Automatically submit LTI grade on each score run

With this commit, we refactor the overall score handling of CodeOcean. Previously, "Score" and "Submit" were two distinct actions, requiring users to confirm the LTI transmission of their score (after assessing their submission). This yielded many questions and was unnecessary, since LTI parameters are no longer expiring after each use. Therefore, we can now transmit the current grade on each score run with the very same LTI parameters. As a consequence, the LTI consumer gets a more detailed history of the scores, enabling further analytical insights.

For users, the previous "Submit" button got replaced with a notification that is shown as soon as the full score got reached. Then, learners can decide to "finalize" their work on the given exercise, which will initiate a redirect to a follow-up action (as defined in the RedirectBehavior). This RedirectBehavior has also been unified and simplified for better readability.

As part of this refactoring, we rephrased the notifications and UX workflow of a) the LTI transmission, b) the finalization of an exercise (measured by reaching the full score) and c) the deadline handling (on time, within grace period, too late). Those information are now separately shown, potentially resulting in multiple notifications. As a side effect, they are much better maintainable, and the LTI transmission is more decoupled from this notification handling.

app/controllers/concerns/lti.rb

@@ -123,47 +123,68 @@ module Lti
       raise Error.new("Score #{submission.normalized_score} must be between 0 and #{MAXIMUM_SCORE}!")
     end
 
-    submission.users.map {|user| send_score_for submission, user }
+    # Prepare score to be sent
+    score = submission.normalized_score
+    deadline = :none
+    if submission.before_deadline?
+      # Keep the full score
+      deadline = :before_deadline
+    elsif submission.within_grace_period?
+      # Reduce score by 20%
+      score *= 0.8
+      deadline = :within_grace_period
+    elsif submission.after_late_deadline?
+      # Reduce score by 100%
+      score *= 0.0
+      deadline = :after_late_deadline
+    end
+
+    # Actually send the score for all users
+    detailed_results = submission.users.map {|user| send_score_for submission, user, score }
+
+    # Prepare return value
+    erroneous_results = detailed_results.filter {|result| result[:status] == 'error' }
+    unsupported_results = detailed_results.filter {|result| result[:status] == 'unsupported' }
+    statistics = {
+      all: detailed_results,
+      success: detailed_results - erroneous_results - unsupported_results,
+      error: erroneous_results,
+      unsupported: unsupported_results,
+    }
+
+    {
+      users: statistics.transform_values {|value| value.pluck(:user) },
+      score: {original: submission.normalized_score, sent: score},
+      deadline:,
+      detailed_results:,
+    }
   end
 
   private :send_scores
 
-  def send_score_for(submission, user)
-    if user.external_user? && user.consumer
-      lti_parameter = user.lti_parameters.find_by(exercise: submission.exercise, study_group: submission.study_group)
-      provider = build_tool_provider(consumer: user.consumer, parameters: lti_parameter&.lti_parameters)
-    end
+  def send_score_for(submission, user, score)
+    return {status: 'error', user:} unless user.external_user? && user.consumer
 
-    if provider.nil?
-      {status: 'error', user: user.displayname}
-    elsif provider.outcome_service?
-      Sentry.set_extras({
-        provider: provider.inspect,
-        score: submission.normalized_score,
-        lti_parameter: lti_parameter.inspect,
-        session: session.to_hash,
-        exercise_id: submission.exercise_id,
-      })
-      normalized_lti_score = submission.normalized_score
-      if submission.before_deadline?
-        # Keep the full score
-      elsif submission.within_grace_period?
-        # Reduce score by 20%
-        normalized_lti_score *= 0.8
-      elsif submission.after_late_deadline?
-        # Reduce score by 100%
-        normalized_lti_score *= 0.0
-      end
+    lti_parameter = user.lti_parameters.find_by(exercise: submission.exercise, study_group: submission.study_group)
+    provider = build_tool_provider(consumer: user.consumer, parameters: lti_parameter&.lti_parameters)
+    return {status: 'error', user:} if provider.nil?
+    return {status: 'unsupported', user:} unless provider.outcome_service?
 
-      begin
-        response = provider.post_replace_result!(normalized_lti_score)
-        {code: response.response_code, message: response.post_response.body, status: response.code_major, score_sent: normalized_lti_score, user: user.displayname}
-      rescue IMS::LTI::XMLParseError, Net::OpenTimeout, Net::ReadTimeout, Errno::ECONNRESET, SocketError, EOFError
-        # A parsing error might happen if the LTI provider is down and doesn't return a valid XML response
-        {status: 'error', user: user.displayname}
-      end
-    else
-      {status: 'unsupported', user: user.displayname}
+    Sentry.set_extras({
+      provider: provider.inspect,
+      normalized_score: submission.normalized_score,
+      score:,
+      lti_parameter: lti_parameter.inspect,
+      session: defined?(session) ? session.to_hash : nil,
+      exercise_id: submission.exercise_id,
+    })
+
+    begin
+      response = provider.post_replace_result!(score)
+      {code: response.response_code, message: response.post_response.body, status: response.code_major, user:}
+    rescue IMS::LTI::XMLParseError, Net::OpenTimeout, Net::ReadTimeout, Errno::ECONNRESET, SocketError, EOFError
+      # A parsing error might happen if the LTI provider is down and doesn't return a valid XML response
+      {status: 'error', user:}
     end
   end