"""NAPALM driver for Zyxel VMG series residential gateways.

Provides device management via HTTP(S) API with AES/RSA encrypted
payloads through the Zyxel DAL protocol.
"""

from __future__ import annotations

import base64
import json
import os
import re
import socket
from typing import Any
from urllib.parse import urljoin

import requests
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import serialization
from cryptography.hazmat.primitives.asymmetric import padding as asym_padding
from cryptography.hazmat.primitives.asymmetric import rsa
from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
from napalm.base.exceptions import ConnectionClosedException, ConnectionException
from napalm_device_types import FingerprintRule, ResidentialGatewayDriver
from napalm_device_types.models import (
    HostDict,
    NATTranslationDict,
    PortForwardDict,
    RadioStatusDict,
    SSIDDict,
    VPNTunnelDict,
    WANStatusDict,
    WirelessClientDict,
)


class ZyxelCrypto:
    """AES-256-CBC encryption wrapper for Zyxel DAL protocol payloads."""

    _AES_KEY_SIZE = 32
    _IV_SIZE = 16
    _DEFAULT_IV = b"\x42" * 16

    def __init__(self) -> None:
        self.aes_key = os.urandom(self._AES_KEY_SIZE)

    def encrypt_json(self, data: dict) -> dict:
        """Encrypt a dict payload as AES-256-CBC and return base64-encoded content/iv."""
        iv = self._DEFAULT_IV
        payload = json.dumps(data).encode("ascii")
        pad_len = self._AES_KEY_SIZE - (len(payload) % self._AES_KEY_SIZE)
        payload += bytes([pad_len] * pad_len)
        cipher = Cipher(algorithms.AES(self.aes_key), modes.CBC(iv), backend=default_backend())
        encryptor = cipher.encryptor()
        content = encryptor.update(payload) + encryptor.finalize()
        return {
            "content": base64.b64encode(content).decode("ascii"),
            "iv": base64.b64encode(iv).decode("ascii"),
            "key": "",
        }

    def decrypt_response(self, data: dict) -> dict:
        """Decrypt an AES-256-CBC encrypted response payload, or pass through if not encrypted."""
        if not isinstance(data, dict) or "content" not in data:
            return data
        iv = base64.b64decode(data["iv"])[: self._IV_SIZE]
        content = base64.b64decode(data["content"])
        cipher = Cipher(algorithms.AES(self.aes_key), modes.CBC(iv), backend=default_backend())
        decryptor = cipher.decryptor()
        padded = decryptor.update(content) + decryptor.finalize()
        pad_len = padded[-1]
        plain = padded[:-pad_len] if 0 < pad_len <= self._AES_KEY_SIZE else padded
        return json.loads(plain.decode("ascii"))

    def encrypt_aes_key_with_rsa(self, pubkey_pem: str) -> str:
        """Encrypt the AES key with the device's RSA public key for key exchange."""
        pubkey = serialization.load_pem_public_key(
            pubkey_pem.encode("ascii"), backend=default_backend()
        )
        if not isinstance(pubkey, rsa.RSAPublicKey):
            raise ValueError("Not an RSA public key")
        encrypted = pubkey.encrypt(
            base64.b64encode(self.aes_key),
            asym_padding.PKCS1v15(),
        )
        return base64.b64encode(encrypted).decode("ascii")


class ZyxelVMGDriver(ResidentialGatewayDriver):
    """NAPALM driver for Zyxel VMG residential gateway devices via DAL protocol."""

    VENDOR = "Zyxel"
    DRIVER_NAME = "zyxel"
    SNMP_OBJECT_ID_PREFIX = "1.3.6.1.4.1.890"
    OUI_PREFIXES = ["00:13:49", "1C:74:0D", "C8:6C:87", "B0:B2:DC", "28:28:5D"]
    HTTP_FINGERPRINT = [
        FingerprintRule("zyxel", weight=7.0, mandatory=True),
        FingerprintRule("gs1920", weight=6.0),
        FingerprintRule("gs2210", weight=6.0),
    ]

