feat: Report email with LIT authorization path (#3011)

To act on spam reports, the teacher needs to sign in through the
course to authenticate in the study group. The LTI return URL is used
to link back to the course.

Co-authored-by: Sebastian Serth <[email protected]

Relates to #2715

Author: arkirchner

app/mailers/report_mailer.rb

@@ -5,6 +5,13 @@ class ReportMailer < ApplicationMailer
 
   def report_content
     @reported_content = params.fetch(:reported_content)
+    study_group = @reported_content.submission.study_group
+    exercise = @reported_content.exercise
+
+    # NOTE: This implementation assumes the course URL is static and does not vary per user.
+    # This is currently valid for a majority of use cases. However, in dynamic scenarios (such as
+    # content trees in openHPI used in conjunction with A/B/n testing) this assumption may no longer hold true.
+    @course_url = LtiParameter.find_by(study_group:, exercise:)&.lti_parameters&.[]('launch_presentation_return_url')
 
     mail(subject: I18n.t('report_mailer.report_content.subject', content_name: @reported_content.model_name.human))
   end

app/views/report_mailer/report_content.html.slim

@@ -2,3 +2,5 @@ h3 = t('.prolog')
 blockquote style="white-space: pre-wrap;" = @reported_content.question
 p = t('.take_action')
 p = link_to(request_for_comment_url(@reported_content), request_for_comment_url(@reported_content))
+- if @course_url.present?
+  p = link_to(t('.authentication'), @course_url)

app/views/report_mailer/report_content.text.slim

@@ -5,3 +5,8 @@
 == t('.take_action')
 == "\n\n"
 == request_for_comment_url(@reported_content)
+== "\n\n"
+- if @course_url.present?
+  == t('.authentication')
+  == "\n\n"
+  == @course_url

config/locales/de/report.yml

@@ -2,6 +2,7 @@
 de:
   report_mailer:
     report_content:
+      authentication: Kurs-URL für die LTI-Authentifizierung.
       prolog: 'Die folgenden Inhalte wurden als unangemessen gemeldet:'
       subject: 'Spam Report: Ein %{content_name} in CodeOcean wurde als unangemessen markiert.'
       take_action: Bitte ergreifen Sie gegebenenfalls Maßnahmen.

config/locales/en/report.yml

@@ -2,6 +2,7 @@
 en:
   report_mailer:
     report_content:
+      authentication: Course URL for LTI authentication.
       prolog: 'The following content has been reported as inappropriate:'
       subject: 'Spam Report: A %{content_name} on CodeOcean has been marked as inappropriate.'
       take_action: Please take action if required.

spec/mailers/report_mailer_spec.rb

@@ -22,6 +22,15 @@
         expect(mail.text_part.body).to include(question)
         expect(mail.html_part.body).to include(question)
       end
+
+      it 'includes the LTI retrun URL for course authentication' do
+        create(:lti_parameter,
+          exercise: reported_content.exercise,
+          study_group: reported_content.submission.study_group)
+
+        expect(mail.text_part.body).to match(%r{https.+/courses/})
+        expect(mail.html_part.body).to match(%r{https.+/courses/})
+      end
     end
   end
 end