优化考试排考

src/Jiaowu.Api/Controllers/ExamsController.cs

@@ -88,6 +88,10 @@ public sealed class ExamsController(
         if (plan.Status != ExamPlanStatus.Draft)
             return ConflictProblem("只有草稿考试计划可以删除。");
 
+        var rooms = await db.ExamRooms
+            .Where(x => x.ExamPlanId == id)
+            .ToListAsync(cancellationToken);
+        db.ExamRooms.RemoveRange(rooms);
         db.ExamPlans.Remove(plan);
         try
         {
@@ -147,6 +151,39 @@ public sealed class ExamsController(
             }).FirstOrDefaultAsync(cancellationToken);
         if (plan is null) return NotFound();
 
+        var roomEntities = await db.ExamRooms.AsNoTracking()
+            .Include(x => x.Classroom)
+                .ThenInclude(x => x!.Building)
+            .Include(x => x.SessionLinks)
+            .Include(x => x.Seats)
+            .Include(x => x.Invigilators)
+                .ThenInclude(x => x.Teacher)
+            .Where(x => x.ExamPlanId == id)
+            .ToListAsync(cancellationToken);
+        var roomsBySession = roomEntities
+            .SelectMany(room => room.SessionLinks.Select(link => new
+            {
+                link.ExamSessionId,
+                Room = new
+                {
+                    link.ExamRoomId,
+                    room.ClassroomId,
+                    ClassroomName = room.Classroom!.Name,
+                    BuildingName = room.Classroom.Building!.Name,
+                    ClassroomCapacity = room.Classroom.Capacity,
+                    SeatCount = room.Seats.Count(seat =>
+                        seat.ExamSessionId == link.ExamSessionId),
+                    TotalSeatCount = room.Seats.Count,
+                    IsMixed = room.SessionLinks.Count > 1,
+                    InvigilatorIds = room.Invigilators
+                        .Select(invigilator => invigilator.TeacherId)
+                        .ToList(),
+                    InvigilatorNames = room.Invigilators
+                        .Select(invigilator => invigilator.Teacher!.Name)
+                        .ToList()
+                }
+            }))
+            .ToLookup(x => x.ExamSessionId, x => x.Room);
         var rosterCounts = (await TeachingTaskRosterQuery.LoadForTasksAsync(
                 db,
                 plan.Sessions.Select(x => x.TeachingTaskId),
@@ -185,6 +222,7 @@ public sealed class ExamsController(
                 item.Notes,
                 item.InvigilatorIds,
                 item.InvigilatorNames,
+                ExamRooms = roomsBySession[item.Id],
                 StudentCount = rosterCounts.GetValueOrDefault(item.TeachingTaskId)
             })
         });
@@ -358,6 +396,7 @@ public sealed class ExamsController(
         session.RequiredInvigilatorCount = request.RequiredInvigilatorCount;
         session.Notes = Normalize(request.Notes);
 
+        await RemoveRoomsForSessionsAsync([id], cancellationToken);
         db.ExamSessionInvigilators.RemoveRange(session.Invigilators);
         session.Invigilators = (request.InvigilatorIds ?? []).Distinct().Select(tid =>
             new ExamSessionInvigilator { TeacherId = tid }).ToList();
@@ -377,6 +416,7 @@ public sealed class ExamsController(
         if (session is null) return NotFound();
         if (session.ExamPlan!.Status != ExamPlanStatus.Draft)
             return ConflictProblem("已发布的考试计划不能调整场次。");
+        await RemoveRoomsForSessionsAsync([id], cancellationToken);
         db.ExamSessions.Remove(session);
         return await SaveAsync(id, false, cancellationToken);
     }
@@ -408,6 +448,7 @@ public sealed class ExamsController(
             return ConflictProblem(
                 "所选考试场次包含不存在或不属于当前计划的记录，请刷新后重新选择。");
 
+        await RemoveRoomsForSessionsAsync(sessionIds, cancellationToken);
         db.ExamSessions.RemoveRange(sessions);
         try
         {
@@ -485,6 +526,19 @@ public sealed class ExamsController(
 
         var occupiedIds = await occupiedQuery.Select(x => x.ClassroomId!.Value)
             .ToListAsync(cancellationToken);
+        var occupiedRoomQuery = db.ExamRooms.AsNoTracking()
+            .Where(x => x.StartsAt < endsAt && startsAt < x.EndsAt);
+        if (planId.HasValue)
+            occupiedRoomQuery = occupiedRoomQuery.Where(
+                x => x.ExamPlanId == planId.Value);
+        if (excludeSessionId.HasValue)
+            occupiedRoomQuery = occupiedRoomQuery.Where(
+                x => !x.SessionLinks.Any(link =>
+                    link.ExamSessionId == excludeSessionId.Value));
+        occupiedIds.AddRange(await occupiedRoomQuery
+            .Select(x => x.ClassroomId)
+            .ToListAsync(cancellationToken));
+        occupiedIds = occupiedIds.Distinct().ToList();
 
         if (occupiedIds.Count > 0)
             query = query.WhereNotIn(occupiedIds, x => x.Id);
@@ -528,6 +582,20 @@ public sealed class ExamsController(
 
         var busyIds = await busyQuery.Select(x => x.TeacherId)
             .ToListAsync(cancellationToken);
+        var roomBusyQuery = db.ExamRoomInvigilators.AsNoTracking()
+            .Where(x => x.ExamRoom!.StartsAt < endsAt &&
+                        startsAt < x.ExamRoom.EndsAt);
+        if (planId.HasValue)
+            roomBusyQuery = roomBusyQuery.Where(
+                x => x.ExamRoom!.ExamPlanId == planId.Value);
+        if (excludeSessionId.HasValue)
+            roomBusyQuery = roomBusyQuery.Where(
+                x => !x.ExamRoom!.SessionLinks.Any(link =>
+                    link.ExamSessionId == excludeSessionId.Value));
+        busyIds.AddRange(await roomBusyQuery
+            .Select(x => x.TeacherId)
+            .ToListAsync(cancellationToken));
+        busyIds = busyIds.Distinct().ToList();
 
         return Ok(await db.Teachers.AsNoTracking()
             .Where(x => x.Status == TeacherStatus.Active)
@@ -570,7 +638,17 @@ public sealed class ExamsController(
     [Authorize(Roles = Managers)]
     public async Task<ActionResult> Publish(Guid id, CancellationToken cancellationToken)
     {
-        var plan = await db.ExamPlans.Include(x => x.Sessions)
+        var plan = await db.ExamPlans
+            .Include(x => x.Sessions)
+                .ThenInclude(x => x.Invigilators)
+            .Include(x => x.Sessions)
+                .ThenInclude(x => x.RoomLinks)
+                    .ThenInclude(x => x.ExamRoom)
+                        .ThenInclude(x => x!.Seats)
+            .Include(x => x.Sessions)
+                .ThenInclude(x => x.RoomLinks)
+                    .ThenInclude(x => x.ExamRoom)
+                        .ThenInclude(x => x!.Invigilators)
             .FirstOrDefaultAsync(x => x.Id == id, cancellationToken);
         if (plan is null) return NotFound();
         if (plan.Status != ExamPlanStatus.Draft)
@@ -578,11 +656,39 @@ public sealed class ExamsController(
         if (!plan.Sessions.Any())
             return ConflictProblem("至少安排一个考试场次后才能发布。");
 
