"""Alembic environment using the application's async PostgreSQL settings."""

from __future__ import annotations

import asyncio
import selectors
import sys

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

from ragcore.config import get_settings

config = context.config
target_metadata = None


def _database_url() -> str:
    return get_settings().database_url


def _set_database_url() -> None:
    config.set_main_option("sqlalchemy.url", _database_url().replace("%", "%%"))


def run_migrations_offline() -> None:
    """Run migrations without creating a database connection."""

    _set_database_url()
    context.configure(
        url=_database_url(),
        target_metadata=target_metadata,
        literal_binds=True,
        dialect_opts={"paramstyle": "named"},
    )
    with context.begin_transaction():
        context.run_migrations()


def do_run_migrations(connection: Connection) -> None:
    context.configure(connection=connection, target_metadata=target_metadata)
    with context.begin_transaction():
        context.run_migrations()


async def run_async_migrations() -> None:
    _set_database_url()
    connectable = async_engine_from_config(
        config.get_section(config.config_ini_section, {}),
        prefix="sqlalchemy.",
        poolclass=pool.NullPool,
    )
    async with connectable.connect() as connection:
        await connection.run_sync(do_run_migrations)
    await connectable.dispose()


def run_migrations_online() -> None:
    if sys.platform == "win32":
        asyncio.run(
            run_async_migrations(),
            loop_factory=lambda: asyncio.SelectorEventLoop(selectors.SelectSelector()),
        )
    else:
        asyncio.run(run_async_migrations())


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