feat: 初始功能

Services/PathHelper.cs

@@ -0,0 +1,35 @@
+using System.IO;
+
+namespace CloudPrint.Client.Services;
+
+public static class PathHelper
+{
+    public static string CreateUniqueFilePath(string directory, string fileName)
+    {
+        Directory.CreateDirectory(directory);
+
+        var safeFileName = SanitizeFileName(string.IsNullOrWhiteSpace(fileName) ? "untitled" : fileName);
+        var name = Path.GetFileNameWithoutExtension(safeFileName);
+        var extension = Path.GetExtension(safeFileName);
+        var candidate = Path.Combine(directory, safeFileName);
+        var index = 1;
+
+        while (File.Exists(candidate))
+        {
+            candidate = Path.Combine(directory, $"{name}_{index++}{extension}");
+        }
+
+        return candidate;
+    }
+
+    public static string SanitizePathSegment(string value)
+    {
+        var invalidChars = Path.GetInvalidFileNameChars();
+        return new string(value.Select(ch => invalidChars.Contains(ch) ? '_' : ch).ToArray());
+    }
+
+    private static string SanitizeFileName(string fileName)
+    {
+        return SanitizePathSegment(fileName);
+    }
+}