feat(ui): complete Avalonia UI port with 7 main pages, tool settings & top MenuBar

src/ClawdDotNet.Core/Scheduling/CronExpression.cs

@@ -90,6 +90,9 @@ public sealed class CronExpression
 
         foreach (var part in field.Split(','))
         {
+            if (part.Length == 0)
+                throw Bad(field, "leeres Teilfeld");
+
             if (part == "*")
             {
                 for (var i = min; i <= max; i++) result.Add(i);
@@ -97,23 +100,44 @@ public sealed class CronExpression
             else if (part.Contains('/'))
             {
                 var split = part.Split('/');
-                var start = split[0] == "*" ? min : int.Parse(split[0]);
-                var step = int.Parse(split[1]);
+                if (split.Length != 2)
+                    throw Bad(field, "Schrittangabe erwartet die Form 'basis/schritt'");
+
+                var start = split[0] == "*" ? min : ParseNumber(field, split[0], min, max);
+                var step = ParseNumber(field, split[1], 1, max); // Schritt 0 wäre eine Endlosschleife
                 for (var i = start; i <= max; i += step) result.Add(i);
             }
             else if (part.Contains('-'))
             {
                 var split = part.Split('-');
-                var from = int.Parse(split[0]);
-                var to = int.Parse(split[1]);
+                if (split.Length != 2)
+                    throw Bad(field, "Bereich erwartet die Form 'von-bis'");
+
+                var from = ParseNumber(field, split[0], min, max);
+                var to = ParseNumber(field, split[1], min, max);
+                if (from > to)
+                    throw Bad(field, $"Bereich {from}-{to} ist rückwärts");
+
                 for (var i = from; i <= to; i++) result.Add(i);
             }
             else
             {
-                result.Add(int.Parse(part));
+                result.Add(ParseNumber(field, part, min, max));
             }
         }
 
         return result;
     }
+
+    private static int ParseNumber(string field, string value, int min, int max)
+    {
+        if (!int.TryParse(value, out var n))
+            throw Bad(field, $"'{value}' ist keine Zahl");
+        if (n < min || n > max)
+            throw Bad(field, $"{n} liegt außerhalb von {min}-{max}");
+        return n;
+    }
+
+    private static FormatException Bad(string field, string reason)
+        => new($"Ungültiges Cron-Feld '{field}': {reason}.");
 }