# frozen_string_literal: true

module ZuoraConnectUi
  class Serializer
    # The configuration for a relationship between models
    class Relationship
      # key may be plural, record_type will always be singular
      attr_reader :key, :relationship_type, :id_method_name,
                  :record_type, :plural_type

      def initialize(key:, relationship_type:)
        @key = key
        @relationship_type = relationship_type

        set_id_method_name
      end

      def serialize(resources, fields)
        resources.each_with_object({}) do |resource, hash|
          relations = resource.public_send(key)
          relations = [relations] unless @relationship_type == :has_many

          relations.each do |relation|
            next if hash.key? relation.id.to_s.to_sym

            hash[relation.id.to_s.to_sym] = record_hash(relation, fields)
          end
        end
      end

      private

      def record_hash(resource, fields)
        hash = { id: resource.id }

        fields.each do |field|
          hash[key_transform(field)] = resource.public_send(field)
        end

        hash
      end

      def set_id_method_name
        if @relationship_type == :has_many
          singular_key = @key.to_s.singularize
          id_postfix = '_ids'
        else
          singular_key = @key.to_s
          id_postfix = '_id'
        end

        @record_type = singular_key.to_sym
        @plural_type = singular_key.pluralize.to_sym
        @id_method_name = "#{singular_key}#{id_postfix}".to_sym
      end

      def key_transform(input)
        input.to_s.camelize(:lower).to_sym
      end
    end
  end
end