Fix scroll position one-off because of the last seen indicator

Clover/app/src/main/java/org/floens/chan/core/presenter/ThreadPresenter.java

@@ -285,8 +285,8 @@ public class ThreadPresenter implements ChanLoader.ChanLoaderCallback, PostAdapt
         showPosts();
     }
 
-    public void scrollTo(int position, boolean smooth) {
-        threadPresenterCallback.scrollTo(position, smooth);
+    public void scrollTo(int displayPosition, boolean smooth) {
+        threadPresenterCallback.scrollTo(displayPosition, smooth);
     }
 
     public void scrollToImage(PostImage postImage, boolean smooth) {
@@ -652,7 +652,7 @@ public class ThreadPresenter implements ChanLoader.ChanLoaderCallback, PostAdapt
 
         void showImages(List<PostImage> images, int index, Loadable loadable, ThumbnailView thumbnail);
 
-        void scrollTo(int position, boolean smooth);
+        void scrollTo(int displayPosition, boolean smooth);
 
         void highlightPost(Post post);
 

Clover/app/src/main/java/org/floens/chan/ui/adapter/PostAdapter.java

@@ -264,7 +264,7 @@ public class PostAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
         this.postViewMode = postViewMode;
     }
 
-    private int getPostPosition(int position) {
+    public int getPostPosition(int position) {
         int postPosition = position;
         if (lastSeenIndicatorPosition >= 0 && position > lastSeenIndicatorPosition) {
             postPosition--;
@@ -272,6 +272,14 @@ public class PostAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
         return postPosition;
     }
 
+    public int getScrollPosition(int displayPosition) {
+        int postPosition = displayPosition;
+        if (lastSeenIndicatorPosition >= 0 && displayPosition > lastSeenIndicatorPosition) {
+            postPosition++;
+        }
+        return postPosition;
+    }
+
     private boolean showStatusView() {
         return postAdapterCallback.getLoadable().isThreadMode();
     }

Clover/app/src/main/java/org/floens/chan/ui/layout/ThreadLayout.java

@@ -309,8 +309,8 @@ public class ThreadLayout extends CoordinatorLayout implements ThreadPresenter.T
     }
 
     @Override
-    public void scrollTo(int position, boolean smooth) {
-        threadListLayout.scrollTo(position, smooth);
+    public void scrollTo(int displayPosition, boolean smooth) {
+        threadListLayout.scrollTo(displayPosition, smooth);
     }
 
     @Override

Clover/app/src/main/java/org/floens/chan/ui/layout/ThreadListLayout.java

@@ -366,20 +366,22 @@ public class ThreadListLayout extends LinearLayout implements ReplyLayout.ReplyL
         return thumbnail;
     }
 
-    public void scrollTo(int position, boolean smooth) {
-        if (position < 0) {
-            position = recyclerView.getAdapter().getItemCount() - 1;
+    public void scrollTo(int displayPosition, boolean smooth) {
+        if (displayPosition < 0) {
+            displayPosition = recyclerView.getAdapter().getItemCount() - 1;
         }
 
-        int difference = Math.abs(position - getTopAdapterPosition());
+        int scrollPosition = postAdapter.getScrollPosition(displayPosition);
+
+        int difference = Math.abs(scrollPosition - getTopAdapterPosition());
         if (difference > MAX_SMOOTH_SCROLL_DISTANCE) {
             smooth = false;
         }
 
         if (smooth) {
-            recyclerView.smoothScrollToPosition(position);
+            recyclerView.smoothScrollToPosition(scrollPosition);
         } else {
-            recyclerView.scrollToPosition(position);
+            recyclerView.scrollToPosition(scrollPosition);
         }
     }