lycan / app / firehose_client.rb

require 'skyfall'

require_relative 'init'
require_relative 'models/post'
require_relative 'models/subscription'
require_relative 'models/user'

class FirehoseClient
  attr_accessor :start_cursor, :service

  DEFAULT_RELAY = 'bsky.network'

  def initialize
    @env = (ENV['APP_ENV'] || ENV['RACK_ENV'] || :development).to_sym
    @service = DEFAULT_RELAY
  end

  def start
    return if @sky

    @active_users = load_users

    log "Starting firehose process (YJIT = #{RubyVM::YJIT.enabled? ? 'on' : 'off'})"

    last_cursor = load_or_init_cursor
    cursor = @start_cursor || last_cursor

    @sky = Skyfall::Firehose.new(@service, :subscribe_repos, cursor)
    @sky.user_agent = "Lycan (https://tangled.sh/@mackuba.eu/lycan) #{@sky.version_string}"
    @sky.check_heartbeat = true

    @sky.on_message do |m|
      start_time = Time.now
      diff = start_time - @last_update

      if diff > 30
        log "Receiving messages again after #{sprintf('%.1f', diff)}s, starting from #{m.time.getlocal}"
      end

      @last_update = start_time
      process_message(m)
    end

    @sky.on_connecting { |u| log "Connecting to #{u}..." }
    @sky.on_connect {
      log "Connected ✓"

      @replaying = true
      @last_update = Time.now

      @timer ||= EM::PeriodicTimer.new(20) do
        now = Time.now
        diff = now - @last_update

        if diff > 30
          log "Timer: last update #{sprintf('%.1f', diff)}s ago"
        end
      end
    }

    @sky.on_disconnect {
      log "Disconnected."
    }

    @sky.on_reconnect {
      log "Connection lost, reconnecting..."

      @timer&.cancel
      @timer = nil
    }

    @sky.on_timeout {
      log "Trying to reconnect..."
    }

    @sky.on_error { |e| log "ERROR: #{e.class} #{e.message}" }

    @sky.connect
  end

  def stop
    save_cursor(@sky.cursor) unless @sky.nil?

    @sky&.disconnect
    @sky = nil
  end

  def load_or_init_cursor
    if sub = Subscription.find_by(service: @service)
      sub.cursor
    else
      Subscription.create!(service: @service, cursor: 0)
      nil
    end
  end

  def save_cursor(cursor)
    Subscription.where(service: @service).update_all(cursor: cursor)
  end

  def load_users
    User.active.map { |u| [u.did, u] }.then { |list| Hash[list] }
  end

  def process_message(msg)
    save_cursor(msg.seq) if msg.seq % 1000 == 0

    case msg.type
    when :info
      log "InfoMessage: #{msg}"
    when :account
      process_account_event(msg)
    when :commit
      if @replaying
        log "Replaying events since #{msg.time.getlocal} -->"
        @replaying = false
      end

      @current_user = @active_users[msg.repo]

      msg.operations.each do |op|
        case op.type
        when :bsky_like
          process_like(msg, op)
        when :bsky_repost
          process_repost(msg, op)
        when :bsky_post
          process_post(msg, op)
        end
      end
    end
  end

  def process_account_event(msg)
    if msg.status == :deleted
      if user = User.find_by(did: msg.repo)
        user.destroy
      end
    end
  end

  def process_like(msg, op)
    return unless @current_user

    if op.action == :create
      @current_user.likes.import_from_record(op.uri, op.raw_record)
    elsif op.action == :delete
      @current_user.likes.where(rkey: op.rkey).delete_all
    end
  end

  def process_repost(msg, op)
    return unless @current_user

    if op.action == :create
      @current_user.reposts.import_from_record(op.uri, op.raw_record)
    elsif op.action == :delete
      @current_user.reposts.where(rkey: op.rkey).delete_all
    end
  end

  def process_post(msg, op)
    if op.action == :create
      if @current_user
        @current_user.quotes.import_from_record(op.uri, op.raw_record)
        @current_user.pins.import_from_record(op.uri, op.raw_record)
      end
    elsif op.action == :delete
      if @current_user
        @current_user.quotes.where(rkey: op.rkey).delete_all
        @current_user.pins.where(rkey: op.rkey).delete_all
      end

      if post = Post.find_by_at_uri(op.uri)
        post.destroy
      end
    end
  end

  def log(text)
    puts "[#{Time.now}] #{text}"
  end

  def inspect
    vars = instance_variables - [:@timer]
    values = vars.map { |v| "#{v}=#{instance_variable_get(v).inspect}" }.join(", ")
    "#<#{self.class}:0x#{object_id} #{values}>"
  end
end