# Copyright 2019-2025 VyOS maintainers and contributors <maintainers@vyos.io>
#
# This library 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 library 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 library.  If not, see <http://www.gnu.org/licenses/>.

import os
import time

from datetime import timedelta
from tempfile import NamedTemporaryFile

from hurry.filesize import size
from hurry.filesize import alternative

from vyos.configquery import ConfigTreeQuery
from vyos.ifconfig import Interface
from vyos.ifconfig import Operational
from vyos.template import is_ipv6
from vyos.template import is_ipv4

class WireGuardOperational(Operational):
    def _dump(self):
        """Dump wireguard data in a python friendly way."""
        last_device = None
        output = {}

        # Dump wireguard connection data
        _f = self._cmd('wg show all dump')
        for line in _f.split('\n'):
            if not line:
                # Skip empty lines and last line
                continue
            items = line.split('\t')

            if last_device != items[0]:
                # We are currently entering a new node
                device, private_key, public_key, listen_port, fw_mark = items
                last_device = device

                output[device] = {
                    'private_key': None if private_key == '(none)' else private_key,
                    'public_key': None if public_key == '(none)' else public_key,
                    'listen_port': int(listen_port),
                    'fw_mark': None if fw_mark == 'off' else int(fw_mark),
                    'peers': {},
                }
            else:
                # We are entering a peer
                (
                    device,
                    public_key,
                    preshared_key,
                    endpoint,
                    allowed_ips,
                    latest_handshake,
                    transfer_rx,
                    transfer_tx,
                    persistent_keepalive,
                ) = items
                if allowed_ips == '(none)':
                    allowed_ips = []
                else:
                    allowed_ips = allowed_ips.split('\t')
                output[device]['peers'][public_key] = {
                    'preshared_key': None if preshared_key == '(none)' else preshared_key,
                    'endpoint': None if endpoint == '(none)' else endpoint,
                    'allowed_ips': allowed_ips,
                    'latest_handshake': None if latest_handshake == '0' else int(latest_handshake),
                    'transfer_rx': int(transfer_rx),
                    'transfer_tx': int(transfer_tx),
                    'persistent_keepalive': None if persistent_keepalive == 'off' else int(persistent_keepalive),
                }
        return output

    def show_interface(self):
        from vyos.config import Config

        c = Config()

        wgdump = self._dump().get(self.config['ifname'], None)

        c.set_level(['interfaces', 'wireguard', self.config['ifname']])
        description = c.return_effective_value(['description'])
        ips = c.return_effective_values(['address'])
        hostnames = c.return_effective_values(['host-name'])

        answer = 'interface: {}\n'.format(self.config['ifname'])
        if description:
            answer += '  description: {}\n'.format(description)
        if ips:
            answer += '  address: {}\n'.format(', '.join(ips))
        if hostnames:
            answer += '  hostname: {}\n'.format(', '.join(hostnames))

        answer += '  public key: {}\n'.format(wgdump['public_key'])
        answer += '  private key: (hidden)\n'
        answer += '  listening port: {}\n'.format(wgdump['listen_port'])
        answer += '\n'

        for peer in c.list_effective_nodes(['peer']):
            if wgdump['peers']:
                pubkey = c.return_effective_value(['peer', peer, 'public-key'])
                if pubkey in wgdump['peers']:
                    wgpeer = wgdump['peers'][pubkey]

                    answer += '  peer: {}\n'.format(peer)
                    answer += '    public key: {}\n'.format(pubkey)

