notifyDataSetUpdate()
+        updateTabIconsAndContentDescriptions()
+        updateTabLayoutVisibility()
+    }
+
     fun updateTabLayoutVisibility() {
         if (nullableBinding == null) {
             // If binding is null we do not need to and should not do anything with its object(s)
@@ -1418,6 +1447,7 @@ class VideoDetailFragment :
         setInitialData(info.serviceId, info.originalUrl, info.name, playQueue)
 
         updateTabs(info)
+        addLiveChatTabIfNeeded(info)
 
         binding.detailThumbnailPlayButton.animate(true, 200)
         binding.detailVideoTitleView.text = title
@@ -2342,6 +2372,7 @@ class VideoDetailFragment :
             App.PACKAGE_NAME + ".VideoDetailFragment.ACTION_VIDEO_FRAGMENT_STOPPED"
 
         private const val COMMENTS_TAB_TAG = "COMMENTS"
+        private const val LIVE_CHAT_TAB_TAG = "LIVE_CHAT"
         private const val RELATED_TAB_TAG = "NEXT VIDEO"
         private const val DESCRIPTION_TAB_TAG = "DESCRIPTION TAB"
         private const val EMPTY_TAB_TAG = "EMPTY TAB"

app/src/main/java/org/schabi/newpipe/fragments/list/comments/LiveChatFragment.kt

@@ -0,0 +1,39 @@
+package org.schabi.newpipe.fragments.list.comments
+
+import android.os.Bundle
+import android.view.LayoutInflater
+import android.view.ViewGroup
+import androidx.compose.material3.Surface
+import androidx.core.os.bundleOf
+import androidx.fragment.app.Fragment
+import androidx.fragment.compose.content
+import org.schabi.newpipe.ui.components.video.comment.LiveChatSection
+import org.schabi.newpipe.ui.theme.AppTheme
+import org.schabi.newpipe.util.KEY_SERVICE_ID
+import org.schabi.newpipe.util.KEY_URL
+import org.schabi.newpipe.viewmodels.LiveChatViewModel
+
+class LiveChatFragment : Fragment() {
+    override fun onCreateView(
+        inflater: LayoutInflater,
+        container: ViewGroup?,
+        savedInstanceState: Bundle?
+    ) = content {
+        AppTheme {
+            Surface {
+                LiveChatSection()
+            }
+        }
+    }
+
+    companion object {
+        @JvmStatic
+        fun getInstance(serviceId: Int, url: String?, liveChatContinuation: String) = LiveChatFragment().apply {
+            arguments = bundleOf(
+                KEY_SERVICE_ID to serviceId,
+                KEY_URL to url,
+                LiveChatViewModel.KEY_LIVE_CHAT_CONTINUATION to liveChatContinuation
+            )
+        }
+    }
+}

app/src/main/java/org/schabi/newpipe/ui/components/video/comment/CommentInfo.kt

@@ -3,13 +3,12 @@ package org.schabi.newpipe.ui.components.video.comment
 import androidx.compose.runtime.Immutable
 import org.schabi.newpipe.extractor.Page
 import org.schabi.newpipe.extractor.comments.CommentsInfo
-import org.schabi.newpipe.extractor.comments.CommentsInfoItem
 
 @Immutable
 class CommentInfo(
     val serviceId: Int,
     val url: String,
-    val comments: List<CommentsInfoItem>,
+    val comments: List<org.schabi.newpipe.extractor.comments.CommentsInfoItem>,
     val nextPage: Page?,
     val commentCount: Int,
     val isCommentsDisabled: Boolean

app/src/main/java/org/schabi/newpipe/ui/components/video/comment/CommentSection.kt

