From 95d784fb414c6270e560fc0cf7ed289765ddd3ab Mon Sep 17 00:00:00 2001
From: matin <matin.kaufmann@gmail.com>
Date: Fri, 12 Sep 2025 20:45:28 +0200
Subject: AI refactoring (see architecture analysis and refactoring_summary)

---
 date_service.py | 105 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 105 insertions(+)
 create mode 100644 date_service.py

(limited to 'date_service.py')

diff --git a/date_service.py b/date_service.py
new file mode 100644
index 0000000..4a0706a
--- /dev/null
+++ b/date_service.py
@@ -0,0 +1,105 @@
+# date_service.py
+from datetime import datetime, timedelta
+from dateutil.relativedelta import relativedelta
+from PyQt5.QtCore import QDate
+from config import EventConfig
+
+class DateService:
+    """Centralized date operations and utilities"""
+    
+    @staticmethod
+    def format_date_for_display(date, format_string=None):
+        """Format a datetime object for display"""
+        if format_string is None:
+            format_string = EventConfig.DATE_FORMAT
+        
+        if isinstance(date, datetime):
+            return date.strftime(format_string.replace('dd', '%d').replace('MM', '%m').replace('yyyy', '%Y'))
+        elif isinstance(date, QDate):
+            return date.toString(format_string)
+        return str(date)
+    
+    @staticmethod
+    def parse_date_from_string(date_string):
+        """Parse a date string to datetime object"""
+        try:
+            return datetime.fromisoformat(date_string)
+        except ValueError:
+            # Try alternative formats
+            try:
+                return datetime.strptime(date_string, "%d.%m.%Y")
+            except ValueError:
+                raise ValueError(f"Unable to parse date string: {date_string}")
+    
+    @staticmethod
+    def qdate_to_datetime(qdate):
+        """Convert QDate to datetime"""
+        if isinstance(qdate, QDate):
+            return datetime(qdate.year(), qdate.month(), qdate.day())
+        return qdate
+    
+    @staticmethod
+    def datetime_to_qdate(dt):
+        """Convert datetime to QDate"""
+        if isinstance(dt, datetime):
+            return QDate(dt.year, dt.month, dt.day)
+        return dt
+    
+    @staticmethod
+    def validate_date_range(start_date, end_date):
+        """Validate that start_date is not after end_date"""
+        if isinstance(start_date, str):
+            start_date = DateService.parse_date_from_string(start_date)
+        if isinstance(end_date, str):
+            end_date = DateService.parse_date_from_string(end_date)
+        
+        return start_date <= end_date
+    
+    @staticmethod
+    def calculate_days_between(start_date, end_date):
+        """Calculate number of days between two dates"""
+        if isinstance(start_date, str):
+            start_date = DateService.parse_date_from_string(start_date)
+        if isinstance(end_date, str):
+            end_date = DateService.parse_date_from_string(end_date)
+        
+        return (end_date.date() - start_date.date()).days + 1
+    
+    @staticmethod
+    def calculate_months_between(start_date, end_date):
+        """Calculate number of months between two dates using relativedelta"""
+        if isinstance(start_date, str):
+            start_date = DateService.parse_date_from_string(start_date)
+        if isinstance(end_date, str):
+            end_date = DateService.parse_date_from_string(end_date)
+        
+        rd = relativedelta(end_date.date(), start_date.date())
+        return rd.years * 12 + rd.months + 1
+    
+    @staticmethod
+    def format_date_for_iso(date):
+        """Format date for ISO string (yyyy-MM-dd)"""
+        if isinstance(date, datetime):
+            return date.strftime("%Y-%m-%d")
+        elif isinstance(date, QDate):
+            return date.toString("yyyy-MM-dd")
+        return str(date)
+    
+    @staticmethod
+    def get_current_date():
+        """Get current date as datetime"""
+        return datetime.now()
+    
+    @staticmethod
+    def add_days_to_date(date, days):
+        """Add days to a date"""
+        if isinstance(date, str):
+            date = DateService.parse_date_from_string(date)
+        return date + timedelta(days=days)
+    
+    @staticmethod
+    def add_months_to_date(date, months):
+        """Add months to a date using relativedelta"""
+        if isinstance(date, str):
+            date = DateService.parse_date_from_string(date)
+        return date + relativedelta(months=months)
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