# frozen_string_literal: true

require 'dotenv/load'
require 'midi-smtp-server'
require 'mail'
require 'bunny'

# Server class
class BettermailProxy < MidiSmtpServer::Smtpd

  def stop(wait_seconds_before_close: nil, gracefully: nil)
    super()
    @bunny_conn&.close
  end

  def bunny
    if @bunny.nil?
      @bunny_conn = Bunny.new
      @bunny_conn.start
      ch = @bunny_conn.create_channel
      ch.direct(ENV['RABBIT_CHANNEL'])
      ch.queue(ENV['RABBIT_MAIL_QUEUE'])
      @bunny = ch.default_exchange
    end
    @bunny
  end

  # update local welcome and helo response
  def on_connect_event(ctx)
    ctx[:server][:local_response] = 'Client connected'
    ctx[:server][:helo_response] = 'Welcome to the BetterMail proxy - an SMTP drop in replacement'
  end

  def on_message_data_headers_event(ctx)
    # check and append all headers
    ctx[:message][:data] << "X-bettermail: Received by proxy at #{Time.now}" << ctx[:message][:crlf]
  end

  # check the authentication
  # if any value returned, that will be used for ongoing processing
  # otherwise the original value will be used for authorization_id
  def on_auth_event(ctx, authorization_id, authentication_id, authentication)
    # to proceed this test use commands ...
    # auth plain
    # > AGFkbWluaXN0cmF0b3IAcGFzc3dvcmQ=
    # auth login
    # > YWRtaW5pc3RyYXRvcg==
    # > cGFzc3dvcmQ=
    # if authorization_id == '' && authentication_id == 'administrator' && authentication == 'password'
    #   # yes
    #   return 'supervisor'
    # end
    # # otherwise exit with authentication exception
    # raise MidiSmtpServer::Smtpd535Exception
    logger.debug("Authenticated id: #{authentication_id} with authentication: #{authentication} from: #{ctx[:server][:remote_ip]}:#{ctx[:server][:remote_port]}")
    authentication_id
  end


  # get each message after DATA <message> .
  def on_message_data_event(ctx)
    # Just decode message once to make sure, that this message ist readable
    mail = Mail.read_from_string(ctx[:message][:data])
    logger.info('Message good. Sending to queue for processing')
    bunny.publish(mail.to_s, :headers => { 'x-smtp' => mail.header.to_s }, :routing_key => ENV["RABBIT_MAIL_QUEUE"])
    logger.info('Done')
  end
end

# Create a new server instance for listening at localhost interfaces 127.0.0.1:2525
# and accepting a maximum of 4 simultaneous connections per default
service = BettermailProxy.new(
  ports: ENV['PROXY_PORTS'],
  hosts: ENV['PROXY_HOSTS'],
  max_processings: 10,
  auth_mode: :AUTH_REQUIRED,
  tls_mode: :TLS_REQUIRED,
  tls_cert_path: './ssl/cert.pem',
  tls_key_path: './ssl/key.pem'
)

service_name='BetterMail::SMTPProxy'
# Create a new server instance for listening at localhost interfaces 127.0.0.1:2525
# and accepting a maximum of 4 simultaneous connections per default

# save flag for Ctrl-C pressed
flag_status_ctrl_c_pressed = false

# try to gracefully shutdown on Ctrl-C
trap('INT') do
  # print an empty line right after ^C
  puts
  # notify flag about Ctrl-C was pressed
  flag_status_ctrl_c_pressed = true
  # signal exit to app
  exit(0)
end

# Output for debug
puts("Starting #{service_name}")

# setup exit code
at_exit do
  # check to shutdown connection
  if service
    # Output for debug
    puts('Ctrl-C interrupted, exit now...') if flag_status_ctrl_c_pressed
    # info about shutdown
    puts("Shutdown #{service_name}...")
    # stop all threads and connections gracefully
    service.stop
  end

  # Output for debug
  puts "#{service_name} stopped!"
end

# Start the server
service.start

# Run on server forever
service.join