                    """ figure out if the tunnel is recently active or not """
                    status = 'inactive'
                    if wgpeer['latest_handshake'] is None:
                        """ no handshake ever """
                        status = 'inactive'
                    else:
                        if int(wgpeer['latest_handshake']) > 0:
                            delta = timedelta(
                                seconds=int(time.time() - wgpeer['latest_handshake'])
                            )
                            answer += '    latest handshake: {}\n'.format(delta)
                            if time.time() - int(wgpeer['latest_handshake']) < (60 * 5):
                                """ Five minutes and the tunnel is still active """
                                status = 'active'
                            else:
                                """ it's been longer than 5 minutes """
                                status = 'inactive'
                        elif int(wgpeer['latest_handshake']) == 0:
                            """ no handshake ever """
                            status = 'inactive'
                        answer += '    status: {}\n'.format(status)

                    if wgpeer['endpoint'] is not None:
                        answer += '    endpoint: {}\n'.format(wgpeer['endpoint'])

                    if wgpeer['allowed_ips'] is not None:
                        answer += '    allowed ips: {}\n'.format(
                            ','.join(wgpeer['allowed_ips']).replace(',', ', ')
                        )

                    if wgpeer['transfer_rx'] > 0 or wgpeer['transfer_tx'] > 0:
                        rx_size = size(wgpeer['transfer_rx'], system=alternative)
                        tx_size = size(wgpeer['transfer_tx'], system=alternative)
                        answer += '    transfer: {} received, {} sent\n'.format(
                            rx_size, tx_size
                        )

                    if wgpeer['persistent_keepalive'] is not None:
                        answer += '    persistent keepalive: every {} seconds\n'.format(
                            wgpeer['persistent_keepalive']
                        )
                answer += '\n'
        return answer

    def get_latest_handshakes(self):
        """Get latest handshake time for each peer"""
        output = {}

        # Dump wireguard last handshake
        tmp = self._cmd(f'wg show {self.ifname} latest-handshakes')
        # Output:
        # PUBLIC-KEY=    1732812147
        for line in tmp.split('\n'):
            if not line:
                # Skip empty lines and last line
                continue
            items = line.split('\t')

            if len(items) != 2:
                continue

            output[items[0]] = int(items[1])

        return output

    def reset_peer(self, peer_name=None, public_key=None):
        c = ConfigTreeQuery()
        tmp = c.get_config_dict(['interfaces', 'wireguard', self.ifname],
                                effective=True, get_first_key=True,
                                key_mangling=('-', '_'), with_defaults=True)

        current_peers = self._dump().get(self.ifname, {}).get('peers', {})

        for peer, peer_config in tmp['peer'].items():
            peer_public_key = peer_config['public_key']
            if peer_name is None or peer == peer_name or public_key == peer_public_key:
                if ('address' not in peer_config and 'host_name' not in peer_config) or 'port' not in peer_config:
                    if peer_name is not None:
                        print(f'WireGuard interface "{self.ifname}" peer "{peer_name}" address/host-name unset!')
                    continue

                # As we work with an effective config, a port CLI node is always
                # available when an address/host-name is defined on the CLI
                port = peer_config['port']

                # address has higher priority than host-name
                if 'address' in peer_config:
                    address = peer_config['address']
                    new_endpoint = f'{address}:{port}'
                else:
                    host_name = peer_config['host_name']
                    new_endpoint = f'{host_name}:{port}'

                if 'disable' in peer_config:
                    print(f'WireGuard interface "{self.ifname}" peer "{peer_name}" disabled!')
                    continue

                cmd = f'wg set {self.ifname} peer {peer_public_key} endpoint {new_endpoint}'
                try:
                    if (peer_public_key in current_peers
                        and 'endpoint' in current_peers[peer_public_key]
                        and current_peers[peer_public_key]['endpoint'] is not None
                    ):
                        current_endpoint = current_peers[peer_public_key]['endpoint']
                        message = f'Resetting {self.ifname} peer {peer_public_key} from {current_endpoint} endpoint to {new_endpoint} ... '
                    else:
                        message = f'Resetting {self.ifname} peer {peer_public_key} endpoint to {new_endpoint} ... '
                    print(message, end='')

                    self._cmd(cmd, env={'WG_ENDPOINT_RESOLUTION_RETRIES':
                                        tmp['max_dns_retry']})
                    print('done')
                except:
                    print(f'Error\nPlease try to run command manually:\n{cmd}\n')


