create_signed_cloudfront_url.rb

# frozen_string_literal: true

class CreateSignedCloudfrontUrl < Service
  attr_reader :url, :expires_at

  def initialize(url:, expires_in:)
    @url = url
    @expires_at = expires_in.from_now.to_i
  end

  def call
    Aws::CloudFront::UrlSigner
      .new(
        key_pair_id: ENV['AWS_PRIVATE_KEY_PAIR_ID'],
        private_key: ENV['AWS_PRIVATE_KEY']
      )
      .signed_url(url, policy: cloudfront_policy.to_json)
  end

  private

  def cloudfront_policy
    {
      "Statement": [
        {
          "Resource": url,
          "Condition": {
            "DateLessThan": {
              "AWS:EpochTime": expires_at
            }
          }
        }
      ]
    }
  end
end