Handle no comments and comments disabled scenarios

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

@@ -882,8 +882,7 @@ public final class VideoDetailFragment
         tabContentDescriptions.clear();
 
         if (shouldShowComments()) {
-            pageAdapter.addFragment(
-                    CommentsFragment.getInstance(serviceId, url), COMMENTS_TAB_TAG);
+            pageAdapter.addFragment(CommentsFragment.getInstance(serviceId, url), COMMENTS_TAB_TAG);
             tabIcons.add(R.drawable.ic_comment);
             tabContentDescriptions.add(R.string.comments_tab_description);
         }

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

@@ -69,85 +69,83 @@ fun Comment(comment: CommentsInfoItem) {
     var isExpanded by rememberSaveable { mutableStateOf(false) }
     var showReplies by rememberSaveable { mutableStateOf(false) }
 
-    Surface(color = MaterialTheme.colorScheme.background) {
-        Row(
-            modifier = Modifier
-                .fillMaxWidth()
-                .clickable { isExpanded = !isExpanded }
-                .padding(all = 8.dp),
-            horizontalArrangement = Arrangement.spacedBy(8.dp)
-        ) {
-            if (ImageStrategy.shouldLoadImages()) {
-                AsyncImage(
-                    model = ImageStrategy.choosePreferredImage(comment.uploaderAvatars),
-                    contentDescription = null,
-                    placeholder = painterResource(R.drawable.placeholder_person),
-                    error = painterResource(R.drawable.placeholder_person),
-                    modifier = Modifier
-                        .size(42.dp)
-                        .clip(CircleShape)
-                        .clickable {
-                            NavigationHelper.openCommentAuthorIfPresent(
-                                context as FragmentActivity, comment
-                            )
-                        }
-                )
-            }
-
-            Column(verticalArrangement = Arrangement.spacedBy(4.dp)) {
-                Row(horizontalArrangement = Arrangement.spacedBy(4.dp)) {
-                    if (comment.isPinned) {
-                        Image(
-                            painter = painterResource(R.drawable.ic_pin),
-                            contentDescription = stringResource(R.string.detail_pinned_comment_view_description)
+    Row(
+        modifier = Modifier
+            .fillMaxWidth()
+            .clickable { isExpanded = !isExpanded }
+            .padding(all = 8.dp),
+        horizontalArrangement = Arrangement.spacedBy(8.dp)
+    ) {
+        if (ImageStrategy.shouldLoadImages()) {
+            AsyncImage(
+                model = ImageStrategy.choosePreferredImage(comment.uploaderAvatars),
+                contentDescription = null,
+                placeholder = painterResource(R.drawable.placeholder_person),
+                error = painterResource(R.drawable.placeholder_person),
+                modifier = Modifier
+                    .size(42.dp)
+                    .clip(CircleShape)
+                    .clickable {
+                        NavigationHelper.openCommentAuthorIfPresent(
+                            context as FragmentActivity, comment
                         )
                     }
+            )
+        }
 
-                    val nameAndDate = remember(comment) {
-                        val date = Localization.relativeTimeOrTextual(
-                            context, comment.uploadDate, comment.textualUploadDate
-                        )
-                        Localization.concatenateStrings(comment.uploaderName, date)
-                    }
-                    Text(text = nameAndDate, color = MaterialTheme.colorScheme.secondary)
+        Column(verticalArrangement = Arrangement.spacedBy(4.dp)) {
+            Row(horizontalArrangement = Arrangement.spacedBy(4.dp)) {
+                if (comment.isPinned) {
+                    Image(
+                        painter = painterResource(R.drawable.ic_pin),
+                        contentDescription = stringResource(R.string.detail_pinned_comment_view_description)
+                    )
                 }
 
-                Text(
-                    text = rememberParsedText(comment.commentText),
-                    // If the comment is expanded, we display all its content
-                    // otherwise we only display the first two lines
-                    maxLines = if (isExpanded) Int.MAX_VALUE else 2,
-                    overflow = TextOverflow.Ellipsis,
-                    style = MaterialTheme.typography.bodyMedium,
-                )
+                val nameAndDate = remember(comment) {
+                    val date = Localization.relativeTimeOrTextual(
+                        context, comment.uploadDate, comment.textualUploadDate
+                    )
+                    Localization.concatenateStrings(comment.uploaderName, date)
+                }
+                Text(text = nameAndDate, color = MaterialTheme.colorScheme.secondary)
+            }
 
