class ExaTemplate

# File lib/exa-template.rb, line 5
def initialize(template, destination, route_refresh = 5)
  @template = template
  @destination = destination
  @bindings = binding
  @services = reset_services
  @route_refresh = route_refresh
end

# File lib/exa-template.rb, line 13
def parse_events
  loop do
    chunks = []
    begin
      loop do
        chunks << STDIN.read_nonblock(4096)
      end
    rescue IO::WaitReadable
      retry if IO.select([STDIN], [], [], @route_refresh)
      chunks.join.chomp.split("\n").each do |line|
        event = JSON.parse(line)
        next unless event['type'] == 'update'

        parse_services(event)
        @bindings.local_variable_set(:services, @services)
        render_template
      end
      route_refresh
    end
  end
end

# File lib/exa-template.rb, line 48
def parse_services(event)
  community = event['neighbor']['message']['update']['attribute']['community']
  community&.each do |c|
    port = c[1]
    event['neighbor']['message']['update']['announce']['ipv4 unicast']&.each do |_, prefix|
      @services[port] << prefix.keys.flatten.first
    end
    event['neighbor']['message']['update']['announce']['ipv6 unicast']&.each do |_, prefix|
      @services[port] << prefix.keys.flatten.first
    end
  end
end

# File lib/exa-template.rb, line 61
def render_template
  template = ERB.new(File.read(@template), nil, '-').result(@bindings)
  File.write(@destination, template)
end

# File lib/exa-template.rb, line 37
def reset_services
  @services = Hash.new { |h,k| h[k] = [] }
end

# File lib/exa-template.rb, line 41
def route_refresh
  reset_services
  $stdout.write 'announce route-refresh ipv4 unicast'
  $stdout.write 'announce route-refresh ipv6 unicast'
  $stdout.flush
end