fix(youtube): read the sort token from the dropdown chip on channels using it

extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/extractors/YoutubeChannelTabExtractor.java

@@ -205,6 +205,42 @@ private String getSortContinuationToken(@Nonnull final JsonObject currentTabData
             throw new ParsingException("YouTube channel tab sort filter is not available");
         }
 
+        // Some channels expose the sort options as a single "Sort by" dropdown chip
+        // (displayType = CHIP_VIEW_MODEL_DISPLAY_TYPE_DROP_DOWN). The actual Latest/Popular/Oldest
+        // tokens then live inside that chip's sheet listItems, not in the chipBar directly.
+        // Reading chips[sortIndex] in that case picked filter chips (e.g. "Members only", "Public")
+        // and returned their continuation tokens, so the sort never applied.
+        if (!chips.isEmpty()) {
+            final JsonObject firstChip = chips.getObject(0).getObject("chipViewModel");
+            if ("CHIP_VIEW_MODEL_DISPLAY_TYPE_DROP_DOWN".equals(firstChip.getString("displayType"))) {
+                final JsonArray listItems = firstChip
+                        .getObject("tapCommand")
+                        .getObject("innertubeCommand")
+                        .getObject("showSheetCommand")
+                        .getObject("panelLoadingStrategy")
+                        .getObject("inlineContent")
+                        .getObject("sheetViewModel")
+                        .getObject("content")
+                        .getObject("listViewModel")
+                        .getArray("listItems");
+                if (listItems.size() <= sortIndex) {
+                    throw new ParsingException("YouTube channel tab sort filter is not available");
+                }
+                final String token = extractContinuationTokenFromListItem(
+                        listItems.getObject(sortIndex).getObject("listItemViewModel"));
+                if (isNullOrEmpty(token)) {
+                    throw new ParsingException(
+                            "Could not get YouTube channel tab sort continuation");
+                }
+                return token;
+            }
+        }
+
+        // Flat format: chips[sortIndex] is itself the sort chip.
+        if (chips.size() <= sortIndex) {
+            throw new ParsingException("YouTube channel tab sort filter is not available");
+        }
+
         final String token = chips.getObject(sortIndex)
                 .getObject("chipViewModel")
                 .getObject("tapCommand")
@@ -219,6 +255,39 @@ private String getSortContinuationToken(@Nonnull final JsonObject currentTabData
         return token;
     }
 
+    /**
+     * Walks a sort-dropdown listItem to find its continuationCommand token.
+     * The token lives inside {@code commandExecutorCommand.commands[]} (typically alongside an
+     * entityUpdateCommand for the chip state). We scan the commands array instead of guessing
+     * an index because other commands can sit before the continuationCommand.
+     */
+    @Nullable
+    private static String extractContinuationTokenFromListItem(
+            @Nonnull final JsonObject listItemViewModel) {
+        final JsonObject innertube = listItemViewModel
+                .getObject("rendererContext")
+                .getObject("commandContext")
+                .getObject("onTap")
+                .getObject("innertubeCommand");
+        final JsonObject executor = innertube.getObject("commandExecutorCommand");
+        if (executor == null) {
+            return null;
+        }
+        final JsonArray commands = executor.getArray("commands");
+        for (final Object o : commands) {
+            final JsonObject command = (JsonObject) o;
+            if (command.has("continuationCommand")) {
+                final String token = command
+                        .getObject("continuationCommand")
+                        .getString("token");
+                if (!isNullOrEmpty(token)) {
+                    return token;
+                }
+            }
+        }
+        return null;
+    }
+
     private int getSelectedSortFilterIndex() throws ParsingException {
         final List<FilterItem> sortFilter = getLinkHandler().getSortFilter();
         if (sortFilter == null || sortFilter.isEmpty()) {