-                Row(
-                    modifier = Modifier.fillMaxWidth(),
-                    horizontalArrangement = Arrangement.SpaceBetween,
-                    verticalAlignment = Alignment.CenterVertically
-                ) {
-                    Row(horizontalArrangement = Arrangement.spacedBy(8.dp)) {
+            Text(
+                text = rememberParsedText(comment.commentText),
+                // If the comment is expanded, we display all its content
+                // otherwise we only display the first two lines
+                maxLines = if (isExpanded) Int.MAX_VALUE else 2,
+                overflow = TextOverflow.Ellipsis,
+                style = MaterialTheme.typography.bodyMedium,
+            )
+
+            Row(
+                modifier = Modifier.fillMaxWidth(),
+                horizontalArrangement = Arrangement.SpaceBetween,
+                verticalAlignment = Alignment.CenterVertically
+            ) {
+                Row(horizontalArrangement = Arrangement.spacedBy(8.dp)) {
+                    Image(
+                        painter = painterResource(R.drawable.ic_thumb_up),
+                        contentDescription = stringResource(R.string.detail_likes_img_view_description)
+                    )
+                    Text(text = Localization.likeCount(context, comment.likeCount))
+
+                    if (comment.isHeartedByUploader) {
                         Image(
-                            painter = painterResource(R.drawable.ic_thumb_up),
-                            contentDescription = stringResource(R.string.detail_likes_img_view_description)
+                            painter = painterResource(R.drawable.ic_heart),
+                            contentDescription = stringResource(R.string.detail_heart_img_view_description)
                         )
-                        Text(text = Localization.likeCount(context, comment.likeCount))
-
-                        if (comment.isHeartedByUploader) {
-                            Image(
-                                painter = painterResource(R.drawable.ic_heart),
-                                contentDescription = stringResource(R.string.detail_heart_img_view_description)
-                            )
-                        }
                     }
+                }
 
-                    if (comment.replies != null) {
-                        TextButton(onClick = { showReplies = true }) {
-                            val text = pluralStringResource(
-                                R.plurals.replies, comment.replyCount, comment.replyCount.toString()
-                            )
-                            Text(text = text)
-                        }
+                if (comment.replies != null) {
+                    TextButton(onClick = { showReplies = true }) {
+                        val text = pluralStringResource(
+                            R.plurals.replies, comment.replyCount, comment.replyCount.toString()
+                        )
+                        Text(text = text)
                     }
                 }
             }
@@ -190,7 +188,7 @@ fun CommentsInfoItem(
     this.replyCount = replyCount
 }
 
-class DescriptionPreviewProvider : PreviewParameterProvider<Description> {
+private class DescriptionPreviewProvider : PreviewParameterProvider<Description> {
     override val values = sequenceOf(
         Description("Hello world!<br><br>This line should be hidden by default.", Description.HTML),
         Description("Hello world!\n\nThis line should be hidden by default.", Description.PLAIN_TEXT),
@@ -214,6 +212,8 @@ private fun CommentPreview(
     )
 
     AppTheme {
-        Comment(comment)
+        Surface(color = MaterialTheme.colorScheme.background) {
+            Comment(comment)
+        }
     }
 }

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

@@ -1,18 +1,33 @@
 package org.schabi.newpipe.fragments.list.comments
 
 import android.content.res.Configuration
+import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.rememberLazyListState
 import androidx.compose.material3.HorizontalDivider
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.derivedStateOf
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.tooling.preview.Preview
+import androidx.compose.ui.tooling.preview.PreviewParameter
+import androidx.compose.ui.tooling.preview.PreviewParameterProvider
 import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import androidx.paging.LoadState
+import androidx.paging.LoadStates
 import androidx.paging.PagingData
 import androidx.paging.compose.collectAsLazyPagingItems
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.flowOf
 import my.nanihadesuka.compose.LazyColumnScrollbar
 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.ui.theme.AppTheme
@@ -23,38 +38,81 @@ fun CommentSection(
     parentComment: CommentsInfoItem? = null,
 ) {
     val replies = flow.collectAsLazyPagingItems()
-    val listState = rememberLazyListState()
+    val itemCount by remember { derivedStateOf { replies.itemCount } }
 
