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

try:
    from ansible.module_utils.generic import SYSTEMD_SERVICE_CONFIG as SYSTEMD_PATH
    from ansible.module_utils.generic import Types
    from ansible.module_utils.module import SystemdUnitModule
except ImportError:
    from generic import SYSTEMD_SERVICE_CONFIG as SYSTEMD_PATH
    from generic import Types
    from module import SystemdUnitModule

SYSTEMD_PATH = pathlib.Path("/etc/systemd/system")

OPTION_MAPPING = dict(
    required_by="RequiredBy",
    wanted_by="WantedBy",
)


class Module(SystemdUnitModule):
    """Creates an systemd mount"""

    name = "systemd_mount"
    module_spec = dict(
        argument_spec=dict(
            fs=Types.str(
                required=True, help="The filesystem that is used for the mount"
            ),
            where=Types.path(
                required=True, help="The Path where the filesystem is mounted to"
            ),
            what=Types.str(
                required=True, help="The device or an string that will be mounted"
            ),
            state=Types.str(
                choices=("present", "absent"),
                default="present",
                help="the state the mount is",
            ),
            options=Types.list(elements=str, help="The options for the mount"),
            description=Types.str(
                help="An description for programs that access systemd"
            ),
            required_by=Types.list(
                elements=str, help="systemd units that require this mount"
            ),
            wanted_by=Types.list(
                elements=str,
                help="systemd units that want the mount, but not explicitly require it. Commonly used for target if not service explicitly require it.",
            ),
        ),
    )

    def prepare(self):
        self.mountdir = pathlib.Path(self.params["where"])
        self.unitfile = SYSTEMD_PATH.joinpath(
            self.mountdir.relative_to("/").as_posix().replace("/", "-")
        ).with_suffix(".mount")
        self.__unit = None

    def unit(self) -> str:
        if self.__unit is None:
            self.__unit = "\n".join(
                (
                    self.header(),
                    self.mount(),
                    self.install(),
                )
            )
        return self.__unit

    def header(self) -> str:
        return "[Unit]\nDescription={}\n".format(
            self.get("description", "Mount for {}".format(self.get("where")))
        )

    def mount(self) -> str:
        output = "[Mount]\n"
        output += "Where={}\n".format(self.get("where"))
        output += "What={}\n".format(self.get("what"))
        output += "Type={}\n".format(self.get("fs"))
        if self.get("options", False):
            output += "Options={}\n".format(",".join(self.get("options")))
        return output

    def install(self) -> str:
        output = "[Install]\n"
        for argument, key in OPTION_MAPPING.items():
            if self.get(argument, False):
                for unit in self.get(argument):
                    output += "{}={}\n".format(key, unit)
        return output

    def post(self):
        if not self.changed:
            return
        systemctl = self.module.get_bin_path("systemctl", required=True)
        self.module.run_command([systemctl, "daemon-reload"], check_rc=True)
        (rc, _, _) = self.module.run_command(
            [systemctl, "is-enabled", self.unitfile.name], check_rc=False
        )
        if rc == 0:
            self.module.run_command(
                [systemctl, "restart", self.unitfile.name], check_rc=True
            )


DOCUMENTATION = """---
description:
- Creates an systemd mount
module: systemd_mount
options:
  description:
    description:
    - An description for programs that access systemd
    required: false
    type: str
  fs:
    description:
    - The filesystem that is used for the mount
    required: true
    type: str
  options:
    default: []
    description:
    - The options for the mount
    elements: str
    required: false
    type: list
  required_by:
    default: []
    description:
    - systemd units that require this mount
    elements: str
    required: false
    type: list
  state:
    choices:
    - present
    - absent
    default: present
    description:
    - the state the mount is
    required: false
    type: str
  wanted_by:
    default: []
    description:
    - systemd units that want the mount, but not explicitly require it. Commonly used
      for target if not service explicitly require it.
    elements: str
    required: false
    type: list
  what:
    description:
    - The device or an string that will be mounted
    required: true
    type: str
  where:
    description:
    - The Path where the filesystem is mounted to
    required: true
    type: path
short_description: Creates an systemd mount
"""

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