优化服务器端分页

src/Jiaowu.Api/Controllers/StudentStatusChangesController.cs

@@ -17,17 +17,53 @@ public sealed class StudentStatusChangesController(
     ICurrentUserDataScope currentUserDataScope) : ControllerBase
 {
     [HttpGet]
-    public async Task<ActionResult> Get(CancellationToken token)
+    public async Task<ActionResult<StudentStatusChangePage>> Get(
+        int page = 1,
+        int pageSize = 20,
+        CancellationToken token = default)
     {
+        if (page < 1 || pageSize is < 1 or > 100)
+            return ValidationProblem("页码必须大于 0，且每页条数应在 1 至 100 之间。");
+
         var source = ScopedChanges().AsNoTracking();
-        return Ok(await source.OrderByDescending(x => x.SubmittedAt).Select(x => new
-        {
-            x.Id, x.StudentId, x.Student!.StudentNumber, x.Student.Name,
-            ClassName = x.Student.AdministrativeClass!.Name,
-            CollegeName = x.Student.AdministrativeClass.Major!.College!.Name,
-            x.Type, x.OriginalStatus, x.TargetStatus, x.Reason, x.State,
-            x.ReviewComment, x.SubmittedAt, x.ReviewedAt, x.ApprovedAt
-        }).ToListAsync(token));
+        var userScope = currentUserDataScope.Current;
+        var total = await source.CountAsync(token);
+        var actionableTotal = await source.CountAsync(change =>
+            (change.State == StudentStatusChangeState.Submitted &&
+             userScope.IsInRole(SystemRoles.Counselor)) ||
+            (change.State == StudentStatusChangeState.CounselorApproved &&
+             userScope.IsInRole(SystemRoles.CollegeAdmin)) ||
+            (change.State == StudentStatusChangeState.CollegeApproved &&
+             (userScope.IsInRole(SystemRoles.AcademicAdmin) ||
+              userScope.IsInRole(SystemRoles.SuperAdmin))), token);
+        var finishedTotal = await source.CountAsync(change =>
+            change.State == StudentStatusChangeState.Approved ||
+            change.State == StudentStatusChangeState.Rejected ||
+            change.State == StudentStatusChangeState.Cancelled, token);
+        var items = await source
+            .OrderByDescending(x => x.SubmittedAt)
+            .ThenByDescending(x => x.Id)
+            .Skip((page - 1) * pageSize)
+            .Take(pageSize)
+            .Select(x => new StudentStatusChangeListItem(
+                x.Id,
+                x.StudentId,
+                x.Student!.StudentNumber,
+                x.Student.Name,
+                x.Student.AdministrativeClass!.Name,
+                x.Student.AdministrativeClass.Major!.College!.Name,
+                x.Type,
+                x.OriginalStatus,
+                x.TargetStatus,
+                x.Reason,
+                x.State,
+                x.ReviewComment,
+                x.SubmittedAt,
+                x.ReviewedAt,
+                x.ApprovedAt))
+            .ToListAsync(token);
+        return Ok(new StudentStatusChangePage(
+            items, total, page, pageSize, actionableTotal, finishedTotal));
     }
 
     [HttpGet("options")]
@@ -199,6 +235,31 @@ public sealed class StudentStatusChangesController(
     });
 }
 
+public sealed record StudentStatusChangePage(
+    IReadOnlyCollection<StudentStatusChangeListItem> Items,
+    int Total,
+    int Page,
+    int PageSize,
+    int ActionableTotal,
+    int FinishedTotal);
+
+public sealed record StudentStatusChangeListItem(
+    Guid Id,
+    Guid StudentId,
+    string StudentNumber,
+    string Name,
+    string ClassName,
+    string CollegeName,
+    StudentStatusChangeType Type,
+    StudentStatus OriginalStatus,
+    StudentStatus TargetStatus,
+    string Reason,
+    StudentStatusChangeState State,
+    string? ReviewComment,
+    DateTime SubmittedAt,
+    DateTime? ReviewedAt,
+    DateTime? ApprovedAt);
+
 public sealed record StudentStatusChangeRequest(
     StudentStatusChangeType Type,
     [Required, MinLength(10), MaxLength(1000)] string Reason);