# frozen_string_literal: true module TTY class Prompt class Paginator DEFAULT_PAGE_SIZE = 6 # The 0-based index of the first item on this page attr_accessor :start_index # The 0-based index of the last item on this page attr_reader :end_index # The 0-based index of the active item on this page attr_reader :current_index # The 0-based index of the previously active item on this page attr_reader :last_index # Create a Paginator # # @api private def initialize(**options) @last_index = Array(options[:default]).flatten.first || 0 @per_page = options[:per_page] @start_index = Array(options[:default]).flatten.first end # Reset current page indexes # # @api private def reset! @start_index = nil @end_index = nil end # Check if page size is valid # # @raise [InvalidArgument] # # @api private def check_page_size! raise InvalidArgument, "per_page must be > 0" if @per_page < 1 end # Paginate collection given an active index # # @param [Array[Choice]] list # a collection of choice items # @param [Integer] active # current choice active index # @param [Integer] per_page # number of choice items per page # # @return [Enumerable] # the list between start and end index # # @api public def paginate(list, active, per_page = nil, &block) current_index = active - 1 default_size = (list.size <= DEFAULT_PAGE_SIZE ? list.size : DEFAULT_PAGE_SIZE) @per_page = @per_page || per_page || default_size check_page_size! @start_index ||= (current_index / @per_page) * @per_page @end_index ||= @start_index + @per_page - 1 # Don't paginate short lists if list.size <= @per_page @start_index = 0 @end_index = list.size - 1 if block return list.each_with_index(&block) else return list.each_with_index.to_enum end end step = (current_index - @last_index).abs if current_index > @last_index # going up if current_index >= @end_index && current_index < list.size - 1 last_page = list.size - @per_page @start_index = [@start_index + step, last_page].min end elsif current_index < @last_index # going down if current_index <= @start_index && current_index > 0 @start_index = [@start_index - step, 0].max end end # Cycle list if current_index.zero? @start_index = 0 elsif current_index == list.size - 1 @start_index = list.size - 1 - (@per_page - 1) end @end_index = @start_index + (@per_page - 1) @last_index = current_index sliced_list = list[@start_index..@end_index] page_range = (@start_index..@end_index) return sliced_list.zip(page_range).to_enum unless block_given? sliced_list.each_with_index do |item, index| block[item, @start_index + index] end end end # Paginator end # Prompt end # TTY