paginated_resource.rb

# frozen_string_literal: true

module DropletKit
 class PaginatedResource
 include Enumerable

 PER_PAGE = 20

 attr_reader :action, :resource, :collection
 attr_accessor :total

 def initialize(action, resource, *args)
 @current_page = 0
 @total = nil
 @action = action
 @resource = resource
 @collection = []
 @args = args
 @options = args.last.kind_of?(Hash) ? args.last : {}
 end

 def per_page
 @options[:per_page] || PER_PAGE
 end

 def [](index)
 @collection[index]
 end

 def each(start = 0, &block)
 # Start off with the first page if we have no idea of anything yet
 fetch_next_page if total.nil?

 return to_enum(:each, start) unless block_given?
 Array(@collection[start..-1]).each do |element|
 yield(element)
 end

 unless last?
 start = [@collection.size, start].max
 fetch_next_page
 each(start, &block)
 end

 self
 end

 def last?
 return true if self.total.nil?
 @current_page == total_pages || self.total.zero?
 end

 def total_pages
 return nil if self.total.nil?

 (self.total.to_f / per_page.to_f).ceil
 end

 def ==(other)
 each_with_index.each.all? {|object, index| object == other[index] }
 end

 private

 def fetch_next_page
 @current_page += 1
 retrieve(@current_page)
 end

 def retrieve(page, per_page = self.per_page)
 invoker = ResourceKit::ActionInvoker.new(action, resource, *@args)
 invoker.options[:per_page] ||= per_page
 invoker.options[:page] = page

 @collection += invoker.handle_response

 if total.nil?
 meta = MetaInformation.extract_single(invoker.response.body, :read)
 self.total = meta.total.to_i
 end
 end
 end
end