import datetime
from pathlib import Path
from subprocess import list2cmdline
from typing import Union

import paramiko

from openwrt_backup.config import HOSTNAME, NUMBER


def client_from_config(name: str, ssh_config_root: Path):
    """Create a client from a Host entry in the .ssh/config file"""
    config = paramiko.config.SSHConfig()
    cp = ssh_config_root / "config"
    with open(cp) as file:
        config.parse(file)
    info = config.lookup(name)
    info["username"] = info.pop("user", None)
    info["key_filename"] = info.pop("identityfile", None)
    info["port"] = int(info.pop("port", 22))
    params = dict(
        hostname=None,
        port=22,
        username=None,
        password=None,
        pkey=None,
        key_filename=None,
        timeout=None,
        allow_agent=True,
        look_for_keys=True,
        compress=False,
        sock=None,
        gss_auth=False,
        gss_kex=False,
        gss_deleg_creds=True,
        gss_host=None,
        banner_timeout=None,
        auth_timeout=None,
        gss_trust_dns=True,
        passphrase=None,
        disabled_algorithms=None,
    )
    for key, value in info.items():
        if key in params.keys():
            params[key] = value
    client = paramiko.client.SSHClient()
    client.load_host_keys(ssh_config_root / "known_hosts")
    client.connect(**params)
    return client


def exec_remote(client: paramiko.SSHClient, command: Union[str, list]):
    """Function to execute specified command on conection"""
    if not isinstance(command, str):
        command = list2cmdline(command)
    stdin, stdout, stderr = client.exec_command(command)
    return stdout, stderr


def get_next_number(backup_path: Path, hostname):
    f_names = (path.name for path in backup_path.glob("*.tar.gz"))
    f_names_fields = map(lambda s: s.split("__"), f_names)
    f_names_fields_filtered = filter(
        lambda fields: fields[HOSTNAME] == hostname, f_names_fields
    )
    try:
        return max(int(fields[NUMBER]) for fields in f_names_fields_filtered) + 1
    except ValueError:
        return 0


def get_new_backup_filepath(backup_path: Path, time_format, hostname):
    next_number = get_next_number(backup_path, hostname)
    dt = datetime.datetime.today()
    return (
        backup_path
        / f"{hostname}__{next_number:03d}__{dt.strftime(time_format)}.tar.gz"
    )