import os
import pwd
import subprocess

import lib.UserExceptions


class System:
    """Class to interact with the system specifically to support our needs 0w0
    :Example:
    >>> from lib.System import System as System
    >>> Sys_ctl = System("Test", dryrun=True)
    >>> Sys_ctl.register()
    >>> Sys_ctl.lock_user_pw()
    >>> Sys_ctl.add_to_usergroup()
    >>> Sys_ctl.make_ssh_usable("sshkey")
    """

    dry: bool = False
    create_command = []
    home: str = ""
    user: str

    def setUser(self, username: str):
        self.user = username

    def __init__(self, username: str, dryrun: bool = False, home: str = "/home/"):
        """Creates an objects. Can set dry run.

        :param username: Username to manipulate
        :type username: str
        :param dryrun: Run all command in a dry-run? When enabled, doesn't make any changes to the system (defaults to
        false)
        :type dryrun: bool
        :param home: Standard directory to search for the home directories of your users(default is /home/)
        :type home: str
        :raises:
            ValueError: if homedir can not be found
        """

        self.dry = dryrun
        if not home.endswith("/"):
            home += "/"
        if not os.path.isdir(home):
            raise ValueError("home should be an existent directory...")
        self.home = home
        self.user = username

    def aio_approve(self, pubkey, group="tilde"):
        """ Executes all neccessary steps to create a user from itself. Raises ALOT of possible exceptions

        :Note: CAREFULL! You MUST except the exceptions!
        :param pubkey: Users public ssh key
        :type pubkey: str
        :param group: User-group. Defaults to tilde
        :type group: str
        :return: None
        :raises:
                lib.UserExceptions.UserExistsAlready: User Exists already on system
                lib.UserExceptions.UnknownReturnCode: Unknown Return Code from useradd
                lib.UserExceptions.SSHDirUncreatable: Users SSH Dir couldnt be created
                lib.UserExceptions.ModifyFilesystem: Something with CHMOD failed
        """
        self.register()
        self.lock_user_pw()
        self.add_to_usergroup(group)
        self.make_ssh_usable(pubkey)

    def register(self, cc: tuple = tuple(["useradd", "-m"])) -> bool:
        """Creates an local account for the given username

        :param cc: Tuple with commands separated to execute on the machine. (defaults to useradd -m)
        :type cc: tuple
        :return: True, if worked, raises lib.UserExceptions.UserExistsAlready when not
        :rtype: bool
        :raises:
            lib.UserExceptions.UserExistsAlready: when username specified already exists on the system
        """

        create_command = cc
        cc = create_command + tuple([self.user])
        if self.dry:
            self.printTuple(cc)
            return True
        elif not self.dry:
            rt = subprocess.call(cc)
            if rt != 0:
                raise lib.UserExceptions.UserExistsAlready(self.user)
            return True

    def unregister(self) -> bool:
        """ Just an alias function for removeUser

        :return: True, when success, False(or exception) when not
        :rtype: bool
        """

        return self.remove_user()

    def make_ssh_usable(self, pubkey: str, sshdir: str = ".ssh/") -> bool:
        """ Make SSH usable for our newly registered user

        :param pubkey: Public SSH Key for the User you want accessible by SSH
        :type pubkey: str
        :param sshdir: Directory to write the authorized_keys File to. PWD is $HOME of said user. (defaults to ".ssh/")
        :type sshdir: str
        :return: True, if worked, raises lib.UserExceptions.UnknownReturnCode, lib.UserExceptions.HomeDirExistsAlready
         or lib.UserExceptions.ModifyFilesystem when not
        :rtype: bool
        :raises:
            lib.UserExceptions.SSHDirUncreatable: if the ssh-dir couldnt be created nor exist
            lib.UserExceptions.ModifyFilesystem: When chmod to .ssh and authorized_keys failed
            lib.UserExceptions.General: if PWD cant find the specified user
        """

        if self.dry:
            print("Nah, @TODO, but actually kinda too lazy for this lul. Just a lot happening here")
            return True
        if not sshdir.endswith("/"):
            sshdir += "/"
        ssh_dir = self.home + self.user + "/" + sshdir
        try:
            os.mkdir(ssh_dir)
        except FileExistsError:
            pass  # thats actually a good one for us :D
        except OSError as e:
            raise lib.UserExceptions.SSHDirUncreatable(f"Could not create {ssh_dir}: Exception: {e}")

        try:
            self.write_ssh(pubkey, ssh_dir)
        except OSError as e:
            raise lib.UserExceptions.ModifyFilesystem(
                f"Could not write and/or chmod 0700 {ssh_dir} or {ssh_dir}/authorized_keys, Exception: {e}")
        try:
            pwdnam = pwd.getpwnam(self.user)
            os.chown(ssh_dir, pwdnam[2], pwdnam[3])  # 2=>uid, 3=>gid
            os.chown(ssh_dir + "authorized_keys", pwd.getpwnam(self.user)[2], pwd.getpwnam(self.user)[3])
        except OSError as e:  # by os.chown
            raise lib.UserExceptions.ModifyFilesystem(
                f"Could not chown {ssh_dir} and/or authorized_keys to {self.user} and their group, Exception: {e}", )
        except KeyError as e:  # by PWD
            raise lib.UserExceptions.General(f"PWD can't find {self.user}: {e}")
        return True

