import sqlmodel

from .apikey import apikey
from .password import password
from .builder import builder
from .code_key import code_key
from .code_key import code_key_manager

class user(sqlmodel.SQLModel, table = True):
    """
    This represents user in database. All users has own unique nick and api
    key. Nick and password is used to login, api key is long, random and
    used to access database via API.
    """

    id: int = sqlmodel.Field(default = None, primary_key = True)
    nick: str = sqlmodel.Field(index = True, unique = True)
    password: str = sqlmodel.Field(index = False)
    apikey: str = sqlmodel.Field(index = True, unique = True)
    code_key: str = sqlmodel.Field(index = False)

    def key(self, password: str) -> code_key_manager | None:
        """
        This return crypto key wrapper, to manage, recrypt, encrypt, decrypt
        and other with key. It require password, and when code key is not 
        set, return None.

        Parameters:
            password (str): Password used to decrypt crypto key

        Returns:
            (code_key_manager): Crypto key wrapper
        """

        if self.code_key is None:
            return None

        return code_key(password = password, crypted_key = self.code_key)

    @property
    def in_database(self) -> bool:
        """ True when user exists in database. """

        return self.id is not None

    @property
    def ready(self) -> bool:
        """ True when all fields are filled. """

        if self.nick is None:
            return False

        if self.password is None:
            return False

        if self.apikey is None:
            return False

        if self.code_key is None:
            return False

        return True

    def __str__(self) -> str:
        """
        This function dump user to string, very usefull for debug.

        Returns:
            (str): User as string
        """

        result = ""
        result = result + "User "

        if self.id is not None:
            result = result + "(" + str(self.id) + ")"

        result = result + "\n"
        
        result = result + "Nick: " + self.nick + "\n"
        result = result + "Password: " + self.password + "\n"
        result = result + "API key: " + self.apikey + "\n"
        result = result + "Code KEY: " + self.code_key + "\n"

        return result

class user_builder(builder, target_type = user):
    """
    This class is responsible for building new user.
    """

    def __init__(self, target: user | None = None) -> None:
        """ 
        This create new user builder. It can be initialized by already
        created user. When None create empty user.

        Parameters:
            target(user | None): Target to initialize builder with
        """

        super().__init__(target)
        self._target.apikey = apikey()

    @property
    def nick(self) -> str | None:
        """
        return: str | None - Current nick of the user in builder
        """

        return self._target.nick

    @property
    def password(self) -> bool:
        """
        return: bool - True when password is set, false if not
        """

        return self._target.password is not None

    @nick.setter
    def nick(self, target: str) -> None:
        """
        target: str - New nick for the user
        """

        self._target.nick = target.upper()

    def set_password(
        self, 
        password: str, 
        old_password: str | None = None
    ) -> None:
        """
        This function set password to user. When only password is given, then 
        it try to init user, which not have password and crypto key yet. User
        which already set password, and crypto key, must being updated with
        also old password.

        Parameters:
            password (str): New password to set
            old_password (str | None) = None: Old password, require to recrypt
        """

        if old_password is None:
            self.__init_password(password)
            return

        self.__change_password(old_password, password)

    def __init_password(self, target: str) -> None:
        """
        This function initialize user with new password. User can not already 
        have both password, and crypto key. When user already have crypto key
        or password, then Exception is raised, to protect crypto key to not
        being overwrited.

        Parameters:
            target (str): New password to set
        """

        if self._target.password is not None:
            raise Exception("Password and code key is already set.")

        if self._target.code_key is not None:
            raise Exception("Password and code key is already set.")

        self._target.password = password(target).result
        self._target.code_key = code_key(password = target)

    def __change_password(self, old_password: str, new_password: str) -> None:
        """
        This change password, when user already have password and code key. It
        recrypt crypto key, to could use new password for secret decrypting.

        Parameters:
            old_password (str): Old password
            new_password (str): New password to set
        """

        if old_password == new_password:
            raise Exception("New password is same as old password.")

        key = self._target.key(old_password)

        if key is None or self._target.password is None:
            raise Exception("User crypto key is not initialized yet.")

        self._target.code_key = key.recrypt(new_password).encrypted
        self._target.password = password(new_password).result