# dnsrecon-reduced/utils/helpers.py

import ipaddress
from typing import Union

def _is_valid_domain(domain: str) -> bool:
    """
    Basic domain validation.

    Args:
        domain: Domain string to validate

    Returns:
        True if domain appears valid
    """
    if not domain or len(domain) > 253:
        return False

    # Check for valid characters and structure
    parts = domain.split('.')
    if len(parts) < 2:
        return False

    for part in parts:
        if not part or len(part) > 63:
            return False
        if not part.replace('-', '').replace('_', '').isalnum():
            return False

    return True

def _is_valid_ip(ip: str) -> bool:
    """
    IP address validation supporting both IPv4 and IPv6.

    Args:
        ip: IP address string to validate

    Returns:
        True if IP appears valid (IPv4 or IPv6)
    """
    if not ip:
        return False
    
    try:
        # This handles both IPv4 and IPv6 validation
        ipaddress.ip_address(ip.strip())
        return True
    except (ValueError, AttributeError):
        return False

def is_valid_target(target: str) -> bool:
    """
    Checks if the target is a valid domain or IP address (IPv4/IPv6).

    Args:
        target: The target string to validate.

    Returns:
        True if the target is a valid domain or IP, False otherwise.
    """
    return _is_valid_domain(target) or _is_valid_ip(target)

def get_ip_version(ip: str) -> Union[int, None]:
    """
    Get the IP version (4 or 6) of a valid IP address.
    
    Args:
        ip: IP address string
        
    Returns:
        4 for IPv4, 6 for IPv6, None if invalid
    """
    try:
        addr = ipaddress.ip_address(ip.strip())
        return addr.version
    except (ValueError, AttributeError):
        return None

def normalize_ip(ip: str) -> Union[str, None]:
    """
    Normalize an IP address to its canonical form.
    
    Args:
        ip: IP address string
        
    Returns:
        Normalized IP address string, None if invalid
    """
    try:
        addr = ipaddress.ip_address(ip.strip())
        return str(addr)
    except (ValueError, AttributeError):
        return None