feat: Teilnehmerlisten in Lerngruppen importieren

2026-08-18 00:44:07 +02:00
parent cdac335ad1
commit 99efa3a0fe
11 changed files with 489 additions and 79 deletions
@@ -0,0 +1,40 @@
+using System.Text;
+
+namespace LehrerApp.Core.Importing;
+
+/// <summary>Erkennt den Notenlistenexport und erklärt dessen fehlende Teilnehmerdaten.</summary>
+public sealed class MarksPerLessonCsvImportHandler : IImportHandler<ImportedStudent>
+{
+    private static readonly string[] SignatureHeaders =
+        ["Datum", "Name", "Klasse", "Fach", "Prüfungsart", "Note", "Bemerkung", "Benutzer", "Schlüssel (extern)", "Gesamtnote"];
+    private static readonly UTF8Encoding StrictUtf8 = new(false, true);
+
+    public ImportFormatId FormatId => StudentImportFormats.MarksPerLessonCsv;
+    public string DisplayName => "Unterrichts-Notenliste";
+    public IReadOnlyCollection<string> SupportedExtensions { get; } = [".csv"];
+
+    public ValueTask<ImportDetection> DetectAsync(ImportFile file, CancellationToken cancellationToken = default)
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        string text;
+        try { text = StrictUtf8.GetString(file.Content.Span); }
+        catch (DecoderFallbackException) { return ValueTask.FromResult(ImportDetection.NoMatch()); }
+        var end = text.IndexOfAny(['\r', '\n']);
+        var firstLine = (end >= 0 ? text[..end] : text).TrimStart('\uFEFF');
+        var headers = firstLine.Split('\t').Select(x => x.Trim()).ToHashSet(StringComparer.OrdinalIgnoreCase);
+        return ValueTask.FromResult(SignatureHeaders.All(headers.Contains)
+            ? ImportDetection.Match(file.Extension.Equals(".csv", StringComparison.OrdinalIgnoreCase) ? 100 : 95)
+            : ImportDetection.NoMatch());
+    }
+
+    public ValueTask<ImportParseResult<ImportedStudent>> ParseAsync(ImportFile file, CancellationToken cancellationToken = default)
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+        IReadOnlyList<ImportMessage> messages =
+        [
+            new(ImportMessageSeverity.Error, "marks-per-lesson.no-participants",
+                "Die Notenliste enthält keine verlässlichen Teilnehmerdaten. Bitte exportiere die echte Kurs-/Teilnehmerliste.")
+        ];
+        return ValueTask.FromResult(new ImportParseResult<ImportedStudent>([], messages));
+    }
+}