# Copyright 2021-2024 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/>.

# T2816: T3642: Move IPSec/L2TP code into vpn_ipsec.py and update to use PKI.

import os

from vyos.configtree import ConfigTree
from vyos.pki import load_certificate
from vyos.pki import load_private_key
from vyos.pki import encode_certificate
from vyos.pki import encode_private_key
from vyos.utils.process import run

base = ['vpn', 'l2tp', 'remote-access', 'ipsec-settings']
pki_base = ['pki']

AUTH_DIR = '/config/auth'

def wrapped_pem_to_config_value(pem):
    return "".join(pem.strip().split("\n")[1:-1])

def migrate(config: ConfigTree) -> None:
    if not config.exists(base):
        return

    if not config.exists(base + ['authentication', 'x509']):
        return

    x509_base = base + ['authentication', 'x509']
    pki_name = 'l2tp_remote_access'

    if not config.exists(pki_base + ['ca']):
        config.set(pki_base + ['ca'])
        config.set_tag(pki_base + ['ca'])

    if not config.exists(pki_base + ['certificate']):
        config.set(pki_base + ['certificate'])
        config.set_tag(pki_base + ['certificate'])

    if config.exists(x509_base + ['ca-cert-file']):
        cert_file = config.return_value(x509_base + ['ca-cert-file'])
        cert_path = os.path.join(AUTH_DIR, cert_file)
        cert = None

        if os.path.isfile(cert_path):
            if not os.access(cert_path, os.R_OK):
                run(f'sudo chmod 644 {cert_path}')

            with open(cert_path, 'r') as f:
                cert_data = f.read()
                cert = load_certificate(cert_data, wrap_tags=False)

        if cert:
            cert_pem = encode_certificate(cert)
            config.set(pki_base + ['ca', pki_name, 'certificate'], value=wrapped_pem_to_config_value(cert_pem))
            config.set(x509_base + ['ca-certificate'], value=pki_name)
        else:
            print(f'Failed to migrate CA certificate on l2tp remote-access config')

        config.delete(x509_base + ['ca-cert-file'])

    if config.exists(x509_base + ['crl-file']):
        crl_file = config.return_value(x509_base + ['crl-file'])
        crl_path = os.path.join(AUTH_DIR, crl_file)
        crl = None

        if os.path.isfile(crl_path):
            if not os.access(crl_path, os.R_OK):
                run(f'sudo chmod 644 {crl_path}')

            with open(crl_path, 'r') as f:
                crl_data = f.read()
                crl = load_certificate(crl_data, wrap_tags=False)

        if crl:
            crl_pem = encode_certificate(crl)
            config.set(pki_base + ['ca', pki_name, 'crl'], value=wrapped_pem_to_config_value(crl_pem))
        else:
            print(f'Failed to migrate CRL on l2tp remote-access config')

        config.delete(x509_base + ['crl-file'])

    if config.exists(x509_base + ['server-cert-file']):
        cert_file = config.return_value(x509_base + ['server-cert-file'])
        cert_path = os.path.join(AUTH_DIR, cert_file)
        cert = None

        if os.path.isfile(cert_path):
            if not os.access(cert_path, os.R_OK):
                run(f'sudo chmod 644 {cert_path}')

            with open(cert_path, 'r') as f:
                cert_data = f.read()
                cert = load_certificate(cert_data, wrap_tags=False)

        if cert:
            cert_pem = encode_certificate(cert)
            config.set(pki_base + ['certificate', pki_name, 'certificate'], value=wrapped_pem_to_config_value(cert_pem))
            config.set(x509_base + ['certificate'], value=pki_name)
        else:
            print(f'Failed to migrate certificate on l2tp remote-access config')

        config.delete(x509_base + ['server-cert-file'])

    if config.exists(x509_base + ['server-key-file']):
        key_file = config.return_value(x509_base + ['server-key-file'])
        key_passphrase = None

        if config.exists(x509_base + ['server-key-password']):
            key_passphrase = config.return_value(x509_base + ['server-key-password'])

        key_path = os.path.join(AUTH_DIR, key_file)
        key = None

        if os.path.isfile(key_path):
            if not os.access(key_path, os.R_OK):
                run(f'sudo chmod 644 {key_path}')

            with open(key_path, 'r') as f:
                key_data = f.read()
                key = load_private_key(key_data, passphrase=key_passphrase, wrap_tags=False)

        if key:
            key_pem = encode_private_key(key, passphrase=key_passphrase)
            config.set(pki_base + ['certificate', pki_name, 'private', 'key'], value=wrapped_pem_to_config_value(key_pem))

            if key_passphrase:
                config.set(pki_base + ['certificate', pki_name, 'private', 'password-protected'])
                config.set(x509_base + ['private-key-passphrase'], value=key_passphrase)
        else:
            print(f'Failed to migrate private key on l2tp remote-access config')

        config.delete(x509_base + ['server-key-file'])
        if config.exists(x509_base + ['server-key-password']):
            config.delete(x509_base + ['server-key-password'])