#!/usr/bin/env python3
#
# Copyright (C) 2019 VyOS maintainers and contributors
#
# 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/>.
#
#

"""Load config file from within config session.
Config file specified by URI or path (without scheme prefix).
Example: load https://somewhere.net/some.config
        or
         load /tmp/some.config
"""

import os
import sys
import gzip
import tempfile
import vyos.defaults
import vyos.remote
from vyos.configsource import ConfigSourceSession
from vyos.configtree import ConfigTree, DiffTree
from vyos.migrator import Migrator, VirtualMigrator, MigratorError
from vyos.util import cmd, DEVNULL

class LoadConfig(ConfigSourceSession):
    """A subclass for loading a config file.
    This does not belong in configsource.py, and only has a single caller.
    """
    def load_config(self, file_path):
        try:
            with open(file_path) as f:
                config_file = f.read()
            load_ct = ConfigTree(config_file)
        except (OSError, ValueError) as e:
            print(e)
            return

        eff_ct, _ = self.get_configtree_tuple()
        diff = DiffTree(eff_ct, load_ct)
        commands = diff.to_commands()
        # on an empty set of 'add' or 'delete' commands, to_commands
        # returns '\n'; prune below
        command_list = commands.splitlines()
        command_list = [c for c in command_list if c]

        if not command_list:
            return
        for op in command_list:
            try:
                cmd(f'/opt/vyatta/sbin/my_{op}', shell=True, stderr=DEVNULL)
            except OSError as e:
                print(e)
                return

file_name = sys.argv[1] if len(sys.argv) > 1 else 'config.boot'
configdir = vyos.defaults.directories['config']
protocols = ['scp', 'sftp', 'http', 'https', 'ftp', 'tftp']

def get_local_config(filename):
    if os.path.isfile(filename):
        fname = filename
    elif os.path.isfile(os.path.join(configdir, filename)):
        fname = os.path.join(configdir, filename)
    else:
        sys.exit(f"No such file '{filename}'")

    if fname.endswith('.gz'):
        with gzip.open(fname, 'rb') as f:
            try:
                config_str = f.read().decode()
            except OSError as e:
                sys.exit(e)
    else:
        with open(fname, 'r') as f:
            try:
                config_str = f.read()
            except OSError as e:
                sys.exit(e)

    return config_str

if any(x in file_name for x in protocols):
    config_string = vyos.remote.get_remote_config(file_name)
    if not config_string:
        sys.exit(f"No such config file at '{file_name}'")
else:
    config_string = get_local_config(file_name)

config = LoadConfig()

print(f"Loading configuration from '{file_name}'")

with tempfile.NamedTemporaryFile() as fp:
    with open(fp.name, 'w') as fd:
        fd.write(config_string)

    virtual_migration = VirtualMigrator(fp.name)
    try:
        virtual_migration.run()
    except MigratorError as err:
        sys.exit('{}'.format(err))

    migration = Migrator(fp.name)
    try:
        migration.run()
    except MigratorError as err:
        sys.exit('{}'.format(err))

    config.load_config(fp.name)

if config.session_changed():
    print("Load complete. Use 'commit' to make changes effective.")
else:
    print("No configuration changes to commit.")