校历优化

src/Jiaowu.Api/Controllers/AcademicCalendarController.cs

@@ -119,21 +119,23 @@ public sealed class AcademicCalendarController(AppDbContext db, HolidayCnClient
         catch (InvalidOperationException exception) { return ValidationProblem(exception.Message); }
 
         var existing = await db.AcademicCalendarEvents.Where(item => item.AcademicTermId == request.AcademicTermId && item.Source == AcademicCalendarEventSource.HolidayCn && item.SourceYear == request.Year).ToListAsync(cancellationToken);
+        var ranges = HolidayCnRanges.Group(source.Days);
         db.AcademicCalendarEvents.RemoveRange(existing);
-        db.AcademicCalendarEvents.AddRange(source.Days.Select(day => new AcademicCalendarEvent
+        db.AcademicCalendarEvents.AddRange(ranges.Select(range => new AcademicCalendarEvent
         {
             AcademicTermId = request.AcademicTermId,
-            Title = day.Name,
+            Title = range.Name,
             Kind = AcademicCalendarEventKind.PublicHoliday,
-            StartsOn = day.Date,
-            ReminderDays = day.IsOffDay ? 3 : 0,
-            Description = day.IsOffDay ? "法定节假日或调休休息日" : "调休上班日",
+            StartsOn = range.StartsOn,
+            EndsOn = range.StartsOn == range.EndsOn ? null : range.EndsOn,
+            ReminderDays = range.IsOffDay ? 3 : 0,
+            Description = range.IsOffDay ? "法定节假日或调休休息日" : "调休上班日",
             Source = AcademicCalendarEventSource.HolidayCn,
             SourceYear = request.Year,
-            IsOffDay = day.IsOffDay
+            IsOffDay = range.IsOffDay
         }));
         await db.SaveChangesAsync(cancellationToken);
-        return Ok(new { Year = request.Year, SyncedCount = source.Days.Count, ReplacedCount = existing.Count, source.Papers });
+        return Ok(new { Year = request.Year, SyncedCount = ranges.Count, SourceDayCount = source.Days.Count, ReplacedCount = existing.Count, source.Papers });
     }
 
     private async Task<ActionResult?> ValidateAsync(AcademicCalendarEventRequest request, CancellationToken cancellationToken)

src/Jiaowu.Api/Infrastructure/AcademicCalendar/HolidayCnClient.cs

@@ -21,3 +21,42 @@ public sealed class HolidayCnClient(HttpClient httpClient)
 
 public sealed record HolidayCnYear(int Year, IReadOnlyList<string> Papers, IReadOnlyList<HolidayCnDay> Days);
 public sealed record HolidayCnDay(string Name, DateOnly Date, bool IsOffDay);
+
+/// <summary>
+/// 将数据源中按日列出的同一连续节假日归并为一个校历日程。
+/// 调休上班日与休息日即使同名也必须分别保留，避免错误地把工作日包含在假期范围内。
+/// </summary>
+public static class HolidayCnRanges
+{
+    public static IReadOnlyList<HolidayCnRange> Group(IEnumerable<HolidayCnDay> days) => days
+        .OrderBy(day => day.Date)
+        .GroupBy(day => new { day.Name, day.IsOffDay })
+        .SelectMany(group => GroupConsecutive(group.Key.Name, group.Key.IsOffDay, group))
+        .OrderBy(range => range.StartsOn)
+        .ToList();
+
+    private static IEnumerable<HolidayCnRange> GroupConsecutive(
+        string name,
+        bool isOffDay,
+        IEnumerable<HolidayCnDay> days)
+    {
+        HolidayCnDay? first = null;
+        HolidayCnDay? previous = null;
+        foreach (var day in days.OrderBy(item => item.Date))
+        {
+            if (first is not null && previous is not null && day.Date > previous.Date.AddDays(1))
+            {
+                yield return new HolidayCnRange(name, first.Date, previous.Date, isOffDay);
+                first = null;
+            }
+
+            first ??= day;
+            previous = day;
+        }
+
+        if (first is not null && previous is not null)
+            yield return new HolidayCnRange(name, first.Date, previous.Date, isOffDay);
+    }
+}
+
+public sealed record HolidayCnRange(string Name, DateOnly StartsOn, DateOnly EndsOn, bool IsOffDay);

tests/Jiaowu.Api.Tests/CaptchaKitIntegrationTests.cs

@@ -1,6 +1,7 @@
 using CaptchaKit.AspNetCore;
 using CaptchaKit;
 using Microsoft.Extensions.DependencyInjection;
+using SkiaSharp;
 
 namespace Jiaowu.Api.Tests;
 
@@ -34,6 +35,28 @@ public sealed class CaptchaKitIntegrationTests
         Assert.True(challenge.Challenge.ImageBytes!.AsSpan().StartsWith(new byte[] { 137, 80, 78, 71 }));
     }
 
+    [Fact]
+    public void Selection_visual_keeps_the_target_character_visible_above_noise()
+    {
+        var challenge = new SkiaTextCaptchaGenerator().CreateVisualChallenge(
+            new CaptchaGenerationRequest("test", DateTimeOffset.UtcNow.AddMinutes(1), 5),
+            "A", "choice-A", CaptchaChallengeType.Selection, "请选择对应字符");
+
+        using var bitmap = SKBitmap.Decode(challenge.Challenge.ImageBytes!);
+        Assert.NotNull(bitmap);
+
+        var targetPixelCount = 0;
+        for (var y = 0; y < bitmap!.Height; y++)
+        for (var x = bitmap.Width / 4; x < bitmap.Width * 3 / 4; x++)
+        {
+            var pixel = bitmap.GetPixel(x, y);
+            if (pixel.Red <= 30 && pixel.Green is >= 40 and <= 60 && pixel.Blue is >= 70 and <= 90)
+                targetPixelCount++;
+        }
+
+        Assert.True(targetPixelCount > 20, "The target character should be visibly rendered in the image center.");
+    }
+
     [Fact]
     public void Random_generator_produces_each_enabled_challenge_type()
     {