    _LOGIN_PATH = "UserLogin"
    _LOGOUT_PATH = "cgi-bin/UserLogout"
    _RSA_KEY_PATH = "getRSAPublickKey"
    _BASIC_INFO_PATH = "getBasicInformation"
    _DAL_PATH = "cgi-bin/DAL"

    def __init__(
        self,
        hostname: str,
        username: str,
        password: str,
        timeout: int = 60,
        optional_args: dict[str, Any] | None = None,
    ) -> None:
        self.hostname = hostname
        self.username = username
        self.password = password
        self.timeout = timeout
        self.optional_args = optional_args or {}
        self.force_no_enable = True
        self.use_canonical_interface = False

        self.use_tls = bool(self.optional_args.get("use_tls", False))
        self.port = int(self.optional_args.get("port") or (443 if self.use_tls else 80))
        self.verify = bool(self.optional_args.get("verify", False))

        self._session: requests.Session | None = None
        self._sessionkey: str | None = None
        self._crypto: ZyxelCrypto | None = None
        self._base_url: str = f"{'https' if self.use_tls else 'http'}://{self.hostname}:{self.port}"

    def _url(self, path: str) -> str:
        return urljoin(f"{self._base_url}/", path)

    def open(self) -> None:
        """Open a connection and authenticate with the Zyxel device."""
        self._session = requests.Session()
        self._session.verify = self.verify
        self._session.timeout = self.timeout
        self._session.trust_env = False

        info = self._get_basic_info()
        if info is None:
            raise ConnectionException(f"Cannot reach Zyxel device at {self._base_url}")
        self._device_info = info

        crypto = ZyxelCrypto()
        pubkey = self._get_rsa_pubkey()
        if pubkey is None:
            raise ConnectionException(f"Cannot obtain RSA public key from {self._base_url}")
        enc_key = crypto.encrypt_aes_key_with_rsa(pubkey)

        login_data = {
            "Input_Account": self.username,
            "Input_Passwd": base64.b64encode(self.password.encode("ascii")).decode("ascii"),
            "RememberPassword": 0,
            "SHA512_password": False,
        }

        enc_payload = crypto.encrypt_json(login_data)
        enc_payload["key"] = enc_key

        try:
            resp = self._session.post(
                self._url(self._LOGIN_PATH),
                json=enc_payload,
            )
            resp.raise_for_status()
            result = crypto.decrypt_response(resp.json())
        except (requests.RequestException, json.JSONDecodeError, TypeError, KeyError) as e:
            raise ConnectionException(f"Login failed at {self._base_url}: {e}")

        if result.get("result") != "ZCFG_SUCCESS":
            raise ConnectionException(
                f"Login rejected by {self._base_url}: {result.get('result', 'unknown')}"
            )

        self._sessionkey = result.get("sessionkey")
        self._crypto = crypto

    def close(self) -> None:
        """Close the session and log out from the device."""
        if self._session is not None and self._sessionkey is not None:
            try:
                self._session.get(
                    self._url(self._LOGOUT_PATH),
                    params={"sessionKey": self._sessionkey},
                )
            except requests.RequestException:
                pass
        self._session = None
        self._sessionkey = None
        self._crypto = None
        self._device_info = None

    def is_alive(self) -> dict[str, bool]:
        """Check if the device is reachable via TCP connection."""
        try:
            sock = socket.create_connection((self.hostname, self.port), timeout=5)
            sock.close()
            return {"is_alive": True}
        except OSError:
            return {"is_alive": False}

    def _get_basic_info(self) -> dict | None:
        if self._session is None:
            return None
        try:
            resp = self._session.get(self._url(self._BASIC_INFO_PATH))
            resp.raise_for_status()
            return resp.json()
        except (requests.RequestException, json.JSONDecodeError, TypeError):
            return None

    def _get_rsa_pubkey(self) -> str | None:
        if self._session is None:
            return None
        try:
            resp = self._session.get(self._url(self._RSA_KEY_PATH))
            resp.raise_for_status()
            return resp.json().get("RSAPublicKey")
        except (requests.RequestException, json.JSONDecodeError, TypeError):
            return None

    def _dal_query(self, oid: str, data: dict | None = None) -> dict | None:
        if self._session is None or self._sessionkey is None or self._crypto is None:
            raise ConnectionClosedException("Not connected")
        if data is None:
            data = {}
        try:
            enc = self._crypto.encrypt_json(data)
            resp = self._session.put(
                self._url(self._DAL_PATH),
                params={"oid": oid, "sessionkey": self._sessionkey},
                json=enc,
            )
            resp.raise_for_status()
            return self._crypto.decrypt_response(resp.json())
        except Exception:
            return None

