Added user certificate REPP endpoint and mailer

app/controllers/repp/v1/certificates_controller.rb

@@ -0,0 +1,51 @@
+module Repp
+  module V1
+    class CertificatesController < BaseController
+      THROTTLED_ACTIONS = %i[create].freeze
+      include Shunter::Integration::Throttle
+
+      api :POST, '/repp/v1/certificates'
+      desc 'Submit a new api user certificate signing request'
+      def create
+        authorize! :create, Certificate
+        @api_user = current_user.registrar.api_users.find(cert_params[:api_user_id])
+
+        csr = decode_cert_params(cert_params[:csr])
+
+        @certificate = @api_user.certificates.build(csr: csr)
+        unless @certificate.save
+          handle_non_epp_errors(@certificate)
+          return
+        end
+
+        notify_admins
+        render_success(data: { api_user: { id: @api_user.id } })
+      end
+
+      private
+
+      def cert_params
+        params.require(:certificate).permit(:api_user_id, csr: %i[body type])
+      end
+
+      def decode_cert_params(csr_params)
+        return if csr_params.blank?
+
+        Base64.decode64(csr_params[:body])
+      end
+
+      def notify_admins
+        admin_users_emails = User.all.select { |u| u.roles.include? 'admin' }.pluck(:email)
+
+        return if admin_users_emails.empty?
+
+        admin_users_emails.each do |email|
+          CertificateMailer.new_certificate_signing_request(email: email,
+                                                            api_user: @api_user,
+                                                            csr: @certificate)
+                           .deliver_now
+        end
+      end
+    end
+  end
+end