jpmckinney/multi_mail

module MultiMail
  module Sender
    # SendGrid's outgoing mail sender.
    class SendGrid
      include MultiMail::Sender::Base

      # @see http://sendgrid.com/docs/API_Reference/Web_API/
      requires :api_user, :api_key

      # Initializes a SendGrid outgoing email sender.
      #
      # @param [Hash] options required and optional arguments
      # @option options [String] :api_user a SendGrid API user
      # @option options [String] :api_key a SendGrid API key
      # @option options [Hash,String] the X-SMTPAPI SendGrid header
      # @see http://sendgrid.com/docs/API_Reference/SMTP_API/index.html
      def initialize(options = {})
        super
        if Hash === settings[:'x-smtpapi']
          settings[:'x-smtpapi'] = JSON.dump(settings[:'x-smtpapi'])
        end
      end

      # Delivers a message via the SendGrid API.
      #
      # @param [Mail::Message] mail a message
      # @see http://sendgrid.com/docs/API_Reference/Web_API/mail.html
      def deliver!(mail)
        parameters = settings.dup
        parameters.delete(:return_response)
        message = MultiMail::Message::SendGrid.new(mail).to_sendgrid_hash.merge(parameters)

        connection = Faraday.new do |conn|
          conn.request :multipart
          conn.request :url_encoded
          conn.adapter Faraday.default_adapter
        end

        response = connection.post('https://sendgrid.com/api/mail.send.json', message)

        body = JSON.load(response.body)

        unless response.status == 200
          if body['message'] == 'error'
            case body['errors']
            when ['Bad username / password']
              raise InvalidAPIKey, body['errors'].first
            when ['Empty from email address (required)']
              raise MissingSender, body['errors'].first
            when ['Missing destination email']
              raise MissingRecipients, body['errors'].first
            when ['Missing subject']
              raise MissingSubject, body['errors'].first
            when ['Missing email body']
              raise MissingBody, body['errors'].first
            else
              raise body['errors'].join
            end
          else
            raise body['errors'].join
          end
        end

        if settings[:return_response]
          body
        else
          self
        end
      end
    end
  end
end