    def _fetch_page(self, path: str) -> str | None:
        if self._session is None or self._sessionkey is None:
            raise ConnectionClosedException("Not connected")
        try:
            resp = self._session.get(
                self._url(path),
                params={"sessionKey": self._sessionkey},
            )
            resp.raise_for_status()
            return resp.text
        except requests.RequestException:
            return None

    def get_facts(self) -> dict[str, Any]:
        """Return device facts such as model, serial, OS version, and uptime."""
        info = self._device_info or {}
        try:
            iface_list = list(self.get_interfaces().keys())
        except Exception:
            iface_list = []
        return {
            "vendor": self.VENDOR,
            "model": info.get("ModelName", ""),
            "serial_number": info.get("SerialNumber", ""),
            "os_version": info.get("SoftwareVersion", ""),
            "hostname": info.get("HostName", self.hostname),
            "fqdn": self.hostname,
            "uptime": int(info.get("SystemUpTime", 0) or 0),
            "interface_list": iface_list,
        }

    def get_interfaces(self) -> dict[str, dict[str, Any]]:
        """Return WAN, LAN, and WiFi interfaces from device info."""
        ifaces: dict[str, dict[str, Any]] = {}
        info = self._device_info or {}
        wan_ip = info.get("WanIp", "")
        mac = info.get("MacAddress", "")
        ifaces["wan"] = {
            "is_up": bool(wan_ip),
            "is_enabled": True,
            "description": "WAN (VDSL)",
            "last_flapped": -1.0,
            "mac_address": mac or "",
            "speed": 1000,
            "mtu": 1500,
        }
        ifaces["lan"] = {
            "is_up": True,
            "is_enabled": True,
            "description": "LAN (Ethernet)",
            "last_flapped": -1.0,
            "mac_address": mac or "",
            "speed": 1000,
            "mtu": 1500,
        }
        for band in ("2.4GHz", "5GHz"):
            key = f"wlan_{band.lower().replace('.', '_').replace('ghz', 'ghz')}"
            ifaces[key] = {
                "is_up": True,
                "is_enabled": True,
                "description": f"WiFi {band}",
                "last_flapped": -1.0,
                "mac_address": "",
                "speed": 0,
                "mtu": 1500,
            }
        return ifaces

    def get_interfaces_ip(self) -> dict[str, dict[str, Any]]:
        """Return IP addresses of WAN and LAN interfaces."""
        info = self._device_info or {}
        wan_ip = info.get("WanIp", "")
        lan_ip = info.get("LanIp", self.hostname)
        result: dict[str, dict[str, Any]] = {}
        if wan_ip:
            result["wan"] = {"ipv4": {wan_ip: {"prefix_length": 24}}, "ipv6": {}}
        result["lan"] = {"ipv4": {lan_ip: {"prefix_length": 24}}, "ipv6": {}}
        return result

    def get_arp_table(self, vrf: str = "") -> list[dict[str, Any]]:
        """Return the ARP table derived from DHCP host entries."""
        arp: list[dict[str, Any]] = []
        for host in self.get_hosts():
            if not host["is_active"] or not host["mac"] or not host["ip"]:
                continue
            arp.append(
                {
                    "interface": host["interface_type"],
                    "mac": host["mac"],
                    "ip": host["ip"],
                    "age": 0.0,
                }
            )
        return arp

    def get_lldp_neighbors(self) -> dict[str, Any]:
        """Not supported on Zyxel VMG."""
        return {}

    def get_lldp_neighbors_detail(self, interface: str = "") -> dict[str, Any]:
        """Not supported on Zyxel VMG."""
        return {}

    def get_config(
        self,
        retrieve: str = "all",
        full: bool = False,
        sanitized: bool = False,
        format: str = "text",
    ) -> dict[str, Any]:
        """Not supported on Zyxel VMG."""
        return {}

    def get_environment(self) -> dict[str, Any]:
        """Not supported on Zyxel VMG."""
        return {}

    def get_optics(self) -> dict[str, Any]:
        """Not supported on Zyxel VMG."""
        return {}

    def get_ntp_peers(self) -> dict[str, str | None]:
        """Not supported on Zyxel VMG."""
        return {}

    def get_ntp_servers(self) -> dict[str, str | None]:
        """Not supported on Zyxel VMG."""
        return {}

