class Twitter < ApplicationRecord
  self.table_name = "twitter_tokens"

  validates_presence_of :marshaled_client, :marshaled_token

  class RetryableTwitterApiError < StandardError; end

  # For testing
  def self.user_lookup
    poll_api(
      url: "https://api.twitter.com/2/users/me",
      method: :get,
      successful_response_code: 200,
      params: {}
    )
  end

  def self.tweet(tweet)
    poll_api(
      url: "https://api.twitter.com/2/tweets",
      method: :post,
      successful_response_code: 201,
      params: {
        body: {
          text: tweet,
        }.to_json  
      }
    )
  end

  private_class_method def self.poll_api(url:, method:, successful_response_code:, params:)
    attempts ||= 0
    attempts += 1

    instance = self.first

    options = {
      method: method, 
      headers: { 
        "Content-Type" => "application/json",
        Authorization: "Bearer #{instance.access_token}" 
      },
    }.merge(params)
    request = Typhoeus::Request.new(url, options)
    response = request.run
    if response.code == 401 && attempts < 2
      raise RetryableTwitterApiError
    end

    raise "#{response.code} response code received polling #{url}" if response.code != successful_response_code

    JSON.parse(response.body)
  rescue RetryableTwitterApiError
    instance.refresh_token!
    retry
  end


  delegate :access_token, to: :token

  def refresh_token!
    client.refresh_token = token.refresh_token
    new_token = client.access_token!
    update(
      marshaled_client: Marshal.dump(client),
      marshaled_token: Marshal.dump(new_token),  
    )
  end

  private

  #TODO: don't use Marshal.load here, it violates a security concern according to rubocop
  def client
    @client ||= Marshal.load(marshaled_client)
  end

  def token
    @token ||= Marshal.load(marshaled_token)
  end
end