from __future__ import annotations

import asyncio
import os
from logging.config import fileConfig

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

from app.db.base import Base
from app.db import models  # noqa: F401

config = context.config

if config.config_file_name is not None:
    fileConfig(config.config_file_name)

target_metadata = Base.metadata


def _get_database_url() -> str:
    # Prefer env var so CI/containers can override without rewriting ini.
    url = os.getenv("DATABASE_URL")
    if url:
        return url
    # Fallback to app settings (reads .env via pydantic-settings).
    from app.config import get_settings

    return get_settings().database_url


def run_migrations_offline() -> None:
    url = _get_database_url()
    context.configure(
        url=url,
        target_metadata=target_metadata,
        literal_binds=True,
        dialect_opts={"paramstyle": "named"},
        compare_type=True,
        compare_server_default=True,
    )

    with context.begin_transaction():
        context.run_migrations()


def do_run_migrations(connection: Connection) -> None:
    context.configure(
        connection=connection,
        target_metadata=target_metadata,
        compare_type=True,
        compare_server_default=True,
    )

    with context.begin_transaction():
        context.run_migrations()


async def run_migrations_online() -> None:
    configuration = config.get_section(config.config_ini_section) or {}
    configuration["sqlalchemy.url"] = _get_database_url()

    connectable = async_engine_from_config(
        configuration,
        prefix="sqlalchemy.",
        poolclass=pool.NullPool,
    )

    async with connectable.connect() as connection:
        await connection.run_sync(do_run_migrations)

    await connectable.dispose()


def run_migrations() -> None:
    if context.is_offline_mode():
        run_migrations_offline()
    else:
        asyncio.run(run_migrations_online())


run_migrations()