Add batch proxy booking for self-scheduled experiments

src/Jiaowu.Api/Controllers/ExperimentsController.cs

@@ -1308,6 +1308,104 @@ public sealed class ExperimentsController(
             IsolationLevel.Serializable);
     }
 
+    [HttpPost("sessions/{id:guid}/proxy-bookings/batch")]
+    [Authorize(Roles = Managers)]
+    public async Task<ActionResult> CreateProxyBookings(
+        Guid id,
+        ProxyExperimentBookingBatchRequest request,
+        CancellationToken cancellationToken)
+    {
+        var studentIds = request.StudentIds.Distinct().ToArray();
+        if (studentIds.Length == 0)
+            return ValidationProblem("请至少选择一名学生。");
+        if (studentIds.Length > 100)
+            return ValidationProblem("单次最多可代选 100 名学生。");
+
+        return await db.ExecuteInRetriableTransactionAsync<ActionResult>(
+            async transaction =>
+            {
+                db.ChangeTracker.Clear();
+                var session = await LoadManagedSessionAsync(id, cancellationToken);
+                if (session is null) return NotFound();
+                if (!CanManageSession(session)) return Forbid();
+                if (session.Status != ExperimentSessionStatus.Scheduled ||
+                    session.ExperimentProject!.Status != ExperimentProjectStatus.Published ||
+                    session.ExperimentProject.ArrangementMode != ExperimentArrangementMode.SelfScheduled)
+                    return ConflictProblem("只能为已发布的自行安排实验场次代选学生。");
+
+                var students = await db.Students
+                    .WhereIn(studentIds, x => x.Id)
+                    .OrderBy(x => x.StudentNumber)
+                    .ToListAsync(cancellationToken);
+                if (students.Count != studentIds.Length)
+                    return ValidationProblem("存在无效的学生档案。");
+                var inactive = students.FirstOrDefault(x => x.Status != StudentStatus.Active);
+                if (inactive is not null)
+                    return ConflictProblem($"学生 {inactive.StudentNumber} {inactive.Name} 当前不是在籍状态。");
+
+                var roster = await TeachingTaskRosterQuery.LoadForTasksAsync(
+                    db, [session.ExperimentProject.TeachingTaskId], cancellationToken);
+                var eligibleStudentIds = roster.Select(x => x.StudentId).ToHashSet();
+                var outOfRoster = students.FirstOrDefault(x => !eligibleStudentIds.Contains(x.Id));
+                if (outOfRoster is not null)
+                    return ConflictProblem($"学生 {outOfRoster.StudentNumber} {outOfRoster.Name} 不在本实验项目的教学任务名单内。");
+
+                var existingBookings = await db.ExperimentBookings
+                    .Where(x => x.ExperimentProjectId == session.ExperimentProjectId)
+                    .WhereIn(studentIds, x => x.StudentId)
+                    .ToListAsync(cancellationToken);
+                var booked = existingBookings.FirstOrDefault(x =>
+                    x.Status == ExperimentBookingStatus.Booked);
+                if (booked is not null)
+                {
+                    var student = students.First(x => x.Id == booked.StudentId);
+                    return ConflictProblem(booked.ExperimentSessionId == session.Id
+                        ? $"学生 {student.StudentNumber} {student.Name} 已预约本实验场次。"
+                        : $"学生 {student.StudentNumber} {student.Name} 已预约本实验项目的其他场次。");
+                }
+
+                foreach (var student in students)
+                {
+                    var scheduleProblem = await StudentConflictAsync(student.Id, session, cancellationToken);
+                    if (scheduleProblem is not null)
+                        return ConflictProblem($"学生 {student.StudentNumber} {student.Name}：{scheduleProblem}");
+                }
+
+                var reservedCount = await db.ExperimentBookings.CountAsync(x =>
+                    x.ExperimentSessionId == session.Id && x.Status == ExperimentBookingStatus.Booked,
+                    cancellationToken);
+                if (reservedCount + students.Count > session.Capacity)
+                    return ConflictProblem($"该实验场次仅剩 {Math.Max(0, session.Capacity - reservedCount)} 个名额，无法完成本次代选。");
+
+                foreach (var student in students)
+                {
+                    var existing = existingBookings.FirstOrDefault(x => x.StudentId == student.Id);
+                    if (existing is null)
+                    {
+                        db.ExperimentBookings.Add(new ExperimentBooking
+                        {
+                            ExperimentProjectId = session.ExperimentProjectId,
+                            ExperimentSessionId = session.Id,
+                            StudentId = student.Id
+                        });
+                    }
+                    else
+                    {
+                        existing.ExperimentSessionId = session.Id;
+                        existing.Status = ExperimentBookingStatus.Booked;
+                        existing.BookedAt = DateTime.UtcNow;
+                        existing.CancelledAt = null;
+                    }
+                }
+                session.ReservedCount = reservedCount + students.Count;
+                await db.SaveChangesAsync(cancellationToken);
+                await transaction.CommitAsync(cancellationToken);
+                return Ok(new { BookedCount = students.Count });
+            },
+            cancellationToken,
+            IsolationLevel.Serializable);
+    }
+
     [HttpPost("sessions/{id:guid}/book")]
     [Authorize(Roles = SystemRoles.Student)]
     public async Task<ActionResult> Book(
@@ -1967,6 +2065,9 @@ public sealed record ExperimentSessionRequest(
 
 public sealed record ProxyExperimentBookingRequest(Guid StudentId);
 
+public sealed record ProxyExperimentBookingBatchRequest(
+    [Required, MinLength(1)] IReadOnlyCollection<Guid> StudentIds);
+
 public sealed record ExperimentSessionBatchRequest(
     [Required] IReadOnlyList<ExperimentSessionBatchItem> Items);