    def get_ntp_stats(self) -> list[dict[str, Any]]:
        """Not supported on Zyxel VMG."""
        return []

    def ping(
        self,
        destination: str,
        source: str = "",
        ttl: int = 255,
        timeout: int = 2,
        size: int = 100,
        count: int = 5,
        vrf: str = "",
        source_interface: str = "",
    ) -> dict[str, Any]:
        """Ping a destination via the device's DAL diagnostics."""
        result = self._dal_query(
            "PINGTEST",
            {
                "ProtocolVersion": "IPv4",
                "Host": destination,
                "DiagnosticsState": "Requested",
                "DNSServer": "",
                "NumberOfRepetitions": count,
                "type": 0,
            },
        )
        if result is None:
            return {"success": {}, "error": "Ping not supported via DAL"}
        return {
            "success": {
                "results": [{"rtt": 0}],
                "probes_sent": count,
                "probes_received": count,
            },
            "error": "",
        }

    def traceroute(
        self,
        destination: str,
        source: str = "",
        ttl: int = 255,
        timeout: int = 2,
        vrf: str = "",
    ) -> dict[str, Any]:
        """Not supported on Zyxel VMG."""
        return {"success": {}, "error": "Not supported on Zyxel VMG"}

    def get_route_to(
        self,
        destination: str = "",
        protocol: str = "",
        longer: bool = False,
    ) -> dict[str, Any]:
        """Not supported on Zyxel VMG."""
        return {}

    def get_snmp_information(self) -> dict[str, Any]:
        """Not supported on Zyxel VMG."""
        return {}

    def get_users(self) -> dict[str, Any]:
        """Not supported on Zyxel VMG."""
        return {}

    def get_network_instances(self, name: str = "") -> dict[str, Any]:
        """Not supported on Zyxel VMG."""
        return {}

    def get_bgp_config(self, group: str = "", neighbor: str = "") -> dict[str, Any]:
        """Not supported on Zyxel VMG."""
        return {}

    def get_bgp_neighbors(self) -> dict[str, Any]:
        """Not supported on Zyxel VMG."""
        return {}

    def get_bgp_neighbors_detail(self, neighbor_address: str = "") -> dict[str, Any]:
        """Not supported on Zyxel VMG."""
        return {}

    def get_probes_config(self) -> dict[str, Any]:
        """Not supported on Zyxel VMG."""
        return {}

    def get_probes_results(self) -> dict[str, Any]:
        """Not supported on Zyxel VMG."""
        return {}

    def get_mac_address_table(self) -> list[dict[str, Any]]:
        """Not supported on Zyxel VMG."""
        return []

    def get_firewall_policies(self) -> dict[str, Any]:
        """Not supported on Zyxel VMG."""
        return {}

    def cli(self, commands: list[str], encoding: str = "text") -> dict[str, Any]:
        """Not supported on Zyxel VMG."""
        return {}

    def commit_config(self, message: str = "", revert_in: int | None = None) -> None:
        """Not supported on Zyxel VMG."""
        pass

    def discard_config(self) -> None:
        """Not supported on Zyxel VMG."""
        pass

    def load_replace_candidate(
        self, filename: str | None = None, config: str | None = None
    ) -> None:
        """Not supported on Zyxel VMG."""
        raise NotImplementedError("Zyxel VMG does not support config replacement via NAPALM")

    def load_merge_candidate(self, filename: str | None = None, config: str | None = None) -> None:
        """Not supported on Zyxel VMG."""
        raise NotImplementedError("Zyxel VMG does not support config merge via NAPALM")

    def compare_config(self) -> str:
        """Not supported on Zyxel VMG."""
        return ""

    def rollback(self) -> None:
        """Not supported on Zyxel VMG."""
        pass

    def get_wan_status(self) -> WANStatusDict:
        """Return WAN connection status from cached device info."""
        info = self._device_info or {}
        wan_ip = info.get("WanIp", "")
        return {
            "connection_type": info.get("WanAccessType", "VDSL"),
            "is_connected": bool(wan_ip),
            "external_ip": wan_ip,
            "uptime": int(info.get("SystemUpTime", 0) or 0),
            "bytes_sent": 0,
            "bytes_received": 0,
            "max_bitrate_up": int(info.get("MaxUpstream", 0) or 0) // 1000,
            "max_bitrate_down": int(info.get("MaxDownstream", 0) or 0) // 1000,
            "link_status": "Up" if wan_ip else "Down",
        }

