import subprocess as sp
import random
import logging
import ipaddress

logger = logging.getLogger(__name__)


def random_bytes(num=6):
    return [random.randrange(256) for _ in range(num)]


def generate_mac(uaa=False, multicast=False, oui=None, separator=":", byte_fmt="%02x"):
    mac = random_bytes()
    if oui:
        if type(oui) == str:
            oui = [int(chunk) for chunk in oui.split(separator)]
        mac = oui + random_bytes(num=6 - len(oui))
    else:
        if multicast:
            mac[0] |= 1  # set bit 0
        else:
            mac[0] &= ~1  # clear bit 0
        if uaa:
            mac[0] &= ~(1 << 1)  # clear bit 1
        else:
            mac[0] |= 1 << 1  # set bit 1
    return separator.join(byte_fmt % b for b in mac)


def create_dev(script, _id, dev, ip=None):
    command = [
        "sudo",
        "-p",
        "Enter password to create network devices for vm: ",
        script,
        str(_id),
        dev,
    ]
    if ip:
        command.append(ip)
    try:
        output = sp.check_output(command, stderr=sp.PIPE)
    except Exception:
        logger.exception("Creation of interface %s failed.", dev)
        return None
    else:
        return output.decode("utf-8").strip()


def delete_network_interface(iface):
    try:
        sp.check_output(
            [
                "sudo",
                "-p",
                "Enter password to remove {} network device: ".format(
                    iface
                ),
                "ip",
                "link",
                "del",
                iface,
            ],
            stderr=sp.PIPE,
        )
    except Exception:
        logger.exception("Interface %s Deletion failed", iface)


def mac2ipv6(mac, prefix):
    # only accept MACs separated by a colon
    parts = mac.split(':')

    # modify parts to match IPv6 value
    parts.insert(3, 'ff')
    parts.insert(4, 'fe')
    parts[0] = '%x' % (int(parts[0], 16) ^ 2)

    # format output
    ipv6_parts = [str(0)] * 4
    for i in range(0, len(parts), 2):
        ipv6_parts.append(''.join(parts[i: i + 2]))

    lower_part = ipaddress.IPv6Address(':'.join(ipv6_parts))
    prefix = ipaddress.IPv6Address(prefix)
    return str(prefix + int(lower_part))