Implement central logging function and debug mode switching

internal/config/logging.go

@@ -0,0 +1,37 @@
+// Fail2ban UI - A Swiss made, management interface for Fail2ban.
+//
+// Copyright (C) 2025 Swissmakers GmbH (https://swissmakers.ch)
+//
+// Licensed under the GNU General Public License, Version 3 (GPL-3.0)
+// You may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.gnu.org/licenses/gpl-3.0.en.html
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package config
+
+import (
+	"log"
+)
+
+// DebugLog prints debug messages only if debug mode is enabled.
+func DebugLog(format string, v ...interface{}) {
+	// Avoid deadlocks by not calling GetSettings() inside DebugLog.
+	debugEnabled := false
+	debugEnabled = currentSettings.Debug
+	if !debugEnabled {
+		return
+	}
+	// Ensure correct usage of fmt.Printf-style formatting
+	if len(v) > 0 {
+		log.Printf(format, v...) // Uses format directives
+	} else {
+		log.Println(format) // Just prints the message
+	}
+}