"""
Config related tools.
"""

import dataclasses
import yaml

from typing import Optional

@dataclasses.dataclass
class Config:
    username: str
    homeserver: str
    password: str
    alert_rooms: list[str]
    port: int = 8000
    host: str = "127.0.0.1"
    endpoint: str = "/webhook"
    tls: bool = False
    tls_auth: bool = False
    tls_crt: Optional[str] = None
    tls_key: Optional[str] = None
    ca_crt: Optional[str] = None
    default_template: Optional[str] = None
    templates: dict[str, str] = dataclasses.field(default_factory=dict)

    def check_integrity(self)->bool:
        """ Check the integrity of the config.
            Raise an error if the config is invalid,
            should always return True (or raise an error).
        """
        if self.tls_auth and not self.tls:
            raise ValueError("tls_auth is enable, but not tls.")
        if self.tls and self.tls_crt is None:
            raise ValueError("tls is enable but tls_crt was not provided")
        if self.tls and self.tls_key is None:
            raise ValueError("tls is enable but tls_key was not provided")
        if self.tls_auth and self.ca_crt is None:
            raise ValueError("tls_auth is enable, but ca_crt was not provided")
        return True


def load_config(file:str)->Config:
    """
        Load the config from the config file.
    """
    with open(file, 'r') as f:
        data = yaml.load(f, Loader=yaml.loader.SafeLoader)
    config = Config(**data)
    config.check_integrity()
    return config