"""Alembic env.py for an async engine (from `alembic init -t async`), wired to the app's models.

The URL comes from DATABASE_URL, never from alembic.ini, so no credentials are committed.
"""

import asyncio
import os

from alembic import context
from sqlalchemy import pool
from sqlalchemy.engine import Connection
from sqlalchemy.ext.asyncio import create_async_engine

import app.models  # noqa: F401  (registers every model on Base.metadata)
from app.db import Base

target_metadata = Base.metadata
URL = os.environ.get("DATABASE_URL", "sqlite+aiosqlite:///./app.db")


def run_migrations_offline() -> None:
    context.configure(url=URL, target_metadata=target_metadata, literal_binds=True, render_as_batch=True)
    with context.begin_transaction():
        context.run_migrations()


def do_run_migrations(connection: Connection) -> None:
    # render_as_batch lets ALTER-style changes work on SQLite; harmless elsewhere.
    context.configure(connection=connection, target_metadata=target_metadata, render_as_batch=True)
    with context.begin_transaction():
        context.run_migrations()


async def run_migrations_online() -> None:
    engine = create_async_engine(URL, poolclass=pool.NullPool)
    async with engine.connect() as connection:
        await connection.run_sync(do_run_migrations)
    await engine.dispose()


if context.is_offline_mode():
    run_migrations_offline()
else:
    asyncio.run(run_migrations_online())