"""Application configuration loader.

Reads environment variables (with .env file support) and provides
a typed, validated Settings object used throughout the application.
"""

from functools import lru_cache
from pathlib import Path

from dotenv import load_dotenv
from pydantic_settings import BaseSettings
from pydantic_settings import SettingsConfigDict

# Load .env file from project root
_env_path = Path(__file__).resolve().parent.parent / ".env"
load_dotenv(_env_path)


class Settings(BaseSettings):
    """Typed application settings loaded from environment variables.

    Attributes:
        admin_username: Admin login username (from ADMIN_USERNAME env var).
        admin_password: Admin login password (from ADMIN_PASSWORD env var).
        app_env: Runtime environment — 'development' or 'production'.
        app_host: Host address to bind the server to.
        app_port: Port number for the server.
        app_log_level: Minimum log level for structlog output.
        database_url: SQLite connection string.
    """

    admin_username: str
    admin_password: str
    app_env: str = "development"
    app_host: str = "0.0.0.0"
    app_port: int = 8000
    app_log_level: str = "info"
    database_url: str = "sqlite:///data/sneakyswole.db"

    model_config = SettingsConfigDict(
        env_file=".env",
        env_file_encoding="utf-8",
    )


@lru_cache(maxsize=1)
def get_settings() -> Settings:
    """Return a cached Settings instance (singleton pattern).

    Returns:
        The application Settings object.
    """
    return Settings()