Implement live chat polling in CommentsViewModel

Author: Ecomont

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

@@ -1,44 +1,97 @@
 package org.schabi.newpipe.viewmodels
 
+import android.util.Log
 import androidx.lifecycle.SavedStateHandle
 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.delay
+import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.filterIsInstance
 import kotlinx.coroutines.flow.flatMapLatest
+import kotlinx.coroutines.flow.flow
 import kotlinx.coroutines.flow.flowOn
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.stateIn
+import org.schabi.newpipe.extractor.NewPipe
 import org.schabi.newpipe.extractor.comments.CommentsInfo
+import org.schabi.newpipe.extractor.comments.CommentsInfoItem
 import org.schabi.newpipe.paging.CommentsSource
 import org.schabi.newpipe.ui.components.video.comment.CommentInfo
 import org.schabi.newpipe.util.KEY_URL
 import org.schabi.newpipe.viewmodels.util.Resource
 
 class CommentsViewModel(savedStateHandle: SavedStateHandle) : ViewModel() {
+    companion object {
+        private const val TAG = "CommentsViewModel"
+    }
+
     val uiState = savedStateHandle.getStateFlow(KEY_URL, "")
         .map {
             try {
-                Resource.Success(CommentInfo(CommentsInfo.getInfo(it)))
+                val info = CommentsInfo.getInfo(it)
+                Log.i(
+                    TAG,
+                    "Loaded CommentsInfo: disabled=${info.isCommentsDisabled}, " +
+                        "liveChat=${info.isLiveChat}, items=${info.relatedItems.size}, " +
+                        "nextPage=${info.nextPage != null}"
+                )
+                Resource.Success(CommentInfo(info))
             } catch (e: Exception) {
+                Log.e(TAG, "Failed to load comments", e)
                 Resource.Error(e)
             }
         }
         .flowOn(Dispatchers.IO)
         .stateIn(viewModelScope, SharingStarted.WhileSubscribed(), Resource.Loading)
 
+    // Live chat via PagingData (broken approach)
     @OptIn(ExperimentalCoroutinesApi::class)
-    val comments = uiState
+    val comments: Flow<PagingData<CommentsInfoItem>> = uiState
         .filterIsInstance<Resource.Success<CommentInfo>>()
         .flatMapLatest {
-            Pager(PagingConfig(pageSize = 20, enablePlaceholders = false)) {
-                CommentsSource(it.data)
-            }.flow
+            val info = it.data
+            Log.i(TAG, "flatMapLatest: isLiveChat=${info.isLiveChat}, items=${info.comments.size}")
+            if (info.isLiveChat) {
+                liveChatPagingData(info)
+            } else {
+                Pager(PagingConfig(pageSize = 20, enablePlaceholders = false)) {
+                    CommentsSource(info)
+                }.flow
+            }
         }
         .cachedIn(viewModelScope)
+
+    private fun liveChatPagingData(info: CommentInfo): Flow<PagingData<CommentsInfoItem>> = flow {
+        val allItems = info.comments.toMutableList()
+        emit(PagingData.from(allItems))
+        var nextPage = info.nextPage
+        while (true) {
+            delay(3000)
+            if (nextPage == null) {
+                Log.d(TAG, "liveChatPolling: nextPage is null, skipping")
+                continue
+            }
+            try {
+                Log.d(TAG, "liveChatPolling: fetching more items...")
+                val result = CommentsInfo.getMoreItems(
+                    NewPipe.getService(info.serviceId),
+                    info.url,
+                    nextPage
+                )
+                Log.i(TAG, "liveChatPolling: fetched ${result.items.size} items")
+                allItems.addAll(result.items)
+                emit(PagingData.from(allItems))
+                nextPage = result.nextPage
+            } catch (e: Exception) {
+                Log.e(TAG, "liveChatPolling: failed to fetch more items", e)
+            }
+        }
+    }
 }