ama-team / ruby-entity-mapper

require_relative 'path/segment'

module AMA

  module Entity

    class Mapper

      # Wrapper for simple array. Helps to understand where exactly processing

      # is taking place.

      class Path

        attr_reader :segments

        def initialize(stack = [])

          @segments = stack

        end

        def empty?

          @segments.empty?

        end

        # @param [String, Symbol, Integer] name

        # @return [AMA::Entity::Mapper::Path]

        def index(name)

          push(Segment.index(name))

        end

        # @param [String, Symbol] name

        # @return [AMA::Entity::Mapper::Path]

        def attribute(name)

          push(Segment.attribute(name))

        end

        # @param [String, Symbol] name

        # @return [AMA::Entity::Mapper::Path]

        def property(name)

          push(Segment.property(name))

        end

        # @param [Array<AMA::Entity::Mapper::Path::Segment>] segments

        # @return [AMA::Entity::Mapper::Path]

        def push(*segments)

          segments = segments.map do |segment|

            next segment if segment.is_a?(Segment)

            Segment.attribute(segment)

          end

          self.class.new(@segments + segments)

        end

        # @return [AMA::Entity::Mapper::Path]

        def pop

          self.class.new(@segments[0..-2])

        end

        # @return [AMA::Entity::Mapper::Path::Segment]

        def current

          @segments.last

        end

        def reduce(carrier)

          @segments.reduce(carrier) do |inner_carrier, item|

            yield(inner_carrier, item)

          end

        end

        # @param [AMA::Entity::Mapper::Path] path

        # @return [AMA::Entity::Mapper::Path]

        def merge(path)

          push(*path.segments)

        end

        def size

          @segments.size

        end

        # @return [Array<AMA::Entity::Mapper::Path::Segment>]

        def to_a

          @segments.clone

        end

        # @return [String]

        def to_s

          "$#{@segments.join}"

        end

      end

    end

  end

end