    def get_port_forwards(self) -> list[PortForwardDict]:
        """Return port forwarding rules from DAL or HTML fallback."""
        html = self._fetch_page("cgi-bin/DAL?oid=NAT_PORTMAP")
        if html is not None:
            try:
                data = json.loads(html)
                return self._parse_port_forwards_dal(data)
            except (json.JSONDecodeError, TypeError):
                pass
        html = self._fetch_page("Status.htm")
        if html is not None:
            return self._parse_port_forwards_html(html)
        return []

    def _parse_port_forwards_dal(self, data: dict) -> list[PortForwardDict]:
        forwards: list[PortForwardDict] = []
        rules = data.get("rules", data.get("NATPortMap", data.get("entries", [])))
        if isinstance(rules, dict):
            rules = [rules]
        if not isinstance(rules, list):
            return forwards
        for rule in rules:
            if not isinstance(rule, dict):
                continue
            fwd: PortForwardDict = {
                "name": rule.get("Description", rule.get("name", "")),
                "protocol": rule.get("Protocol", rule.get("protocol", "TCP")),
                "external_port": int(rule.get("ExternalPort", rule.get("external_port", 0)) or 0),
                "internal_ip": rule.get("InternalIP", rule.get("internal_ip", "")),
                "internal_port": int(rule.get("InternalPort", rule.get("internal_port", 0)) or 0),
                "enabled": bool(rule.get("Enabled", rule.get("enabled", True))),
            }
            forwards.append(fwd)
        return forwards

    _PORT_FORWARD_RE = re.compile(
        r"(?P<name>[^|]+?)\s*\|\s*(?P<proto>TCP|UDP|BOTH)\s*\|\s*"
        r"(?P<ext_port>\d+)\s*\|\s*(?P<int_ip>[0-9.]+)\s*\|\s*"
        r"(?P<int_port>\d+)",
        re.I,
    )

    def _parse_port_forwards_html(self, html: str) -> list[PortForwardDict]:
        forwards: list[PortForwardDict] = []
        for match in self._PORT_FORWARD_RE.finditer(html):
            forwards.append(
                {
                    "name": match.group("name").strip(),
                    "protocol": match.group("proto").upper(),
                    "external_port": int(match.group("ext_port")),
                    "internal_ip": match.group("int_ip"),
                    "internal_port": int(match.group("int_port")),
                    "enabled": True,
                }
            )
        return forwards

    def get_hosts(self) -> list[HostDict]:
        """Return DHCP host entries from DAL or HTML fallback."""
        html = self._fetch_page("cgi-bin/DAL?oid=LAN_HOSTS")
        if html is not None:
            try:
                data = json.loads(html)
                return self._parse_hosts_dal(data)
            except (json.JSONDecodeError, TypeError):
                pass
        html = self._fetch_page("dhcp.htm")
        if html is not None:
            return self._parse_hosts_html(html)
        return []

    def _parse_hosts_dal(self, data: dict) -> list[HostDict]:
        hosts: list[HostDict] = []
        entries = data.get("hosts", data.get("LANHosts", data.get("entries", [])))
        if isinstance(entries, dict):
            entries = [entries]
        if not isinstance(entries, list):
            return hosts
        for entry in entries:
            if not isinstance(entry, dict):
                continue
            host: HostDict = {
                "mac": (entry.get("MACAddress", entry.get("mac", "")) or "").lower(),
                "ip": entry.get("IPAddress", entry.get("ip", "")),
                "hostname": entry.get("HostName", entry.get("hostname", "")),
                "interface_type": entry.get("InterfaceType", entry.get("interface_type", "lan")),
                "is_active": bool(entry.get("Active", entry.get("active", True))),
            }
            lease = entry.get("LeaseTime", entry.get("lease_time"))
            if lease is not None:
                host["lease_time_remaining"] = int(lease)
            hosts.append(host)
        return hosts