+        var rosterCounts = (await TeachingTaskRosterQuery.LoadForTasksAsync(
+                db,
+                plan.Sessions.Select(x => x.TeachingTaskId),
+                cancellationToken))
+            .GroupBy(x => x.TeachingTaskId)
+            .ToDictionary(x => x.Key, x => x.Count());
         var unassigned = plan.Sessions.Count(x =>
-            !x.ClassroomId.HasValue || x.Invigilators.Count == 0);
+        {
+            if (x.RoomLinks.Count == 0)
+                return !x.ClassroomId.HasValue || x.Invigilators.Count == 0;
+            var assignedSeatCount = x.RoomLinks
+                .SelectMany(link => link.ExamRoom!.Seats)
+                .Count(seat => seat.ExamSessionId == x.Id);
+            return assignedSeatCount !=
+                   rosterCounts.GetValueOrDefault(x.TeachingTaskId) ||
+                   x.RoomLinks.Any(link =>
+                       link.ExamRoom!.Invigilators.Count <
+                       link.ExamRoom.RequiredInvigilatorCount);
+        });
         if (unassigned > 0)
             return ConflictProblem(
-                $"还有 {unassigned} 个场次未分配考场或监考教师，请先完成自动编排。");
+                $"还有 {unassigned} 个教学班未完成考场座位或监考安排，请先完成自动编排。");
+
+        var invalidMixedRoomCount = await db.ExamRooms.AsNoTracking()
+            .CountAsync(room =>
+                room.ExamPlanId == id &&
+                (room.Seats.Count > room.Classroom!.Capacity ||
+                 room.SessionLinks.Any(link =>
+                     link.ExamSession!.TeachingTask!.CourseId != room.CourseId)),
+                cancellationToken);
+        if (invalidMixedRoomCount > 0)
+            return ConflictProblem(
+                $"发现 {invalidMixedRoomCount} 个考场容量超限或混入不同课程，请重新编排。");
 
         plan.Status = ExamPlanStatus.Published;
         plan.PublishedAt = DateTime.UtcNow;
@@ -610,6 +716,51 @@ public sealed class ExamsController(
             }).FirstOrDefaultAsync(cancellationToken);
         if (session is null) return NotFound();
 
+        var assignedStudents = await db.ExamSeats.AsNoTracking()
+            .Where(x => x.ExamSessionId == id)
+            .OrderBy(x => x.ExamRoom!.Classroom!.Building!.Name)
+            .ThenBy(x => x.ExamRoom!.Classroom!.Name)
+            .ThenBy(x => x.SeatNumber)
+            .Select(x => new
+            {
+                x.StudentId,
+                x.Student!.StudentNumber,
+                x.Student.Name,
+                ClassName = x.Student.AdministrativeClass!.Name,
+                x.ExamRoomId,
+                ClassroomName = x.ExamRoom!.Classroom!.Name,
+                BuildingName = x.ExamRoom.Classroom.Building!.Name,
+                x.SeatNumber
+            })
+            .ToListAsync(cancellationToken);
+        if (assignedStudents.Count > 0)
+        {
+            return Ok(new
+            {
+                session.Id,
+                session.TeachingTaskId,
+                session.TaskNumber,
+                session.CourseName,
+                ClassroomName = string.Join(
+                    "、",
+                    assignedStudents
+                        .Select(x => $"{x.BuildingName} · {x.ClassroomName}")
+                        .Distinct()),
+                session.StartsAt,
+                Students = assignedStudents.Select(student => new
+                {
+                    student.StudentId,
+                    student.StudentNumber,
+                    student.Name,
+                    student.ClassName,
+                    student.ExamRoomId,
+                    student.ClassroomName,
+                    student.BuildingName,
+                    SeatNumber = student.SeatNumber.ToString("D3")
+                })
+            });
+        }
+
         var students = await TeachingTaskRosterQuery.LoadForTasksAsync(
             db,
             [session.TeachingTaskId],
@@ -645,45 +796,92 @@ public sealed class ExamsController(
             .Select(x => new
             {
                 x.Name,
-                TermName = x.AcademicTerm!.Name,
+                TermName = x.AcademicTerm!.Name
-                Sessions = x.Sessions
-                    .OrderBy(session => session.ExamDate)
-                    .ThenBy(session => session.StartPeriod)
-                    .Select(session => new
-                    {
-                        session.Id,
-                        session.TeachingTaskId,
-                        session.ExamDate,
-                        session.StartsAt,
-                        session.EndsAt,
-                        CourseCode = session.TeachingTask!.Course!.Code,
-                        CourseName = session.TeachingTask.Course.Name,
-                        session.TeachingTask.TaskNumber,
-                        BuildingName = session.Classroom != null
-                            ? session.Classroom.Building!.Name
-                            : null,
-                        ClassroomName = session.Classroom != null
-                            ? session.Classroom.Name
-                            : null,
-                        InvigilatorNames = session.Invigilators
-                            .OrderBy(item => item.Teacher!.TeacherNumber)
-                            .Select(item => item.Teacher!.Name)
-                    })
             })
             .FirstOrDefaultAsync(cancellationToken);
         if (plan is null) return NotFound();
-        if (!plan.Sessions.Any())
+
+        var rooms = await db.ExamRooms.AsNoTracking()
+            .Include(x => x.Course)
+            .Include(x => x.Classroom)
+                .ThenInclude(x => x!.Building)
+            .Include(x => x.Invigilators)
+                .ThenInclude(x => x.Teacher)
+            .Include(x => x.SessionLinks)
+                .ThenInclude(x => x.ExamSession)
+                    .ThenInclude(x => x!.TeachingTask)
+            .Include(x => x.Seats)
+                .ThenInclude(x => x.Student)
+                    .ThenInclude(x => x!.AdministrativeClass)
+            .Where(x => x.ExamPlanId == id)
+            .OrderBy(x => x.ExamDate)
+            .ThenBy(x => x.StartPeriod)
+            .ThenBy(x => x.Classroom!.Building!.Name)
+            .ThenBy(x => x.Classroom!.Name)
+            .ToListAsync(cancellationToken);
+        var legacySessions = await db.ExamSessions.AsNoTracking()
+            .Where(x => x.ExamPlanId == id)
+            .Where(x => !x.RoomLinks.Any())
+            .OrderBy(x => x.ExamDate)
+            .ThenBy(x => x.StartPeriod)
+            .Select(session => new
+            {
+                session.Id,
+                session.TeachingTaskId,
+                session.ExamDate,
+                session.StartsAt,
+                session.EndsAt,
+                CourseCode = session.TeachingTask!.Course!.Code,
+                CourseName = session.TeachingTask.Course.Name,
+                session.TeachingTask.TaskNumber,
+                BuildingName = session.Classroom != null
+                    ? session.Classroom.Building!.Name
+                    : null,
+                ClassroomName = session.Classroom != null
+                    ? session.Classroom.Name
+                    : null,
+                InvigilatorNames = session.Invigilators
+                    .OrderBy(item => item.Teacher!.TeacherNumber)
+                    .Select(item => item.Teacher!.Name)
+            })
+            .ToListAsync(cancellationToken);
+        if (rooms.Count == 0 && legacySessions.Count == 0)
             return ConflictProblem("当前考试计划没有可导出的考试场次。");
 
