require 'active_record/log_subscriber'

module ActiveReplicas
  class LogSubscriber < ActiveRecord::LogSubscriber
    def sql(event)
      self.class.runtime += event.duration
      return unless logger.debug?

      payload = event.payload

      return if IGNORE_PAYLOAD_NAMES.include?(payload[:name])

      pool  = nil
      name  = "#{payload[:name]} (#{event.duration.round(1)}ms)"
      sql   = payload[:sql]
      binds = nil

      proxy = ActiveRecord::Base.connection_handler.retrieve_handler.current_proxy
      connection_pool = proxy.pool_which_owns_connection payload[:connection_id]
      if connection_pool
        role =
          if proxy.primary_pool? connection_pool
            'primary'
          elsif proxy.replica_pool? connection_pool
            pool_name = proxy.replica_pools.key connection_pool
            "replica=#{pool_name}"
          else
            'unknown'
          end

        pool = "[#{role}] "
      end

      unless (payload[:binds] || []).empty?
        binds = ' ' + payload[:binds].map { |column, value| render_bind(column, value) }.inspect
      end

      debug "#{pool}#{name} #{sql}#{binds}"
    end

    def logger
      ActiveRecord::Base.logger
    end

    # Take over logging duties from `ActiveRecord::LogSubscriber`.
    def self.hijack_active_record
      self.attach_to :active_record

      subscriber = ActiveSupport::Notifications.notifier.listeners_for('sql.active_record').find do |subscriber|
        ActiveRecord::LogSubscriber === subscriber.instance_eval { @delegate }
      end

      ActiveSupport::Notifications.notifier.unsubscribe(subscriber) if subscriber
    end
  end
end