# Copyright (C) 2012 Canonical Ltd.
# Copyright (C) 2012 Cosmin Luta
# Copyright (C) 2012 Yahoo! Inc.
# Copyright (C) 2012 Gerard Dethier
# Copyright (C) 2013 Hewlett-Packard Development Company, L.P.
#
# Author: Cosmin Luta <q4break@gmail.com>
# Author: Scott Moser <scott.moser@canonical.com>
# Author: Joshua Harlow <harlowja@yahoo-inc.com>
# Author: Gerard Dethier <g.dethier@gmail.com>
# Author: Juerg Haefliger <juerg.haefliger@hp.com>
#
# This file is part of cloud-init. See LICENSE file for license information.

import logging
import os
import time
from contextlib import suppress
from socket import gaierror, getaddrinfo, inet_ntoa
from struct import pack

from cloudinit import dmi, net, performance, sources
from cloudinit import url_helper as uhelp
from cloudinit import util
from cloudinit.net import dhcp
from cloudinit.net.dhcp import NoDHCPLeaseError
from cloudinit.net.ephemeral import EphemeralIPNetwork
from cloudinit.sources.helpers import ec2

LOG = logging.getLogger(__name__)

CLOUD_STACK_DMI_NAME = "CloudStack"


class CloudStackPasswordServerClient:
    """
    Implements password fetching from the CloudStack password server.

    http://cloudstack-administration.readthedocs.org/
       en/latest/templates.html#adding-password-management-to-your-templates
    has documentation about the system.  This implementation is following that
    found at
    https://github.com/shankerbalan/cloudstack-scripts/
       blob/master/cloud-set-guest-password-debian
    """

    def __init__(self, virtual_router_address):
        self.virtual_router_address = virtual_router_address

    def _do_request(self, domu_request):
        url = f"http://{self.virtual_router_address}:8080"
        headers = {"DomU_Request": domu_request}

        resp = uhelp.readurl(url, headers=headers, timeout=20, retries=3)

        if not resp.ok():
            raise RuntimeError("Failed to fetch VM password from CloudStack")

        return resp.contents.decode("utf-8").strip()

    @performance.timed("Getting password", log_mode="always")
    def get_password(self):
        password = self._do_request("send_my_password")
        if password in ["", "saved_password"]:
            return None
        if password == "bad_request":
            raise RuntimeError("Error when attempting to fetch root password.")
        self._do_request("saved_password")
        return password


class DataSourceCloudStack(sources.DataSource):
    perform_dhcp_setup = False
    dsname = "CloudStack"

    # Setup read_url parameters per get_url_params.
    url_max_wait = 120
    url_timeout = 50

    def __init__(self, sys_cfg, distro, paths):
        super().__init__(sys_cfg, distro, paths)
        self.seed_dir = os.path.join(paths.seed_dir, "cs")
        # Cloudstack has its metadata/userdata URLs located at
        # http://<virtual-router-ip>/latest/
        self.api_ver = "latest"
        self.cfg = {}
        self.vr_addr = None

    def _get_domainname(self):
        """Try obtaining a "domain-name" DHCP lease parameter:
        - From systemd-networkd lease (case-insensitive)
        - From ISC dhclient
        - From network manager dhcp client
        - From dhcpcd (ephemeral)
        - Return empty string if not found (non-fatal)
        """

        LOG.debug("Try obtaining domain name from networkd leases")
        for key in ["DOMAINNAME", "Domain", "domain-name"]:
            domainname = dhcp.networkd_get_option_from_leases(key)
            if domainname:
                return domainname.strip()

        LOG.debug(
            "Could not obtain FQDN from networkd leases. Falling back to "
            "ISC dhclient"
        )
        with suppress(dhcp.NoDHCPLeaseMissingDhclientError):
            domain_name = dhcp.IscDhclient().get_key_from_latest_lease(
                self.distro, "domain-name"
            )
            if domain_name:
                return domain_name.strip()

        LOG.debug(
            "Could not obtain FQDN from ISC dhclient leases. Falling back to "
            "Network Manager leases"
        )
        with suppress(
            dhcp.NoDHCPLeaseMissingDhclientError, dhcp.NoDHCPLeaseError
        ):
            domain_name = dhcp.network_manager_get_option_from_leases(
                "domain_name"
            )
            if domain_name:
                return domain_name.strip()

