from __future__ import annotations

import dataclasses
import logging
import os.path

import yaml

_cached_config: Config | None = None
_logger = logging.getLogger(__name__)


@dataclasses.dataclass
class Config:
    _source_filename: str
    controllers: list[str]
    server_names: list[str]
    comm_secret: str
    cookie_secret: str
    venue_info_url: str | None
    session_timeout: int  # in seconds
    api_port: int
    controller_port: int
    database_file: str  # empty str: disable database
    custom: str
    debug: bool

    @staticmethod
    def load_default_once(filename: str | None = None) -> Config:
        global _cached_config
        if not _cached_config:
            _cached_config = Config.load(filename)
        elif not filename is None and filename != _cached_config._source_filename:
            raise RuntimeError(
                f"Already loaded different config from {_cached_config._source_filename!r} instead of {filename!r}",
            )
        return _cached_config

    @staticmethod
    def load(filename: str | None = None) -> Config:
        if filename is None:
            for name in ("capport.yaml", "/etc/capport.yaml"):
                if os.path.exists(name):
                    return Config.load(name)
            raise RuntimeError("Missing config file")
        with open(filename) as f:
            data = yaml.safe_load(f)
        if not isinstance(data, dict):
            raise RuntimeError(f"Invalid yaml config data, expected dict: {data!r}")
        controllers = list(map(str, data.pop("controllers")))
        config = Config(
            _source_filename=filename,
            controllers=controllers,
            server_names=data.pop("server-names", []),
            comm_secret=str(data.pop("comm-secret")),
            cookie_secret=str(data.pop("cookie-secret")),
            venue_info_url=str(data.pop("venue-info-url")),
            session_timeout=data.pop("session-timeout", 3600),
            api_port=data.pop("api-port", 8000),
            controller_port=data.pop("controller-port", 5000),
            database_file=str(data.pop("database-file", "capport.state")),
            custom=str(data.pop("custom", "custom")),
            debug=data.pop("debug", False),
        )
        if data:
            _logger.error(f"Unknown config elements: {list(data.keys())}")
        return config