import os

class apikey:
    """
    This class represents API key, and it is also creating new apikeys from 
    device random numbers generator.

    Methods
    -------
    get_raw_size() : int
        Return size of bytes which was loaded from device random number 
        generator.

    get_size() : int
        Return lenght of the API key as string.

    get_prefix() : str
        Return prefix of the API keys.

    create() : apikey
        Create new random API key.

    export() : str
        Export API key as string.
    """

    def __init__(self, content: str) -> None:
        """
        It recreate API key object from key, which was previously exported
        to string.

        Raises
        ------
        ValueError
            When API key lenght is not correct.

        Parameters
        ----------
        content : str
            Preiviously exported API key string.
        """
        
        if len(content) != self.get_size():
            raise ValueError("API key lenght is not correct.")

        self.__content = content
    
    @staticmethod
    def get_raw_size() -> int:
        """
        It return lenght of the random bytes in the API key.

        Returns
        -------
        int
            Lenght of the random bytes in the API key.
        """

        return 128

    @staticmethod
    def get_size() -> int:
        """
        It return lenght of the API key string, with prefix and random bytes
        converted to the hex string.

        Returns
        -------
        int
            Lenght of the API key string.
        """

        return len(apikey.get_prefix()) + apikey.get_raw_size() * 2

    @staticmethod
    def get_prefix() -> str:
        """
        It return API key prefix.

        Returns
        -------
        str
            Prefix for the API key.
        """

        return "cxtk_"

    @staticmethod
    def create() -> object:
        """
        It create new API key from random number generator device.

        Returns
        -------
        apikey
            New random API key.
        """

        raw = os.urandom(apikey.get_raw_size())
        key = apikey.get_prefix() + raw.hex()

        return apikey(key)

    def export(self) -> str:
        """
        It export API key as string.

        Returns
        -------
        str
            API key string content.
        """

        return self.__content

    def __repr__(self) -> str:
        """
        It return readable API key description (first 32 letters).

        Returns
        -------
        str
            Readable API key description.
        """

        return "API key: \"" + self.__content[0:32] + "...\""

    def __str__(self) -> str:
        """
        It return API key string content.

        Returns
        -------
        str
            API key as string.
        """

        return self.__content

    def __eq__(self, other) -> bool:
        """
        It check that API keys are same.

        Returns
        -------
        bool  
            True when API keys are same.
        """

        return self.__content == other.__content

    def __ne__(self, other) -> bool:
        """
        It check that API keys are not same.

        Returns 
        -------
        bool
            True when API keys are not same.
        """

        return self.__content != other.__content