        LOG.debug(
            "Could not obtain FQDN from NM leases. Falling back to %s",
            self.distro.dhcp_client.client_name,
        )
        try:
            latest_lease = self.distro.dhcp_client.get_newest_lease(
                self.distro.fallback_interface
            )
            domain_name = latest_lease.get("domain-name")
            if domain_name:
                return domain_name.strip()
        except (NoDHCPLeaseError, FileNotFoundError, AttributeError):
            pass

        LOG.debug("No domain name found in any DHCP lease; returning empty")
        return ""

    def get_hostname(
        self,
        fqdn=False,
        resolve_ip=False,
        metadata_only=False,
    ):
        """
        Returns instance's hostname / fqdn
        First probes the parent class method.

        If fqdn is requested, and the parent method didn't return it,
        then attach the domain-name from DHCP response.
        """
        hostname = super().get_hostname(fqdn, resolve_ip, metadata_only)
        if fqdn and "." not in hostname.hostname:
            LOG.debug("FQDN requested")
            domainname = self._get_domainname()
            if domainname:
                fqdn = f"{hostname.hostname}.{domainname}"
                LOG.debug("Obtained the following FQDN: %s", fqdn)
                return sources.DataSourceHostname(fqdn, hostname.is_default)
            LOG.debug(
                "Could not determine domain name for FQDN. "
                "Fall back to hostname as an FQDN: %s",
                fqdn,
            )
        return hostname

    def wait_for_metadata_service(self):
        url_params = self.get_url_params()

        if url_params.max_wait_seconds <= 0:
            return False

        urls = [
            uhelp.combine_url(
                self.metadata_address, "latest/meta-data/instance-id"
            )
        ]
        start_time = time.monotonic()
        url, _response = uhelp.wait_for_url(
            urls=urls,
            max_wait=url_params.max_wait_seconds,
            timeout=url_params.timeout_seconds,
            status_cb=LOG.warning,
        )

        if url:
            LOG.debug("Using metadata source: '%s'", url)
        else:
            LOG.critical(
                "Giving up on waiting for the metadata from %s"
                " after %s seconds",
                urls,
                int(time.monotonic() - start_time),
            )

        return bool(url)

    def get_config_obj(self):
        return self.cfg

    @staticmethod
    def ds_detect() -> bool:
        """Check if running on this datasource"""
        return is_platform_viable()

    def _get_data(self):
        seed_ret = {}
        if util.read_optional_seed(seed_ret, base=(self.seed_dir + "/")):
            self.userdata_raw = seed_ret["user-data"]
            self.metadata = seed_ret["meta-data"]
            LOG.debug("Using seeded cloudstack data from: %s", self.seed_dir)
            return True
        if self.perform_dhcp_setup:
            primary_nic = net.find_fallback_nic()
            LOG.debug("Attempting DHCP on: %s", primary_nic)
            network_context = EphemeralIPNetwork(self.distro, primary_nic)
        else:
            network_context = util.nullcontext()
        try:
            with network_context:
                vr_addr = get_vr_address(self.distro)
                # If vr_addr is a dict, we have the DHCP lease
                self.vr_addr = (
                    vr_addr.get("dhcp-server-identifier")
                    if isinstance(vr_addr, dict)
                    else vr_addr
                )
                if not self.vr_addr:
                    raise RuntimeError("No virtual router found!")
                self.metadata_address = f"http://{self.vr_addr}/"
                if not self.wait_for_metadata_service():
                    return False

                return self._crawl_metadata()
        except NoDHCPLeaseError:
            LOG.warning("Unable to obtain a DHCP lease on %s", primary_nic)
            return False
        except Exception as e:
            LOG.warning("Failed fetching metadata service: %s", str(e))
            return False

    @performance.timed("Crawling metadata", log_mode="always")
    def _crawl_metadata(self):
        self.userdata_raw = ec2.get_instance_userdata(
            self.api_ver, self.metadata_address
        )
        self.metadata = ec2.get_instance_metadata(
            self.api_ver, self.metadata_address
        )

        password_client = CloudStackPasswordServerClient(self.vr_addr)
        try:
            set_password = password_client.get_password()
        except Exception:
            util.logexc(
                LOG,
                "Failed to fetch password from virtual router %s",
                self.vr_addr,
            )
        else:
            if set_password:
                self.cfg = {
                    "ssh_pwauth": True,
                    "password": set_password,
                    "chpasswd": {
                        "expire": False,
                    },
                }
        return True

    def get_instance_id(self):
        return self.metadata["instance-id"]

    @property
    def availability_zone(self):
        return self.metadata["availability-zone"]


class DataSourceCloudStackLocal(DataSourceCloudStack):
    """Run in init-local using a dhcp discovery prior to metadata crawl.