-    LazyColumnScrollbar(state = listState, settings = ScrollbarSettings.Default) {
-        LazyColumn(state = listState) {
-            if (parentComment != null) {
-                item {
-                    CommentRepliesHeader(comment = parentComment)
-                    HorizontalDivider(thickness = 1.dp)
+    Surface(color = MaterialTheme.colorScheme.background) {
+        val refresh = replies.loadState.refresh
+        if (itemCount == 0 && refresh !is LoadState.Loading) {
+            NoCommentsMessage((refresh as? LoadState.Error)?.error)
+        } else {
+            val listState = rememberLazyListState()
+
+            LazyColumnScrollbar(state = listState, settings = ScrollbarSettings.Default) {
+                LazyColumn(state = listState) {
+                    if (parentComment != null) {
+                        item {
+                            CommentRepliesHeader(comment = parentComment)
+                            HorizontalDivider(thickness = 1.dp)
+                        }
+                    }
+
+                    items(itemCount) {
+                        Comment(comment = replies[it]!!)
+                    }
                 }
             }
-
-            items(replies.itemCount) {
-                Comment(comment = replies[it]!!)
-            }
         }
     }
 }
 
+@Composable
+private fun NoCommentsMessage(error: Throwable?) {
+    val message = if (error is CommentsDisabledException) {
+        R.string.comments_are_disabled
+    } else {
+        R.string.no_comments
+    }
+
+    Column(horizontalAlignment = Alignment.CenterHorizontally) {
+        Text(text = "(╯°-°)╯", fontSize = 35.sp)
+        Text(text = stringResource(id = message), fontSize = 24.sp)
+    }
+}
+
+private class CommentDataProvider : PreviewParameterProvider<PagingData<CommentsInfoItem>> {
+    private val notLoading = LoadState.NotLoading(true)
+
+    override val values = sequenceOf(
+        // Normal view
+        PagingData.from(
+            (1..100).map {
+                CommentsInfoItem(
+                    commentText = Description("Comment $it", Description.PLAIN_TEXT),
+                    uploaderName = "Test"
+                )
+            }
+        ),
+        // Comments disabled
+        PagingData.from(
+            listOf<CommentsInfoItem>(),
+            LoadStates(LoadState.Error(CommentsDisabledException()), notLoading, notLoading)
+        ),
+        // No comments
+        PagingData.from(
+            listOf<CommentsInfoItem>(),
+            LoadStates(notLoading, notLoading, notLoading)
+        )
+    )
+}
+
 @Preview(name = "Light mode", uiMode = Configuration.UI_MODE_NIGHT_NO)
 @Preview(name = "Dark mode", uiMode = Configuration.UI_MODE_NIGHT_YES)
 @Composable
-private fun CommentSectionPreview() {
-    val comments = (1..100).map {
-        CommentsInfoItem(
-            commentText = Description("Comment $it", Description.PLAIN_TEXT),
-            uploaderName = "Test"
-        )
-    }
-    val flow = flowOf(PagingData.from(comments))
-
+private fun CommentSectionPreview(
+    @PreviewParameter(CommentDataProvider::class) pagingData: PagingData<CommentsInfoItem>
+) {
     AppTheme {
-        CommentSection(flow = flow)
+        CommentSection(flow = flowOf(pagingData))
     }
 }
 

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

@@ -25,7 +25,7 @@ class CommentsSource(
             .subscribeOn(Schedulers.io())
             .map {
                 if (it.isCommentsDisabled) {
-                    LoadResult.Invalid()
+                    LoadResult.Error(CommentsDisabledException())
                 } else {
                     LoadResult.Page(it.relatedItems, null, it.nextPage)
                 }
@@ -34,3 +34,5 @@ class CommentsSource(
 
     override fun getRefreshKey(state: PagingState<Page, CommentsInfoItem>) = null
 }
+
+class CommentsDisabledException : RuntimeException()