import typing
from collections.abc import AsyncGenerator
from logging import getLogger

import httpx
import pydantic
import pydantic_settings
from fastapi import Depends
from fastapi.templating import Jinja2Templates
from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine

log = getLogger(__name__)


class _Config(
    pydantic_settings.BaseSettings,
    env_prefix="backend_",
    env_file=".env",
    env_file_encoding="utf-8",
    env_nested_delimiter="__",
    extra="ignore",
):
    """General configuration settings for the service."""

    debug: bool = False
    git_sha: str = "development"
    signing_key: pydantic.SecretStr

    database_url: pydantic.SecretStr
    super_admin_token: pydantic.SecretStr
    printful_token: pydantic.SecretStr
    printful_store_id: pydantic.SecretStr

    app_prefix: str = ""
    templates: Jinja2Templates = Jinja2Templates(directory="src/templates")

    cors_origins: list[str] = []


CONFIG = _Config()


class Connections:
    """How to connect to other, internal services."""

    DB_ENGINE = create_async_engine(CONFIG.database_url.get_secret_value(), echo=CONFIG.debug)
    DB_SESSION_MAKER = async_sessionmaker(DB_ENGINE)


async def _get_printful_client() -> AsyncGenerator[httpx.AsyncClient, None]:
    """Yield an authenticated httpx client for printful, for use with a FastAPI dependency."""
    client = httpx.AsyncClient(
        headers={
            "Authorization": f"Bearer {CONFIG.printful_token.get_secret_value()}",
            "X-PF-Store-Id": CONFIG.printful_store_id.get_secret_value(),
        },
        base_url="https://api.printful.com",
    )
    async with client as c:
        yield c


async def _get_db_session() -> AsyncGenerator[AsyncSession, None]:
    """Yield a database session, for use with a FastAPI dependency."""
    async with Connections.DB_SESSION_MAKER() as session, session.begin():
        yield session


DBSession = typing.Annotated[AsyncSession, Depends(_get_db_session)]
PrintfulClient = typing.Annotated[httpx.AsyncClient, Depends(_get_printful_client)]