import os
from functools import lru_cache

from pydantic import Field
from pydantic_settings import BaseSettings, SettingsConfigDict


class _BaseConfig(BaseSettings):
    model_config = SettingsConfigDict(
        env_file=".env", extra="ignore", nested_model_default_partial_update=True
    )


class _AppSettings(_BaseConfig):
    environment: str = Field(default=os.getenv("ENVIRONMENT"))


class _DbSettings(_BaseConfig):
    username: str = Field(default=os.getenv("PG_USER"), alias="PG_USER")
    password: str = Field(default=os.getenv("PG_PASSWORD"), alias="PG_PASSWORD")
    db_name: str = Field(default=os.getenv("PG_DB_NAME"), alias="PG_DB_NAME")


class _Settings(_BaseConfig):
    app: _AppSettings = _AppSettings()
    db: _DbSettings = _DbSettings()


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