require_relative 'servers_bootstrapper'

# Bootstrap groups of servers based on priorities: higher first.
# Doesn't start bootstrap of next group if bootstrap of previous group failed.
class PrioritizedGroupsBootstrapper
  include PutsAndFlush
  attr_reader :out

  def initialize(out, jid, servers_with_priorities)
    @out, @jid, @servers_with_priorities = out, jid, servers_with_priorities
  end

  # @param servers_with_priorities [Hash] is a Hash like
  #   {1 => [server1, server2]}
  # Starts bootstrapping another group only after successful bootstrapping of previous.
  def bootstrap_servers_by_priority
    sorted_priorities.each do |priority|
      puts_and_flush "Bootstrap servers with priority '#{priority}':"
      bootstrapper = ServersBootstrapper.new(@out, @jid, @servers_with_priorities[priority])
      bootstrap_results = bootstrapper.bootstrap_group
      error = most_critical_error(bootstrap_results)
      return error if error
    end
    ServersBootstrapper::Result.from_reason(:ok)
  end

  private

  def sorted_priorities
    @servers_with_priorities.keys.sort.reverse
  end

  def most_critical_error(results)
    results.detect(&:bootstrap_error?) || results.detect(&:failed?)
  end
end