Refactor email configuration handling and improve logging for email delivery

Web/modules/emailservice/email.py

@@ -3,11 +3,18 @@ from email.mime.text import MIMEText
 from email.mime.application import MIMEApplication
 import smtplib
 import time
+import logging
 
 import Web.modules.database.settings as cfg
 
 
+logger = logging.getLogger(__name__)
+
+
 def _build_smtp_client():
+    if not cfg.EMAIL_SMTP_HOST:
+        raise RuntimeError('EMAIL_SMTP_HOST ist nicht konfiguriert')
+
     smtp = smtplib.SMTP(
         cfg.EMAIL_SMTP_HOST,
         cfg.EMAIL_SMTP_PORT,
@@ -31,11 +38,12 @@ def _normalize_recipients(email: list | str) -> list[str]:
 def _send_message(email: list | str, subject: str, note: str, sender: str, attachment=None) -> bool:
     """Send a plain/HTML message, optionally with one PDF attachment."""
     if not cfg.MODULES.is_enabled("mail"):
-        print("Debug: Module not enabled")
+        logger.info("Email delivery skipped because the mail module is disabled")
         return False
 
     recipients = _normalize_recipients(email)
     if not recipients:
+        logger.warning("Email delivery skipped because no recipients were provided")
         return False
 
     body_message = note
@@ -104,7 +112,7 @@ def _send_message(email: list | str, subject: str, note: str, sender: str, attac
 
         return True
     except Exception as e:
-        print(f"Debug: Fehler beim Senden der E-Mail: {e}")
+        logger.exception("Email delivery failed: %s", e)
         return False
     finally:
         if smtp: