# SPDX-FileCopyrightText: 2020 The Magma Authors.
# SPDX-FileCopyrightText: 2022 Open Networking Foundation <support@opennetworking.org>
#
# SPDX-License-Identifier: BSD-3-Clause

import asyncio
import ipaddress
import os
from enum import Enum

import netifaces
import snowflake


class IpPreference(Enum):
    IPV4_ONLY = 1
    IPV4_PREFERRED = 2
    IPV6_PREFERRED = 3
    IPV6_ONLY = 4


def get_if_ip_with_netmask(interface, preference=IpPreference.IPV4_PREFERRED):
    """
    Get IP address and netmask (in form /255.255.255.0)
    from interface name and return as tuple (ip, netmask).
    Note: If multiple v4/v6 addresses exist, the first is chosen

    Raise ValueError if unable to get requested IP address.
    """
    # Raises ValueError if interface is unavailable
    ip_addresses = netifaces.ifaddresses(interface)

    try:
        ipv4_address = (
            ip_addresses[netifaces.AF_INET][0]['addr'],
            ip_addresses[netifaces.AF_INET][0]['netmask'],
        )
    except KeyError:
        ipv4_address = None

    try:
        ipv6_address = (
            ip_addresses[netifaces.AF_INET6][0]["addr"].split("%")[0],
            ip_addresses[netifaces.AF_INET6][0]["netmask"],
        )

    except KeyError:
        ipv6_address = None

    if preference == IpPreference.IPV4_ONLY:
        if ipv4_address is not None:
            return ipv4_address
        else:
            raise ValueError('Error getting IPv4 address for %s' % interface)

    elif preference == IpPreference.IPV4_PREFERRED:
        if ipv4_address is not None:
            return ipv4_address
        elif ipv6_address is not None:
            return ipv6_address
        else:
            raise ValueError('Error getting IPv4/6 address for %s' % interface)

    elif preference == IpPreference.IPV6_PREFERRED:
        if ipv6_address is not None:
            return ipv6_address
        elif ipv4_address is not None:
            return ipv4_address
        else:
            raise ValueError('Error getting IPv6/4 address for %s' % interface)

    elif preference == IpPreference.IPV6_ONLY:
        if ipv6_address is not None:
            return ipv6_address
        else:
            raise ValueError('Error getting IPv6 address for %s' % interface)

    else:
        raise ValueError('Unknown IP preference %s' % preference)


def get_all_if_ips_with_netmask(
    interface,
    preference=IpPreference.IPV4_PREFERRED,
):
    """
    Get all IP addresses and netmasks (in form /255.255.255.0)
    from interface name and return as a list of tuple (ip, netmask).

    Raise ValueError if unable to get requested IP addresses.
    """
    # Raises ValueError if interface is unavailable
    ip_addresses = netifaces.ifaddresses(interface)

    try:
        ipv4_addresses = [(ip_address['addr'], ip_address['netmask']) for
                          ip_address in ip_addresses[netifaces.AF_INET]]
    except KeyError:
        ipv4_addresses = None

    try:
        ipv6_addresses = [(ip_address['addr'], ip_address['netmask']) for
                          ip_address in ip_addresses[netifaces.AF_INET6]]
    except KeyError:
        ipv6_addresses = None

    if preference == IpPreference.IPV4_ONLY:
        if ipv4_addresses is not None:
            return ipv4_addresses
        else:
            raise ValueError('Error getting IPv4 addresses for %s' % interface)

    elif preference == IpPreference.IPV4_PREFERRED:
        if ipv4_addresses is not None:
            return ipv4_addresses
        elif ipv6_addresses is not None:
            return ipv6_addresses
        else:
            raise ValueError(
                'Error getting IPv4/6 addresses for %s' % interface,
            )

    elif preference == IpPreference.IPV6_PREFERRED:
        if ipv6_addresses is not None:
            return ipv6_addresses
        elif ipv4_addresses is not None:
            return ipv4_addresses
        else:
            raise ValueError(
                'Error getting IPv6/4 addresses for %s' % interface,
            )

    elif preference == IpPreference.IPV6_ONLY:
        if ipv6_addresses is not None:
            return ipv6_addresses
        else:
            raise ValueError('Error getting IPv6 addresses for %s' % interface)

    else:
        raise ValueError('Unknown IP preference %s' % preference)


def get_ip_from_if(iface_name, preference=IpPreference.IPV4_PREFERRED):
    """
    Get ip address from interface name and return as string.
    Extract only ip address from (ip, netmask)
    """
    return get_if_ip_with_netmask(iface_name, preference)[0]


def get_all_ips_from_if(iface_name, preference=IpPreference.IPV4_PREFERRED):
    """
    Get all ip addresses from interface name and return as a list of string.
    Extract only ip address from (ip, netmask)
    """
    return [
        ip[0] for ip in
        get_all_if_ips_with_netmask(iface_name, preference)
    ]


def get_ip_from_if_cidr(iface_name, preference=IpPreference.IPV4_PREFERRED):
    """
    Get IPAddress with netmask from interface name and
    transform into CIDR (eth1 -> 192.168.60.142/24)
    notation return as string.
    """
    ip, netmask = get_if_ip_with_netmask(iface_name, preference)
    ip = '%s/%s' % (ip, netmask)
    interface = ipaddress.ip_interface(ip).with_prefixlen  # Set CIDR notation
    return interface


def get_all_ips_from_if_cidr(
    iface_name,
    preference=IpPreference.IPV4_PREFERRED,
):
    """
    Get all IPAddresses with netmask from interface name and
    transform into CIDR (eth1 -> 192.168.60.142/24) notation
    return as a list of string.
    """

    def ip_cidr_gen():
        for ip, netmask in get_all_if_ips_with_netmask(iface_name, preference):
            ip = '%s/%s' % (ip, netmask)
            # Set CIDR notation
            ip_cidr = ipaddress.ip_interface(ip).with_prefixlen
            yield ip_cidr

    return [ip_cidr for ip_cidr in ip_cidr_gen()]


def cidr_to_ip_netmask_tuple(cidr_network):
    """
    Convert CIDR-format IP network string (e.g. 10.0.0.1/24) to a tuple
    (ip, netmask) where netmask is in the form (n.n.n.n).

    Args:
        cidr_network (str): IPv4 network in CIDR notation

    Returns:
        (str, str): 2-tuple of IP address and netmask
    """
    network = ipaddress.ip_network(cidr_network)
    return '{}'.format(network.network_address), '{}'.format(network.netmask)


def get_if_mac_address(interface):
    """
    Returns the MAC address of an interface.
    Note: If multiple MAC addresses exist, the first one is chosen.

    Raise ValueError if unable to get requested IP address.
    """
    addr = netifaces.ifaddresses(interface)
    try:
        return addr[netifaces.AF_LINK][0]['addr']
    except KeyError:
        raise ValueError('Error getting MAC address for %s' % interface)


def get_gateway_hwid() -> str:
    """
    Returns the HWID of the gateway
    Note: Currently this uses the snowflake at /etc/snowflake
    """
    return snowflake.snowflake()


def is_interface_up(interface):
    """
    Returns whether an interface is up.
    """
    try:
        addr = netifaces.ifaddresses(interface)
    except ValueError:
        return False
    return netifaces.AF_INET in addr


def call_process(cmd, callback, loop):
    loop = loop or asyncio.get_event_loop()
    loop.create_task(
        loop.subprocess_shell(
        lambda: SubprocessProtocol(callback), "nohup " + cmd,
        preexec_fn=os.setsid,
        ),
    )


class SubprocessProtocol(asyncio.SubprocessProtocol):
    def __init__(self, callback):
        self._callback = callback
        self._transport = None

    def connection_made(self, transport):
        self._transport = transport

    def process_exited(self):
        self._callback(self._transport.get_returncode())