module EdgeCache
  class Bust
    def self.call(*args)
      new(*args).call
    end

    def initialize(path)
      @path = path
      @provider = determine_provider
      @response = nil
    end

    def call
      return unless provider

      provider_class = "#{self.class}::#{provider.capitalize}".constantize

      if provider_class.respond_to?(:call)
        @response = provider_class.call(path)
      else
        @response = nil
        Rails.logger.warn("#{provider_class} cannot be used without a #call implementation!")
        DatadogStatsClient.increment("edgecache_bust.invalid_provider_class",
                                     tags: ["provider_class:#{provider_class}"])
      end

      self
    end

    attr_reader :provider, :path, :response

    private

    def determine_provider
      if fastly_enabled?
        "fastly"
      elsif nginx_enabled?
        "nginx"
      end
    end

    def fastly_enabled?
      ApplicationConfig["FASTLY_API_KEY"].present? && ApplicationConfig["FASTLY_SERVICE_ID"].present?
    end

    def nginx_enabled?
      ApplicationConfig["OPENRESTY_PROTOCOL"].present? && ApplicationConfig["OPENRESTY_DOMAIN"].present?
    end
  end
end