Allow random selection for ProxyExercise

app/controllers/proxy_exercises_controller.rb

@@ -42,7 +42,7 @@ class ProxyExercisesController < ApplicationController
 
   def proxy_exercise_params
     if params[:proxy_exercise].present?
-      params[:proxy_exercise].permit(:description, :title, :public, exercise_ids: []).merge(user_id: current_user.id,
+      params[:proxy_exercise].permit(:description, :title, :algorithm, :public, exercise_ids: []).merge(user_id: current_user.id,
         user_type: current_user.class.name)
     end
   end

app/models/proxy_exercise.rb

@@ -4,6 +4,11 @@ class ProxyExercise < ApplicationRecord
   include Creation
   include DefaultValues
 
+  enum algorithm: {
+    best_match: 0,
+    random: 1,
+  }, _default: :write, _prefix: true
+
   after_initialize :generate_token
   after_initialize :set_reason
   after_initialize :set_default_values
@@ -47,16 +52,25 @@ class ProxyExercise < ApplicationRecord
       Rails.logger.debug { "retrieved assigned exercise for user #{user.id}: Exercise #{assigned_user_proxy_exercise.exercise}" }
       assigned_user_proxy_exercise.exercise
     else
-      Rails.logger.debug { "find new matching exercise for user #{user.id}" }
       matching_exercise =
-        begin
-          find_matching_exercise(user)
-        rescue StandardError => e # fallback
-          Rails.logger.error("finding matching exercise failed. Fall back to random exercise! Error: #{$ERROR_INFO}")
-          @reason[:reason] = 'fallback because of error'
-          @reason[:error] = "#{$ERROR_INFO}:\n\t#{e.backtrace.join("\n\t")}"
-          exercises.where('expected_difficulty > 1').sample # difficulty should be > 1 to prevent dummy exercise from being chosen.
+        case algorithm
+          when 'best_match'
+            Rails.logger.debug { "find new matching exercise for user #{user.id}" }
+            begin
+              find_matching_exercise(user)
+            rescue StandardError => e # fallback
+              Rails.logger.error("finding matching exercise failed. Fall back to random exercise! Error: #{$ERROR_INFO}")
+              @reason[:reason] = 'fallback because of error'
+              @reason[:error] = "#{$ERROR_INFO}:\n\t#{e.backtrace.join("\n\t")}"
+              exercises.where('expected_difficulty > 1').sample # difficulty should be > 1 to prevent dummy exercise from being chosen.
+            end
+          when 'random'
+            @reason[:reason] = 'random exercise requested'
+            exercises.sample
+          else
+            raise "Unknown algorithm #{algorithm}"
         end
+
       user.user_proxy_exercise_exercises << UserProxyExerciseExercise.create(user:,
         exercise: matching_exercise, proxy_exercise: self, reason: @reason.to_json)
       matching_exercise

app/views/proxy_exercises/_form.html.slim

@@ -6,6 +6,9 @@
   .mb-3
     = f.label(:description, class: 'form-label')
     = f.pagedown :description, input_html: { preview: true, rows: 10 }
+  .mb-3
+    = f.label(:algorithm, class: 'form-label')
+    = f.collection_select(:algorithm, ProxyExercise.algorithms.map { |algorithm, _id| [t("activerecord.attributes.proxy_exercise.algorithm_type.#{algorithm}"), algorithm] }, :second, :first, {}, class: 'form-control form-control-sm')
   .form-check.mb-3
     label.form-check-label
       = f.check_box(:public, class: 'form-check-input')

app/views/proxy_exercises/show.html.slim

@@ -5,6 +5,7 @@ h1
 = row(label: 'exercise.title', value: @proxy_exercise.title)
 = row(label: 'exercise.user', value: link_to_if(policy(@proxy_exercise.author).show?, @proxy_exercise.author, @proxy_exercise.author))
 = row(label: 'proxy_exercise.files_count', value: @exercises.count)
+= row(label: 'proxy_exercise.algorithm', value: t("activerecord.attributes.proxy_exercise.algorithm_type.#{@proxy_exercise.algorithm}"))
 = row(label: 'exercise.public', value: @proxy_exercise.public?)
 = row(label: 'exercise.description', value: @proxy_exercise.description)
 = row(label: 'exercise.embedding_parameters', class: 'mb-4') do