kiranh/rockdove

module Rockdove
  class CollectMail
    UNDELIVERABLE = /Undeliverable/i
    AUTO_REPLY = /Automatic reply/i
    SPAM = /SPAM/i
    FAILURE = /Delivery(.+)Failure/i
    AUTO_REPLIES_HEADER = "X-Auto-Response-Suppress"

    class << self
      attr_accessor :mail_stack, :inbox_connection
    end

    def initialize(mail_stack = nil, inbox = nil)
      @mail_stack = mail_stack
      @inbox_connection = inbox
    end

    def self.watch &block
      loop do
        begin
          new().send_rockdove_to_watch_mail(&block)
        rescue Exception => e
          Rockdove.logger.error [e, *e.backtrace].join("\n")
        ensure
          sleep(Rockdove::Config.watch_interval)
        end
      end
    end

    def send_rockdove_to_watch_mail(&block)
      Rockdove.logger.info "Rockdove on watch for new mail..."
      parsed_mails = group_of_mails
      if parsed_mails        
        Rockdove.logger.info "Rockdove calling App block"
        block.call(parsed_mails)
        process()
      end
    end

    def group_of_mails
      return no_mail_alert unless fetch_from_box      
      Rockdove.logger.info "Rockdove collected #{@mail_stack.count} mail(s)."
      letters = RockdoveCollection.new
      @mail_stack.reverse.each do |item|
        if ignore_mail?(item) || bounce_type_mail?(item)
          item.delete!
          @mail_stack.delete(item)
        else           
          letters << retrieve_mail(item)
        end
      end
      letters
    end

    def ignore_mail?(item)
      email = item.from.email_address
      ignore_list = Rockdove::Config.ignore_mails
      return false unless ignore_list && !(ignore_list.empty?)
      if ignore_list.include?(email)
        Rockdove.logger.info "Rockdove detected #{email} under ignore mail list."
        true 
      else
        false
      end
    end

    def bounce_type_mail?(item)
      case item.subject
      when UNDELIVERABLE, AUTO_REPLY, SPAM, FAILURE
        Rockdove.logger.info "Rockdove deleting this mail: #{item.subject}."
        true
      else
        item.headers.include?(AUTO_REPLIES_HEADER) ? true : false
      end
    end

    def retrieve_mail(fetched_mail) 
      @inbox_connection ||= inbox
      Rockdove::ExchangeMail.new(fetched_mail, @inbox_connection)
    end

    def no_mail_alert
      Rockdove.logger.info "Rockdove observed no mail yet."
      nil
    end

    def fetch_from_box
      @inbox_connection = inbox
      return nil if @inbox_connection.nil? || @inbox_connection == true
      @mail_stack = @inbox_connection.find_items
      return nil if @mail_stack.empty?
      @mail_stack
    end

    def inbox
      @incoming_folder = Rockdove::Config.incoming_folder
      Viewpoint::EWS::Folder.get_folder_by_name(@incoming_folder)
    rescue
      reconnect_and_raise_error
    end

    def reconnect_and_raise_error
      Rockdove.logger.info "Reconnecting to the Exchange Server & Fetching the mail now."
      Rockdove::Config.connect
      Viewpoint::EWS::Folder.get_folder_by_name(@incoming_folder)
    rescue Viewpoint::EWS::EwsError
      send_connection_failed_message
    end

    def send_connection_failed_message
      Rockdove.logger.info "Rockdove unable to connect to the Exchange Server"
      return nil
    end

    def process      
      @mail_stack.each {|item| archive(item) }
      @mail_stack = nil
    end

    def archive(item)
      @to_folder = Rockdove::Config.archive_folder
      if @to_folder.blank?
        item.delete!
        Rockdove.logger.info "Rockdove delivered & deleted the mail."
      else
        item.move!(destination(@to_folder))
        Rockdove.logger.info "Rockdove delivered & archived the mail."
      end
    end

    def destination(to_folder)
      Viewpoint::EWS::Folder.get_folder_by_name(to_folder)
    end
  end
end