Fix PagingSource for comments

The previous implementation was skipping the first page of comments

Author: Stypox

app/src/main/java/org/schabi/newpipe/paging/CommentRepliesSource.kt

@@ -0,0 +1,27 @@
+package org.schabi.newpipe.paging
+
+import androidx.paging.PagingSource
+import androidx.paging.PagingState
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+import org.schabi.newpipe.extractor.NewPipe
+import org.schabi.newpipe.extractor.Page
+import org.schabi.newpipe.extractor.comments.CommentsInfo
+import org.schabi.newpipe.extractor.comments.CommentsInfoItem
+
+class CommentRepliesSource(
+    private val commentInfo: CommentsInfoItem,
+) : PagingSource<Page, CommentsInfoItem>() {
+    private val service = NewPipe.getService(commentInfo.serviceId)
+
+    override suspend fun load(params: LoadParams<Page>): LoadResult<Page, CommentsInfoItem> {
+        // params.key is null the first time load() is called, and we need to return the first page
+        val repliesPage = params.key ?: commentInfo.replies
+        val info = withContext(Dispatchers.IO) {
+            CommentsInfo.getMoreItems(service, commentInfo.url, repliesPage)
+        }
+        return LoadResult.Page(info.items, null, info.nextPage)
+    }
+
+    override fun getRefreshKey(state: PagingState<Page, CommentsInfoItem>) = null
+}

app/src/main/java/org/schabi/newpipe/paging/CommentsSource.kt

@@ -9,35 +9,20 @@ import org.schabi.newpipe.extractor.Page
 import org.schabi.newpipe.extractor.comments.CommentsInfo
 import org.schabi.newpipe.extractor.comments.CommentsInfoItem
 import org.schabi.newpipe.ui.components.video.comment.CommentInfo
-import org.schabi.newpipe.util.NO_SERVICE_ID
 
-class CommentsSource(
-    serviceId: Int,
-    private val url: String,
-    private val repliesPage: Page?,
-    private val commentInfo: CommentInfo? = null,
-) : PagingSource<Page, CommentsInfoItem>() {
-    constructor(commentInfo: CommentInfo) : this(
-        commentInfo.serviceId, commentInfo.url, commentInfo.nextPage, commentInfo
-    )
-
-    init {
-        require(serviceId != NO_SERVICE_ID) { "serviceId is NO_SERVICE_ID" }
-    }
-    private val service = NewPipe.getService(serviceId)
+class CommentsSource(private val commentInfo: CommentInfo) : PagingSource<Page, CommentsInfoItem>() {
+    private val service = NewPipe.getService(commentInfo.serviceId)
 
     override suspend fun load(params: LoadParams<Page>): LoadResult<Page, CommentsInfoItem> {
-        // repliesPage is non-null only when used to load the comment replies
-        val nextKey = params.key ?: repliesPage
-
-        return withContext(Dispatchers.IO) {
-            nextKey?.let {
-                val info = CommentsInfo.getMoreItems(service, url, it)
-                LoadResult.Page(info.items, null, info.nextPage)
-            } ?: run {
-                val info = commentInfo ?: CommentInfo(CommentsInfo.getInfo(service, url))
-                LoadResult.Page(info.comments, null, info.nextPage)
+        // params.key is null the first time the load() function is called, so we need to return the
+        // first batch of already-loaded comments
+        if (params.key == null) {
+            return LoadResult.Page(commentInfo.comments, null, commentInfo.nextPage)
+        } else {
+            val info = withContext(Dispatchers.IO) {
+                CommentsInfo.getMoreItems(service, commentInfo.url, params.key)
             }
+            return LoadResult.Page(info.items, null, info.nextPage)
         }
     }
 

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

@@ -32,7 +32,7 @@ import my.nanihadesuka.compose.ScrollbarSettings
 import org.schabi.newpipe.R
 import org.schabi.newpipe.extractor.comments.CommentsInfoItem
 import org.schabi.newpipe.extractor.stream.Description
-import org.schabi.newpipe.paging.CommentsSource
+import org.schabi.newpipe.paging.CommentRepliesSource
 import org.schabi.newpipe.ui.components.common.LoadingIndicator
 import org.schabi.newpipe.ui.components.common.NoItemsMessage
 import org.schabi.newpipe.ui.theme.AppTheme
@@ -46,8 +46,9 @@ fun CommentRepliesDialog(
     val coroutineScope = rememberCoroutineScope()
     val commentsFlow = remember {
         Pager(PagingConfig(pageSize = 20, enablePlaceholders = false)) {
-            CommentsSource(parentComment.serviceId, parentComment.url, parentComment.replies)
-        }.flow
+            CommentRepliesSource(parentComment)
+        }
+            .flow
             .cachedIn(coroutineScope)
     }