newcontext-oss/kitchen-terraform

# frozen_string_literal: true

# Copyright 2016-2021 Copado NCS LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

require "kitchen/terraform/config_attribute_cacher"
require "kitchen/terraform/config_attribute_definer"

module Kitchen
  module Terraform
    # ConfigAttribute is the class of objects which apply the behaviour of a configuration attribute to a module which must
    # be included by a plugin class.
    class ConfigAttribute
      # #apply applies the configuration attribute behaviour to a module.
      #
      # @param config_attribute [Module] a module.
      # @return [self]
      def apply(config_attribute:)
        self.config_attribute = config_attribute
        define_singleton_included
        define_singleton_to_sym
        define_config_attribute_default_value

        self
      end

      # #initialize prepares a new instance of the class.
      #
      # @param attribute [Symbol] the name of the attribute.
      # @param default_value [Proc] a block which returns the default value for the attribute.
      # @param schema [Dry::Validation::Schema] the schema of the attribute.
      def initialize(attribute:, default_value:, schema:)
        self.attribute = attribute
        self.default_value = default_value
        self.schema = schema
      end

      private

      attr_accessor(
        :attribute,
        :config_attribute,
        :default_value,
        :schema
      )

      def define_config_attribute_default_value
        config_attribute
          .send(
            :define_method,
            "config_#{attribute}_default_value",
            &default_value
          )
      end

      def define_singleton_included
        local_schema = schema

        config_attribute.define_singleton_method :included do |plugin_class|
          ::Kitchen::Terraform::ConfigAttributeDefiner.new(attribute: self, schema: local_schema).define(
            plugin_class: plugin_class,
          )
        end
      end

      def define_singleton_to_sym
        local_attribute = attribute

        config_attribute.define_singleton_method :to_sym do
          local_attribute
        end
        config_attribute.extend ::Kitchen::Terraform::ConfigAttributeCacher
      end
    end
  end
end