@@ -30,7 +30,6 @@ import kotlinx.coroutines.flow.flowOf
 import org.schabi.newpipe.R
 import org.schabi.newpipe.error.ErrorInfo
 import org.schabi.newpipe.error.UserAction
-import org.schabi.newpipe.extractor.Page
 import org.schabi.newpipe.extractor.comments.CommentsInfoItem
 import org.schabi.newpipe.extractor.stream.Description
 import org.schabi.newpipe.ui.components.common.ErrorPanel
@@ -82,7 +81,6 @@ private fun CommentSection(
                                 modifier = Modifier
                                     .fillMaxWidth()
                                     .heightIn(min = 128.dp)
-
                             )
                         }
                     } else if (count == 0) {
@@ -95,7 +93,6 @@ private fun CommentSection(
                             )
                         }
                     } else {
-                        // do not show anything if the comment count is unknown
                         if (count >= 0) {
                             item {
                                 Text(
@@ -107,6 +104,7 @@ private fun CommentSection(
                                 )
                             }
                         }
+
                         when (val refresh = comments.loadState.refresh) {
                             is LoadState.Loading -> {
                                 item {
@@ -136,8 +134,19 @@ private fun CommentSection(
                             }
 
                             else -> {
-                                items(comments.itemCount) {
-                                    Comment(comment = comments[it]!!) {}
+                                if (comments.itemCount == 0) {
+                                    item {
+                                        EmptyStateComposable(
+                                            spec = EmptyStateSpec.NoComments,
+                                            modifier = Modifier
+                                                .fillMaxWidth()
+                                                .heightIn(min = 128.dp)
+                                        )
+                                    }
+                                } else {
+                                    items(comments.itemCount) {
+                                        Comment(comment = comments[it]!!) {}
+                                    }
                                 }
                             }
                         }
@@ -191,7 +200,7 @@ private fun CommentSectionSuccessPreview() {
                 Description.PLAIN_TEXT
             ),
             uploaderName = "Test",
-            replies = Page(""),
+            replies = org.schabi.newpipe.extractor.Page(""),
             replyCount = 10
         )
     ) + (2..10).map {

app/src/main/java/org/schabi/newpipe/ui/components/video/comment/LiveChatSection.kt

