#!/usr/bin/env python3
#
# Copyright VyOS maintainers and contributors <maintainers@vyos.io>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 or later as
# published by the Free Software Foundation.
#
# 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

from sys import exit

from vyos.config import Config
from vyos.configdep import set_dependents
from vyos.configdep import call_dependents
from vyos.configdict import get_interface_dict
from vyos.configdict import is_source_interface
from vyos.configdict import is_node_changed
from vyos.configdict import is_vrf_changed
from vyos.configverify import verify_vrf
from vyos.configverify import verify_address
from vyos.configverify import verify_bridge_delete
from vyos.configverify import verify_source_interface
from vyos.configverify import verify_vlan_config
from vyos.configverify import verify_mtu_parent
from vyos.configverify import verify_mtu_ipv6
from vyos.configverify import verify_mirror_redirect
from vyos.ifconfig import MACVLANIf
from vyos.utils.network import interface_exists
from vyos import ConfigError

from vyos import airbag
airbag.enable()

def get_config(config=None):
    """
    Retrieve CLI config as dictionary. Dictionary can never be empty, as at
    least the interface name will be added or a deleted flag
    """
    if config:
        conf = config
    else:
        conf = Config()
    base = ['interfaces', 'pseudo-ethernet']
    ifname, peth = get_interface_dict(conf, base)

    mode = is_node_changed(conf, ['mode'])
    if mode: peth.update({'shutdown_required' : {}})

    if is_node_changed(conf, base + [ifname, 'mode']):
        peth.update({'rebuild_required': {}})

    if 'source_interface' in peth:
        _, peth['parent'] = get_interface_dict(conf, ['interfaces', 'ethernet'],
                                               peth['source_interface'])
        # test if source-interface is maybe already used by another interface
        tmp = is_source_interface(conf, peth['source_interface'], ['macsec'])
        if tmp and tmp != ifname: peth.update({'is_source_interface' : tmp})

    # Protocols static arp dependency
    if 'static_arp' in peth:
        set_dependents('static_arp', conf)

    # Check vrf membership, to ensure firewall is updated
    if is_vrf_changed(conf, ifname):
        set_dependents('firewall', conf)

    return peth

def _verify_anycast_gateway(peth: dict):
    """Validate anycast-gateway requirements."""

    if 'anycast_gateway' not in peth:
        return

    ifname = peth['ifname']

    # Requirement 1: MAC address must be explicitly configured
    if 'mac' not in peth:
        raise ConfigError(
            f'Anycast-gateway requires an explicit MAC address to be set on interface {ifname}. '
            f'Use: set interfaces pseudo-ethernet {ifname} mac <mac>'
        )

    # Requirement 2: source-interface must be a bridge or bridge sub-interface
    source_iface = peth.get('source_interface')
    if not source_iface:
        raise ConfigError(
            f'Anycast-gateway requires source-interface to be set on interface {ifname}'
        )

    if not source_iface.startswith('br'):
        raise ConfigError(
            'Anycast-gateway requires source-interface to be a bridge '
            'or a bridge vlan interface (e.g. br0 or br0.100), but '
            f'"{source_iface}" is neither of these two.'
        )

def verify(peth):
    if 'deleted' in peth:
        verify_bridge_delete(peth)
        return None

    verify_source_interface(peth)
    verify_vrf(peth)
    verify_address(peth)
    verify_mtu_parent(peth, peth['parent'])
    verify_mtu_ipv6(peth)
    verify_mirror_redirect(peth)
    # use common function to verify VLAN configuration
    verify_vlan_config(peth)

    _verify_anycast_gateway(peth)

    return None

def generate(peth):
    return None

def apply(peth):
    # Check if the MACVLAN interface already exists
    if 'rebuild_required' in peth or 'deleted' in peth:
        if interface_exists(peth['ifname']):
            p = MACVLANIf(**peth)
            # MACVLAN is always needs to be recreated,
            # thus we can simply always delete it first.
            p.remove()

    if 'deleted' not in peth:
        p = MACVLANIf(**peth)
        p.update(peth)

    # run the dependents
    call_dependents()

    return None

if __name__ == '__main__':
    try:
        c = get_config()
        verify(c)
        generate(c)
        apply(c)
    except ConfigError as e:
        print(e)
        exit(1)