import json
import shutil


class Config:
    def __init__(self, path):
        self.path = path
        self.config_values = [
            "version",
            "server_name",
            "server_description",
            "secret_key",
            "captcha_key",
            "registration_enabled",
            "login_required",
            "threads_per_page",
            "user_css",
        ]
        self._update_class(self._read_values())

    def get_config(self):
        current = self._read_values()
        self._update_class(current)
        return self

    def set_config(self, **kwargs):
        for key in kwargs:
            if key not in self.config_values:
                raise ValueError(f"Unknown config key {key}!")

        current = self._read_values()
        current.update(kwargs)
        self._update_class(current)
        self._write_values(current)

    def set_config_secrets(self, secret_key, captcha_key):
        current = self._read_values()
        current["secret_key"] = secret_key
        current["captcha_key"] = captcha_key
        self._update_class(current)
        self._write_values(current)

    def _read_values(self):
        with open(self.path, "rt") as fp:
            return json.load(fp)

    def _write_values(self, values):
        shutil.copy(self.path, self.path + ".bkp")
        with open(self.path, "wt") as fp:
            json.dump(values, fp, indent=2, sort_keys=True)

    def _update_class(self, values):
        for item in values:
            setattr(self, item, values[item])