module Eco::API::UseCases::GraphQL::Helpers::Location
  class TagsRemap
    def self.correct_pair?(pair)
      correct_pair = pair.is_a?(Array)
      correct_pair && pair.length == 2
    end

    attr_reader :src_maps
    attr_reader :from, :to

    def each(&block)
      return to_enum(:each) unless block
      src_maps.each(&block)
    end

    def to_csv(filename)
      CSV.open(filename, "w") do |fd|
        fd << ["src_tags", "dst_tags"]
        each do |tags_map|
          fd << tags_map.to_csv_row
        end
      end
    end

    def to_s
      "".tap do |str|
        each.map do |tags_map|
          from, to = tags_map.to_csv_row
          str << " • from: #{from}\n"
          str << "   • to: #{to}\n"
        end
      end
    end

    # Sorts the maps in the correct order
    # @note it assumes that:
    #   1. renames go before moving nodes
    #   2. moving nodes does not include a rename
    #   3. moving nodes includes all the path on both, source and destination tags
    # @note DISABLED: the order should be that in what the operations happened!
    #   An important thing is that all the path is always included in the mappings.
    #   * The only way that this would work is to apply upper (previous) tags_maps
    #   to subsequent ones. But the order should still be kept!
    # def sorted_maps
    #   [].tap do |sorted|
    #     src_maps.each do |curr_map|
    #       pos = nil
    #       sorted.each_with_index.reverse_each do |prev_map, idx|
    #         pos = idx + 1 if prev_map.goes_before?(curr_map)
    #         break if pos
    #       end
    #       sorted.insert(pos || 0, curr_map)
    #     end
    #   end
    # end

    def empty?
      src_maps.empty?
    end

    def <<(pair)
      raise ArgumentError, "Expecting pair of Array in Array. Given: #{pair}" unless self.class.correct_pair?(pair)
      add(*pair)
    end

    def add(from, to)
      raise ArgumentError, "Expecting Array. Given: #{from.class}" unless from.is_a?(Array)
      raise ArgumentError, "Expecting Array. Given: #{to.class}"   unless to.is_a?(Array)
      new_src TagsMap.new(from, to)
    end

    private

    attr_reader :src_maps
    attr_reader :from_key, :to_key

    def new_src(tags_map)
      src_maps << tags_map
    end

    def src_maps
      @src_maps ||= []
    end
  end
end

require_relative 'tags_remap/tags_map'
require_relative 'tags_remap/tags_set'