         var roster = await TeachingTaskRosterQuery.LoadForTasksAsync(
             db,
-            plan.Sessions.Select(x => x.TeachingTaskId),
+            legacySessions.Select(x => x.TeachingTaskId),
             cancellationToken);
         var studentsByTask = roster.ToLookup(x => x.TeachingTaskId);
-        var data = new ExamSignInWorkbookData(
+        var sheets = rooms.Select(room => new ExamSignInSessionData(
-            plan.Name,
+                room.Id,
-            plan.TermName,
+                room.ExamDate,
-            plan.Sessions.Select(session => new ExamSignInSessionData(
+                room.StartsAt,
+                room.EndsAt,
+                room.Course!.Code,
+                room.Course.Name,
+                string.Join(
+                    "、",
+                    room.SessionLinks
+                        .Select(link => link.ExamSession!.TeachingTask!.TaskNumber)
+                        .Distinct()
+                        .OrderBy(x => x)),
+                room.Classroom!.Building!.Name,
+                room.Classroom.Name,
+                room.Invigilators
+                    .OrderBy(item => item.Teacher!.TeacherNumber)
+                    .Select(item => item.Teacher!.Name)
+                    .ToList(),
+                room.Seats
+                    .OrderBy(seat => seat.SeatNumber)
+                    .Select(seat => new ExamSignInStudentData(
+                        seat.StudentId,
+                        seat.Student!.StudentNumber,
+                        seat.Student.Name,
+                        seat.Student.AdministrativeClass!.Name,
+                        seat.SeatNumber))
+                    .ToList()))
+            .Concat(legacySessions.Select(session => new ExamSignInSessionData(
                 session.Id,
                 session.ExamDate,
                 session.StartsAt,
@@ -695,13 +893,18 @@ public sealed class ExamsController(
                 session.ClassroomName,
                 session.InvigilatorNames.ToList(),
                 studentsByTask[session.TeachingTaskId]
-                    .Select(student => new ExamSignInStudentData(
+                    .Select((student, index) => new ExamSignInStudentData(
                         student.StudentId,
                         student.StudentNumber,
                         student.Name,
-                        student.ClassName))
+                        student.ClassName,
-                    .ToList()))
+                        index + 1))
-                .ToList());
+                    .ToList())))
+            .ToList();
+        var data = new ExamSignInWorkbookData(
+            plan.Name,
+            plan.TermName,
+            sheets);
 
         var bytes = ExamSignInWorkbookExporter.Create(data);
         return File(
@@ -724,11 +927,37 @@ public sealed class ExamsController(
                 .Select(x => (Guid?)x.Id).FirstOrDefaultAsync(cancellationToken);
             if (!studentId.HasValue)
                 return ConflictProblem("当前账号未关联学生档案。");
+
+            var assignedSchedule = await db.ExamSeats.AsNoTracking()
+                .Where(x =>
+                    x.StudentId == studentId.Value &&
+                    x.ExamRoom!.ExamPlan!.Status == ExamPlanStatus.Published)
+                .Select(x => new
+                {
+                    x.ExamSessionId,
+                    PlanName = x.ExamRoom!.ExamPlan!.Name,
+                    x.ExamRoom.ExamDate,
+                    x.ExamRoom.StartPeriod,
+                    x.ExamRoom.PeriodCount,
+                    x.ExamRoom.StartsAt,
+                    x.ExamRoom.EndsAt,
+                    x.ExamSession!.TeachingTask!.TaskNumber,
+                    CourseCode = x.ExamRoom.Course!.Code,
+                    CourseName = x.ExamRoom.Course.Name,
+                    ClassroomName = x.ExamRoom.Classroom!.Name,
+                    BuildingName = x.ExamRoom.Classroom.Building!.Name,
+                    InvigilatorNames = x.ExamRoom.Invigilators
+                        .Select(i => i.Teacher!.Name),
+                    x.SeatNumber
+                })
+                .ToListAsync(cancellationToken);
+
             var rosterTaskIds = TeachingTaskRosterQuery.TaskIdsForStudent(
                 db,
                 studentId.Value);
-            var schedule = await db.ExamSessions.AsNoTracking()
+            var legacySchedule = await db.ExamSessions.AsNoTracking()
                 .Where(x => x.ExamPlan!.Status == ExamPlanStatus.Published &&
+                    !x.RoomLinks.Any() &&
                     rosterTaskIds.Contains(x.TeachingTaskId))
                 .OrderBy(x => x.ExamDate).ThenBy(x => x.StartPeriod)
                 .Select(x => new
@@ -750,9 +979,10 @@ public sealed class ExamsController(
                     IsExam = true
                 })
                 .ToListAsync(cancellationToken);
-            if (schedule.Count == 0) return Ok(schedule);
+            var taskIds = legacySchedule
-
+                .Select(x => x.TeachingTaskId)
-            var taskIds = schedule.Select(x => x.TeachingTaskId).Distinct().ToArray();
+                .Distinct()
+                .ToArray();
             var seatRows = await TeachingTaskRosterQuery.LoadForTasksAsync(
                 db,
                 taskIds,
@@ -767,29 +997,77 @@ public sealed class ExamsController(
                 }))
                 .ToDictionary(x => (x.TeachingTaskId, x.StudentId), x => x.SeatNumber);
 
-            return Ok(schedule.Select(x => new
+            return Ok(assignedSchedule.Select(x => new ExamScheduleResponse(
-            {
+                    x.ExamSessionId,
-                x.Id,
+                    x.PlanName,
-                x.PlanName,
+                    x.ExamDate,
-                x.ExamDate,
+                    x.StartPeriod,
-                x.StartPeriod,
+                    x.PeriodCount,
-                x.PeriodCount,
+                    x.StartsAt,
-                x.StartsAt,
+                    x.EndsAt,
-                x.EndsAt,
+                    x.TaskNumber,
-                x.TaskNumber,
+                    x.CourseCode,
-                x.CourseCode,
+                    x.CourseName,
-                x.CourseName,
+                    x.ClassroomName,
-                x.ClassroomName,
+                    x.BuildingName,
-                x.BuildingName,
+                    x.InvigilatorNames.ToList(),
-                x.InvigilatorNames,
+                    x.SeatNumber.ToString("D3"),
-                SeatNumber = seatNumbers.GetValueOrDefault((x.TeachingTaskId, studentId.Value)),
+                    null,
-                x.IsExam
+                    true))
-            }));
+                .Concat(legacySchedule.Select(x => new ExamScheduleResponse(
+                    x.Id,
+                    x.PlanName,
+                    x.ExamDate,
+                    x.StartPeriod,
+                    x.PeriodCount,
+                    x.StartsAt,
+                    x.EndsAt,
+                    x.TaskNumber,
+                    x.CourseCode,
+                    x.CourseName,
+                    x.ClassroomName,
+                    x.BuildingName,
+                    x.InvigilatorNames.ToList(),
+                    seatNumbers.GetValueOrDefault(
+                        (x.TeachingTaskId, studentId.Value)),
+                    null,
+                    x.IsExam)))
+                .OrderBy(x => x.ExamDate)
+                .ThenBy(x => x.StartPeriod));
         }
         if (scope.IsInRole(SystemRoles.Teacher))
         {
-            var schedule = await db.ExamSessions.AsNoTracking()
+            var roomSchedule = await db.ExamRooms.AsNoTracking()
+                .Where(x =>
+                    x.ExamPlan!.Status == ExamPlanStatus.Published &&
+                    x.Invigilators.Any(i => i.Teacher!.UserId == scope.UserId))
+                .OrderBy(x => x.ExamDate)
+                .ThenBy(x => x.StartPeriod)
+                .Select(x => new
+                {
+                    x.Id,
+                    PlanName = x.ExamPlan!.Name,
+                    x.ExamDate,
+                    x.StartPeriod,
+                    x.PeriodCount,
+                    x.StartsAt,
+                    x.EndsAt,
+                    TaskNumbers = x.SessionLinks
+                        .Select(link =>
+                            link.ExamSession!.TeachingTask!.TaskNumber),
+                    CourseCode = x.Course!.Code,
+                    CourseName = x.Course.Name,
+                    ClassroomName = x.Classroom!.Name,
+                    BuildingName = x.Classroom.Building!.Name,
+                    InvigilatorNames = x.Invigilators
+                        .Select(i => i.Teacher!.Name),
+                    StudentCount = x.Seats.Count
+                })
+                .ToListAsync(cancellationToken);
+
+            var legacySchedule = await db.ExamSessions.AsNoTracking()
                 .Where(x => x.ExamPlan!.Status == ExamPlanStatus.Published &&
+                    !x.RoomLinks.Any() &&
                     x.Invigilators.Any(i => i.Teacher!.UserId == scope.UserId))
                 .OrderBy(x => x.ExamDate).ThenBy(x => x.StartPeriod)
                 .Select(x => new
@@ -813,28 +1091,46 @@ public sealed class ExamsController(
                 .ToListAsync(cancellationToken);
             var rosterCounts = (await TeachingTaskRosterQuery.LoadForTasksAsync(
                     db,
-                    schedule.Select(x => x.TeachingTaskId),
+                    legacySchedule.Select(x => x.TeachingTaskId),
                     cancellationToken))
                 .GroupBy(x => x.TeachingTaskId)
                 .ToDictionary(x => x.Key, x => x.Count());
-            return Ok(schedule.Select(x => new
+            return Ok(roomSchedule.Select(x => new ExamScheduleResponse(
-            {
+                    x.Id,
-                x.Id,
+                    x.PlanName,
-                x.PlanName,
+                    x.ExamDate,
-                x.ExamDate,
+                    x.StartPeriod,
-                x.StartPeriod,
+                    x.PeriodCount,
-                x.PeriodCount,
+                    x.StartsAt,
-                x.StartsAt,
+                    x.EndsAt,
-                x.EndsAt,
+                    string.Join("、", x.TaskNumbers.OrderBy(value => value)),
-                x.TaskNumber,
+                    x.CourseCode,
-                x.CourseCode,
+                    x.CourseName,
-                x.CourseName,
+                    x.ClassroomName,
-                x.ClassroomName,
+                    x.BuildingName,
-                x.BuildingName,
+                    x.InvigilatorNames.ToList(),
-                x.InvigilatorNames,
+                    null,
-                StudentCount = rosterCounts.GetValueOrDefault(x.TeachingTaskId),
+                    x.StudentCount,
-                x.IsExam
+                    true))
-            }));
+                .Concat(legacySchedule.Select(x => new ExamScheduleResponse(
+                    x.Id,
+                    x.PlanName,
+                    x.ExamDate,
+                    x.StartPeriod,
+                    x.PeriodCount,
+                    x.StartsAt,
+                    x.EndsAt,
+                    x.TaskNumber,
+                    x.CourseCode,
+                    x.CourseName,
+                    x.ClassroomName,
+                    x.BuildingName,
+                    x.InvigilatorNames.ToList(),
+                    null,
+                    rosterCounts.GetValueOrDefault(x.TeachingTaskId),
+                    x.IsExam)))
+                .OrderBy(x => x.ExamDate)
+                .ThenBy(x => x.StartPeriod));
         }
         return Ok(Array.Empty<object>());
     }
@@ -843,6 +1139,24 @@ public sealed class ExamsController(
     //  Private helpers
     // ═══════════════════════════════════════════
 
