#
# Copyright (c) 2019 Red Hat, Inc.
#
# This file is part of nmstate
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation, either version 2.1 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
#

import socket

from libnmstate import iplib
from libnmstate.error import NmstateValueError
from libnmstate.schema import Interface
from libnmstate.schema import Route
from libnmstate.schema import RouteRule

from .common import GLib
from .common import NM

IPV4_DEFAULT_GATEWAY_DESTINATION = "0.0.0.0/0"
IPV6_DEFAULT_GATEWAY_DESTINATION = "::/0"

# NM require route rule priority been set explicitly, use 30,000 when
# desire state instruct to use USE_DEFAULT_PRIORITY
ROUTE_RULE_DEFAULT_PRIORIRY = 30000


def add_routes(setting_ip, routes):
    for route in routes:
        _add_specfic_route(setting_ip, route)


def _add_specfic_route(setting_ip, route):
    destination, prefix_len = route[Route.DESTINATION].split("/")
    prefix_len = int(prefix_len)
    if iplib.is_ipv6_address(destination):
        family = socket.AF_INET6
    else:
        family = socket.AF_INET
    metric = route.get(Route.METRIC, Route.USE_DEFAULT_METRIC)
    if route[Route.NEXT_HOP_ADDRESS]:
        next_hop = route[Route.NEXT_HOP_ADDRESS]
    else:
        # NM.IPRoute.new() need None instead of ""
        next_hop = None
    ip_route = NM.IPRoute.new(
        family, destination, prefix_len, next_hop, metric
    )
    table_id = route.get(Route.TABLE_ID, Route.USE_DEFAULT_ROUTE_TABLE)
    ip_route.set_attribute(
        NM.IP_ROUTE_ATTRIBUTE_TABLE, GLib.Variant.new_uint32(table_id)
    )
    # Duplicate route entry will be ignored by libnm.
    setting_ip.add_route(ip_route)


def get_static_gateway_iface(family, iface_routes):
    """
    Return one interface with gateway for given IP family.
    Return None if not found.
    """
    destination = (
        IPV6_DEFAULT_GATEWAY_DESTINATION
        if family == Interface.IPV6
        else IPV4_DEFAULT_GATEWAY_DESTINATION
    )
    for iface_name, routes in iface_routes.items():
        for route in routes:
            if route[Route.DESTINATION] == destination:
                return iface_name
    return None


def add_route_rules(setting_ip, family, rules):
    for rule in rules:
        setting_ip.add_routing_rule(_rule_info_to_nm_rule(rule, family))


def _rule_info_to_nm_rule(rule, family):
    nm_rule = NM.IPRoutingRule.new(family)
    ip_from = rule.get(RouteRule.IP_FROM)
    ip_to = rule.get(RouteRule.IP_TO)
    if not ip_from and not ip_to:
        raise NmstateValueError(
            f"Neither {RouteRule.IP_FROM} or {RouteRule.IP_TO} is defined"
        )

    if ip_from:
        nm_rule.set_from(*iplib.ip_address_full_to_tuple(ip_from))
    if ip_to:
        nm_rule.set_to(*iplib.ip_address_full_to_tuple(ip_to))

    priority = rule.get(RouteRule.PRIORITY)
    if priority and priority != RouteRule.USE_DEFAULT_PRIORITY:
        nm_rule.set_priority(priority)
    else:
        nm_rule.set_priority(ROUTE_RULE_DEFAULT_PRIORIRY)
    table = rule.get(RouteRule.ROUTE_TABLE)
    if table and table != RouteRule.USE_DEFAULT_ROUTE_TABLE:
        nm_rule.set_table(table)
    else:
        nm_rule.set_table(iplib.KERNEL_MAIN_ROUTE_TABLE_ID)
    return nm_rule