# app/api/dependencies/database.py
from typing import AsyncIterator, Callable, Type

from asyncpg import Connection, Pool
from fastapi import Depends
from starlette.requests import Request

from app.db.repositories.base import BaseRepository


def _get_db_pool(request: Request) -> Pool:
    """
    从 app.state.pool 取得连接池；若未初始化给出清晰报错。
    """
    pool = getattr(request.app.state, "pool", None)
    if pool is None:
        raise RuntimeError("Database pool not initialized on app.state.pool")
    return pool


async def _get_connection_from_pool(
    pool: Pool = Depends(_get_db_pool),
) -> AsyncIterator[Connection]:
    """
    私有实现：从连接池借出一个连接，使用后自动归还。
    """
    async with pool.acquire() as conn:
        yield conn


# ✅ 公共别名：供路由里直接使用 Depends(get_connection)
get_connection = _get_connection_from_pool


def get_repository(
    repo_type: Type[BaseRepository],
) -> Callable[[Connection], BaseRepository]:
    """
    兼容旧用法：Depends(get_repository(UserRepo))
    内部依赖 get_connection，因此两种写法都能共存。
    """
    def _get_repo(conn: Connection = Depends(get_connection)) -> BaseRepository:
        return repo_type(conn)

    return _get_repo