"""Environment-driven configuration for the scopa application.

Mirrors kaya's own pattern: read ``os.environ`` directly into a plain
dataclass. No pydantic-settings, no settings module.
"""
from __future__ import annotations

import os
from dataclasses import dataclass
from typing import Optional


def _env(name: str, default: Optional[str] = None) -> str:
    value = os.environ.get(name)
    if value is None or value == "":
        if default is None:
            raise RuntimeError(f"Missing required environment variable: {name}")
        return default
    return value


@dataclass(frozen=True)
class Settings:
    database_url: str
    oidc_issuer: str
    oidc_client_id: str
    oidc_client_secret: Optional[str]
    oidc_redirect_uri: str
    # Where the browser is sent after login/logout. In production the SPA is
    # served by this app ("/"); in development point these at the trunk dev
    # server (e.g. "http://localhost:8000/").
    oidc_post_login_redirect: str
    oidc_post_logout_redirect: str
    app_host: str
    app_port: int
    redis_url: Optional[str]
    # How long a live game (and its join-code index) survives in Redis
    # without activity, in seconds. Defaults to 24h.
    game_ttl_seconds: int
    # Directory holding the compiled frontend (trunk's dist output),
    # served for every path that is not under /api or /auth.
    static_dir: str

    @staticmethod
    def from_env() -> "Settings":
        return Settings(
            database_url=_env("DATABASE_URL", "postgres://scopa:scopa@localhost:5432/scopa"),
            oidc_issuer=_env("OIDC_ISSUER", "http://localhost:8180/scopa"),
            oidc_client_id=_env("OIDC_CLIENT_ID", "scopa"),
            oidc_client_secret=os.environ.get("OIDC_CLIENT_SECRET"),
            oidc_redirect_uri=_env("OIDC_REDIRECT_URI", "http://localhost:8080/auth/callback"),
            oidc_post_login_redirect=_env("OIDC_POST_LOGIN_REDIRECT", "/"),
            oidc_post_logout_redirect=_env("OIDC_POST_LOGOUT_REDIRECT", "/"),
            app_host=_env("APP_HOST", "0.0.0.0"),
            app_port=int(_env("APP_PORT", "8080")),
            # When unset, sessions and live games fall back to in-memory
            # stores (tests, ephemeral dev). Set to e.g.
            # redis://localhost:6379/0 to persist both in Redis.
            redis_url=os.environ.get("REDIS_URL"),
            game_ttl_seconds=int(_env("GAME_TTL_SECONDS", "86400")),
            static_dir=_env("STATIC_DIR", "web/dist"),
        )


settings: Settings = Settings.from_env()