Creates an array of pages not bigger than 9 elements, with ellipsis to signal gaps.

page_order.rb

def page_order(page, total_pages, links=9)
  bck = ((page > links ? page-links : 1)..page).entries.reverse
  fwd = (page..((total_pages - page > links ? page+links : total_pages))).entries
  
  order = fwd.size > page ? fwd.zip(bck) : bck.zip(fwd)
  order = order.flatten.compact.uniq[0,links].sort
  
  if order[0] !=1
    order[1]='...'
    order[0]=1
  end
  if order[-1] !=total_pages
    order[-2]='...'
    order[-1]=total_pages
  end
  order
end


# Example:

example = [[1,2],[2,2],[1,6],[3,6],[6,6],[1,13],[3,13],[7,13],[12,13], [3,200], [50,1000]]

example.each do |t|
  p page_order(*t)
end