"""
Phone Utilities - Phone number normalization and validation
"""


def normalize_kenyan_phone(phone: str) -> str:
    """
    Normalize Kenyan phone number to +254XXX format.
    
    Handles formats:
    - +254712345678 (already normalized)
    - 254712345678
    - 0712345678
    - 712345678
    
    Returns normalized +254XXXXXXXXX or original if invalid.
    """
    if not phone:
        return phone
    
    # Remove spaces, dashes, parentheses, keep only digits and +
    phone = ''.join(c for c in str(phone) if c.isdigit() or c == '+')
    
    if not phone:
        return phone
    
    # Already normalized
    if phone.startswith('+254') and len(phone) == 13:
        return phone
    
    # Remove leading +254
    if phone.startswith('+254'):
        phone = phone[4:]
    
    # Remove leading 254
    if phone.startswith('254'):
        phone = phone[3:]
    
    # Remove leading 0
    if phone.startswith('0'):
        phone = phone[1:]
    
    # Should now have 9 digits (7XXXXXXXX or 1XXXXXXXX)
    if len(phone) == 9 and phone[0] in ['7', '1']:
        return f'+254{phone}'
    
    # Invalid format - return original input (don't break)
    return phone