hummingbird-me/kitsu-server

# frozen_string_literal: true

class BufferedStreamClient
  class UnfollowBuffer < RedisBuffer
    # The numbers below are slightly below the max rate limit just for safety
    # We can send 250 unfollow requests per 60 seconds
    RATE_LIMIT = 240 / 60 * 5
    # Match a valid feed name
    VALID_FEED = /\A[\w-]+:[\w-]+\z/i

    def initialize
      super('unfollows')
    end

    def push(*unfollows)
      unless unfollows.all? { |f| valid_follow?(f) }
        return Sentry.capture_message('Invalid Unfollow', level: 'error', extra: f)
      end
      super(*unfollows, group: 'default')
    end

    def flush_batch
      # TODO: switch to unfollow-many
      unfollows = next_batch_for(size: RATE_LIMIT)
      return if unfollows.blank?
      begin
        unfollows.each do |unfollow|
          source = unfollow['source'].split(':')
          target = unfollow['target'].split(':')
          feed = StreamRails.client.feed(*source)
          feed.unfollow(*target, unfollow['keep_history'])
        end
      rescue StandardError
        return_batch_to(unfollows, group: 'default')
        raise
      end
    end

    private

    def valid_follow?(follow)
      follow = follow.stringify_keys
      valid_feed?(follow['source']) && valid_feed?(follow['target'])
    end

    def valid_feed?(feed)
      VALID_FEED =~ feed
    end
  end
end