from functools import lru_cache
from pathlib import Path

from pydantic import Field
from pydantic_settings import BaseSettings, SettingsConfigDict

BASE_DIR = Path(__file__).resolve().parent.parent


class Settings(BaseSettings):
    # Core
    data_dir: Path = Field(default=BASE_DIR / "data")
    db_path: Path | None = None  # defaults to <data_dir>/bike_admin.db when None
    secret_key: str = Field(default="change-me", min_length=8)  # CSRF/session HMAC
    username: str = Field(default="admin", min_length=1)
    password: str | None = None  # REQUIRED on first run (see ensure_user)

    # Hosting posture
    is_production: bool = False  # True => Secure cookies + stricter headers
    bind_host: str = "127.0.0.1"
    bind_port: int = 8000
    trust_proxy: bool = True  # honor X-Forwarded-For/Proto behind a reverse proxy

    # Sessions
    session_ttl_seconds: int = 7 * 24 * 3600

    # Login throttling
    login_max_attempts: int = 8
    login_window_seconds: int = 300

    # Service hint: flag a bike as "book soon" when it is this close to due.
    service_due_soon_miles: int = 200

    # Event types (preset)
    event_types: list[str] = [
        "service",
        "fuel",
        "tyre",
        "chain",
        "brake",
        "repair",
        "other",
    ]

    model_config = SettingsConfigDict(env_prefix="BIKE_ADMIN_", env_file=".env", extra="ignore")

    @property
    def resolved_db_path(self) -> Path:
        return self.db_path or (self.data_dir / "bike_admin.db")


@lru_cache
def get_settings() -> Settings:
    return Settings()