# encoding: utf-8
module Mongoid #:nodoc:
  module Contexts #:nodoc:
    module Paging
      # Paginates the documents.
      #
      # Example:
      #
      # <tt>context.paginate(:page => 6, :per_page => 25)</tt>
      #
      # Returns:
      #
      # A collection of documents paginated.
      # All previous <tt>limit</tt> and <tt>skip</tt> call will be ignored.
      def paginate(pager_options={})
        if pager_options[:per_page]
          options[:limit] = pager_options[:per_page].to_i
          if pager_options[:page]
            options[:skip]  = (pager_options[:page].to_i - 1) * pager_options[:per_page].to_i
          end
        end

        @collection ||= execute(true)
        WillPaginate::Collection.create(page, per_page, count) do |pager|
          pager.replace(@collection.to_a)
        end
      end

      # Either returns the page option and removes it from the options, or
      # returns a default value of 1.
      #
      # Returns:
      #
      # An +Integer+ page number.
      def page
        skips, limits = options[:skip], options[:limit]
        (skips && limits) ? (skips + limits) / limits : 1
      end

      # Get the number of results per page or the default of 20.
      #
      # Returns:
      #
      # The +Integer+ number of documents in each page.
      def per_page
        (options[:limit] || 20).to_i
      end
    end
  end
end