"""Alembic environment — async engine + pgvector.

NFR-MAINT-06 / 架构文档 §14.3: 迁移必须向后兼容（加列不删列、先双写后切读），
并且必须可逆或明确标注不可逆。CI runs upgrade → downgrade → upgrade.
"""

from __future__ import annotations

import asyncio
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 packages.shared.config import get_settings
from packages.shared.models import Base

config = context.config

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

config.set_main_option("sqlalchemy.url", get_settings().database_url)

target_metadata = Base.metadata


def _include_object(
    obj: object, name: str | None, type_: str, reflected: bool, compare_to: object
) -> bool:
    # pgvector installs its own tables/types; never autogenerate against them.
    return not (type_ == "table" and name in {"vector", "spatial_ref_sys"})


def run_migrations_offline() -> None:
    context.configure(
        url=config.get_main_option("sqlalchemy.url"),
        target_metadata=target_metadata,
        literal_binds=True,
        dialect_opts={"paramstyle": "named"},
        compare_type=True,
        include_object=_include_object,
    )
    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,
        include_object=_include_object,
    )
    with context.begin_transaction():
        context.run_migrations()


async def run_async_migrations() -> None:
    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:
    asyncio.run(run_async_migrations())


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