@@ -0,0 +1,129 @@
+package org.schabi.newpipe.ui.components.video.comment
+
+import androidx.compose.animation.AnimatedVisibility
+import androidx.compose.animation.fadeIn
+import androidx.compose.animation.fadeOut
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.heightIn
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.rememberLazyListState
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.KeyboardArrowUp
+import androidx.compose.material3.Badge
+import androidx.compose.material3.BadgedBox
+import androidx.compose.material3.FloatingActionButton
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.derivedStateOf
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.input.nestedscroll.nestedScroll
+import androidx.compose.ui.platform.rememberNestedScrollInteropConnection
+import androidx.compose.ui.unit.dp
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import androidx.lifecycle.viewmodel.compose.viewModel
+import kotlinx.coroutines.launch
+import org.schabi.newpipe.ui.components.common.LazyColumnThemedScrollbar
+import org.schabi.newpipe.ui.components.common.LoadingIndicator
+import org.schabi.newpipe.viewmodels.LiveChatViewModel
+
+@Composable
+fun LiveChatSection(liveChatViewModel: LiveChatViewModel = viewModel()) {
+    val liveChatItems by liveChatViewModel.liveChatItems.collectAsStateWithLifecycle()
+    val state = rememberLazyListState()
+    val nestedScrollInterop = rememberNestedScrollInteropConnection()
+    val coroutineScope = rememberCoroutineScope()
+
+    // Track whether user is at the top of the list
+    val isAtTop by remember { derivedStateOf { state.firstVisibleItemIndex == 0 } }
+
+    // Track how many messages were seen while at the top
+    val lastSeenCount = remember { mutableStateOf(0) }
+    if (isAtTop && liveChatItems.isNotEmpty()) {
+        lastSeenCount.value = liveChatItems.size
+    }
+
+    val unreadCount = liveChatItems.size - lastSeenCount.value
+
+    Box(modifier = Modifier.fillMaxSize()) {
+        LazyColumnThemedScrollbar(state = state) {
+            LazyColumn(
+                modifier = Modifier
+                    .fillMaxSize()
+                    .nestedScroll(nestedScrollInterop),
+                state = state
+            ) {
+                item {
+                    Text(
+                        modifier = Modifier.padding(start = 12.dp, end = 12.dp, bottom = 4.dp),
+                        text = "Live Chat",
+                        style = MaterialTheme.typography.titleMedium
+                    )
+                }
+
+                if (liveChatItems.isEmpty()) {
+                    item {
+                        Box(
+                            modifier = Modifier
+                                .fillMaxWidth()
+                                .heightIn(min = 128.dp),
+                            contentAlignment = Alignment.Center
+                        ) {
+                            LoadingIndicator()
+                        }
+                    }
+                } else {
+                    items(liveChatItems.size, key = { liveChatItems[it].commentId }) {
+                        Comment(comment = liveChatItems[it]) {}
+                    }
+                }
+            }
+        }
+
+        // Floating button to jump to newest messages
+        AnimatedVisibility(
+            visible = !isAtTop && unreadCount > 0,
+            modifier = Modifier
+                .align(Alignment.BottomEnd)
+                .padding(16.dp),
+            enter = fadeIn(),
+            exit = fadeOut()
+        ) {
+            FloatingActionButton(
+                onClick = {
+                    coroutineScope.launch {
+                        state.scrollToItem(0)
+                    }
+                }
+            ) {
+                BadgedBox(
+                    badge = {
+                        Badge(
+                            containerColor = MaterialTheme.colorScheme.error,
+                            contentColor = MaterialTheme.colorScheme.onError
+                        ) {
+                            Text(
+                                text = unreadCount.toString(),
+                                style = MaterialTheme.typography.labelSmall
+                            )
+                        }
+                    }
+                ) {
+                    Icon(
+                        imageVector = Icons.Default.KeyboardArrowUp,
+                        contentDescription = "Scroll to new messages"
+                    )
+                }
+            }
+        }
+    }
+}

app/src/main/java/org/schabi/newpipe/util/InfoCache.java

@@ -56,7 +56,7 @@ public enum Type {
         CHANNEL_TAB,
         COMMENTS,
         PLAYLIST,
-        KIOSK,
+        KIOSK
     }
 
     public static InfoCache getInstance() {

app/src/main/java/org/schabi/newpipe/viewmodels/CommentsViewModel.kt

@@ -5,9 +5,11 @@ import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import androidx.paging.Pager
 import androidx.paging.PagingConfig
+import androidx.paging.PagingData
 import androidx.paging.cachedIn
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.filterIsInstance
 import kotlinx.coroutines.flow.flatMapLatest
@@ -24,7 +26,8 @@ class CommentsViewModel(savedStateHandle: SavedStateHandle) : ViewModel() {
     val uiState = savedStateHandle.getStateFlow(KEY_URL, "")
         .map {
             try {
-                Resource.Success(CommentInfo(CommentsInfo.getInfo(it)))
+                val info = CommentsInfo.getInfo(it)
+                Resource.Success(CommentInfo(info))
             } catch (e: Exception) {
                 Resource.Error(e)
             }
@@ -33,7 +36,7 @@ class CommentsViewModel(savedStateHandle: SavedStateHandle) : ViewModel() {
         .stateIn(viewModelScope, SharingStarted.WhileSubscribed(), Resource.Loading)
 
     @OptIn(ExperimentalCoroutinesApi::class)
-    val comments = uiState
+    val comments: Flow<PagingData<org.schabi.newpipe.extractor.comments.CommentsInfoItem>> = uiState
         .filterIsInstance<Resource.Success<CommentInfo>>()
         .flatMapLatest {
             Pager(PagingConfig(pageSize = 20, enablePlaceholders = false)) {