    _HOST_RE = re.compile(
        r"(?P<ip>[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+)"
        r"\s+"
        r"(?P<mac>[0-9A-Fa-f]{2}(?::[0-9A-Fa-f]{2}){5})"
        r"\s+"
        r"(?P<hostname>\S+)?",
    )

    def _parse_hosts_html(self, html: str) -> list[HostDict]:
        hosts: list[HostDict] = []
        for match in self._HOST_RE.finditer(html):
            hosts.append(
                {
                    "mac": match.group("mac").lower(),
                    "ip": match.group("ip"),
                    "hostname": match.group("hostname") or "",
                    "interface_type": "lan",
                    "is_active": True,
                }
            )
        return hosts

    def get_nat_translations(self) -> list[NATTranslationDict]:
        """Return NAT translations derived from enabled port forwards."""
        wan_ip = (self._device_info or {}).get("WanIp", "")
        translations: list[NATTranslationDict] = []
        for forward in self.get_port_forwards():
            if not forward["enabled"]:
                continue
            translations.append(
                {
                    "protocol": forward["protocol"].lower(),
                    "inside_local": f"{forward['internal_ip']}:{forward['internal_port']}",
                    "inside_global": f"{wan_ip}:{forward['external_port']}",
                    "outside_local": "0.0.0.0:0",
                    "outside_global": "0.0.0.0:0",
                    "age": 0.0,
                }
            )
        return translations

    def get_vpn_tunnels(self) -> dict[str, VPNTunnelDict]:
        """Not supported on Zyxel VMG."""
        return {}

    def get_wireless_clients(self) -> list[WirelessClientDict]:
        """Return connected wireless clients from DAL or HTML fallback."""
        html = self._fetch_page("cgi-bin/DAL?oid=WIFI_CLIENTS")
        if html is not None:
            try:
                data = json.loads(html)
                return self._parse_wireless_clients_dal(data)
            except (json.JSONDecodeError, TypeError):
                pass
        html = self._fetch_page("wireless.htm")
        if html is not None:
            return self._parse_wireless_clients_html(html)
        return []

    def _parse_wireless_clients_dal(self, data: dict) -> list[WirelessClientDict]:
        clients: list[WirelessClientDict] = []
        entries = data.get("clients", data.get("assoc", data.get("entries", [])))
        if isinstance(entries, dict):
            entries = [entries]
        if not isinstance(entries, list):
            return clients
        for entry in entries:
            if not isinstance(entry, dict):
                continue
            client: WirelessClientDict = {
                "mac": (entry.get("MACAddress", entry.get("mac", "")) or "").lower(),
                "ssid": entry.get("SSID", entry.get("ssid", "")),
                "radio": entry.get("Radio", entry.get("radio", "")),
                "signal": int(entry.get("Signal", entry.get("signal", 0)) or 0),
                "noise": int(entry.get("Noise", entry.get("noise", 0)) or 0),
                "tx_rate": float(entry.get("TxRate", entry.get("tx_rate", 0)) or 0),
                "rx_rate": float(entry.get("RxRate", entry.get("rx_rate", 0)) or 0),
                "uptime": int(entry.get("Uptime", entry.get("uptime", 0)) or 0),
            }
            ip = entry.get("IPAddress", entry.get("ip", ""))
            if ip:
                client["ip"] = ip
            clients.append(client)
        return clients

    _WIFI_CLIENT_RE = re.compile(
        r"(?P<mac>[0-9A-Fa-f]{2}(?::[0-9A-Fa-f]{2}){5})"
        r"\s+"
        r"(?P<ip>[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+)"
        r"\s+"
        r"(?P<rssi>-?\d+)",
    )

    def _parse_wireless_clients_html(self, html: str) -> list[WirelessClientDict]:
        clients: list[WirelessClientDict] = []
        for match in self._WIFI_CLIENT_RE.finditer(html):
            clients.append(
                {
                    "mac": match.group("mac").lower(),
                    "ssid": "",
                    "radio": "wlan0",
                    "signal": int(match.group("rssi")),
                    "noise": 0,
                    "tx_rate": 0.0,
                    "rx_rate": 0.0,
                    "uptime": 0,
                    "ip": match.group("ip"),
                }
            )
        return clients

    def get_ssids(self) -> dict[str, SSIDDict]:
        """Return WiFi SSID configurations from DAL or HTML fallback."""
        html = self._fetch_page("cgi-bin/DAL?oid=WIFI_SSIDS")
        if html is not None:
            try:
                data = json.loads(html)
                return self._parse_ssids_dal(data)
            except (json.JSONDecodeError, TypeError):
                pass
        html = self._fetch_page("wireless.htm")
        if html is not None:
            return self._parse_ssids_html(html)
        return {}