+    private async Task RemoveRoomsForSessionsAsync(
+        IReadOnlyCollection<Guid> sessionIds,
+        CancellationToken cancellationToken)
+    {
+        var ids = sessionIds.Distinct().ToArray();
+        if (ids.Length == 0) return;
+        var roomIds = await db.ExamRoomSessions.AsNoTracking()
+            .WhereIn(ids, x => x.ExamSessionId)
+            .Select(x => x.ExamRoomId)
+            .Distinct()
+            .ToListAsync(cancellationToken);
+        if (roomIds.Count == 0) return;
+        var rooms = await db.ExamRooms
+            .WhereIn(roomIds, x => x.Id)
+            .ToListAsync(cancellationToken);
+        db.ExamRooms.RemoveRange(rooms);
+    }
+
     private (DateTime StartsAt, DateTime EndsAt, ActionResult? Error) ResolveExamTime(
         Guid academicTermId,
         DateOnly examDate,
@@ -926,6 +1240,16 @@ public sealed class ExamsController(
             if (await overlaps.AnyAsync(
                     x => x.ClassroomId == classroomId.Value, cancellationToken))
                 return ConflictProblem("该时段考场已被占用。");
+            if (await db.ExamRooms.AsNoTracking().AnyAsync(
+                    room =>
+                        room.ClassroomId == classroomId.Value &&
+                        room.StartsAt < endsAt &&
+                        startsAt < room.EndsAt &&
+                        (!currentId.HasValue ||
+                         !room.SessionLinks.Any(link =>
+                             link.ExamSessionId == currentId.Value)),
+                    cancellationToken))
+                return ConflictProblem("该时段考场已被混排考试占用。");
         }
 
         if (teacherIds.Length > 0)
@@ -935,6 +1259,16 @@ public sealed class ExamsController(
                     .WhereIn(teacherIds, i => i.TeacherId)
                     .AnyAsync(cancellationToken))
                 return ConflictProblem("监考教师在该时段已有考试任务。");
+            if (await db.ExamRoomInvigilators.AsNoTracking()
+                    .Where(i =>
+                        i.ExamRoom!.StartsAt < endsAt &&
+                        startsAt < i.ExamRoom.EndsAt &&
+                        (!currentId.HasValue ||
+                         !i.ExamRoom.SessionLinks.Any(link =>
+                             link.ExamSessionId == currentId.Value)))
+                    .WhereIn(teacherIds, i => i.TeacherId)
+                    .AnyAsync(cancellationToken))
+                return ConflictProblem("监考教师在该时段已有混排考场任务。");
         }
 
         var overlappingTaskIds = await overlaps
@@ -1034,3 +1368,21 @@ public sealed record ExamAutoArrangeRequest(
     IReadOnlyCollection<Guid>? SessionIds = null,
     bool AssignClassrooms = true,
     bool AssignInvigilators = true);
+
+public sealed record ExamScheduleResponse(
+    Guid Id,
+    string PlanName,
+    DateOnly ExamDate,
+    int StartPeriod,
+    int PeriodCount,
+    DateTime StartsAt,
+    DateTime EndsAt,
+    string TaskNumber,
+    string CourseCode,
+    string CourseName,
+    string? ClassroomName,
+    string? BuildingName,
+    IReadOnlyCollection<string> InvigilatorNames,
+    string? SeatNumber,
+    int? StudentCount,
+    bool IsExam);

src/Jiaowu.Api/Domain/Academic/ExamEntities.cs

@@ -11,6 +11,7 @@ public sealed class ExamPlan : EntityBase
     public string? Notes { get; set; }
     public DateTime? PublishedAt { get; set; }
     public ICollection<ExamSession> Sessions { get; set; } = [];
+    public ICollection<ExamRoomAssignment> Rooms { get; set; } = [];
 }
 
 public sealed class ExamSession : EntityBase
@@ -31,6 +32,8 @@ public sealed class ExamSession : EntityBase
     public int RequiredInvigilatorCount { get; set; } = 2;
     public string? Notes { get; set; }
     public ICollection<ExamSessionInvigilator> Invigilators { get; set; } = [];
+    public ICollection<ExamRoomSession> RoomLinks { get; set; } = [];
+    public ICollection<ExamSeatAssignment> SeatAssignments { get; set; } = [];
 }
 
 public sealed class ExamSessionInvigilator
@@ -41,6 +44,52 @@ public sealed class ExamSessionInvigilator
     public Teacher? Teacher { get; set; }
 }
 
