from flask import Blueprint, request, jsonify
import ipaddress
from util.logger import logger
from auth.token import verify_token

ipcalc_blueprint = Blueprint('ipcalc_tool', __name__)


@ipcalc_blueprint.route('/api/ip/calculate', methods=['POST'])
def ip_calculate():
    user = verify_token()
    if not user:
        return jsonify({"message": "Nicht autorisiert"}), 401
    try:
        data = request.get_json(silent=True) or {}
        cidr = data.get("cidr", "").strip()

        try:
            network = ipaddress.IPv4Network(cidr, strict=False)
        except ValueError as e:
            return jsonify({"message": f"Ungültige CIDR-Notation: {e}"}), 400

        prefix = network.prefixlen
        net_int = int(network.network_address)
        bcast_int = int(network.broadcast_address)

        # Avoid materialising millions of host objects for large networks.
        if prefix == 32:
            # Single-host route: the address is both network and host.
            total_hosts = 1
            first_host = str(network.network_address)
            last_host = str(network.network_address)
        elif prefix == 31:
            # RFC 3021 point-to-point: both addresses are usable hosts,
            # there is no dedicated network or broadcast address.
            total_hosts = 2
            first_host = str(network.network_address)
            last_host = str(network.broadcast_address)
        else:
            total_hosts = network.num_addresses - 2
            first_host = str(ipaddress.IPv4Address(net_int + 1))
            last_host = str(ipaddress.IPv4Address(bcast_int - 1))

        netmask_int = int(network.netmask)
        # Python's ~ on an int yields a negative arbitrary-precision value;
        # mask to 32 bits to get the correct unsigned wildcard address.
        wildcard = str(ipaddress.IPv4Address((~netmask_int) & 0xFFFFFFFF))
        ip_class = "Privat" if network.is_private else "Öffentlich"

        return jsonify({
            "network": str(network.network_address),
            "broadcast": str(network.broadcast_address),
            "netmask": str(network.netmask),
            "wildcard": wildcard,
            "first_host": first_host,
            "last_host": last_host,
            "total_hosts": total_hosts,
            "prefix_length": prefix,
            "ip_class": ip_class,
        })

    except Exception as e:
        logger.error(f"Fehler ipcalc: {e}")
        return jsonify({"message": "Fehler bei der Berechnung"}), 500