@Interface.register
class WireGuardIf(Interface):
    OperationalClass = WireGuardOperational
    definition = {
        **Interface.definition,
        **{
            'section': 'wireguard',
            'prefixes': ['wg', ],
            'bridgeable': False,
        },
    }

    def _create(self):
        super()._create('wireguard')

    def get_mac(self):
        """Get a synthetic MAC address."""
        return self.get_mac_synthetic()

    def update(self, config):
        """General helper function which works on a dictionary retrived by
        get_config_dict(). It's main intention is to consolidate the scattered
        interface setup code and provide a single point of entry when workin
        on any interface."""
        tmp_file = NamedTemporaryFile('w')
        tmp_file.write(config['private_key'])
        tmp_file.flush()

        # Wireguard base command is identical for every peer
        base_cmd = f'wg set {self.ifname}'
        interface_cmd = base_cmd
        if 'port' in config:
            interface_cmd += ' listen-port {port}'
        if 'fwmark' in config:
            interface_cmd += ' fwmark {fwmark}'

        interface_cmd += f' private-key {tmp_file.name}'
        interface_cmd = interface_cmd.format(**config)
        # T6490: execute command to ensure interface configured
        self._cmd(interface_cmd)

        # If no PSK is given remove it by using /dev/null - passing keys via
        # the shell (usually bash) is considered insecure, thus we use a file
        no_psk_file = '/dev/null'

        if 'peer' in config:
            for peer, peer_config in config['peer'].items():
                # T4702: No need to configure this peer when it was explicitly
                # marked as disabled - also active sessions are terminated as
                # the public key was already removed when entering this method!
                if 'disable' in peer_config:
                    # remove peer if disabled, no error report even if peer not exists
                    cmd = base_cmd + ' peer {public_key} remove'
                    self._cmd(cmd.format(**peer_config))
                    continue

                psk_file = no_psk_file

                # start of with a fresh 'wg' command
                peer_cmd = base_cmd + ' peer {public_key}'

                try:
                    cmd = peer_cmd

                    if 'preshared_key' in peer_config:
                        psk_file = '/tmp/tmp.wireguard.psk'
                        with open(psk_file, 'w') as f:
                            f.write(peer_config['preshared_key'])
                    cmd += f' preshared-key {psk_file}'

                    # Persistent keepalive is optional
                    if 'persistent_keepalive' in peer_config:
                        cmd += ' persistent-keepalive {persistent_keepalive}'

                    # Multiple allowed-ip ranges can be defined - ensure we are always
                    # dealing with a list
                    if isinstance(peer_config['allowed_ips'], str):
                        peer_config['allowed_ips'] = [peer_config['allowed_ips']]
                    cmd += ' allowed-ips ' + ','.join(peer_config['allowed_ips'])

                    self._cmd(cmd.format(**peer_config))

                    cmd = peer_cmd

                    # Ensure peer is created even if dns not working
                    if {'address', 'port'} <= set(peer_config):
                        if is_ipv6(peer_config['address']):
                            cmd += ' endpoint [{address}]:{port}'
                        elif is_ipv4(peer_config['address']):
                            cmd += ' endpoint {address}:{port}'
                        else:
                            # don't set endpoint if address uses domain name
                            continue
                    elif {'host_name', 'port'} <= set(peer_config):
                        cmd += ' endpoint {host_name}:{port}'

                    self._cmd(cmd.format(**peer_config), env={
                        'WG_ENDPOINT_RESOLUTION_RETRIES': config['max_dns_retry']})
                except:
                    # todo: logging
                    pass
                finally:
                    # PSK key file is not required to be stored persistently as its backed by CLI
                    if psk_file != no_psk_file and os.path.exists(psk_file):
                        os.remove(psk_file)

        # call base class
        super().update(config)