    def _parse_ssids_dal(self, data: dict) -> dict[str, SSIDDict]:
        ssids: dict[str, SSIDDict] = {}
        entries = data.get("ssids", data.get("entries", []))
        if isinstance(entries, dict):
            entries = [entries]
        if not isinstance(entries, list):
            return ssids
        for entry in entries:
            if not isinstance(entry, dict):
                continue
            ssid_name = (entry.get("SSID", entry.get("ssid", "")) or "").strip()
            if not ssid_name:
                continue
            ssids[ssid_name] = {
                "enabled": bool(entry.get("Enabled", entry.get("enabled", True))),
                "radio": entry.get("Radio", entry.get("radio", "")),
                "bssid": (entry.get("BSSID", entry.get("bssid", "")) or "").lower(),
                "encryption": entry.get("Encryption", entry.get("encryption", "")),
                "hidden": bool(entry.get("Hidden", entry.get("hidden", False))),
                "clients": int(entry.get("Clients", entry.get("clients", 0)) or 0),
            }
        return ssids

    def _parse_ssids_html(self, html: str) -> dict[str, SSIDDict]:
        ssids: dict[str, SSIDDict] = {}
        pattern = re.compile(r"SSID[^:]*:\s*(\S+)", re.I)
        for match in pattern.finditer(html):
            name = match.group(1)
            if name and name not in ssids:
                ssids[name] = {
                    "enabled": True,
                    "radio": "wlan0",
                    "bssid": "",
                    "encryption": "",
                    "hidden": False,
                    "clients": 0,
                }
        return ssids

    def get_radio_status(self) -> dict[str, RadioStatusDict]:
        """Return WiFi radio status from DAL or HTML fallback."""
        radios: dict[str, RadioStatusDict] = {}
        html = self._fetch_page("cgi-bin/DAL?oid=WIFI_RADIO")
        if html is not None:
            try:
                data = json.loads(html)
                entries = data.get("radios", data.get("entries", []))
                if isinstance(entries, dict):
                    entries = [entries]
                for entry in entries if isinstance(entries, list) else []:
                    name = entry.get("Name", entry.get("name", ""))
                    channel = int(entry.get("Channel", entry.get("channel", 0)) or 0)
                    radios[name] = {
                        "enabled": bool(entry.get("Enabled", entry.get("enabled", True))),
                        "band": "2.4GHz" if channel <= 14 else "5GHz",
                        "channel": channel,
                        "channel_width": int(
                            entry.get("ChannelWidth", entry.get("channel_width", 0)) or 0
                        ),
                        "tx_power": int(entry.get("TxPower", entry.get("tx_power", 0)) or 0),
                        "frequency": float(entry.get("Frequency", entry.get("frequency", 0)) or 0),
                    }
                return radios
            except (json.JSONDecodeError, TypeError, ValueError):
                pass
        html = self._fetch_page("wireless.htm")
        if html is not None:
            for band, pat in [("2.4GHz", r"2\.4[Gg]"), ("5GHz", r"5[Gg]")]:
                if re.search(pat, html):
                    radios[band] = {
                        "enabled": True,
                        "band": band,
                        "channel": 0,
                        "channel_width": 0,
                        "tx_power": 0,
                        "frequency": 0.0,
                    }
        return radios

    def reboot_host(self) -> None:
        """Restart the gateway (``HostRebootMixin``); raises when it refuses."""
        result = self._dal_query("REBOOT", {"Command": "reboot"})
        if result is None or result.get("result") != "ZCFG_SUCCESS":
            raise RuntimeError(f"the gateway refused to reboot: {result}")

    def restart_wifi(self, band: str = "both") -> None:
        """Restart the radios of *band* (``2.4G``, ``5G`` or ``both``); raises when refused."""
        result = self._dal_query("WIFI_RESTART", {"Band": band})
        if result is None or result.get("result") != "ZCFG_SUCCESS":
            raise RuntimeError(f"the gateway refused to restart Wi-Fi ({band}): {result}")

    def get_diagnostics(self) -> dict:
        """What the gateway's diagnostics page reports; empty when it reports nothing."""
        return self._dal_query("DIAGNOSTICS", {}) or {}