    @staticmethod
    def write_ssh(key: str, ssh_dir: str) -> None:
        """ Write SSH key to a specified directory(appends authorized_keys itself!)

        :param key: Key to write
        :type key: str
        :param ssh_dir: SSH Directory to write to
        :type ssh_dir: str
        :return: None
        """

        with open(ssh_dir + "authorized_keys", "w") as f:
            print(key, file=f)
            f.close()
        os.chmod(ssh_dir + "authorized_keys", 0o700)  # we dont care about the directory here

    def lock_user_pw(self, cc: tuple = tuple(["usermod", "--lock"])) -> bool:
        """Lock a users password so it stays empty

        :param cc: Commands to run in the subprocess to lock it down(defaults to usermod --lock)
        :type cc: tuple
        :rtype: bool
        :return: True, if worked, raises lib.UserExceptions.UnknownReturnCode when not
        :raises:
            lib.UserExceptions.UnknownReturnCode: When cc returns something else then 0
        """

        lock_command = cc
        cc = lock_command + tuple([self.user])
        if self.dry:
            self.printTuple(cc)
            return True
        elif not self.dry:
            rt = subprocess.call(cc)
            if rt != 0:
                raise lib.UserExceptions.UnknownReturnCode(f"Could not lock user '{self.user}'; '{cc}' returned '{rt}'")
            return True

    def add_to_usergroup(self, group: str = "tilde", cc: tuple = tuple(["usermod", "-a", "-G"])) -> bool:
        """ Adds a given user to a given group

        :param group: Groupname where you want to add your user to
        :type group: str
        :param cc: Commands to execute that adds your user to said specific group(defaults to usermod -a -G")
        :type cc: tuple
        :return: True, if worked, raises lib.UserExceptions.UnknownReturnCode when not
        :rtype bool
        :raises:
            lib.UserExceptions.UnknownReturnCode: if cc returned something else then 0
        """

        add_command = cc
        cc = add_command + tuple([group, self.user])
        if self.dry:
            self.printTuple(cc)
            return True
        elif not self.dry:
            rt = subprocess.call(cc)
            if rt != 0:
                raise lib.UserExceptions.UnknownReturnCode(
                    f"Could not add user '{self.user}' to group '{group}' with command '{cc}', returned '{rt}'", )
            return True

    @staticmethod
    def printTuple(tup: tuple) -> None:
        """Prints a tuple with spaces as separators

        :param tup: Tuple you want to print
        :type tup: tuple
        :rtype: None
        :returns: Nothing
        """

        pp = ""
        for i in tup:
            pp += i + " "
        print(pp)

    def remove_user(self, cc: tuple = tuple(["userdel", "-r"])) -> bool:
        """Removes the specified user from the system

        :param cc: Commands to execute to delete the user from the System(defaults to userdel -r)
        :type cc: tuple
        :return: True, if worked, raises lib.UserExceptions.UnknownReturnCode when not
        :rtype: bool
        :raises:
            lib.UserExceptions.UnknownReturnCode: When cc returns something else then 0 or 6
        """

        remove_command = cc
        cc = remove_command + tuple([self.user])
        if self.dry:
            self.printTuple(cc)
            return True
        else:
            ret = subprocess.Popen(cc, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
            ret.wait()  # wait for cc
            stdio, err_io = ret.communicate()  # get stdout as well as stderr
            if ret.returncode != 0 and ret.returncode != 6:  # userdel returns 6 when no mail dir was found but success
                raise lib.UserExceptions.UnknownReturnCode(
                    f"Could not delete user with command {cc}. Return code: {ret.returncode},"
                    f" stdout/stderr: {stdio + err_io}")
            return True


if __name__ == "__main__":
    try:
        S = System("dar", dryrun=True)
        S.register()
        S.lock_user_pw()
        S.add_to_usergroup()
        # if not S.make_ssh_usable("dar", "SSHpub"):
        #    print("Huh, error :shrug:")
        exit(0)
    except KeyboardInterrupt:
        pass