module Terraformer
  module Credentials
    class AwsMissingCredentals < RuntimeError
      attr_reader :key

      def initialize(key)
        @key = key

        super(message)
      end

      def message
        "'#{key}' not passed. set it via CLI --#{key} or #{key.upcase} enviroment variable."
      end
    end

    class Aws
      KEYS = %w(aws_region aws_access_key_id aws_secret_access_key).freeze

      def self.get_from_options(options)
        KEYS.inject({}) do |credentials, key|
          aws_key = key.sub("aws_", "").to_sym
          credentials[aws_key] = options[key.to_sym].nil? ? options[key] : options[key.to_sym]
          credentials[aws_key] = ENV[key.upcase] if credentials[aws_key].nil?
          raise AwsMissingCredentals.new(key) if credentials[aws_key].nil?

          credentials
        end
      end
    end
  end
end