+public sealed class ExamRoomAssignment : EntityBase
+{
+    public Guid ExamPlanId { get; set; }
+    public ExamPlan? ExamPlan { get; set; }
+    public Guid CourseId { get; set; }
+    public Course? Course { get; set; }
+    public Guid ClassroomId { get; set; }
+    public Classroom? Classroom { get; set; }
+    public DateOnly ExamDate { get; set; }
+    public int StartPeriod { get; set; }
+    public int PeriodCount { get; set; }
+    public DateTime StartsAt { get; set; }
+    public DateTime EndsAt { get; set; }
+    public int RequiredInvigilatorCount { get; set; } = 2;
+    public ICollection<ExamRoomSession> SessionLinks { get; set; } = [];
+    public ICollection<ExamSeatAssignment> Seats { get; set; } = [];
+    public ICollection<ExamRoomInvigilator> Invigilators { get; set; } = [];
+}
+
+public sealed class ExamRoomSession
+{
+    public Guid ExamRoomId { get; set; }
+    public ExamRoomAssignment? ExamRoom { get; set; }
+    public Guid ExamSessionId { get; set; }
+    public ExamSession? ExamSession { get; set; }
+}
+
+public sealed class ExamSeatAssignment
+{
+    public Guid ExamRoomId { get; set; }
+    public ExamRoomAssignment? ExamRoom { get; set; }
+    public Guid ExamSessionId { get; set; }
+    public ExamSession? ExamSession { get; set; }
+    public Guid StudentId { get; set; }
+    public Student? Student { get; set; }
+    public int SeatNumber { get; set; }
+}
+
+public sealed class ExamRoomInvigilator
+{
+    public Guid ExamRoomId { get; set; }
+    public ExamRoomAssignment? ExamRoom { get; set; }
+    public Guid TeacherId { get; set; }
+    public Teacher? Teacher { get; set; }
+}
+
 public enum ExamPlanStatus
 {
     Draft = 1,

src/Jiaowu.Api/Infrastructure/Exams/ExamArrangementService.cs

@@ -7,8 +7,27 @@ namespace Jiaowu.Api.Infrastructure.Exams;
 
 public sealed class ExamArrangementService(AppDbContext db)
 {
-    private sealed record RoomOccupancy(Guid ClassroomId, DateTime StartsAt, DateTime EndsAt);
+    private sealed record RoomGroupKey(
-    private sealed record InvigilatorOccupancy(Guid TeacherId, DateTime StartsAt, DateTime EndsAt);
+        Guid CourseId,
+        DateOnly ExamDate,
+        int StartPeriod,
+        int PeriodCount,
+        Guid? RequiredBuildingId);
+
+    private sealed record RoomOccupancy(
+        Guid ClassroomId,
+        DateTime StartsAt,
+        DateTime EndsAt);
+
+    private sealed record InvigilatorOccupancy(
+        Guid TeacherId,
+        DateTime StartsAt,
+        DateTime EndsAt);
+
+    private sealed record CandidateSeat(
+        Guid ExamSessionId,
+        Guid StudentId,
+        string StudentNumber);
 
     public async Task<ExamArrangementResult> ArrangeAsync(
         Guid planId,
@@ -30,6 +49,12 @@ public sealed class ExamArrangementService(AppDbContext db)
             .Include(x => x.Sessions)
                 .ThenInclude(x => x.TeachingTask)
                     .ThenInclude(x => x!.Course)
+            .Include(x => x.Rooms)
+                .ThenInclude(x => x.SessionLinks)
+            .Include(x => x.Rooms)
+                .ThenInclude(x => x.Seats)
+            .Include(x => x.Rooms)
+                .ThenInclude(x => x.Invigilators)
             .FirstOrDefaultAsync(x => x.Id == planId, cancellationToken);
 
         if (plan is null)
@@ -46,206 +71,524 @@ public sealed class ExamArrangementService(AppDbContext db)
             plan.Sessions.Count(x => requestedIds.Contains(x.Id)) != requestedIds.Count)
             return ExamArrangementResult.Fail("所选场次不存在或不属于当前考试计划。");
 
-        var sessions = plan.Sessions
-            .Where(x => requestedIds.Count == 0 || requestedIds.Contains(x.Id))
-            .OrderBy(x => x.ExamDate)
-            .ThenBy(x => x.StartPeriod)
-            .ThenByDescending(x => x.RequiredInvigilatorCount)
-            .ToList();
-        if (sessions.Count == 0)
-            return ExamArrangementResult.Fail("没有可处理的考试场次。");
-
-        var termId = plan.AcademicTermId;
         var timeSlots = await db.ScheduleTimeSlots.AsNoTracking()
-            .Where(x => x.AcademicTermId == termId && x.IsEnabled)
+            .Where(x => x.AcademicTermId == plan.AcademicTermId && x.IsEnabled)
             .OrderBy(x => x.PeriodNumber)
             .ToListAsync(cancellationToken);
-
         if (timeSlots.Count == 0)
             return ExamArrangementResult.Fail("当前学期未配置上课时间表，无法计算考试时间段。");
 
         var timeSlotLookup = timeSlots.ToDictionary(x => x.PeriodNumber);
-        var rosterCounts = (await TeachingTaskRosterQuery.LoadForTasksAsync(
+        foreach (var session in plan.Sessions)
-                db,
-                sessions.Select(x => x.TeachingTaskId),
-                cancellationToken))
-            .GroupBy(x => x.TeachingTaskId)
-            .ToDictionary(x => x.Key, x => x.Count());
-
-        int assignedRooms = 0;
-        int assignedInvigilators = 0;
-        int unavailableRooms = 0;
-        int unavailableInvigilators = 0;
-        var messages = new List<string>();
-
-        // Track occupied time slots to avoid conflicts
-        var occupiedRooms = sessions
-            .Where(x => x.ClassroomId.HasValue)
-            .Select(x => new RoomOccupancy(x.ClassroomId!.Value, x.StartsAt, x.EndsAt))
-            .ToList();
-
-        var occupiedInvigilators = sessions
-            .SelectMany(x => x.Invigilators.Select(i =>
-                new InvigilatorOccupancy(i.TeacherId, x.StartsAt, x.EndsAt)))
-            .ToList();
-
-        foreach (var session in sessions)
-        {
-            // Compute StartsAt/EndsAt from time slots
             ComputeTimesFromSlots(session, timeSlotLookup);
-            var studentCount = rosterCounts.GetValueOrDefault(session.TeachingTaskId);
 
