# Author: Ben Howard  <bh@digitalocean.com>
#
# This file is part of cloud-init. See LICENSE file for license information.

import json
import logging
import random

from cloudinit import dmi
from cloudinit import net as cloudnet
from cloudinit import subp, url_helper, util

NIC_MAP = {"public": "eth0", "private": "eth1"}

LOG = logging.getLogger(__name__)


def assign_ipv4_link_local(distro, nic=None):
    """Bring up NIC using an address using link-local (ip4LL) IPs.
    On DigitalOcean, the link-local domain is per-droplet routed, so there
    is no risk of collisions. However, to be more safe, the ip4LL
    address is random.
    """

    if not nic:
        nic = get_link_local_nic(distro)
        LOG.debug("selected interface '%s' for reading metadata", nic)

    if not nic:
        raise RuntimeError(
            "unable to find interfaces to access the"
            "meta-data server. This droplet is broken."
        )

    addr = "169.254.{0}.{1}/16".format(
        random.randint(1, 168), random.randint(0, 255)
    )

    ip_addr_cmd = ["ip", "addr", "add", addr, "dev", nic]
    ip_link_cmd = ["ip", "link", "set", "dev", nic, "up"]

    if not subp.which("ip"):
        raise RuntimeError(
            "No 'ip' command available to configure ip4LL address"
        )

    try:
        subp.subp(ip_addr_cmd)
        LOG.debug("assigned ip4LL address '%s' to '%s'", addr, nic)
        subp.subp(ip_link_cmd)
        LOG.debug("brought device '%s' up", nic)
    except Exception:
        util.logexc(
            LOG,
            "ip4LL address assignment of '%s' to '%s' failed."
            " Droplet networking will be broken",
            addr,
            nic,
        )
        raise

    return nic


def get_link_local_nic(distro):
    nics = [
        f
        for f in cloudnet.get_devicelist()
        if distro.networking.is_physical(f)
    ]
    if not nics:
        return None
    return min(nics, key=lambda d: cloudnet.read_sys_net_int(d, "ifindex"))


def del_ipv4_link_local(nic=None):
    """Remove the ip4LL address. While this is not necessary, the ip4LL
    address is extraneous and confusing to users.
    """
    if not nic:
        LOG.debug(
            "no link_local address interface defined, skipping link "
            "local address cleanup"
        )
        return

    LOG.debug("cleaning up ipv4LL address")

    ip_addr_cmd = ["ip", "addr", "flush", "dev", nic]

    try:
        subp.subp(ip_addr_cmd)
        LOG.debug("removed ip4LL addresses from %s", nic)

    except Exception as e:
        util.logexc(LOG, "failed to remove ip4LL address from '%s'.", nic, e)


def convert_network_configuration(config, dns_servers):
    """Convert the DigitalOcean Network description into Cloud-init's netconfig
    format.

    Example JSON:
     {'public': [
           {'mac': '04:01:58:27:7f:01',
            'ipv4': {'gateway': '45.55.32.1',
                     'netmask': '255.255.224.0',
                     'ip_address': '45.55.50.93'},
            'anchor_ipv4': {
                     'gateway': '10.17.0.1',
                     'netmask': '255.255.0.0',
                     'ip_address': '10.17.0.9'},
            'type': 'public',
            'ipv6': {'gateway': '....',
                     'ip_address': '....',
                     'cidr': 64}}
        ],
       'private': [
           {'mac': '04:01:58:27:7f:02',
            'ipv4': {'gateway': '10.132.0.1',
                     'netmask': '255.255.0.0',
                     'ip_address': '10.132.75.35'},
            'type': 'private'}
        ]
     }
    """

    def _get_subnet_part(pcfg):
        subpart = {
            "type": "static",
            "control": "auto",
            "address": pcfg.get("ip_address"),
            "gateway": pcfg.get("gateway"),
        }

        if ":" in pcfg.get("ip_address"):
            subpart["address"] = "{0}/{1}".format(
                pcfg.get("ip_address"), pcfg.get("cidr")
            )
        else:
            subpart["netmask"] = pcfg.get("netmask")

        return subpart

    nic_configs = []
    macs_to_nics = cloudnet.get_interfaces_by_mac()
    LOG.debug("nic mapping: %s", macs_to_nics)

    for n in config:
        nic = config[n][0]
        LOG.debug("considering %s", nic)

        mac_address = nic.get("mac")
        if mac_address not in macs_to_nics:
            raise RuntimeError(
                "Did not find network interface on system "
                "with mac '%s'. Cannot apply configuration: %s"
                % (mac_address, nic)
            )

        sysfs_name = macs_to_nics.get(mac_address)
        nic_type = nic.get("type", "unknown")

        if_name = NIC_MAP.get(nic_type, sysfs_name)
        if if_name != sysfs_name:
            LOG.debug(
                "Found %s interface '%s' on '%s', assigned name of '%s'",
                nic_type,
                mac_address,
                sysfs_name,
                if_name,
            )
        else:
            msg = (
                "Found interface '%s' on '%s', which is not a public "
                "or private interface. Using default system naming."
            )
            LOG.debug(msg, mac_address, sysfs_name)

        ncfg = {
            "type": "physical",
            "mac_address": mac_address,
            "name": if_name,
        }

        subnets = []
        for netdef in ("ipv4", "ipv6", "anchor_ipv4", "anchor_ipv6"):
            raw_subnet = nic.get(netdef, None)
            if not raw_subnet:
                continue

            sub_part = _get_subnet_part(raw_subnet)
            if nic_type != "public" or "anchor" in netdef:
                del sub_part["gateway"]

            subnets.append(sub_part)

        ncfg["subnets"] = subnets
        nic_configs.append(ncfg)
        LOG.debug("nic '%s' configuration: %s", if_name, ncfg)

    if dns_servers:
        LOG.debug("added dns servers: %s", dns_servers)
        nic_configs.append({"type": "nameserver", "address": dns_servers})

    return {"version": 1, "config": nic_configs}


def read_metadata(url, timeout=2, sec_between=2, retries=30):
    response = url_helper.readurl(
        url, timeout=timeout, sec_between=sec_between, retries=retries
    )
    if not response.ok():
        raise RuntimeError("unable to read metadata at %s" % url)
    return json.loads(response.contents.decode())


def read_sysinfo():
    # DigitalOcean embeds vendor ID and instance/droplet_id in the
    # SMBIOS information

    # Detect if we are on DigitalOcean and return the Droplet's ID
    vendor_name = dmi.read_dmi_data("system-manufacturer")
    if vendor_name != "DigitalOcean":
        return (False, None)

    droplet_id = dmi.read_dmi_data("system-serial-number")
    if droplet_id:
        LOG.debug(
            "system identified via SMBIOS as DigitalOcean Droplet: %s",
            droplet_id,
        )
    else:
        msg = (
            "system identified via SMBIOS as a DigitalOcean "
            "Droplet, but did not provide an ID. Please file a "
            "support ticket at: "
            "https://cloud.digitalocean.com/support/tickets/new"
        )
        LOG.critical(msg)
        raise RuntimeError(msg)

    return (True, droplet_id)