#!/usr/bin/python3
import pathlib
from typing import List, Union

from ansible.module_utils.generic import SYSTEMD_NETWORK_CONFIG as SYSTEMD_PATH
from ansible.module_utils.generic import Types
from ansible.module_utils.module import SystemdUnitModule

def boolconvert(b: Union[bool, str]) -> str:
    if b is True:
        return "yes"
    elif b is False:
        return "no"
    return b


class Module(SystemdUnitModule):
    """Sets up the systemd network unit"""

    name = "systemd_network"
    module_spec = dict(
        argument_spec=dict(
            mac=Types.str(help="The MAC-Address of the device"),
            device=Types.str(help="The name of the network device"),
            name=Types.str(required=True, help="name of the unit"),
            description=Types.str(help="An optional description"),
            dot=Types.bool(help="if DNS-over-TLS should be required or disabled. If it is unset, it will used if the server supports it"),
            dnssec=Types.bool("if the Domainqueries should require DNSSEC or not. If its missing, domains that have DNSSEC enabled will be validated, all others it will be assumed to be okay."),
            dns=Types.list(elements=str, help="List of DNS-Servers"),
            domain=Types.list(elements=str, help="List of domains that are on this device"),
            defaultdns=Types.bool(help="If the DNS-Server(s) on this device should be used for all domains that are not set on other devices"),
            address=Types.list(elements=str, required=True, help="IP-Addresses of this networkdevice"),
            route=Types.list(elements=str, help="Routes of networks that can be reached with this device"),
        ),
        required_if=(("defaultdns", True, ("dns",), False),),
        required_one_of=(("mac", "device"),),
    )

    def prepare(self):
        self.unitfile = SYSTEMD_PATH.joinpath(self.get("name")).with_suffix(".network")
        self.__unit = None

    def unit(self) -> str:
        if self.__unit is None:
            self.__unit = "\n".join(
                (
                    self.match(),
                    self.network(),
                    self.addresses(),
                    self.routes(),
                )
            )
        return self.__unit

    def match(self) -> str:
        matches = []
        if self.get("mac", False):
            matches.append("MACAddress={}\n".format(self.get("mac")))
        if self.get("device", False):
            matches.append("Name={}\n".format(self.get("device")))
        return "[Match]\n" + "".join(matches)

    def network(self) -> str:
        output = "[Network]\n"
        options = []
        try:
            options.append("Description={}".format(self.get("description")))
        except KeyError:
            pass
        try:
            for server in self.get("dns", []):
                options.append(f"DNS={server}")
            options.append("DNSDefaultRoute={}".format(self.get("defaultdns", False)))
        except KeyError:
            pass
        try:
            domain = self.get("domain")
            self.set("domainlog", str(domain))
            options.append("Domains={}".format(" ".join(domain)))
            options.append(
                "DNSOverTLS={}".format(boolconvert(self.get("dot", "opportunistic")))
            )
            options.append(
                "DNSSEC={}".format(boolconvert(self.get("dnssec", "allow-downgrade")))
            )
        except KeyError:
            pass
        output += "\n".join(options)
        return output

    def addresses(self) -> str:
        output = []
        for address in self.get("address"):
            output.append(f"[Address]\nAddress={address}\n")
        return "\n".join(output)

    def routes(self) -> str:
        output = []
        routes = self.get("route", [])
        self.set("routes", routes)
        for gw in routes:
            output.append(f"[Route]\nGateway={gw}\nGatewayOnLink=yes\nQuickAck=yes\n")
        self.set("routes", output)
        return "\n".join(output)


DOCUMENTATION = """---
description:
- Sets up the systemd network unit
module: systemd_network
options:
  address:
    description:
    - IP-Addresses of this networkdevice
    elements: str
    required: true
    type: list
  defaultdns:
    description:
    - If the DNS-Server(s) on this device should be used for all domains that are
      not set on other devices
    required: false
    type: bool
  description:
    description:
    - An optional description
    required: false
    type: str
  device:
    description:
    - The name of the network device
    required: false
    type: str
  dns:
    default: []
    description:
    - List of DNS-Servers
    elements: str
    required: false
    type: list
  dnssec:
    required: true
    type: bool
  domain:
    default: []
    description:
    - List of domains that are on this device
    elements: str
    required: false
    type: list
  dot:
    description:
    - if DNS-over-TLS should be required or disabled. If it is unset, it will used
      if the server supports it
    required: false
    type: bool
  mac:
    description:
    - The MAC-Address of the device
    required: false
    type: str
  name:
    description:
    - name of the unit
    required: true
    type: str
  route:
    default: []
    description:
    - Routes of networks that can be reached with this device
    elements: str
    required: false
    type: list
short_description: Sets up the systemd network unit
"""


if __name__ == "__main__":
    Module()()