-            // ── Auto-assign classroom ──
+        var explicitlySelected = plan.Sessions
-            if (assignClassrooms && !session.ClassroomId.HasValue)
+            .Where(x => requestedIds.Count == 0 || requestedIds.Contains(x.Id))
+            .ToList();
+        if (explicitlySelected.Count == 0)
+            return ExamArrangementResult.Fail("没有可处理的考试场次。");
+
+        var selectedKeys = explicitlySelected
+            .Select(GroupKey)
+            .ToHashSet();
+        var sessions = plan.Sessions
+            .Where(x => selectedKeys.Contains(GroupKey(x)))
+            .OrderBy(x => x.ExamDate)
+            .ThenBy(x => x.StartPeriod)
+            .ThenBy(x => x.TeachingTask!.Course!.Code)
+            .ThenBy(x => x.TeachingTask!.TaskNumber)
+            .ToList();
+        var sessionIds = sessions.Select(x => x.Id).ToHashSet();
+
+        var roster = await TeachingTaskRosterQuery.LoadForTasksAsync(
+            db,
+            sessions.Select(x => x.TeachingTaskId),
+            cancellationToken);
+        var sessionByTaskId = sessions
+            .GroupBy(x => x.TeachingTaskId)
+            .ToDictionary(x => x.Key, x => x.First());
+
+        var replacedRooms = assignClassrooms
+            ? plan.Rooms
+                .Where(room => room.SessionLinks.Any(link =>
+                    sessionIds.Contains(link.ExamSessionId)))
+                .ToList()
+            : [];
+        var replacedRoomIds = replacedRooms.Select(x => x.Id).ToHashSet();
+        if (replacedRooms.Count > 0)
+            db.ExamRooms.RemoveRange(replacedRooms);
+
+        var occupiedRooms = await LoadOccupiedRoomsAsync(
+            plan,
+            sessionIds,
+            replacedRoomIds,
+            cancellationToken);
+        var rooms = await db.Classrooms.AsNoTracking()
+            .Include(x => x.Building)
+            .Where(x => x.IsEnabled)
+            .OrderBy(x => x.Building!.Name)
+            .ThenBy(x => x.Name)
+            .ToListAsync(cancellationToken);
+
+        var targetRooms = new List<ExamRoomAssignment>();
+        var messages = new List<string>();
+        var seatedStudents = 0;
+        var unavailableStudents = 0;
+
+        if (assignClassrooms)
+        {
+            foreach (var session in sessions)
             {
-                var room = await FindBestClassroomAsync(
+                session.ClassroomId = null;
-                    session, studentCount, occupiedRooms, cancellationToken);
+                if (session.Invigilators.Count > 0)
-                if (room is not null)
                 {
-                    session.ClassroomId = room.Id;
+                    db.ExamSessionInvigilators.RemoveRange(session.Invigilators);
-                    occupiedRooms.Add(new RoomOccupancy(room.Id, session.StartsAt, session.EndsAt));
+                    session.Invigilators.Clear();
-                    assignedRooms++;
-                    messages.Add(
-                        $"“{session.TeachingTask!.Course!.Name}”→{room.Name}({room.Capacity}座)");
-                }
-                else
-                {
-                    unavailableRooms++;
-                    messages.Add(
-                        $"“{session.TeachingTask!.Course!.Name}”：无可用考场（需≥{studentCount}座）");
                 }
             }
-            // ── Auto-assign invigilators ──
+
-            var currentInvigilatorCount = session.Invigilators.Count;
+            foreach (var group in sessions
-            var needed = session.RequiredInvigilatorCount - currentInvigilatorCount;
+                         .GroupBy(GroupKey)
-            if (assignInvigilators && needed > 0)
+                         .OrderBy(x => x.Key.ExamDate)
+                         .ThenBy(x => x.Key.StartPeriod)
+                         .ThenBy(x => x.First().TeachingTask!.Course!.Code))
             {
-                var courseTeacherIds = session.TeachingTask!.Teachers
+                var groupSessions = group.ToList();
-                    .Select(x => x.TeacherId).ToHashSet();
+                var candidates = InterleaveCandidates(
-                var newlyAssigned = await FindInvigilatorsAsync(
+                    groupSessions,
-                    session, needed, courseTeacherIds,
+                    roster,
-                    occupiedInvigilators, cancellationToken);
+                    sessionByTaskId);
-                foreach (var teacher in newlyAssigned)
+                if (candidates.Count == 0)
                 {
-                    session.Invigilators.Add(new ExamSessionInvigilator
+                    messages.Add(
+                        $"“{groupSessions[0].TeachingTask!.Course!.Name}”没有有效考生。");
+                    continue;
+                }
+
+                var availableRooms = rooms
+                    .Where(room =>
+                        (!group.Key.RequiredBuildingId.HasValue ||
+                         room.BuildingId == group.Key.RequiredBuildingId.Value) &&
+                        occupiedRooms.All(occupied =>
+                            occupied.ClassroomId != room.Id ||
+                            !ExamConflictRules.TimeOverlaps(
+                                occupied.StartsAt,
+                                occupied.EndsAt,
+                                groupSessions[0].StartsAt,
+                                groupSessions[0].EndsAt)))
+                    .ToList();
+                var selectedRooms = SelectRooms(
+                    availableRooms,
+                    candidates.Count);
+                if (selectedRooms.Sum(x => x.Capacity) < candidates.Count)
+                {
+                    unavailableStudents += candidates.Count;
+                    messages.Add(
+                        $"“{groupSessions[0].TeachingTask!.Course!.Name}”缺少足够考场容量，" +
+                        $"需 {candidates.Count} 座、可用 {selectedRooms.Sum(x => x.Capacity)} 座。");
+                    continue;
+                }
+
+                var offset = 0;
+                foreach (var classroom in selectedRooms)
+                {
+                    var roomCandidates = candidates
+                        .Skip(offset)
+                        .Take(classroom.Capacity)
+                        .ToList();
+                    if (roomCandidates.Count == 0) break;
+                    offset += roomCandidates.Count;
+
+                    var room = new ExamRoomAssignment
+                    {
+                        ExamPlanId = plan.Id,
+                        CourseId = group.Key.CourseId,
+                        ClassroomId = classroom.Id,
+                        ExamDate = group.Key.ExamDate,
+                        StartPeriod = group.Key.StartPeriod,
+                        PeriodCount = group.Key.PeriodCount,
+                        StartsAt = groupSessions[0].StartsAt,
+                        EndsAt = groupSessions[0].EndsAt,
+                        RequiredInvigilatorCount =
+                            groupSessions.Max(x => x.RequiredInvigilatorCount),
+                        SessionLinks = roomCandidates
+                            .Select(x => x.ExamSessionId)
+                            .Distinct()
+                            .Select(sessionId => new ExamRoomSession
+                            {
+                                ExamSessionId = sessionId
+                            })
+                            .ToList(),
+                        Seats = roomCandidates
+                            .Select((candidate, index) =>
+                                new ExamSeatAssignment
+                                {
+                                    ExamSessionId = candidate.ExamSessionId,
+                                    StudentId = candidate.StudentId,
+                                    SeatNumber = index + 1
+                                })
+                            .ToList()
+                    };
+                    db.ExamRooms.Add(room);
+                    targetRooms.Add(room);
+                    occupiedRooms.Add(new RoomOccupancy(
+                        classroom.Id,
+                        room.StartsAt,
+                        room.EndsAt));
+                    seatedStudents += roomCandidates.Count;
+                }
+
+                messages.Add(
+                    $"“{groupSessions[0].TeachingTask!.Course!.Name}”" +
+                    $"{groupSessions.Count}个教学班混排至{selectedRooms.Count}个考场。");
+            }
+        }
+        else
+        {
+            targetRooms.AddRange(plan.Rooms.Where(room =>
+                room.SessionLinks.Any(link =>
+                    sessionIds.Contains(link.ExamSessionId))));
+            var linkedSessionIds = targetRooms
+                .SelectMany(x => x.SessionLinks)
+                .Select(x => x.ExamSessionId)
+                .ToHashSet();
+            foreach (var session in sessions.Where(x =>
+                         !linkedSessionIds.Contains(x.Id) &&
+                         x.ClassroomId.HasValue))
+            {
+                var legacyRoom = CreateLegacyRoom(
+                    plan,
+                    session,
+                    roster.Where(x =>
+                        x.TeachingTaskId == session.TeachingTaskId));
+                db.ExamRooms.Add(legacyRoom);
+                targetRooms.Add(legacyRoom);
+                session.ClassroomId = null;
+                if (session.Invigilators.Count > 0)
+                {
+                    db.ExamSessionInvigilators.RemoveRange(session.Invigilators);
+                    session.Invigilators.Clear();
+                }
+            }
+            seatedStudents = targetRooms.Sum(x => x.Seats.Count);
+        }
+
+        var assignedInvigilators = 0;
+        var unavailableInvigilators = 0;
+        if (assignInvigilators)
+        {
+            if (targetRooms.Count == 0)
+                return ExamArrangementResult.Fail("尚未生成实际考场，请先分配考场。");
+
+            var occupiedInvigilators = plan.Rooms
+                .Where(x => !replacedRoomIds.Contains(x.Id) &&
+                            !targetRooms.Any(target => target.Id == x.Id))
+                .SelectMany(room => room.Invigilators.Select(item =>
+                    new InvigilatorOccupancy(
+                        item.TeacherId,
+                        room.StartsAt,
+                        room.EndsAt)))
+                .Concat(plan.Sessions
+                    .Where(x => !sessionIds.Contains(x.Id))
+                    .SelectMany(session => session.Invigilators.Select(item =>
+                        new InvigilatorOccupancy(
+                            item.TeacherId,
+                            session.StartsAt,
+                            session.EndsAt))))
+                .ToList();
+
+            foreach (var room in targetRooms
+                         .OrderBy(x => x.ExamDate)
+                         .ThenBy(x => x.StartPeriod)
+                         .ThenBy(x => x.ClassroomId))
+            {
+                var needed = room.RequiredInvigilatorCount -
+                             room.Invigilators.Count;
+                if (needed <= 0) continue;
+
+                var linkedSessionIds = room.SessionLinks
+                    .Select(x => x.ExamSessionId)
+                    .ToHashSet();
+                var excludedTeacherIds = sessions
+                    .Where(x => linkedSessionIds.Contains(x.Id))
+                    .SelectMany(x => x.TeachingTask!.Teachers)
+                    .Select(x => x.TeacherId)
+                    .ToHashSet();
+                var teachers = await FindInvigilatorsAsync(
+                    room,
+                    needed,
+                    excludedTeacherIds,
+                    occupiedInvigilators,
+                    cancellationToken);
+                foreach (var teacher in teachers)
+                {
+                    room.Invigilators.Add(new ExamRoomInvigilator
                     {
-                        ExamSessionId = session.Id,
                         TeacherId = teacher.Id
                     });
                     occupiedInvigilators.Add(new InvigilatorOccupancy(
-                        teacher.Id, session.StartsAt, session.EndsAt));
+                        teacher.Id,
+                        room.StartsAt,
+                        room.EndsAt));
                     assignedInvigilators++;
                 }
 
