pageable.rb

# app/controllers/concerns/pageable.rb

module Pageable
  extend ActiveSupport::Concern

  @@page_size = 20

  def page
    @page ||= (params[:page].to_i > 1) ? params[:page].to_i : 1
  end

  def pageable_query(pageable_relation)
    @pageable_count = pageable_relation.count
    pageable_relation.offset((page - 1) * @@page_size).limit(@@page_size)
  end

  def pageable_count
    @pageable_count
  end

  def total_pages
    @total_pages ||= (pageable_count.to_f / @@page_size).ceil
  end

  def next_page
    @next_page ||= page + 1 if (page + 1) <= total_pages
  end

  def prev_page
    @prev_page ||= page - 1 if (page - 1) > 0
  end

  def pageable_params
    # The including controller should define this as non-empty if there are any params that are important to
    # be passed from page to page eg topic.
    {}
  end

  included do
    helper_method :page_size, :pageable_count, :total_pages, :next_page, :prev_page, :page, :pageable_params
  end

end