#!/usr/bin/env ruby

require 'mail'
require 'erb'
require 'haml'
require 'socket'

require 'em-synchrony'
require 'em/protocols/smtpclient'

require 'flapjack/data/entity_check'
require 'flapjack/gateways/base'

module Flapjack
  module Gateways

    class Email
      extend Flapjack::Gateways::Resque

      class << self

        alias_method :orig_bootstrap, :bootstrap

        def bootstrap(opts = {})
          return if @bootstrapped
          @smtp_config = opts[:config].delete('smtp_config')
          @sent = 0
          orig_bootstrap(opts)
        end

        def perform(notification)
          @logger.debug "Woo, got a notification to send out: #{notification.inspect}"

          notification_type  = notification['notification_type']
          contact_first_name = notification['contact_first_name']
          contact_last_name  = notification['contact_last_name']
          state              = notification['state']
          summary            = notification['summary']
          time               = notification['time']

          entity_check = Flapjack::Data::EntityCheck.for_event_id(notification['event_id'],
            :redis => ::Resque.redis)

          headline_map = {'problem'         => 'Problem: ',
                          'recovery'        => 'Recovery: ',
                          'acknowledgement' => 'Acknowledgement: ',
                          'test'            => 'Test Notification: ',
                          'unknown'         => ''
                         }

          headline = headline_map[notification_type] || ''

          subject = "#{headline}'#{entity_check.check}' on #{entity_check.entity_name}"
          subject += " is #{state.upcase}" unless ['acknowledgement', 'test'].include?(notification_type)

          notification['subject'] = subject

          begin
            host = @smtp_config ? @smtp_config['host'] : nil
            port = @smtp_config ? @smtp_config['port'] : nil

            fqdn       = `/bin/hostname -f`.chomp
            m_from     = "flapjack@#{fqdn}"
            logger.debug("flapjack_mailer: set from to #{m_from}")
            m_reply_to = m_from
            m_to       = notification['address']

            mail = prepare_email(notification,
                    :from => m_from, :to => m_to,
                    :in_scheduled_maintenance   => entity_check.in_scheduled_maintenance?,
                    :in_unscheduled_maintenance => entity_check.in_unscheduled_maintenance?)

            email = EM::P::SmtpClient.send(
              :from     => m_from,
              :to       => m_to,
              :content  => "#{mail.to_s}\r\n.\r\n",
              :domain   => fqdn,
              :host     => host || 'localhost',
              :port     => port || 25)

            response = EM::Synchrony.sync(email)

            # http://tools.ietf.org/html/rfc821#page-36 SMTP response codes
            if response && response.respond_to?(:code) &&
              ((response.code == 250) || (response.code == 251))
              @logger.info "Email sending succeeded"
              @sent += 1
            else
              @logger.info "Email sending failed"
            end

            @logger.info "Email response: #{response.inspect}"

          rescue Exception => e
            @logger.error "Error delivering email to #{mail.to}: #{e.message}"
            @logger.error e.backtrace.join("\n")
          end
        end

      end

    private

      def self.prepare_email(notification, opts = {})

        @notification_type  = notification['notification_type']
        @contact_first_name = notification['contact_first_name']
        @contact_last_name  = notification['contact_last_name']
        @state              = notification['state']
        @summary            = notification['summary']
        @time               = notification['time']
        @entity, @check     = notification['event_id'].split(':')
        @in_unscheduled_maintenance = opts[:in_unscheduled_maintenance]
        @in_scheduled_maintenance   = opts[:in_scheduled_maintenance]

        m_subject  = notification['subject']

        @logger.debug("sending Flapjack::Notification::Email " +
          "#{notification['id']} to: #{opts[:to]} subject: #{m_subject}")

        text_template = ERB.new(File.read(File.dirname(__FILE__) +
          '/email/alert.text.erb'))

        haml_engine = Haml::Engine.new(File.read(File.dirname(__FILE__) +
          '/email/alert.html.haml'))

        mail_scope = self

        # this part is the only use of the mail gem -- maybe this can be done
        # using standard library calls instead?
        mail = Mail.new do
          from     opts[:from]
          to       opts[:to]
          subject  m_subject
          reply_to opts[:from]

          text_part do
            body text_template.result(binding)
          end

          html_part do
            content_type 'text/html; charset=UTF-8'
            body haml_engine.render(mail_scope)
          end
        end
      end

    end
  end
end