class ActionCable::Connection::Subscriptions

def add(data)
  id_key = data["identifier"]
  id_options = ActiveSupport::JSON.decode(id_key).with_indifferent_access
  return if subscriptions.key?(id_key)
  subscription_klass = id_options[:channel].safe_constantize
  if subscription_klass && ActionCable::Channel::Base >= subscription_klass
    subscription = subscription_klass.new(connection, id_key, id_options)
    subscriptions[id_key] = subscription
    subscription.subscribe_to_channel
  else
    logger.error "Subscription class not found: #{id_options[:channel].inspect}"
  end
end

def execute_command(data)
  case data["command"]
  when "subscribe"   then add data
  when "unsubscribe" then remove data
  when "message"     then perform_action data
  else
    logger.error "Received unrecognized command in #{data.inspect}"
  end
rescue Exception => e
  @connection.rescue_with_handler(e)
  logger.error "Could not execute command from (#{data.inspect}) [#{e.class} - #{e.message}]: #{e.backtrace.first(5).join(" | ")}"
end

def find(data)
  if subscription = subscriptions[data["identifier"]]
    subscription
  else
    raise "Unable to find subscription with identifier: #{data['identifier']}"
  end
end

def identifiers
  subscriptions.keys
end

def initialize(connection)
  @connection = connection
  @subscriptions = {}
end

def perform_action(data)
  find(data).perform_action ActiveSupport::JSON.decode(data["data"])
end

def remove(data)
  logger.info "Unsubscribing from channel: #{data['identifier']}"
  remove_subscription find(data)
end

def remove_subscription(subscription)
  subscription.unsubscribe_from_channel
  subscriptions.delete(subscription.identifier)
end

def unsubscribe_from_all
  subscriptions.each { |id, channel| remove_subscription(channel) }
end