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

class Pagy
  DEFAULT[:overflow] = :empty_page

  # Handles OverflowError exceptions with different options
  module OverflowExtra
    # Support for Pagy class
    module Pagy
      # Is the requested page overflowing?
      def overflow?
        @overflow
      end

      # Add rescue clause for different behaviors
      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 initial 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 to be 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

    # Support for Pagy::Countless class
    module Countless
      # Add rescue clause for different behaviors
      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 to be in [:empty_page, :exception]; got #{@vars[:overflow].inspect}"
        end
      end
    end
  end
  prepend OverflowExtra::Pagy
  Countless.prepend OverflowExtra::Countless if defined?(Countless)
end