class Pagy::Countless

def finalize(fetched)
  raise OverflowError.new(self), "page #{@page} got no items" \
        if fetched.zero? && @page > 1
  @pages = @last = (fetched > @items ? @page + 1 : @page)         # set the @pages and @last
  @items = fetched if fetched < @items && fetched.positive?       # adjust items for last non-empty page
  @from  = fetched.zero? ? 0 : @offset + 1 - @outset              # page begins from item
  @to    = fetched.zero? ? 0 : @offset + @items - @outset         # page ends to item
  @prev  = (@page-1 unless @page == 1)                            # nil if no prev page
  @next  = @page == @last ? (1 if @vars[:cycle]) : @page + 1      # nil if no next page, 1 if :cycle
  self
end

def initialize(vars={})  # rubocop:disable Lint/MissingSuper
  @vars = VARS.merge(vars.delete_if{|_,v| v.nil? || v == '' })      # default vars + cleaned vars (can be overridden)
  INSTANCE_VARS_MIN.each do |k,min|                                 # validate instance variables
    raise VariableError.new(self), "expected :#{k} >= #{min}; got #{@vars[k].inspect}" \
          unless @vars[k] && instance_variable_set(:"@#{k}", @vars[k].to_i) >= min
  end
  @offset = @items * (@page - 1) + @outset                          # pagination offset + outset (initial offset)
end