"""Alembic env — async engine, target metadata from core.db.models.

URL comes from `DATABASE_URL` (via core.config.Settings), overriding the
placeholder in alembic.ini. Importing `contract_check.core.db.models` populates
`Base.metadata`; autogenerate is used only to draft, migrations are committed
hand-written (docs/ARCHITECTURE.md §7).
"""

from __future__ import annotations

import asyncio
import sys
from logging.config import fileConfig
from pathlib import Path

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

# ensure src/ is importable when running alembic from the repo root
sys.path.insert(0, str(Path(__file__).resolve().parents[1] / "src"))

import contract_check.core.db.models  # noqa: E402,F401 — populate Base.metadata
from contract_check.core.config import get_settings  # noqa: E402
from contract_check.core.db.models import Base  # noqa: E402

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

target_metadata = Base.metadata


def run_migrations_offline() -> None:
    url = get_settings().database_url
    context.configure(
        url=url,
        target_metadata=target_metadata,
        literal_binds=True,
        dialect_opts={"paramstyle": "named"},
        compare_type=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)
    with context.begin_transaction():
        context.run_migrations()


async def run_migrations_online() -> None:
    connectable = create_async_engine(get_settings().database_url, poolclass=pool.NullPool)
    try:
        async with connectable.connect() as connection:
            await connection.run_sync(do_run_migrations)
    finally:
        await connectable.dispose()


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