refactor: extract common functions to utils

- Add get_redis_client() to calendar_sync_utils.py
- Add get_advoware_employees() to calendar_sync_utils.py
- Add set_employee_lock() and clear_employee_lock() to calendar_sync_utils.py
- Update all step files to use shared utility functions
- Remove duplicate code across calendar_sync_*.py files

bitbylaw/steps/advoware_cal_sync/calendar_sync_utils.py

@@ -1,6 +1,7 @@
 import logging
 import asyncpg
 import os
+import redis
 from config import Config
 from googleapiclient.discovery import build
 from google.oauth2 import service_account
@@ -61,4 +62,45 @@ async def get_google_service(context=None):
         return service
     except Exception as e:
         log_operation('error', f"Failed to initialize Google service: {e}", context=context)
-        raise
+        raise
+
+def get_redis_client(context=None):
+    """Initialize Redis client for calendar sync operations."""
+    try:
+        redis_client = redis.Redis(
+            host=Config.REDIS_HOST,
+            port=int(Config.REDIS_PORT),
+            db=int(Config.REDIS_DB_CALENDAR_SYNC),
+            socket_timeout=Config.REDIS_TIMEOUT_SECONDS
+        )
+        return redis_client
+    except Exception as e:
+        log_operation('error', f"Failed to initialize Redis client: {e}", context=context)
+        raise
+
+async def get_advoware_employees(advoware, context=None):
+    """Fetch list of employees from Advoware."""
+    try:
+        result = await advoware.api_call('api/v1/advonet/Mitarbeiter', method='GET', params={'aktiv': 'true'})
+        employees = result if isinstance(result, list) else []
+        log_operation('info', f"Fetched {len(employees)} Advoware employees", context=context)
+        return employees
+    except Exception as e:
+        log_operation('error', f"Failed to fetch Advoware employees: {e}", context=context)
+        raise
+
+def set_employee_lock(redis_client, kuerzel, triggered_by, context=None):
+    """Set lock for employee sync operation."""
+    employee_lock_key = f'calendar_sync_lock_{kuerzel}'
+    if redis_client.set(employee_lock_key, triggered_by, ex=1800, nx=True) is None:
+        log_operation('info', f"Sync already active for {kuerzel}, skipping", context=context)
+        return False
+    return True
+
+def clear_employee_lock(redis_client, kuerzel, context=None):
+    """Clear lock for employee sync operation."""
+    try:
+        employee_lock_key = f'calendar_sync_lock_{kuerzel}'
+        redis_client.delete(employee_lock_key)
+    except Exception as e:
+        log_operation('warning', f"Failed to clear lock for {kuerzel}: {e}", context=context)