import logging
import subprocess
import tempfile

import typing

import const
import models
import schemas
import os
import re

import util

_LOGGER = logging.getLogger(__name__)


class WGAlreadyStartedError(Exception):
    pass


class WGAlreadyStoppedError(Exception):
    pass


class WGPermissionsError(Exception):
    pass


class TempServerFile():
    def __init__(self, server: schemas.WGServer):
        self.server = server
        self.td = tempfile.TemporaryDirectory(prefix="wg_man_")
        self.server_file = os.path.join(self.td.name, f"{server.interface}.conf")

    def __enter__(self):
        with open(self.server_file, "w+") as f:
            f.write(self.server.configuration)
        return self.server_file

    def __exit__(self, type, value, traceback):
        self.td.cleanup()


def _run_wg(server: schemas.WGServer, command):
    try:
        output = subprocess.check_output(const.CMD_WG_COMMAND + command, stderr=subprocess.STDOUT)
        return output
    except Exception as e:
        if b'Operation not permitted' in e.output:
            raise WGPermissionsError("The user has insufficientt permissions for interface %s" % server.interface)


def is_installed():
    output = subprocess.check_output(const.CMD_WG_COMMAND)
    return output == b'' or b'interface' in output


def generate_keys() -> typing.Dict[str, str]:
    private_key = subprocess.check_output(const.CMD_WG_COMMAND + ["genkey"])
    public_key = subprocess.check_output(
        const.CMD_WG_COMMAND + ["pubkey"],
        input=private_key
    )

    private_key = private_key.decode("utf-8").strip()
    public_key = public_key.decode("utf-8").strip()
    return dict(
        private_key=private_key,
        public_key=public_key
    )


def generate_psk():
    return subprocess.check_output(const.CMD_WG_COMMAND + ["genpsk"]).decode("utf-8").strip()


def start_interface(server: schemas.WGServer):
    with TempServerFile(server) as server_file:
        try:
            #print(*const.CMD_WG_QUICK, "up", server_file)
            output = subprocess.check_output(const.CMD_WG_QUICK + ["up", server_file], stderr=subprocess.STDOUT)
            return output
        except Exception as e:
            if b'already exists' in e.output:
                raise WGAlreadyStartedError("The wireguard device %s is already started." % server.interface)


def stop_interface(server: schemas.WGServer):
    with TempServerFile(server) as server_file:
        try:
            output = subprocess.check_output(const.CMD_WG_QUICK + ["down", server_file], stderr=subprocess.STDOUT)
            return output
        except Exception as e:

            if b'is not a WireGuard interface' in e.output:
                raise WGAlreadyStoppedError("The wireguard device %s is already stopped." % server.interface)


def restart_interface(server: schemas.WGServer):
    try:
        stop_interface(server)
    except WGAlreadyStoppedError:
        pass
    start_interface(server)


def is_running(server: schemas.WGServer):
    try:
        output = _run_wg(server, ["show", server.interface])
        if output is None:
            return False
    except Exception as e:
        if b'No such device' in e.output:
            return False
    return True


def add_peer(server: schemas.WGServer, peer: schemas.WGPeer):
    try:
        output = _run_wg(server, ["set", server.interface, "peer", peer.public_key, "allowed-ips", peer.address])
        return output == b''
    except Exception as e:
        _LOGGER.exception(e)
        return False


def remove_peer(server: schemas.WGServer, peer: schemas.WGPeer):
    try:
        output = _run_wg(server, ["set", server.interface, "peer", peer.public_key, "remove"])
        return output == b''
    except Exception as e:
        _LOGGER.exception(e)
        return False


def get_stats(server: schemas.WGServer):
    try:
        output = _run_wg(server, ["show", server.interface])
        if not output:
            return []
        regex = r"peer:.*?^\n"
        test_str = output.decode("utf-8") + "\n"

        peers = []

        peers_raw = re.findall(regex, test_str, re.MULTILINE | re.DOTALL)

        for peer in peers_raw:
            peer = peer.strip()
            lines = [x.split(": ")[1] for x in peer.split("\n")]

            if len(lines) == 2:
                public_key, allowed_ips = lines
                peers.append(dict(
                    public_key=public_key,
                    client_endpoint=None,
                    allowed_ips=allowed_ips,
                    handshake=None,
                    rx=None,
                    tx=None
                ))
            elif len(lines) == 5 or len(lines) == 6:
                public_key = lines[0]
                client_endpoint, allowed_ips, handshake, rx_tx = lines[-4:]  # [1] is sometimes psk

                rx = re.match(r"^(.*) received", rx_tx).group(1)
                tx = re.match(r"^.*, (.*)sent", rx_tx).group(1)
                peers.append(dict(
                    public_key=public_key,
                    client_endpoint=client_endpoint,
                    allowed_ips=allowed_ips,
                    handshake=handshake,
                    rx=rx,
                    tx=tx
                ))

            else:
                ValueError("We have not handled peers with line number of %s" % str(len(lines)))

        return peers
    except Exception as e:
        _LOGGER.exception(e)
        return []


def move_server_dir(interface, interface1):
    old_server_dir = const.SERVER_DIR(interface)
    old_server_file = const.SERVER_FILE(interface)
    new_server_dir = const.SERVER_DIR(interface1)
    new_server_file = old_server_file.replace(f"{interface}.conf", f"{interface1}.conf")

    os.rename(old_server_file, new_server_file)
    os.rename(old_server_dir, new_server_dir)


def generate_config(obj: typing.Union[typing.Dict[schemas.WGPeer, schemas.WGServer], schemas.WGServer]):
    if isinstance(obj, dict) and "server" in obj and "peer" in obj:
        template = "peer.j2"
    elif isinstance(obj, schemas.WGServer) or isinstance(obj, models.WGServer):
        template = "server.j2"
    else:
        raise ValueError("Incorrect input type. Should be WGPeer or WGServer")

    result = util.jinja_env.get_template(template).render(
        data=obj
    )

    return result