#! /usr/bin/env Python3

import os
from posix import stat 
from jinja2 import Template
import subprocess


def is_root():
    if  os.geteuid() == 0:
        return True
    else:
        return False

class create_unit_service():
    def __init__(self, 
                 UnitName: str,
                 systemd_sysfolder: str = "/etc/systemd/system",
                 UnitExecStart = str,
                 systemd_type: str = "simple",
                 UnitDescription: str = "Meine Unit",
                 UnitUser = str,
                 UnitWorkDir: str = "/home/jonnybravo/"
                 ) -> None:

        self.UnitName = UnitName
        self.systemd_systemfolder = systemd_sysfolder
        self.UnitExecStart = UnitExecStart
        self.UnitDescription = UnitDescription
        self.UnitWorkDir = UnitWorkDir
        self.UnitUser = UnitUser
        if systemd_type == "simple" or systemd_type == "oneshot":
            self.systemd_type = systemd_type
        else:
            print("Kein richtiger Typ")
            raise "systemd_type ist nicht richtig"
    
    def create_unit(self):
        UnitFile = self.systemd_systemfolder + os.sep + self.UnitName + ".service"
        if os.path.exists(self.systemd_systemfolder):
            if os.path.exists(UnitFile):
                print("Gibt es bereits")
            else:
                print("Wird angelegt !!")
                with open('template/LinuxUnit.j2') as f:
                    tmpl = Template(f.read())
                with open(UnitFile, "w") as uf:
                    print(tmpl.render(
                            description = self.UnitDescription,
                            working_dir = self.UnitWorkDir,
                            exec_command = self.UnitExecStart,
                            user = self.UnitUser,
                            env_vars = {"PYTHONPATH": "."},
                            service_type = self.systemd_type
                    ),file=uf)

    def unit_start_and_load(self): 
        UnitFile = self.systemd_systemfolder + os.sep + self.UnitName + ".service"
        status_daemon_reload = subprocess.run(["systemctl", "daemon-reload"])
        if status_daemon_reload.returncode != 0:
            raise Exception( f'Systemd reload Invalid result: { status_daemon_reload.returncode }' )
        else: 
            print(f"{self.UnitName} wurde angelegt und kann genutzt werden !!! Ein starten oder Enable wurde bewusst nicht eingebaut.")

    def delete_unit(self):
        pass

if __name__ == "__main__":
    if is_root():
        new_unit = create_unit_service(UnitName="TestUnit",
                                       UnitExecStart="""/usr/bin/echo "Ich bin eine TestUnit %p" """,
                                       UnitUser="jonnybravo",
                                       systemd_type="oneshot")
        new_unit.create_unit()
        new_unit.unit_start_and_load()
    else:
        print("Du bist nicht root führe das Skript mit sudo aus")
        print('sudo python <skript>')