from datetime import datetime, timedelta


def sanitize_date(date_str):
    if not date_str:
        return None
    d = str(date_str).strip().lower()
    today_dt = datetime.now()
    
    if d in ["today", "आज"]: 
        return today_dt.strftime("%Y-%m-%d")
    if d in ["tomorrow", "कल"]: 
        return (today_dt + timedelta(days=1)).strftime("%Y-%m-%d")
    if d in ["day after tomorrow", "परसों"]: 
        return (today_dt + timedelta(days=2)).strftime("%Y-%m-%d")
        
    return date_str