feat(caddy): support renaming configuration files

CaddyManager.Services/Caddy/CaddyService.cs

@@ -106,6 +106,91 @@ public class CaddyService(
             Content = content
         });
 
+    /// <inheritdoc />
+    public CaddyOperationResponse RenameCaddyConfiguration(string oldFileName, string newFileName)
+    {
+        if (string.IsNullOrWhiteSpace(newFileName))
+        {
+            return Failure("The configuration file name is required");
+        }
+
+        if (oldFileName == CaddyGlobalConfigName || newFileName == CaddyGlobalConfigName)
+        {
+            return Failure("The global Caddyfile cannot be renamed");
+        }
+
+        if (oldFileName == newFileName)
+        {
+            return new CaddyOperationResponse
+            {
+                Success = true,
+                Message = "Configuration file renamed successfully"
+            };
+        }
+
+        if (IsInvalidFileName(newFileName))
+        {
+            return Failure("The configuration file name contains invalid characters");
+        }
+
+        var oldPath = Path.Combine(Configurations.ConfigDir, $"{oldFileName}.caddy");
+        var newPath = Path.Combine(Configurations.ConfigDir, $"{newFileName}.caddy");
+
+        if (!File.Exists(oldPath))
+        {
+            return Failure("The configuration file to rename does not exist");
+        }
+
+        // On case insensitive file systems the target resolves to the source for a case only rename,
+        // so the collision check has to be skipped there
+        var caseOnlyRename = string.Equals(oldFileName, newFileName, StringComparison.OrdinalIgnoreCase);
+        if (!caseOnlyRename && File.Exists(newPath))
+        {
+            return Failure("The configuration file already exists");
+        }
+
+        try
+        {
+            if (caseOnlyRename)
+            {
+                // A direct move would be rejected as an existing destination on a case insensitive
+                // file system, so go through an intermediate name that cannot collide
+                var tempPath = Path.Combine(Configurations.ConfigDir, $"{newFileName}.caddy.renaming");
+                File.Move(oldPath, tempPath);
+                File.Move(tempPath, newPath);
+            }
+            else
+            {
+                File.Move(oldPath, newPath);
+            }
+
+            return new CaddyOperationResponse
+            {
+                Success = true,
+                Message = "Configuration file renamed successfully"
+            };
+        }
+        catch (Exception e)
+        {
+            return Failure(e.Message);
+        }
+    }
+
+    private static CaddyOperationResponse Failure(string message) => new()
+    {
+        Success = false,
+        Message = message
+    };
+
+    /// <summary>
+    /// Guards the rename against path traversal and characters the file system would reject
+    /// </summary>
+    private static bool IsInvalidFileName(string fileName) =>
+        fileName.Contains("..") || fileName.IndexOfAny(InvalidFileNameChars) >= 0;
+
+    private static readonly char[] InvalidFileNameChars =
+        [.. Path.GetInvalidFileNameChars().Union(['/', '\\'])];
+
     /// <inheritdoc />
     public CaddyDeleteOperationResponse DeleteCaddyConfigurations(List<string> configurationNames)
     {