"""
FastRDP-NG IP Utilities
Parse IP ranges, CIDR notation, stick to basics.
"""

import ipaddress
import re
from typing import Generator

IP_RANGE_RE = re.compile(
    r'^(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})\s*-\s*(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})$'
)
SINGLE_IP_RE = re.compile(r'^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$')


def parse_line(line: str) -> Generator[str, None, None]:
    """Parse a single line: single IP, dash range, CIDR."""
    line = line.strip()
    if not line or line.startswith('#') or line.startswith('//'):
        return

    # CIDR: 192.168.1.0/24
    if '/' in line:
        try:
            network = ipaddress.IPv4Network(line, strict=False)
            for host in network.hosts():
                yield str(host)
        except ValueError:
            pass
        return

    # Dash range: 192.168.1.1-192.168.1.255
    match = IP_RANGE_RE.match(line)
    if match:
        try:
            start = int(ipaddress.IPv4Address(match.group(1)))
            end = int(ipaddress.IPv4Address(match.group(2)))
            if start > end:
                start, end = end, start
            # Cap at /16 to prevent memory bombs
            if end - start > 65536:
                end = start + 65536
            for ip_int in range(start, end + 1):
                yield str(ipaddress.IPv4Address(ip_int))
        except ValueError:
            pass
        return

    # Single IP
    if SINGLE_IP_RE.match(line):
        yield line


def parse_ranges_file(filepath: str) -> Generator[str, None, None]:
    """Parse ranges.txt, yield individual IPs lazily."""
    with open(filepath, 'r', encoding='utf-8', errors='ignore') as f:
        for line in f:
            yield from parse_line(line)


def count_ips(filepath: str) -> int:
    """Quick count of total IPs for progress tracking."""
    total = 0
    with open(filepath, 'r', encoding='utf-8', errors='ignore') as f:
        for line in f:
            line = line.strip()
            if not line or line.startswith('#') or line.startswith('//'):
                continue
            if '/' in line:
                try:
                    n = ipaddress.IPv4Network(line, strict=False)
                    total += max(0, n.num_addresses - 2)
                except ValueError:
                    total += 1
            elif IP_RANGE_RE.match(line):
                m = IP_RANGE_RE.match(line)
                if m is None:
                    total += 1
                    continue
                s = int(ipaddress.IPv4Address(m.group(1)))
                e = int(ipaddress.IPv4Address(m.group(2)))
                if s > e:
                    s, e = e, s
                total += min(e - s + 1, 65536)
            elif SINGLE_IP_RE.match(line):
                total += 1
    return total