osem-fcy/app/mailers/mailbot.rb

class Mailbot < ActionMailer::Base
  default from: "no-reply@example.com"

  def registration_mail(conference, user)
    # Send default template if subject or template is blank
    if conference.email_settings.registration_subject.blank? ||
    conference.email_settings.registration_email_template.blank?
      subject = "Registration for #{conference.title}"
      template = 'registration_default_template'
      send_default_mail(template,
                        subject,
                        conference,
                        user)
    else
      build_email(conference,
                  user.email,
                  conference.email_settings.registration_subject,
                  conference.email_settings.generate_registration_email(conference, user))
    end
  end

  def acceptance_mail(event)
    conference = event.conference
    user = event.submitter

    # Send default template if subject or template is blank
    if conference.email_settings.accepted_subject.blank? ||
        conference.email_settings.accepted_email_template.blank?
      subject = 'Your proposal has been accepted'
      template = 'accepted_default_template'
      send_default_mail(template,
                        subject,
                        conference,
                        user,
                        event)
    else
      build_email(conference,
                  user.email,
                  conference.email_settings.accepted_subject,
                  conference.email_settings.generate_accepted_email(event))
    end
  end

  def rejection_mail(event)
    conference = event.conference
    user = event.submitter

    # Send default template if subject or template is blank
    if conference.email_settings.rejected_subject.blank? ||
        conference.email_settings.rejected_email_template.blank?
      subject = 'Your proposal has been rejected'
      template = 'rejected_default_template'
      send_default_mail(template,
                        subject,
                        conference,
                        user,
                        event)
    else
    build_email(conference,
                user.email,
                conference.email_settings.rejected_subject,
                conference.email_settings.generate_rejected_email(event))
    end
  end

  def confirm_reminder_mail(event)
    conference = event.conference
    user = event.submitter

    # Send default template if subject or template is blank
    if conference.email_settings.confirmed_without_registration_subject.blank? ||
        conference.email_settings.confirmed_email_template.blank?
      subject = "Your are not registered for #{conference.title}"
      template = 'confirmed_default_template'
      send_default_mail(template,
                        subject,
                        conference,
                        user,
                        event)
    else
      build_email(conference,
                  user.email,
                  conference.email_settings.confirmed_without_registration_subject,
                  conference.email_settings.confirmed_but_not_registered_email(event))
    end
  end

  def conference_date_update_mail(conference,dates)
    subject = conference.email_settings.updated_conference_dates_subject.blank? ? "#{conference.title} Dates Updated" : conference.email_settings.updated_conference_dates_subject
    partial = "#{conference.title}\n New Dates : #{dates}\n For more information visit #{Rails.application.routes.url_helpers.conference_path(conference.short_title,  host: CONFIG['url_for_emails'])}"
    body = conference.email_settings.updated_conference_dates_template.blank? ? "#{partial}" : "#{conference.email_settings.updated_conference_dates_template}\n #{partial}"
    conference.registrations.each do |u|
      build_email(conference, u.user.email, subject, body)
    end
  end

  def conference_registration_date_update_mail(conference, dates)
    subject = conference.email_settings.updated_conference_registration_dates_subject.blank? ? "#{conference.title} Registration Dates Updated" : conference.email_settings.updated_conference_registration_dates_subject
    partial = "#{conference.title}\n New Registration Dates : #{dates}\n For more information visit #{Rails.application.routes.url_helpers.conference_path(conference.short_title,  host: CONFIG['url_for_emails'])}"
    body = conference.email_settings.updated_conference_registration_dates_template.blank? ? "#{partial}" : "#{conference.email_settings.updated_conference_dates_template}\n #{partial}"
    conference.registrations.each do |u|
      build_email(conference, u.user.email, subject, body)
    end
  end

  def build_email(conference, to, subject, body)
    mail(:to => to,
         :from => conference.contact_email,
         :reply_to => conference.contact_email,
         :subject => subject,
         :body => body)
  end


  def send_default_mail(template, subject, conference, user, event = nil)
    @name = user.name
    @conference = conference
    if event
      @event = event
    end

    mail(to: user.email,
         from: conference.contact_email,
         reply_to: conference.contact_email,
         subject: subject,
         template_name: template,
         )
  end
end