# See the Pagy documentation: https://ddnexus.github.io/pagy/extras/overflow
# frozen_string_literal: true

class Pagy

  module UseOverflowExtra
    VARS[:overflow] = :empty_page

    def overflow? = @overflow

    def initialize(vars)
      @overflow ||= false                         # don't override if :last_page re-run the method after an overflow
      super
    rescue OverflowError
      @overflow = true                            # add the overflow flag
      case @vars[:overflow]
      when :exception
        raise                                     # same as without the extra
      when :last_page
        initial_page = @vars[:page]               # save the very initial page (even after re-run)
        initialize(vars.merge!(page: @last))      # re-run with the last page
        @vars[:page] = initial_page               # restore the inital page
      when :empty_page
        @offset = @items = @from = @to = 0        # vars relative to the actual page
        @prev = @last                             # prev relative to the actual page
        extend(Series)                            # special series for :empty_page
      else
        raise VariableError.new(self), "expected :overflow variable in [:last_page, :empty_page, :exception]; got #{@vars[:overflow].inspect}"
      end
    end

    module Series
      def series(size=@vars[:size])
        @page = @last                             # series for last page
        super(size).tap do |s|                    # call original series
          s[s.index(@page.to_s)] = @page          # string to integer (i.e. no current page)
          @page = @vars[:page]                    # restore the actual page
        end
      end
    end

  end
  prepend UseOverflowExtra


  # support for Pagy::Countless
  if defined?(Pagy::Countless)
    class Countless

      module UseOverflowExtra

        def finalize(items)
          @overflow = false
          super
        rescue OverflowError
          @overflow = true                        # add the overflow flag
          case @vars[:overflow]
          when :exception
            raise                                 # same as without the extra
          when :empty_page
            @offset = @items = @from = @to = 0    # vars relative to the actual page
            @vars[:size] = []                     # no page in the series
            self
          else
            raise VariableError.new(self), "expected :overflow variable in [:empty_page, :exception]; got #{@vars[:overflow].inspect}"
          end
        end

      end
      prepend UseOverflowExtra

    end
  end

end