Update

.drone.yml

@@ -181,3 +181,4 @@ trigger:
     - main
   event:
     - push
+    - promote

.example.env

@@ -23,7 +23,7 @@ POSTGRES_PASSWORD=
 
 # Backend
 BACKEND_MINIMUM_TEACHER_SELECTION_COUNT=6
-BACKEND_ASSIGNMENT_POSSIBILITY_COUNT=500
+BACKEND_ASSIGNMENT_POSSIBILITY_COUNT=65536
 BACKEND_URL=URL
 # Backend - API
 BACKEND_API_JWT_SECRET=

backend/src/backend/api/schema/mutation.cr

@@ -17,7 +17,6 @@
 require "ldap"
 require "uuid"
 require "uuid/json"
-require "random/secure"
 
 module Backend
   module Api

backend/src/backend/cli.cr

@@ -88,11 +88,8 @@ module Backend
         end
 
         user = Db::User.create!(username: username, role: role.to_s, admin: opts.bool["admin"])
-        case role.to_api
-        in Api::Schema::UserRole::Student
+        if role == Db::UserRole::Student
           Db::Student.create!(user_id: user.id)
-        in Api::Schema::UserRole::Teacher
-          # Db::Teacher.create!(user_id: user.id)
         end
 
         Worker::Jobs::CacheLdapUserJob.new(user.id).enqueue

backend/src/backend/worker/jobs/assignment_job.cr

@@ -54,11 +54,96 @@ module Backend
           teachers = Db::Teacher.query
             .where do
               raw("EXISTS (SELECT 1 FROM teacher_votes WHERE teacher_id = teachers.id)") &
-                max_students > 0
+                (max_students > 0)
             end
-          pp! teachers
-          students = Db::Student.query.with_vote(&.with_teacher_votes).to_a
-          pp! students
+            .with_teacher_votes
+            .to_a
+          vote_index = Hash.zip(teachers.map(&.id), [0] * teachers.size)
+          teacher_votes : Hash(Int32, Array(TeacherVote)) = Hash.zip(
+            teachers.map(&.id),
+            teachers.map do |t|
+              t.teacher_votes.map do |tv|
+                vote_index[t.id] += 1
+
+                {
+                  student:  tv.vote.student.id,
+                  priority: tv.priority,
+                }
+              end
+            end
+          )
+          teachers.sort_by! { |t| vote_index[t.id] }
+
+          students = Db::Student.query
+            .with_vote(&.with_teacher_votes(&.order_by(priority: :desc)))
+            .to_a
+          students.each do |s|
+            p! s
+            pp! s.vote.not_nil!.teacher_votes
+          end
+          student_ids = students.map(&.id)
+          votes = Hash.zip(
+            student_ids,
+            students.map do |s|
+              s.vote.not_nil!.teacher_votes
+                .to_a
+                .select { |tv| teacher_votes.has_key?(tv.teacher.id) }
+                .map do |tv|
+                  {
+                    teacher:              tv.teacher.id,
+                    teacher_max_students: tv.teacher.max_students,
+                  }
+                end
+            end
+          )
+          votes_a = votes.to_a
+
+          best : {assignment: Hash(Int32, Assignment), score: UInt32}? = nil
+          Backend.config.assignment_possibility_count.times.each do
+            assignment = {} of Int32 => Assignment
+            assignment_count = Hash.zip(teachers.map(&.id), [0] * teachers.size)
+            votes_a.shuffle(Random::Secure).each do |s, tvs|
+              tvs.each_with_index do |tv, i|
+                if assignment[s]?.nil?
+                  assignment_count[tv[:teacher]] += 1
+                  assignment[s] = {teacher: tv[:teacher], priority: i}
+                elsif assignment_count[tv[:teacher]] < tv[:teacher_max_students]
+                  assignment_count[assignment[s][:teacher]] -= 1
+                  assignment_count[tv[:teacher]] += 1
+                  assignment[s] = {teacher: tv[:teacher], priority: i}
+                end
+              end
+            end
+
+            score = 0_u32
+            assignment.each do |s, a|
+              score += a[:priority] ** 2
+            end
+
+            if best.nil?
+              best = {
+                assignment: assignment,
+                score:      score,
+              }
+            elsif score < best.not_nil![:score]
+              best = {
+                assignment: assignment,
+                score:      score,
+              }
+            end
+          end
+
+          pp! best
+
+          str = String.build do |str|
+            str << "===========================\n"
+            best.not_nil![:assignment].each do |s, a|
+              pp! a
+              str << "#{Db::Student.query.find!(s).user.username} #{s} : #{Db::Teacher.query.find!(a[:teacher]).user.username} #{a[:priority]} (#{votes[s].size - a[:priority]} / #{votes[s].size})\n"
+            end
+            str << "===========================\n"
+          end
+          print str
         end
       end
     end