-                if (newlyAssigned.Count < needed)
+                if (teachers.Count < needed)
-                {
+                    unavailableInvigilators += needed - teachers.Count;
-                    unavailableInvigilators += needed - newlyAssigned.Count;
-                    messages.Add(
-                        $"“{session.TeachingTask!.Course!.Name}”：仅找到{newlyAssigned.Count}/{needed}名监考教师");
-                }
             }
         }
 
         await db.SaveChangesAsync(cancellationToken);
 
+        var expandedCount = sessions.Count - explicitlySelected.Count;
+        var detail = messages.Count > 0
+            ? $" 详情：{string.Join("；", messages.Take(10))}"
+            : "";
         return new ExamArrangementResult(
             true,
-            $"{sessions.Count}个场次处理完成，分配{assignedRooms}个考场、{assignedInvigilators}名监考教师。" +
+            $"{sessions.Count}个教学班场次处理完成，生成{targetRooms.Count}个实际考场，" +
-            (unavailableRooms > 0 ? $" {unavailableRooms}个场次暂无可用考场。" : "") +
+            $"安排{seatedStudents}名考生、{assignedInvigilators}名监考教师。" +
-            (unavailableInvigilators > 0 ? $" 仍缺{unavailableInvigilators}名监考教师。" : "") +
+            (expandedCount > 0
-            (messages.Count > 0 ? $" 详情：{string.Join("；", messages.Take(10))}" : ""));
+                ? $" 为保持混排完整性，自动包含同组{expandedCount}个场次。"
+                : "") +
+            (unavailableStudents > 0
+                ? $" {unavailableStudents}名考生尚未安排考场。"
+                : "") +
+            (unavailableInvigilators > 0
+                ? $" 仍缺{unavailableInvigilators}名监考教师。"
+                : "") +
+            detail);
     }
 
+    private async Task<List<RoomOccupancy>> LoadOccupiedRoomsAsync(
+        ExamPlan plan,
+        IReadOnlySet<Guid> targetSessionIds,
+        IReadOnlySet<Guid> replacedRoomIds,
+        CancellationToken cancellationToken)
+    {
+        var occupied = plan.Rooms
+            .Where(x => !replacedRoomIds.Contains(x.Id))
+            .Select(x => new RoomOccupancy(
+                x.ClassroomId,
+                x.StartsAt,
+                x.EndsAt))
+            .ToList();
+        occupied.AddRange(plan.Sessions
+            .Where(x =>
+                !targetSessionIds.Contains(x.Id) &&
+                x.ClassroomId.HasValue)
+            .Select(x => new RoomOccupancy(
+                x.ClassroomId!.Value,
+                x.StartsAt,
+                x.EndsAt)));
+
+        var externalRooms = await db.ExamRooms.AsNoTracking()
+            .Where(x =>
+                x.ExamPlanId != plan.Id &&
+                x.ExamPlan!.Status != ExamPlanStatus.Archived)
+            .Select(x => new RoomOccupancy(
+                x.ClassroomId,
+                x.StartsAt,
+                x.EndsAt))
+            .ToListAsync(cancellationToken);
+        occupied.AddRange(externalRooms);
+
+        var externalLegacyRooms = await db.ExamSessions.AsNoTracking()
+            .Where(x =>
+                x.ExamPlanId != plan.Id &&
+                x.ExamPlan!.Status != ExamPlanStatus.Archived &&
+                x.ClassroomId != null)
+            .Select(x => new RoomOccupancy(
+                x.ClassroomId!.Value,
+                x.StartsAt,
+                x.EndsAt))
+            .ToListAsync(cancellationToken);
+        occupied.AddRange(externalLegacyRooms);
+        return occupied;
+    }
+
+    private async Task<List<Teacher>> FindInvigilatorsAsync(
+        ExamRoomAssignment room,
+        int needed,
+        HashSet<Guid> excludedTeacherIds,
+        List<InvigilatorOccupancy> occupied,
+        CancellationToken cancellationToken)
+    {
+        var busyTeacherIds = occupied
+            .Where(x => ExamConflictRules.TimeOverlaps(
+                x.StartsAt,
+                x.EndsAt,
+                room.StartsAt,
+                room.EndsAt))
+            .Select(x => x.TeacherId)
+            .ToHashSet();
+
+        var databaseBusyIds = await db.ExamRoomInvigilators.AsNoTracking()
+            .Where(x =>
+                x.ExamRoomId != room.Id &&
+                x.ExamRoom!.ExamPlan!.Status != ExamPlanStatus.Archived &&
+                x.ExamRoom.StartsAt < room.EndsAt &&
+                room.StartsAt < x.ExamRoom.EndsAt)
+            .Select(x => x.TeacherId)
+            .ToListAsync(cancellationToken);
+        foreach (var teacherId in databaseBusyIds)
+            busyTeacherIds.Add(teacherId);
+
+        var legacyBusyIds = await db.ExamSessionInvigilators.AsNoTracking()
+            .Where(x =>
+                x.ExamSession!.ExamPlan!.Status != ExamPlanStatus.Archived &&
+                x.ExamSession.StartsAt < room.EndsAt &&
+                room.StartsAt < x.ExamSession.EndsAt)
+            .Select(x => x.TeacherId)
+            .ToListAsync(cancellationToken);
+        foreach (var teacherId in legacyBusyIds)
+            busyTeacherIds.Add(teacherId);
+        foreach (var teacherId in excludedTeacherIds)
+            busyTeacherIds.Add(teacherId);
+
+        var candidates = await InvigilatorCandidateQuery
+            .Create(db, busyTeacherIds)
+            .ToListAsync(cancellationToken);
+        return candidates
+            .OrderBy(_ => Random.Shared.Next())
+            .Take(needed)
+            .ToList();
+    }
+
+    private static List<Classroom> SelectRooms(
+        IReadOnlyCollection<Classroom> availableRooms,
+        int candidateCount)
+    {
+        var remainingRooms = availableRooms.ToList();
+        var selected = new List<Classroom>();
+        var remainingSeats = candidateCount;
+        while (remainingSeats > 0 && remainingRooms.Count > 0)
+        {
+            var room = remainingRooms
+                           .Where(x => x.Capacity >= remainingSeats)
+                           .OrderBy(x => x.Capacity)
+                           .ThenBy(x => x.Name)
+                           .FirstOrDefault()
+                       ?? remainingRooms
+                           .OrderByDescending(x => x.Capacity)
+                           .ThenBy(x => x.Name)
+                           .First();
+            selected.Add(room);
+            remainingRooms.Remove(room);
+            remainingSeats -= room.Capacity;
+        }
+        return selected;
+    }
+
+    private static List<CandidateSeat> InterleaveCandidates(
+        IReadOnlyCollection<ExamSession> sessions,
+        IReadOnlyCollection<TeachingTaskRosterEntry> roster,
+        IReadOnlyDictionary<Guid, ExamSession> sessionByTaskId)
+    {
+        var sessionIds = sessions.Select(x => x.Id).ToHashSet();
+        var queues = roster
+            .Where(x =>
+                sessionByTaskId.TryGetValue(
+                    x.TeachingTaskId,
+                    out var session) &&
+                sessionIds.Contains(session.Id))
+            .GroupBy(x => x.TeachingTaskId)
+            .OrderBy(x => sessionByTaskId[x.Key].TeachingTask!.TaskNumber)
+            .Select(group => new Queue<CandidateSeat>(
+                group.OrderBy(x => x.StudentNumber)
+                    .Select(x => new CandidateSeat(
+                        sessionByTaskId[x.TeachingTaskId].Id,
+                        x.StudentId,
+                        x.StudentNumber))))
+            .ToList();
+
+        var result = new List<CandidateSeat>();
+        var assignedStudentIds = new HashSet<Guid>();
+        while (queues.Any(x => x.Count > 0))
+        {
+            foreach (var queue in queues)
+            {
+                while (queue.Count > 0)
+                {
+                    var candidate = queue.Dequeue();
+                    if (!assignedStudentIds.Add(candidate.StudentId))
+                        continue;
+                    result.Add(candidate);
+                    break;
+                }
+            }
+        }
+        return result;
+    }
+
+    private static ExamRoomAssignment CreateLegacyRoom(
+        ExamPlan plan,
+        ExamSession session,
+        IEnumerable<TeachingTaskRosterEntry> roster)
+    {
+        var students = roster
+            .OrderBy(x => x.StudentNumber)
+            .ToList();
+        return new ExamRoomAssignment
+        {
+            ExamPlanId = plan.Id,
+            CourseId = session.TeachingTask!.CourseId,
+            ClassroomId = session.ClassroomId!.Value,
+            ExamDate = session.ExamDate,
+            StartPeriod = session.StartPeriod,
+            PeriodCount = session.PeriodCount,
+            StartsAt = session.StartsAt,
+            EndsAt = session.EndsAt,
+            RequiredInvigilatorCount = session.RequiredInvigilatorCount,
+            SessionLinks =
+            [
+                new ExamRoomSession
+                {
+                    ExamSessionId = session.Id
+                }
+            ],
+            Seats = students.Select((student, index) =>
+                new ExamSeatAssignment
+                {
+                    ExamSessionId = session.Id,
+                    StudentId = student.StudentId,
+                    SeatNumber = index + 1
+                }).ToList(),
+            Invigilators = session.Invigilators.Select(x =>
+                new ExamRoomInvigilator
+                {
+                    TeacherId = x.TeacherId
+                }).ToList()
+        };
+    }
+
+    private static RoomGroupKey GroupKey(ExamSession session) => new(
+        session.TeachingTask!.CourseId,
+        session.ExamDate,
+        session.StartPeriod,
+        session.PeriodCount,
+        session.RequiredBuildingId);
+
     private static void ComputeTimesFromSlots(
         ExamSession session,
-        Dictionary<int, ScheduleTimeSlot> timeSlotLookup)
+        IReadOnlyDictionary<int, ScheduleTimeSlot> timeSlotLookup)
     {
         var startSlot = timeSlotLookup.GetValueOrDefault(session.StartPeriod);
         var endSlot = timeSlotLookup.GetValueOrDefault(
             session.StartPeriod + session.PeriodCount - 1);
         if (startSlot is null || endSlot is null) return;
 