    In init-local, no network is available. This subclass sets up minimal
    networking with dhclient on a viable nic so that it can talk to the
    metadata service. If the metadata service provides network configuration
    then render the network configuration for that instance based on metadata.
    """

    perform_dhcp_setup = True  # Get metadata network config if present


def get_data_server():
    # Returns the metadataserver from dns
    try:
        addrinfo = getaddrinfo("data-server", 80)
    except gaierror:
        LOG.debug("DNS Entry data-server not found")
        return None
    else:
        return addrinfo[0][4][0]  # return IP


def get_default_gateway():
    # Returns the default gateway ip address in the dotted format.
    lines = util.load_text_file("/proc/net/route").splitlines()
    for line in lines:
        items = line.split("\t")
        if items[1] == "00000000":
            # Found the default route, get the gateway
            gw = inet_ntoa(pack("<L", int(items[2], 16)))
            LOG.debug("Found default route, gateway is %s", gw)
            return gw
    return None


def get_vr_address(distro):
    # Get the address of the virtual router via dhcp leases
    # If no virtual router is detected, fallback on default gateway.
    # See http://docs.cloudstack.apache.org/projects/cloudstack-administration/en/4.8/virtual_machines/user-data.html # noqa

    # Try data-server DNS entry first
    latest_address = get_data_server()
    if latest_address:
        LOG.debug(
            "Found metadata server '%s' via data-server DNS entry",
            latest_address,
        )
        return latest_address

    # Try networkd second...
    latest_address = dhcp.networkd_get_option_from_leases("SERVER_ADDRESS")
    if latest_address:
        LOG.debug(
            "Found SERVER_ADDRESS '%s' via networkd_leases", latest_address
        )
        return latest_address

    # Try dhcp lease files next
    # get_key_from_latest_lease() needs a Distro object to know which directory
    # stores lease files
    with suppress(dhcp.NoDHCPLeaseMissingDhclientError):
        latest_address = dhcp.IscDhclient().get_key_from_latest_lease(
            distro, "dhcp-server-identifier"
        )
        if latest_address:
            LOG.debug("Found SERVER_ADDRESS '%s' via dhclient", latest_address)
            return latest_address

    # try network manager DHCP lease information
    with suppress(dhcp.NoDHCPLeaseMissingDhclientError, dhcp.NoDHCPLeaseError):
        latest_address = dhcp.network_manager_get_option_from_leases(
            "dhcp_server_identifier"
        )
        if latest_address:
            LOG.debug("Found SERVER_ADDRESS '%s' via nmcli", latest_address)
            return latest_address

    with suppress(FileNotFoundError):
        latest_lease = distro.dhcp_client.get_newest_lease(
            distro.fallback_interface
        )
        if latest_lease:
            LOG.debug(
                "Found SERVER_ADDRESS '%s' via ephemeral %s lease ",
                latest_lease,
                distro.dhcp_client.client_name,
            )
            return latest_lease

    # No virtual router found, fallback to default gateway
    LOG.debug("No DHCP found, using default gateway")
    return get_default_gateway()


def is_platform_viable() -> bool:
    product_name = dmi.read_dmi_data("system-product-name")
    if not product_name:
        LOG.debug("system-product-name not available in dmi data")
        return False
    return product_name.startswith(CLOUD_STACK_DMI_NAME)


# Used to match classes to dependencies
datasources = [
    (DataSourceCloudStackLocal, (sources.DEP_FILESYSTEM,)),
    (DataSourceCloudStack, (sources.DEP_FILESYSTEM, sources.DEP_NETWORK)),
]


# Return a list of data sources that match this set of dependencies
def get_datasource_list(depends):
    return sources.list_from_depends(depends, datasources)