-        var examDate = session.ExamDate;
+        session.StartsAt = session.ExamDate.ToDateTime(
-        session.StartsAt = examDate.ToDateTime(startSlot.StartsAt, DateTimeKind.Utc);
+            startSlot.StartsAt,
-        session.EndsAt = examDate.ToDateTime(endSlot.EndsAt, DateTimeKind.Utc);
+            DateTimeKind.Utc);
-    }
+        session.EndsAt = session.ExamDate.ToDateTime(
-
+            endSlot.EndsAt,
-    private async Task<Classroom?> FindBestClassroomAsync(
+            DateTimeKind.Utc);
-        ExamSession session,
-        int studentCount,
-        List<RoomOccupancy> occupied,
-        CancellationToken cancellationToken)
-    {
-        var query = db.Classrooms.AsNoTracking()
-            .Where(x => x.IsEnabled && x.Capacity >= studentCount);
-
-        if (session.RequiredBuildingId.HasValue)
-            query = query.Where(x => x.BuildingId == session.RequiredBuildingId.Value);
-
-        // Exclude classrooms already occupied in-memory
-        var occupiedRoomIds = occupied
-            .Where(x => ExamConflictRules.TimeOverlaps(
-                x.StartsAt, x.EndsAt, session.StartsAt, session.EndsAt))
-            .Select(x => x.ClassroomId)
-            .ToHashSet();
-
-        if (occupiedRoomIds.Count > 0)
-            query = query.WhereNotIn(occupiedRoomIds, x => x.Id);
-
-        // Exclude classrooms occupied by DB sessions not yet tracked in memory
-        var dbOccupiedRooms = await db.ExamSessions.AsNoTracking()
-            .Where(x => x.ExamPlanId == session.ExamPlanId &&
-                        x.Id != session.Id &&
-                        x.ClassroomId != null &&
-                        x.StartsAt < session.EndsAt &&
-                        session.StartsAt < x.EndsAt)
-            .Select(x => x.ClassroomId!.Value)
-            .ToListAsync(cancellationToken);
-
-        if (dbOccupiedRooms.Count > 0)
-            query = query.WhereNotIn(dbOccupiedRooms, x => x.Id);
-
-        return await query
-            .OrderBy(x => x.Capacity)
-            .FirstOrDefaultAsync(cancellationToken);
-    }
-
-    private async Task<List<Teacher>> FindInvigilatorsAsync(
-        ExamSession session,
-        int needed,
-        HashSet<Guid> excludeTeacherIds,
-        List<InvigilatorOccupancy> occupied,
-        CancellationToken cancellationToken)
-    {
-        var busyTeacherIds = occupied
-            .Where(x => ExamConflictRules.TimeOverlaps(
-                x.StartsAt, x.EndsAt, session.StartsAt, session.EndsAt))
-            .Select(x => x.TeacherId)
-            .ToHashSet();
-
-        var dbBusyIds = await db.ExamSessionInvigilators.AsNoTracking()
-            .Where(x => x.ExamSession!.ExamPlanId == session.ExamPlanId &&
-                        x.ExamSessionId != session.Id &&
-                        x.ExamSession!.StartsAt < session.EndsAt &&
-                        session.StartsAt < x.ExamSession.EndsAt)
-            .Select(x => x.TeacherId)
-            .ToListAsync(cancellationToken);
-
-        foreach (var id in dbBusyIds) busyTeacherIds.Add(id);
-        foreach (var id in excludeTeacherIds) busyTeacherIds.Add(id);
-
-        var candidates = await InvigilatorCandidateQuery
-            .Create(db, busyTeacherIds)
-            .ToListAsync(cancellationToken);
-
-        return candidates
-            .OrderBy(_ => Random.Shared.Next())
-            .Take(needed)
-            .ToList();
     }
 }
 
 public sealed record ExamArrangementResult(bool Success, string Message)
 {
-    public static ExamArrangementResult Fail(string message) => new(false, message);
+    public static ExamArrangementResult Fail(string message) =>
+        new(false, message);
 }